From nobody Sun Sep 14 10:58:35 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 22B68262FD8; Wed, 11 Jun 2025 18:01:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749664888; cv=none; b=fVl00x8ZZ67gxAwxmMRhVbxh/DBHzvQXAgYfygSEenSFjzYUkb0/eRrR7UL/liXerknApFEhwFE1KmFXqoxQFr87ju92PZPdNXZTsQ78muYYk9WluXiXZRb2RtnWkO++s+pqCt5rhetow4NWrsNef/8/IInWwJHZwxWmPGXIW4w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749664888; c=relaxed/simple; bh=fJXo/tJsH8MjxxKpmMQXW/r5YZGqrSF+of8RKE+gE98=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Hi2TPTV4UnHswRC6BwLa2JkStc+jsQ5Be+AJG1FvR3k9tG0rblgQpVmInnIsLvoR2IbTX++dT54xPyN2oikRCD7q1KVw26QAohTDjomexsxPpqpxGgWHHRjui9F943Sb2gk3S+14Vocc1ojW+sok78DqFA2cud0LU6Jt5aquG4k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QHzrkJHc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QHzrkJHc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78A36C4CEEA; Wed, 11 Jun 2025 18:01:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749664887; bh=fJXo/tJsH8MjxxKpmMQXW/r5YZGqrSF+of8RKE+gE98=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=QHzrkJHc8DOuhuS24FB5uJncBaMVzkTV/Qk5LuOXc7yyP1IDgri+Y8v7HS88e7bbx 6x7qvxX8EAztqky6Z/ezii3rkpTevgue8PtcC6iMjbd6zJaZfJJLaWaFnzehZJE+7C iSnZAHCJ/2L29D7DUf4N0xY/7lF7Flw3p810T+STLFQFSmO74NDBn+bOsVgFDJ+wXY 5x/sqAZace9feUb5EG/oqPMX/rrVnAAxJHV1FWQRRArvUQmS2ObefBhhz8MnDw/T6C zTKhk2mN2oWq5qKuX0iJKda3CL3FeklX1PyeIKhU/T8fnaz5G7Xdm8tT0S2qydmh+t hOhGd7Cy5Nshg== From: "Rob Herring (Arm)" Date: Wed, 11 Jun 2025 13:01:11 -0500 Subject: [PATCH v23 1/4] arm64/sysreg: Add BRBE registers and fields Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250611-arm-brbe-v19-v23-1-e7775563036e@kernel.org> References: <20250611-arm-brbe-v19-v23-0-e7775563036e@kernel.org> In-Reply-To: <20250611-arm-brbe-v19-v23-0-e7775563036e@kernel.org> To: Will Deacon , Mark Rutland , Catalin Marinas , Jonathan Corbet , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , James Clark , Anshuman Khandual , Leo Yan Cc: linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, Mark Brown X-Mailer: b4 0.15-dev From: Anshuman Khandual This patch adds definitions related to the Branch Record Buffer Extension (BRBE) as per ARM DDI 0487K.a. These will be used by KVM and a BRBE driver in subsequent patches. Some existing BRBE definitions in asm/sysreg.h are replaced with equivalent generated definitions. Cc: Marc Zyngier Reviewed-by: Mark Brown Signed-off-by: Anshuman Khandual Signed-off-by: Mark Rutland Tested-by: James Clark Acked-by: Will Deacon Signed-off-by: "Rob Herring (Arm)" Acked-by: Mark Rutland --- v19: - split BRBINF.CC field into mantissa and exponent --- arch/arm64/include/asm/sysreg.h | 16 ++--- arch/arm64/tools/sysreg | 132 ++++++++++++++++++++++++++++++++++++= ++++ 2 files changed, 138 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysre= g.h index f1bb0d10c39a..ef76a4b9e240 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -202,16 +202,8 @@ #define SYS_DBGVCR32_EL2 sys_reg(2, 4, 0, 7, 0) =20 #define SYS_BRBINF_EL1(n) sys_reg(2, 1, 8, (n & 15), (((n & 16) >> 2) | 0= )) -#define SYS_BRBINFINJ_EL1 sys_reg(2, 1, 9, 1, 0) #define SYS_BRBSRC_EL1(n) sys_reg(2, 1, 8, (n & 15), (((n & 16) >> 2) | 1= )) -#define SYS_BRBSRCINJ_EL1 sys_reg(2, 1, 9, 1, 1) #define SYS_BRBTGT_EL1(n) sys_reg(2, 1, 8, (n & 15), (((n & 16) >> 2) | 2= )) -#define SYS_BRBTGTINJ_EL1 sys_reg(2, 1, 9, 1, 2) -#define SYS_BRBTS_EL1 sys_reg(2, 1, 9, 0, 2) - -#define SYS_BRBCR_EL1 sys_reg(2, 1, 9, 0, 0) -#define SYS_BRBFCR_EL1 sys_reg(2, 1, 9, 0, 1) -#define SYS_BRBIDR0_EL1 sys_reg(2, 1, 9, 2, 0) =20 #define SYS_TRCITECR_EL1 sys_reg(3, 0, 1, 2, 3) #define SYS_TRCACATR(m) sys_reg(2, 1, 2, ((m & 7) << 1), (2 | (m >> 3))) @@ -277,8 +269,6 @@ /* ETM */ #define SYS_TRCOSLAR sys_reg(2, 1, 1, 0, 4) =20 -#define SYS_BRBCR_EL2 sys_reg(2, 4, 9, 0, 0) - #define SYS_MIDR_EL1 sys_reg(3, 0, 0, 0, 0) #define SYS_MPIDR_EL1 sys_reg(3, 0, 0, 0, 5) #define SYS_REVIDR_EL1 sys_reg(3, 0, 0, 0, 6) @@ -821,6 +811,12 @@ #define OP_COSP_RCTX sys_insn(1, 3, 7, 3, 6) #define OP_CPP_RCTX sys_insn(1, 3, 7, 3, 7) =20 +/* + * BRBE Instructions + */ +#define BRB_IALL_INSN __emit_inst(0xd5000000 | OP_BRB_IALL | (0x1f)) +#define BRB_INJ_INSN __emit_inst(0xd5000000 | OP_BRB_INJ | (0x1f)) + /* Common SCTLR_ELx flags. */ #define SCTLR_ELx_ENTP2 (BIT(60)) #define SCTLR_ELx_DSSBS (BIT(44)) diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg index 8a8cf6874298..81c4e214ba33 100644 --- a/arch/arm64/tools/sysreg +++ b/arch/arm64/tools/sysreg @@ -1329,6 +1329,138 @@ UnsignedEnum 3:0 MTEPERM EndEnum EndSysreg =20 + +SysregFields BRBINFx_EL1 +Res0 63:47 +Field 46 CCU +Field 45:40 CC_EXP +Field 39:32 CC_MANT +Res0 31:18 +Field 17 LASTFAILED +Field 16 T +Res0 15:14 +Enum 13:8 TYPE + 0b000000 DIRECT_UNCOND + 0b000001 INDIRECT + 0b000010 DIRECT_LINK + 0b000011 INDIRECT_LINK + 0b000101 RET + 0b000111 ERET + 0b001000 DIRECT_COND + 0b100001 DEBUG_HALT + 0b100010 CALL + 0b100011 TRAP + 0b100100 SERROR + 0b100110 INSN_DEBUG + 0b100111 DATA_DEBUG + 0b101010 ALIGN_FAULT + 0b101011 INSN_FAULT + 0b101100 DATA_FAULT + 0b101110 IRQ + 0b101111 FIQ + 0b110000 IMPDEF_TRAP_EL3 + 0b111001 DEBUG_EXIT +EndEnum +Enum 7:6 EL + 0b00 EL0 + 0b01 EL1 + 0b10 EL2 + 0b11 EL3 +EndEnum +Field 5 MPRED +Res0 4:2 +Enum 1:0 VALID + 0b00 NONE + 0b01 TARGET + 0b10 SOURCE + 0b11 FULL +EndEnum +EndSysregFields + +SysregFields BRBCR_ELx +Res0 63:24 +Field 23 EXCEPTION +Field 22 ERTN +Res0 21:10 +Field 9 FZPSS +Field 8 FZP +Res0 7 +Enum 6:5 TS + 0b01 VIRTUAL + 0b10 GUEST_PHYSICAL + 0b11 PHYSICAL +EndEnum +Field 4 MPRED +Field 3 CC +Res0 2 +Field 1 ExBRE +Field 0 E0BRE +EndSysregFields + +Sysreg BRBCR_EL1 2 1 9 0 0 +Fields BRBCR_ELx +EndSysreg + +Sysreg BRBFCR_EL1 2 1 9 0 1 +Res0 63:30 +Enum 29:28 BANK + 0b00 BANK_0 + 0b01 BANK_1 +EndEnum +Res0 27:23 +Field 22 CONDDIR +Field 21 DIRCALL +Field 20 INDCALL +Field 19 RTN +Field 18 INDIRECT +Field 17 DIRECT +Field 16 EnI +Res0 15:8 +Field 7 PAUSED +Field 6 LASTFAILED +Res0 5:0 +EndSysreg + +Sysreg BRBTS_EL1 2 1 9 0 2 +Field 63:0 TS +EndSysreg + +Sysreg BRBINFINJ_EL1 2 1 9 1 0 +Fields BRBINFx_EL1 +EndSysreg + +Sysreg BRBSRCINJ_EL1 2 1 9 1 1 +Field 63:0 ADDRESS +EndSysreg + +Sysreg BRBTGTINJ_EL1 2 1 9 1 2 +Field 63:0 ADDRESS +EndSysreg + +Sysreg BRBIDR0_EL1 2 1 9 2 0 +Res0 63:16 +Enum 15:12 CC + 0b0101 20_BIT +EndEnum +Enum 11:8 FORMAT + 0b0000 FORMAT_0 +EndEnum +Enum 7:0 NUMREC + 0b00001000 8 + 0b00010000 16 + 0b00100000 32 + 0b01000000 64 +EndEnum +EndSysreg + +Sysreg BRBCR_EL2 2 4 9 0 0 +Fields BRBCR_ELx +EndSysreg + +Sysreg BRBCR_EL12 2 5 9 0 0 +Fields BRBCR_ELx +EndSysreg + Sysreg ID_AA64ZFR0_EL1 3 0 0 4 4 Res0 63:60 UnsignedEnum 59:56 F64MM --=20 2.47.2 From nobody Sun Sep 14 10:58:35 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 719FF27CCF3; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XpwKKL+n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF4E7C4CEF3; Wed, 11 Jun 2025 18:01:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749664888; bh=4BgC4nqiNTSQ1Rqa7oed7RZlP9iYHjMo12gOL0KOkLA=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=XpwKKL+nOVCj3+yFvzGYlKMcr7+L0WFXQjyaMrmGzbgvcmym2qjj2kVaLhk+tsAS3 fM+9sCcI0FauIsPMDYIFkzduFJQbfMPz3TRccC/I3iIaMcpGhdhJioLNOeLHjThtdv FujeBYSdrSs6r/SnfpCTz2P1ku/yHsiRzvzXgAS4x1o42+88ezkQV/118Y84l3joVu a9OO//LF1OIoSJGo0OX2+KO21bAKP1cW+Eh5d1qMIlMwdcMoQ/BpupNf0rRnXXD8eR am0U08oedP0X/RSp536p7g4gjTRbbYLxNkN0K8rxQ/Seg23behNzjZFfhj3Zd/nawb hidZ7ODQPW/vQ== From: "Rob Herring (Arm)" Date: Wed, 11 Jun 2025 13:01:12 -0500 Subject: [PATCH v23 2/4] arm64: Handle BRBE booting requirements Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250611-arm-brbe-v19-v23-2-e7775563036e@kernel.org> References: <20250611-arm-brbe-v19-v23-0-e7775563036e@kernel.org> In-Reply-To: <20250611-arm-brbe-v19-v23-0-e7775563036e@kernel.org> To: Will Deacon , Mark Rutland , Catalin Marinas , Jonathan Corbet , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , James Clark , Anshuman Khandual , Leo Yan Cc: linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev X-Mailer: b4 0.15-dev From: Anshuman Khandual To use the Branch Record Buffer Extension (BRBE), some configuration is necessary at EL3 and EL2. This patch documents the requirements and adds the initial EL2 setup code, which largely consists of configuring the fine-grained traps and initializing a couple of BRBE control registers. Before this patch, __init_el2_fgt() would initialize HDFGRTR_EL2 and HDFGWTR_EL2 with the same value, relying on the read/write trap controls for a register occupying the same bit position in either register. The 'nBRBIDR' trap control only exists in bit 59 of HDFGRTR_EL2, while bit 59 of HDFGWTR_EL2 is RES0, and so this assumption no longer holds. To handle HDFGRTR_EL2 and HDFGWTR_EL2 having (slightly) different bit layouts, __init_el2_fgt() is changed to accumulate the HDFGRTR_EL2 and HDFGWTR_EL2 control bits separately. While making this change the open-coded value (1 << 62) is replaced with HDFG{R,W}TR_EL2_nPMSNEVFR_EL1_MASK. The BRBCR_EL1 and BRBCR_EL2 registers are unusual and require special initialisation: even though they are subject to E2H renaming, both have an effect regardless of HCR_EL2.TGE, even when running at EL2. So we must initialize BRBCR_EL2 in case we run in nVHE mode. This is handled in __init_el2_brbe() with a comment to explain the situation. Cc: Marc Zyngier Cc: Oliver Upton Reviewed-by: Leo Yan Tested-by: James Clark Signed-off-by: Anshuman Khandual [Mark: rewrite commit message, fix typo in comment] Signed-off-by: Mark Rutland Co-developed-by: "Rob Herring (Arm)" Signed-off-by: "Rob Herring (Arm)" Acked-by: Mark Rutland tested-by: Adam Young --- v22: - Reword booting.rst section name (s/feature/the/) and move next to other PMU related features instead of in the middle of SME features. - Drop setting SYS_BRBCR_EL1 - Drop CONFIG_ARM64_BRBE ifdef - Rework initialization of HFGITR_EL2 v20: - Document that MDCR_EL3.SBRBE can be 0b01 also - Fix "HDFGWTR_EL2 is RES0" in commit msg --- Documentation/arch/arm64/booting.rst | 21 +++++++++++ arch/arm64/include/asm/el2_setup.h | 71 ++++++++++++++++++++++++++++++++= ++-- 2 files changed, 89 insertions(+), 3 deletions(-) diff --git a/Documentation/arch/arm64/booting.rst b/Documentation/arch/arm6= 4/booting.rst index dee7b6de864f..fbdc4b071755 100644 --- a/Documentation/arch/arm64/booting.rst +++ b/Documentation/arch/arm64/booting.rst @@ -388,6 +388,27 @@ Before jumping into the kernel, the following conditio= ns must be met: =20 - SMCR_EL2.EZT0 (bit 30) must be initialised to 0b1. =20 + For CPUs with the Branch Record Buffer Extension (FEAT_BRBE): + + - If EL3 is present: + + - MDCR_EL3.SBRBE (bits 33:32) must be initialised to 0b01 or 0b11. + + - If the kernel is entered at EL1 and EL2 is present: + + - BRBCR_EL2.CC (bit 3) must be initialised to 0b1. + - BRBCR_EL2.MPRED (bit 4) must be initialised to 0b1. + + - HDFGRTR_EL2.nBRBDATA (bit 61) must be initialised to 0b1. + - HDFGRTR_EL2.nBRBCTL (bit 60) must be initialised to 0b1. + - HDFGRTR_EL2.nBRBIDR (bit 59) must be initialised to 0b1. + + - HDFGWTR_EL2.nBRBDATA (bit 61) must be initialised to 0b1. + - HDFGWTR_EL2.nBRBCTL (bit 60) must be initialised to 0b1. + + - HFGITR_EL2.nBRBIALL (bit 56) must be initialised to 0b1. + - HFGITR_EL2.nBRBINJ (bit 55) must be initialised to 0b1. + For CPUs with the Performance Monitors Extension (FEAT_PMUv3p9): =20 - If EL3 is present: diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el= 2_setup.h index ba5df0df02a4..de8a57f728c5 100644 --- a/arch/arm64/include/asm/el2_setup.h +++ b/arch/arm64/include/asm/el2_setup.h @@ -189,6 +189,28 @@ .Lskip_set_cptr_\@: .endm =20 +/* + * Configure BRBE to permit recording cycle counts and branch mispredicts. + * + * At any EL, to record cycle counts BRBE requires that both BRBCR_EL2.CC= =3D1 and + * BRBCR_EL1.CC=3D1. + * + * At any EL, to record branch mispredicts BRBE requires that both + * BRBCR_EL2.MPRED=3D1 and BRBCR_EL1.MPRED=3D1. + * + * Set {CC,MPRED} in BRBCR_EL2 in case nVHE mode is used and we are + * executing in EL1. + */ +.macro __init_el2_brbe + mrs x1, id_aa64dfr0_el1 + ubfx x1, x1, #ID_AA64DFR0_EL1_BRBE_SHIFT, #4 + cbz x1, .Lskip_brbe_\@ + + mov_q x0, BRBCR_ELx_CC | BRBCR_ELx_MPRED + msr_s SYS_BRBCR_EL2, x0 +.Lskip_brbe_\@: +.endm + /* Disable any fine grained traps */ .macro __init_el2_fgt mrs x1, id_aa64mmfr0_el1 @@ -196,20 +218,62 @@ cbz x1, .Lskip_fgt_\@ =20 mov x0, xzr + mov x2, xzr mrs x1, id_aa64dfr0_el1 ubfx x1, x1, #ID_AA64DFR0_EL1_PMSVer_SHIFT, #4 cmp x1, #3 b.lt .Lskip_spe_fgt_\@ /* Disable PMSNEVFR_EL1 read and write traps */ - orr x0, x0, #(1 << 62) + orr x0, x0, #HDFGRTR_EL2_nPMSNEVFR_EL1_MASK + orr x2, x2, #HDFGWTR_EL2_nPMSNEVFR_EL1_MASK =20 .Lskip_spe_fgt_\@: + mrs x1, id_aa64dfr0_el1 + ubfx x1, x1, #ID_AA64DFR0_EL1_BRBE_SHIFT, #4 + cbz x1, .Lskip_brbe_fgt_\@ + + /* + * Disable read traps for the following registers + * + * [BRBSRC|BRBTGT|RBINF]_EL1 + * [BRBSRCINJ|BRBTGTINJ|BRBINFINJ|BRBTS]_EL1 + */ + orr x0, x0, #HDFGRTR_EL2_nBRBDATA_MASK + + /* + * Disable write traps for the following registers + * + * [BRBSRCINJ|BRBTGTINJ|BRBINFINJ|BRBTS]_EL1 + */ + orr x2, x2, #HDFGWTR_EL2_nBRBDATA_MASK + + /* Disable read and write traps for [BRBCR|BRBFCR]_EL1 */ + orr x0, x0, #HDFGRTR_EL2_nBRBCTL_MASK + orr x2, x2, #HDFGWTR_EL2_nBRBCTL_MASK + + /* Disable read traps for BRBIDR_EL1 */ + orr x0, x0, #HDFGRTR_EL2_nBRBIDR_MASK + +.Lskip_brbe_fgt_\@: =20 .Lset_debug_fgt_\@: msr_s SYS_HDFGRTR_EL2, x0 - msr_s SYS_HDFGWTR_EL2, x0 + msr_s SYS_HDFGWTR_EL2, x2 =20 mov x0, xzr + mov x2, xzr + + mrs x1, id_aa64dfr0_el1 + ubfx x1, x1, #ID_AA64DFR0_EL1_BRBE_SHIFT, #4 + cbz x1, .Lskip_brbe_insn_fgt_\@ + + /* Disable traps for BRBIALL instruction */ + orr x2, x2, #HFGITR_EL2_nBRBIALL_MASK + + /* Disable traps for BRBINJ instruction */ + orr x2, x2, #HFGITR_EL2_nBRBINJ_MASK + +.Lskip_brbe_insn_fgt_\@: mrs x1, id_aa64pfr1_el1 ubfx x1, x1, #ID_AA64PFR1_EL1_SME_SHIFT, #4 cbz x1, .Lskip_sme_fgt_\@ @@ -250,7 +314,7 @@ .Lset_fgt_\@: msr_s SYS_HFGRTR_EL2, x0 msr_s SYS_HFGWTR_EL2, x0 - msr_s SYS_HFGITR_EL2, xzr + msr_s SYS_HFGITR_EL2, x2 =20 mrs x1, id_aa64pfr0_el1 // AMU traps UNDEF without AMU ubfx x1, x1, #ID_AA64PFR0_EL1_AMU_SHIFT, #4 @@ -311,6 +375,7 @@ __init_el2_hcrx __init_el2_timers __init_el2_debug + __init_el2_brbe __init_el2_lor __init_el2_stage2 __init_el2_gicv3 --=20 2.47.2 From nobody Sun Sep 14 10:58:35 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7901C28B517; Wed, 11 Jun 2025 18:01:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749664890; cv=none; b=BZErrdn4zzPkIxTp8T7LkKCG8VorXj4JEWhJIGd1HtGmsdoJkdVXbqdOV/XYOmz7MKl5yvEbzbo+uEE2qPZpsURkUpsKbv7DSJPv0uo0dk8oNBR4dlnQc//7dI8JoUo0yVVPClCvhiXKmnHp4XeewZrHPH9Wldr5hS8rhbc+vG0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749664890; c=relaxed/simple; bh=+ZoWV53o+vO6nS7nwIXrhnxgQk9iH15oJz2Wqyur3hU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=Kh3/PTm5FsOUgZZoc34FQc/Es+u9NAHVGKwVwKw7zuJbdAvTlRkxwGh8Moipc9C0oLpVT9SwLNdbZ6MRoDikieV6rcH9kH9ECCm/yQj3cr1fEDL6v+46PihSKG7YzcgI3uNDC/ni0ur124xomX2B0v7diCaSwpOogl1Gmks9qzI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jxHpte+e; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jxHpte+e" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D84AAC4CEF1; Wed, 11 Jun 2025 18:01:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749664890; bh=+ZoWV53o+vO6nS7nwIXrhnxgQk9iH15oJz2Wqyur3hU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=jxHpte+eLzE7ZIrqNZgXZoK0W4PXP/ZsA0/GLptCo0iomaGmySOvpqRpaUFz2eI8i kdvYwmSE0RamXXUx4wKVSqVjGk+tbYk+vUUxiPhU75rKP4KklKqZdsPkpfFdNp7ZL2 XBj5lj1S9/QmzDhmVju3Fsm28ACzmLi3mhsZL4/3WmaaIRA2RYx8JsGL2OGu/5//yw S7f7tOUTU0m8ELAEDw/1H+YiMpU2tRi4EpA4OSPXhlcvXR5S7eOnw4KOCfNFiR2EQF eB7RwiYi3r0VVsgVpf9JCOR2GwU9Z2hHIgqM6BnnE3ioU9BTvq4NOPg/ZIduu3jdXi ZI0LC/gmoSFiA== From: "Rob Herring (Arm)" Date: Wed, 11 Jun 2025 13:01:13 -0500 Subject: [PATCH v23 3/4] KVM: arm64: nvhe: Disable branch generation in nVHE guests Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250611-arm-brbe-v19-v23-3-e7775563036e@kernel.org> References: <20250611-arm-brbe-v19-v23-0-e7775563036e@kernel.org> In-Reply-To: <20250611-arm-brbe-v19-v23-0-e7775563036e@kernel.org> To: Will Deacon , Mark Rutland , Catalin Marinas , Jonathan Corbet , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , James Clark , Anshuman Khandual , Leo Yan Cc: linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev X-Mailer: b4 0.15-dev From: Anshuman Khandual While BRBE can record branches within guests, the host recording branches in guests is not supported by perf (though events are). Support for BRBE in guests will supported by providing direct access to BRBE within the guests. That is how x86 LBR works for guests. Therefore, BRBE needs to be disabled on guest entry and restored on exit. For nVHE, this requires explicit handling for guests. Before entering a guest, save the BRBE state and disable the it. When returning to the host, restore the state. For VHE, it is not necessary. We initialize BRBCR_EL1.{E1BRE,E0BRE}=3D=3D{0,0} at boot time, and HCR_EL2.TGE=3D=3D1 whi= le running in the host. We configure BRBCR_EL2.{E2BRE,E0HBRE} to enable branch recording in the host. When entering the guest, we set HCR_EL2.TGE=3D=3D0 which means BRBCR_EL1 is used instead of BRBCR_EL2. Consequently for VHE, BRBE recording is disabled at EL1 and EL0 when running a guest. Should recording in guests (by the host) ever be desired, the perf ABI will need to be extended to distinguish guest addresses (struct perf_branch_entry.priv) for starters. BRBE records would also need to be invalidated on guest entry/exit as guest/host EL1 and EL0 records can't be distinguished. Signed-off-by: Anshuman Khandual Signed-off-by: Mark Rutland Co-developed-by: Rob Herring (Arm) Signed-off-by: Rob Herring (Arm) Tested-by: James Clark Reviewed-by: Leo Yan Reviewed-by: Suzuki K Poulose Acked-by: Marc Zyngier Acked-by: Mark Rutland --- v23: - Rebase on v6.16-rc1 and update KVM_HOST_DATA_FLAG_HAS_BRBE value v20: - Reword commit message about no guest recording. - Add BRBE to __kvm_vcpu_run() synchronization comment v19: - Rework due to v6.14 debug flag changes - Redo commit message --- arch/arm64/include/asm/kvm_host.h | 2 ++ arch/arm64/kvm/debug.c | 4 ++++ arch/arm64/kvm/hyp/nvhe/debug-sr.c | 32 ++++++++++++++++++++++++++++++++ arch/arm64/kvm/hyp/nvhe/switch.c | 2 +- 4 files changed, 39 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm= _host.h index 6ce2c5173482..52c2a591c447 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -704,6 +704,7 @@ struct kvm_host_data { #define KVM_HOST_DATA_FLAG_EL1_TRACING_CONFIGURED 5 #define KVM_HOST_DATA_FLAG_VCPU_IN_HYP_CONTEXT 6 #define KVM_HOST_DATA_FLAG_L1_VNCR_MAPPED 7 +#define KVM_HOST_DATA_FLAG_HAS_BRBE 8 unsigned long flags; =20 struct kvm_cpu_context host_ctxt; @@ -737,6 +738,7 @@ struct kvm_host_data { u64 trfcr_el1; /* Values of trap registers for the host before guest entry. */ u64 mdcr_el2; + u64 brbcr_el1; } host_debug_state; =20 /* Guest trace filter value */ diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index 0e4c805e7e89..bc6015108a68 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -81,6 +81,10 @@ void kvm_init_host_debug_data(void) !(read_sysreg_s(SYS_PMBIDR_EL1) & PMBIDR_EL1_P)) host_data_set_flag(HAS_SPE); =20 + /* Check if we have BRBE implemented and available at the host */ + if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_BRBE_SHIFT= )) + host_data_set_flag(HAS_BRBE); + if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceFilt_= SHIFT)) { /* Force disable trace in protected mode in case of no TRBE */ if (is_protected_kvm_enabled()) diff --git a/arch/arm64/kvm/hyp/nvhe/debug-sr.c b/arch/arm64/kvm/hyp/nvhe/d= ebug-sr.c index 2f4a4f5036bb..2a1c0f49792b 100644 --- a/arch/arm64/kvm/hyp/nvhe/debug-sr.c +++ b/arch/arm64/kvm/hyp/nvhe/debug-sr.c @@ -92,12 +92,42 @@ static void __trace_switch_to_host(void) *host_data_ptr(host_debug_state.trfcr_el1)); } =20 +static void __debug_save_brbe(u64 *brbcr_el1) +{ + *brbcr_el1 =3D 0; + + /* Check if the BRBE is enabled */ + if (!(read_sysreg_el1(SYS_BRBCR) & (BRBCR_ELx_E0BRE | BRBCR_ELx_ExBRE))) + return; + + /* + * Prohibit branch record generation while we are in guest. + * Since access to BRBCR_EL1 is trapped, the guest can't + * modify the filtering set by the host. + */ + *brbcr_el1 =3D read_sysreg_el1(SYS_BRBCR); + write_sysreg_el1(0, SYS_BRBCR); +} + +static void __debug_restore_brbe(u64 brbcr_el1) +{ + if (!brbcr_el1) + return; + + /* Restore BRBE controls */ + write_sysreg_el1(brbcr_el1, SYS_BRBCR); +} + void __debug_save_host_buffers_nvhe(struct kvm_vcpu *vcpu) { /* Disable and flush SPE data generation */ if (host_data_test_flag(HAS_SPE)) __debug_save_spe(host_data_ptr(host_debug_state.pmscr_el1)); =20 + /* Disable BRBE branch records */ + if (host_data_test_flag(HAS_BRBE)) + __debug_save_brbe(host_data_ptr(host_debug_state.brbcr_el1)); + if (__trace_needs_switch()) __trace_switch_to_guest(); } @@ -111,6 +141,8 @@ void __debug_restore_host_buffers_nvhe(struct kvm_vcpu = *vcpu) { if (host_data_test_flag(HAS_SPE)) __debug_restore_spe(*host_data_ptr(host_debug_state.pmscr_el1)); + if (host_data_test_flag(HAS_BRBE)) + __debug_restore_brbe(*host_data_ptr(host_debug_state.brbcr_el1)); if (__trace_needs_switch()) __trace_switch_to_host(); } diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/swi= tch.c index 73affe1333a4..ad1da5214b5d 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -331,7 +331,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu) * We're about to restore some new MMU state. Make sure * ongoing page-table walks that have started before we * trapped to EL2 have completed. This also synchronises the - * above disabling of SPE and TRBE. + * above disabling of BRBE, SPE and TRBE. * * See DDI0487I.a D8.1.5 "Out-of-context translation regimes", * rule R_LFHQG and subsequent information statements. --=20 2.47.2 From nobody Sun Sep 14 10:58:35 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C03FD29B772; Wed, 11 Jun 2025 18:01:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749664891; cv=none; b=EFzA44wFHEA6H3i0ed2L+YUsUHRvF6h+fHjQdEVZr4m4rrSGEoS3sUr/P350RfG+4hyf4Jvms6HbmcMjbCmZA28tE+SIHhs4693sHdzEiF/E5+lnI4kvOng/9BFLAlmaap92DJRF5N1mO3wn8ont+RJD0vy1Y4+TSg3jwwJI0NQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749664891; c=relaxed/simple; bh=YcQlqVSSGhq68+89aAXidcdxUGzdPJFo9Kra5fqeNN0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=pXhm3PggdwC274ttxX0SIzplquEO7AW2WpZupkyiMINuoPmj5q+h6gP21xCAghTa/Y3UJWs2LG5F5aB9L4/3SLTwmIa+Y/6ae5U3OAMbPBSR1kMZg25IsbbdG456gefFH+WX/9whsguUvALagm/MGTfERwGpIZoz2GGmO2GW9MA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bl1aey++; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bl1aey++" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0F0B9C4CEE3; Wed, 11 Jun 2025 18:01:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1749664891; bh=YcQlqVSSGhq68+89aAXidcdxUGzdPJFo9Kra5fqeNN0=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=bl1aey+++OBGdG2aWz9JakG4YXk6oStl3PhnidRwxIp1apZ27xcLJsQ8kkWSIcsol F7kaTPXPkxvo9R3zlQEbtvcXmO5+69X8HGbkQR2cwPOEWT8zr+VUmaZlO/6aL2wgnh h7F/ypZ/u5a92sgqwnFoj7cPJ/s99uEY/1G8GMWA2lLKQ80vGLlsLYtPkF7+y7vnI1 YjWEHynh6QeILohy3ErOEZGSjg+r0FJkvFZnyL3zzmEsWS9MNulUOEcy7ojY8ulPbB GBmC26H/HpYeYmHs753D4BFNnnyrVHjJkBpIxY/32gWS4hIXgqFDQvDizPzZg9uk3O oBzTWfwtXDdjQ== From: "Rob Herring (Arm)" Date: Wed, 11 Jun 2025 13:01:14 -0500 Subject: [PATCH v23 4/4] perf: arm_pmuv3: Add support for the Branch Record Buffer Extension (BRBE) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250611-arm-brbe-v19-v23-4-e7775563036e@kernel.org> References: <20250611-arm-brbe-v19-v23-0-e7775563036e@kernel.org> In-Reply-To: <20250611-arm-brbe-v19-v23-0-e7775563036e@kernel.org> To: Will Deacon , Mark Rutland , Catalin Marinas , Jonathan Corbet , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , James Clark , Anshuman Khandual , Leo Yan Cc: linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev X-Mailer: b4 0.15-dev The ARMv9.2 architecture introduces the optional Branch Record Buffer Extension (BRBE), which records information about branches as they are executed into set of branch record registers. BRBE is similar to x86's Last Branch Record (LBR) and PowerPC's Branch History Rolling Buffer (BHRB). BRBE supports filtering by exception level and can filter just the source or target address if excluded to avoid leaking privileged addresses. The h/w filter would be sufficient except when there are multiple events with disjoint filtering requirements. In this case, BRBE is configured with a union of all the events' desired branches, and then the recorded branches are filtered based on each event's filter. For example, with one event capturing kernel events and another event capturing user events, BRBE will be configured to capture both kernel and user branches. When handling event overflow, the branch records have to be filtered by software to only include kernel or user branch addresses for that event. In contrast, x86 simply configures LBR using the last installed event which seems broken. It is possible on x86 to configure branch filter such that no branches are ever recorded (e.g. -j save_type). For BRBE, events with a configuration that will result in no samples are rejected. Recording branches in KVM guests is not supported like x86. However, perf on x86 allows requesting branch recording in guests. The guest events are recorded, but the resulting branches are all from the host. For BRBE, events with branch recording and "exclude_host" set are rejected. Requiring "exclude_guest" to be set did not work. The default for the perf tool does set "exclude_guest" if no exception level options are specified. However, specifying kernel or user events defaults to including both host and guest. In this case, only host branches are recorded. BRBE can support some additional exception branch types compared to x86. On x86, all exceptions other than syscalls are recorded as IRQ. With BRBE, it is possible to better categorize these exceptions. One limitation relative to x86 is we cannot distinguish a syscall return from other exception returns. So all exception returns are recorded as ERET type. The FIQ branch type is omitted as the only FIQ user is Apple platforms which don't support BRBE. The debug branch types are omitted as there is no clear need for them. BRBE records are invalidated whenever events are reconfigured, a new task is scheduled in, or after recording is paused (and the records have been recorded for the event). The architecture allows branch records to be invalidated by the PE under implementation defined conditions. It is expected that these conditions are rare. Cc: Catalin Marinas Co-developed-by: Anshuman Khandual Signed-off-by: Anshuman Khandual Co-developed-by: Mark Rutland Signed-off-by: Mark Rutland Tested-by: James Clark Signed-off-by: Rob Herring (Arm) Acked-by: Mark Rutland tested-by: Adam Young --- v23: - Drop the syscall fixup and directly convert BRBE CALL type to perf SYSCALL as only calls to higher EL generate a CALL event v22: - Move branch stack disabling after armpmu_stop() in armpmu_del() - Fix branch_records_alloc() to work on heterogeneous systems - Make setting .sched_task function ptr conditional on BRBE support v21: - update .sched_task() parameters. task_struct added in v6.15 v20: - Fix sparse percpu warning in branch_records_alloc() - Use pr_debug instead of pr_debug_once. Add debug print on all error cases when event.attr is rejected. - Add back some arm64 specific exception types - Convert 'call' from user to kernel to syscall as appropriate - Drop requiring event and branch privileges to match - Only enable exceptions and exception returns if recording kernel branches - Add "branches" caps sysfs attribute like x86 - Drop some unused defines - Use u64 instead of unsigned long for branch record fields - use min() in brbinf_get_cycles() - Reword comment about FZP and MDCR_EL2.HPMN interaction - Add comments on assumptions about calling brbe_enable() - Merge capture_brbe_flags() into perf_entry_from_brbe_regset() - Rework BRBE invalidation to avoid invalidating in interrupt handler when no handled events capture the branch stack. - Also clear BRBCR_ELx in brbe_disable(). This is for KVM nVHE checks if BRBE is enabled. v19: - Drop saving of branch records when task scheduled out. (Mark) - Got rid of added armpmu ops. All BRBE support contained within pmuv3 code. - Dropped armpmu.num_branch_records as reg_brbidr has same info. - Make sched_task() callback actually get called. Enabling requires a call to perf_sched_cb_inc(). - Fix freeze on overflow for VHE - The cycle counter doesn't freeze BRBE on overflow, so avoid assigning it when BRBE is enabled. - Drop all the Arm specific exception branches. Not a clear need for them. - Simplify enable/disable to avoid RMW and document ISBs needed - Fix handling of branch 'cycles' reading. CC field is mantissa/exponent, not an integer. - Save BRBFCR and BRBCR settings in event->hw.branch_reg.config and event->hw.extra_reg.config to avoid recalculating the register value each time the event is installed. - Rework s/w filtering to better match h/w filtering - Reject events with disjoint event filter and branch filter - Reject events if exclude_host is set v18: https://lore.kernel.org/all/20240613061731.3109448-6-anshuman.khandual= @arm.com/ --- drivers/perf/Kconfig | 11 + drivers/perf/Makefile | 1 + drivers/perf/arm_brbe.c | 798 +++++++++++++++++++++++++++++++++++++++= ++++ drivers/perf/arm_brbe.h | 47 +++ drivers/perf/arm_pmu.c | 16 +- drivers/perf/arm_pmuv3.c | 125 ++++++- include/linux/perf/arm_pmu.h | 8 + 7 files changed, 999 insertions(+), 7 deletions(-) diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig index 278c929dc87a..a9188dec36fe 100644 --- a/drivers/perf/Kconfig +++ b/drivers/perf/Kconfig @@ -223,6 +223,17 @@ config ARM_SPE_PMU Extension, which provides periodic sampling of operations in the CPU pipeline and reports this via the perf AUX interface. =20 +config ARM64_BRBE + bool "Enable support for branch stack sampling using FEAT_BRBE" + depends on ARM_PMUV3 && ARM64 + default y + help + Enable perf support for Branch Record Buffer Extension (BRBE) which + records all branches taken in an execution path. This supports some + branch types and privilege based filtering. It captures additional + relevant information such as cycle count, misprediction and branch + type, branch privilege level etc. + config ARM_DMC620_PMU tristate "Enable PMU support for the ARM DMC-620 memory controller" depends on (ARM64 && ACPI) || COMPILE_TEST diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile index de71d2574857..192fc8b16204 100644 --- a/drivers/perf/Makefile +++ b/drivers/perf/Makefile @@ -23,6 +23,7 @@ obj-$(CONFIG_STARFIVE_STARLINK_PMU) +=3D starfive_starlin= k_pmu.o obj-$(CONFIG_THUNDERX2_PMU) +=3D thunderx2_pmu.o obj-$(CONFIG_XGENE_PMU) +=3D xgene_pmu.o obj-$(CONFIG_ARM_SPE_PMU) +=3D arm_spe_pmu.o +obj-$(CONFIG_ARM64_BRBE) +=3D arm_brbe.o obj-$(CONFIG_ARM_DMC620_PMU) +=3D arm_dmc620_pmu.o obj-$(CONFIG_MARVELL_CN10K_TAD_PMU) +=3D marvell_cn10k_tad_pmu.o obj-$(CONFIG_MARVELL_CN10K_DDR_PMU) +=3D marvell_cn10k_ddr_pmu.o diff --git a/drivers/perf/arm_brbe.c b/drivers/perf/arm_brbe.c new file mode 100644 index 000000000000..acdde61a8559 --- /dev/null +++ b/drivers/perf/arm_brbe.c @@ -0,0 +1,798 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Branch Record Buffer Extension Driver. + * + * Copyright (C) 2022-2025 ARM Limited + * + * Author: Anshuman Khandual + */ +#include +#include +#include +#include "arm_brbe.h" + +#define BRBFCR_EL1_BRANCH_FILTERS (BRBFCR_EL1_DIRECT | \ + BRBFCR_EL1_INDIRECT | \ + BRBFCR_EL1_RTN | \ + BRBFCR_EL1_INDCALL | \ + BRBFCR_EL1_DIRCALL | \ + BRBFCR_EL1_CONDDIR) + +/* + * BRBTS_EL1 is currently not used for branch stack implementation + * purpose but BRBCR_ELx.TS needs to have a valid value from all + * available options. BRBCR_ELx_TS_VIRTUAL is selected for this. + */ +#define BRBCR_ELx_DEFAULT_TS FIELD_PREP(BRBCR_ELx_TS_MASK, BRBCR_ELx_= TS_VIRTUAL) + +/* + * BRBE Buffer Organization + * + * BRBE buffer is arranged as multiple banks of 32 branch record + * entries each. An individual branch record in a given bank could + * be accessed, after selecting the bank in BRBFCR_EL1.BANK and + * accessing the registers i.e [BRBSRC, BRBTGT, BRBINF] set with + * indices [0..31]. + * + * Bank 0 + * + * --------------------------------- ------ + * | 00 | BRBSRC | BRBTGT | BRBINF | | 00 | + * --------------------------------- ------ + * | 01 | BRBSRC | BRBTGT | BRBINF | | 01 | + * --------------------------------- ------ + * | .. | BRBSRC | BRBTGT | BRBINF | | .. | + * --------------------------------- ------ + * | 31 | BRBSRC | BRBTGT | BRBINF | | 31 | + * --------------------------------- ------ + * + * Bank 1 + * + * --------------------------------- ------ + * | 32 | BRBSRC | BRBTGT | BRBINF | | 00 | + * --------------------------------- ------ + * | 33 | BRBSRC | BRBTGT | BRBINF | | 01 | + * --------------------------------- ------ + * | .. | BRBSRC | BRBTGT | BRBINF | | .. | + * --------------------------------- ------ + * | 63 | BRBSRC | BRBTGT | BRBINF | | 31 | + * --------------------------------- ------ + */ +#define BRBE_BANK_MAX_ENTRIES 32 + +struct brbe_regset { + u64 brbsrc; + u64 brbtgt; + u64 brbinf; +}; + +#define PERF_BR_ARM64_MAX (PERF_BR_MAX + PERF_BR_NEW_MAX) + +struct brbe_hw_attr { + int brbe_version; + int brbe_cc; + int brbe_nr; + int brbe_format; +}; + +#define BRBE_REGN_CASE(n, case_macro) \ + case n: case_macro(n); break + +#define BRBE_REGN_SWITCH(x, case_macro) \ + do { \ + switch (x) { \ + BRBE_REGN_CASE(0, case_macro); \ + BRBE_REGN_CASE(1, case_macro); \ + BRBE_REGN_CASE(2, case_macro); \ + BRBE_REGN_CASE(3, case_macro); \ + BRBE_REGN_CASE(4, case_macro); \ + BRBE_REGN_CASE(5, case_macro); \ + BRBE_REGN_CASE(6, case_macro); \ + BRBE_REGN_CASE(7, case_macro); \ + BRBE_REGN_CASE(8, case_macro); \ + BRBE_REGN_CASE(9, case_macro); \ + BRBE_REGN_CASE(10, case_macro); \ + BRBE_REGN_CASE(11, case_macro); \ + BRBE_REGN_CASE(12, case_macro); \ + BRBE_REGN_CASE(13, case_macro); \ + BRBE_REGN_CASE(14, case_macro); \ + BRBE_REGN_CASE(15, case_macro); \ + BRBE_REGN_CASE(16, case_macro); \ + BRBE_REGN_CASE(17, case_macro); \ + BRBE_REGN_CASE(18, case_macro); \ + BRBE_REGN_CASE(19, case_macro); \ + BRBE_REGN_CASE(20, case_macro); \ + BRBE_REGN_CASE(21, case_macro); \ + BRBE_REGN_CASE(22, case_macro); \ + BRBE_REGN_CASE(23, case_macro); \ + BRBE_REGN_CASE(24, case_macro); \ + BRBE_REGN_CASE(25, case_macro); \ + BRBE_REGN_CASE(26, case_macro); \ + BRBE_REGN_CASE(27, case_macro); \ + BRBE_REGN_CASE(28, case_macro); \ + BRBE_REGN_CASE(29, case_macro); \ + BRBE_REGN_CASE(30, case_macro); \ + BRBE_REGN_CASE(31, case_macro); \ + default: WARN(1, "Invalid BRB* index %d\n", x); \ + } \ + } while (0) + +#define RETURN_READ_BRBSRCN(n) \ + return read_sysreg_s(SYS_BRBSRC_EL1(n)) +static inline u64 get_brbsrc_reg(int idx) +{ + BRBE_REGN_SWITCH(idx, RETURN_READ_BRBSRCN); + return 0; +} + +#define RETURN_READ_BRBTGTN(n) \ + return read_sysreg_s(SYS_BRBTGT_EL1(n)) +static u64 get_brbtgt_reg(int idx) +{ + BRBE_REGN_SWITCH(idx, RETURN_READ_BRBTGTN); + return 0; +} + +#define RETURN_READ_BRBINFN(n) \ + return read_sysreg_s(SYS_BRBINF_EL1(n)) +static u64 get_brbinf_reg(int idx) +{ + BRBE_REGN_SWITCH(idx, RETURN_READ_BRBINFN); + return 0; +} + +static u64 brbe_record_valid(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_VALID_MASK, brbinf); +} + +static bool brbe_invalid(u64 brbinf) +{ + return brbe_record_valid(brbinf) =3D=3D BRBINFx_EL1_VALID_NONE; +} + +static bool brbe_record_is_complete(u64 brbinf) +{ + return brbe_record_valid(brbinf) =3D=3D BRBINFx_EL1_VALID_FULL; +} + +static bool brbe_record_is_source_only(u64 brbinf) +{ + return brbe_record_valid(brbinf) =3D=3D BRBINFx_EL1_VALID_SOURCE; +} + +static bool brbe_record_is_target_only(u64 brbinf) +{ + return brbe_record_valid(brbinf) =3D=3D BRBINFx_EL1_VALID_TARGET; +} + +static int brbinf_get_in_tx(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_T_MASK, brbinf); +} + +static int brbinf_get_mispredict(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_MPRED_MASK, brbinf); +} + +static int brbinf_get_lastfailed(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_LASTFAILED_MASK, brbinf); +} + +static u16 brbinf_get_cycles(u64 brbinf) +{ + u32 exp, mant, cycles; + /* + * Captured cycle count is unknown and hence + * should not be passed on to userspace. + */ + if (brbinf & BRBINFx_EL1_CCU) + return 0; + + exp =3D FIELD_GET(BRBINFx_EL1_CC_EXP_MASK, brbinf); + mant =3D FIELD_GET(BRBINFx_EL1_CC_MANT_MASK, brbinf); + + if (!exp) + return mant; + + cycles =3D (mant | 0x100) << (exp - 1); + + return min(cycles, U16_MAX); +} + +static int brbinf_get_type(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_TYPE_MASK, brbinf); +} + +static int brbinf_get_el(u64 brbinf) +{ + return FIELD_GET(BRBINFx_EL1_EL_MASK, brbinf); +} + +void brbe_invalidate(void) +{ + // Ensure all branches before this point are recorded + isb(); + asm volatile(BRB_IALL_INSN); + // Ensure all branch records are invalidated after this point + isb(); +} + +static bool valid_brbe_nr(int brbe_nr) +{ + return brbe_nr =3D=3D BRBIDR0_EL1_NUMREC_8 || + brbe_nr =3D=3D BRBIDR0_EL1_NUMREC_16 || + brbe_nr =3D=3D BRBIDR0_EL1_NUMREC_32 || + brbe_nr =3D=3D BRBIDR0_EL1_NUMREC_64; +} + +static bool valid_brbe_cc(int brbe_cc) +{ + return brbe_cc =3D=3D BRBIDR0_EL1_CC_20_BIT; +} + +static bool valid_brbe_format(int brbe_format) +{ + return brbe_format =3D=3D BRBIDR0_EL1_FORMAT_FORMAT_0; +} + +static bool valid_brbidr(u64 brbidr) +{ + int brbe_format, brbe_cc, brbe_nr; + + brbe_format =3D FIELD_GET(BRBIDR0_EL1_FORMAT_MASK, brbidr); + brbe_cc =3D FIELD_GET(BRBIDR0_EL1_CC_MASK, brbidr); + brbe_nr =3D FIELD_GET(BRBIDR0_EL1_NUMREC_MASK, brbidr); + + return valid_brbe_format(brbe_format) && valid_brbe_cc(brbe_cc) && valid_= brbe_nr(brbe_nr); +} + +static bool valid_brbe_version(int brbe_version) +{ + return brbe_version =3D=3D ID_AA64DFR0_EL1_BRBE_IMP || + brbe_version =3D=3D ID_AA64DFR0_EL1_BRBE_BRBE_V1P1; +} + +static void select_brbe_bank(int bank) +{ + u64 brbfcr; + + brbfcr =3D read_sysreg_s(SYS_BRBFCR_EL1); + brbfcr &=3D ~BRBFCR_EL1_BANK_MASK; + brbfcr |=3D SYS_FIELD_PREP(BRBFCR_EL1, BANK, bank); + write_sysreg_s(brbfcr, SYS_BRBFCR_EL1); + /* + * Arm ARM (DDI 0487K.a) D.18.4 rule PPBZP requires explicit sync + * between setting BANK and accessing branch records. + */ + isb(); +} + +static bool __read_brbe_regset(struct brbe_regset *entry, int idx) +{ + entry->brbinf =3D get_brbinf_reg(idx); + + if (brbe_invalid(entry->brbinf)) + return false; + + entry->brbsrc =3D get_brbsrc_reg(idx); + entry->brbtgt =3D get_brbtgt_reg(idx); + return true; +} + +/* + * Generic perf branch filters supported on BRBE + * + * New branch filters need to be evaluated whether they could be supported= on + * BRBE. This ensures that such branch filters would not just be accepted,= to + * fail silently. PERF_SAMPLE_BRANCH_HV is a special case that is selectiv= ely + * supported only on platforms where kernel is in hyp mode. + */ +#define BRBE_EXCLUDE_BRANCH_FILTERS (PERF_SAMPLE_BRANCH_ABORT_TX | \ + PERF_SAMPLE_BRANCH_IN_TX | \ + PERF_SAMPLE_BRANCH_NO_TX | \ + PERF_SAMPLE_BRANCH_CALL_STACK | \ + PERF_SAMPLE_BRANCH_COUNTERS) + +#define BRBE_ALLOWED_BRANCH_TYPES (PERF_SAMPLE_BRANCH_ANY | \ + PERF_SAMPLE_BRANCH_ANY_CALL | \ + PERF_SAMPLE_BRANCH_ANY_RETURN | \ + PERF_SAMPLE_BRANCH_IND_CALL | \ + PERF_SAMPLE_BRANCH_COND | \ + PERF_SAMPLE_BRANCH_IND_JUMP | \ + PERF_SAMPLE_BRANCH_CALL) + + +#define BRBE_ALLOWED_BRANCH_FILTERS (PERF_SAMPLE_BRANCH_USER | \ + PERF_SAMPLE_BRANCH_KERNEL | \ + PERF_SAMPLE_BRANCH_HV | \ + BRBE_ALLOWED_BRANCH_TYPES | \ + PERF_SAMPLE_BRANCH_NO_FLAGS | \ + PERF_SAMPLE_BRANCH_NO_CYCLES | \ + PERF_SAMPLE_BRANCH_TYPE_SAVE | \ + PERF_SAMPLE_BRANCH_HW_INDEX | \ + PERF_SAMPLE_BRANCH_PRIV_SAVE) + +#define BRBE_PERF_BRANCH_FILTERS (BRBE_ALLOWED_BRANCH_FILTERS | \ + BRBE_EXCLUDE_BRANCH_FILTERS) + +/* + * BRBE supports the following functional branch type filters while + * generating branch records. These branch filters can be enabled, + * either individually or as a group i.e ORing multiple filters + * with each other. + * + * BRBFCR_EL1_CONDDIR - Conditional direct branch + * BRBFCR_EL1_DIRCALL - Direct call + * BRBFCR_EL1_INDCALL - Indirect call + * BRBFCR_EL1_INDIRECT - Indirect branch + * BRBFCR_EL1_DIRECT - Direct branch + * BRBFCR_EL1_RTN - Subroutine return + */ +static u64 branch_type_to_brbfcr(int branch_type) +{ + u64 brbfcr =3D 0; + + if (branch_type & PERF_SAMPLE_BRANCH_ANY) { + brbfcr |=3D BRBFCR_EL1_BRANCH_FILTERS; + return brbfcr; + } + + if (branch_type & PERF_SAMPLE_BRANCH_ANY_CALL) { + brbfcr |=3D BRBFCR_EL1_INDCALL; + brbfcr |=3D BRBFCR_EL1_DIRCALL; + } + + if (branch_type & PERF_SAMPLE_BRANCH_ANY_RETURN) + brbfcr |=3D BRBFCR_EL1_RTN; + + if (branch_type & PERF_SAMPLE_BRANCH_IND_CALL) + brbfcr |=3D BRBFCR_EL1_INDCALL; + + if (branch_type & PERF_SAMPLE_BRANCH_COND) + brbfcr |=3D BRBFCR_EL1_CONDDIR; + + if (branch_type & PERF_SAMPLE_BRANCH_IND_JUMP) + brbfcr |=3D BRBFCR_EL1_INDIRECT; + + if (branch_type & PERF_SAMPLE_BRANCH_CALL) + brbfcr |=3D BRBFCR_EL1_DIRCALL; + + return brbfcr; +} + +/* + * BRBE supports the following privilege mode filters while generating + * branch records. + * + * BRBCR_ELx_E0BRE - EL0 branch records + * BRBCR_ELx_ExBRE - EL1/EL2 branch records + * + * BRBE also supports the following additional functional branch type + * filters while generating branch records. + * + * BRBCR_ELx_EXCEPTION - Exception + * BRBCR_ELx_ERTN - Exception return + */ +static u64 branch_type_to_brbcr(int branch_type) +{ + u64 brbcr =3D BRBCR_ELx_FZP | BRBCR_ELx_DEFAULT_TS; + + if (branch_type & PERF_SAMPLE_BRANCH_USER) + brbcr |=3D BRBCR_ELx_E0BRE; + + /* + * When running in the hyp mode, writing into BRBCR_EL1 + * actually writes into BRBCR_EL2 instead. Field E2BRE + * is also at the same position as E1BRE. + */ + if (branch_type & PERF_SAMPLE_BRANCH_KERNEL) + brbcr |=3D BRBCR_ELx_ExBRE; + + if (branch_type & PERF_SAMPLE_BRANCH_HV) { + if (is_kernel_in_hyp_mode()) + brbcr |=3D BRBCR_ELx_ExBRE; + } + + if (!(branch_type & PERF_SAMPLE_BRANCH_NO_CYCLES)) + brbcr |=3D BRBCR_ELx_CC; + + if (!(branch_type & PERF_SAMPLE_BRANCH_NO_FLAGS)) + brbcr |=3D BRBCR_ELx_MPRED; + + /* + * The exception and exception return branches could be + * captured, irrespective of the perf event's privilege. + * If the perf event does not have enough privilege for + * a given exception level, then addresses which falls + * under that exception level will be reported as zero + * for the captured branch record, creating source only + * or target only records. + */ + if (branch_type & PERF_SAMPLE_BRANCH_KERNEL) { + if (branch_type & PERF_SAMPLE_BRANCH_ANY) { + brbcr |=3D BRBCR_ELx_EXCEPTION; + brbcr |=3D BRBCR_ELx_ERTN; + } + + if (branch_type & PERF_SAMPLE_BRANCH_ANY_CALL) + brbcr |=3D BRBCR_ELx_EXCEPTION; + + if (branch_type & PERF_SAMPLE_BRANCH_ANY_RETURN) + brbcr |=3D BRBCR_ELx_ERTN; + } + return brbcr; +} + +bool brbe_branch_attr_valid(struct perf_event *event) +{ + u64 branch_type =3D event->attr.branch_sample_type; + + /* + * Ensure both perf branch filter allowed and exclude + * masks are always in sync with the generic perf ABI. + */ + BUILD_BUG_ON(BRBE_PERF_BRANCH_FILTERS !=3D (PERF_SAMPLE_BRANCH_MAX - 1)); + + if (branch_type & BRBE_EXCLUDE_BRANCH_FILTERS) { + pr_debug("requested branch filter not supported 0x%llx\n", branch_type); + return false; + } + + /* Ensure at least 1 branch type is enabled */ + if (!(branch_type & BRBE_ALLOWED_BRANCH_TYPES)) { + pr_debug("no branch type enabled 0x%llx\n", branch_type); + return false; + } + + /* + * No branches are recorded in guests nor nVHE hypervisors, so + * excluding the host or both kernel and user is invalid. + * + * Ideally we'd just require exclude_guest and exclude_hv, but setting + * event filters with perf for kernel or user don't set exclude_guest. + * So effectively, exclude_guest and exclude_hv are ignored. + */ + if (event->attr.exclude_host || (event->attr.exclude_user && event->attr.= exclude_kernel)) { + pr_debug("branch filter in hypervisor or guest only not supported 0x%llx= \n", branch_type); + return false; + } + + event->hw.branch_reg.config =3D branch_type_to_brbfcr(event->attr.branch_= sample_type); + event->hw.extra_reg.config =3D branch_type_to_brbcr(event->attr.branch_sa= mple_type); + + return true; +} + +unsigned int brbe_num_branch_records(const struct arm_pmu *armpmu) +{ + return FIELD_GET(BRBIDR0_EL1_NUMREC_MASK, armpmu->reg_brbidr); +} + +void brbe_probe(struct arm_pmu *armpmu) +{ + u64 aa64dfr0 =3D read_sysreg_s(SYS_ID_AA64DFR0_EL1); + u32 brbe; + + brbe =3D cpuid_feature_extract_unsigned_field(aa64dfr0, ID_AA64DFR0_EL1_B= RBE_SHIFT); + if (!valid_brbe_version(brbe)) + return; + + u64 brbidr =3D read_sysreg_s(SYS_BRBIDR0_EL1); + if (!valid_brbidr(brbidr)) + return; + + armpmu->reg_brbidr =3D brbidr; +} + +/* + * BRBE is assumed to be disabled/paused on entry + */ +void brbe_enable(const struct arm_pmu *arm_pmu) +{ + struct pmu_hw_events *cpuc =3D this_cpu_ptr(arm_pmu->hw_events); + u64 brbfcr =3D 0, brbcr =3D 0; + + /* + * Merge the permitted branch filters of all events. + */ + for (int i =3D 0; i < ARMPMU_MAX_HWEVENTS; i++) { + struct perf_event *event =3D cpuc->events[i]; + + if (event && has_branch_stack(event)) { + brbfcr |=3D event->hw.branch_reg.config; + brbcr |=3D event->hw.extra_reg.config; + } + } + + /* + * In VHE mode with MDCR_EL2.HPMN equal to PMCR_EL0.N, BRBCR_EL1.FZP + * controls freezing the branch records on counter overflow rather than + * BRBCR_EL2.FZP (which writes to BRBCR_EL1 are redirected to). + * The exception levels are enabled/disabled in BRBCR_EL2, so keep EL1 + * and EL0 recording disabled for guests. + * + * As BRBCR_EL1 CC and MPRED bits also need to match, use the same + * value for both registers just masking the exception levels. + */ + if (is_kernel_in_hyp_mode()) + write_sysreg_s(brbcr & ~(BRBCR_ELx_ExBRE | BRBCR_ELx_E0BRE), SYS_BRBCR_E= L12); + write_sysreg_s(brbcr, SYS_BRBCR_EL1); + isb(); // Ensure BRBCR_ELx settings take effect before unpausing + + // Finally write SYS_BRBFCR_EL to unpause BRBE + write_sysreg_s(brbfcr, SYS_BRBFCR_EL1); + // Synchronization in PMCR write ensures ordering WRT PMU enabling +} + +void brbe_disable(void) +{ + /* + * No need for synchronization here as synchronization in PMCR write + * ensures ordering and in the interrupt handler this is a NOP as + * we're already paused. + */ + write_sysreg_s(BRBFCR_EL1_PAUSED, SYS_BRBFCR_EL1); + write_sysreg_s(0, SYS_BRBCR_EL1); +} + +static const int brbe_type_to_perf_type_map[BRBINFx_EL1_TYPE_DEBUG_EXIT + = 1][2] =3D { + [BRBINFx_EL1_TYPE_DIRECT_UNCOND] =3D { PERF_BR_UNCOND, 0 }, + [BRBINFx_EL1_TYPE_INDIRECT] =3D { PERF_BR_IND, 0 }, + [BRBINFx_EL1_TYPE_DIRECT_LINK] =3D { PERF_BR_CALL, 0 }, + [BRBINFx_EL1_TYPE_INDIRECT_LINK] =3D { PERF_BR_IND_CALL, 0 }, + [BRBINFx_EL1_TYPE_RET] =3D { PERF_BR_RET, 0 }, + [BRBINFx_EL1_TYPE_DIRECT_COND] =3D { PERF_BR_COND, 0 }, + [BRBINFx_EL1_TYPE_CALL] =3D { PERF_BR_SYSCALL, 0 }, + [BRBINFx_EL1_TYPE_ERET] =3D { PERF_BR_ERET, 0 }, + [BRBINFx_EL1_TYPE_IRQ] =3D { PERF_BR_IRQ, 0 }, + [BRBINFx_EL1_TYPE_TRAP] =3D { PERF_BR_IRQ, 0 }, + [BRBINFx_EL1_TYPE_SERROR] =3D { PERF_BR_SERROR, 0 }, + [BRBINFx_EL1_TYPE_ALIGN_FAULT] =3D { PERF_BR_EXTEND_ABI, PERF_BR_NEW_FAUL= T_ALGN }, + [BRBINFx_EL1_TYPE_INSN_FAULT] =3D { PERF_BR_EXTEND_ABI, PERF_BR_NEW_FAULT= _INST }, + [BRBINFx_EL1_TYPE_DATA_FAULT] =3D { PERF_BR_EXTEND_ABI, PERF_BR_NEW_FAULT= _DATA }, +}; + +static void brbe_set_perf_entry_type(struct perf_branch_entry *entry, u64 = brbinf) +{ + int brbe_type =3D brbinf_get_type(brbinf); + + if (brbe_type <=3D BRBINFx_EL1_TYPE_DEBUG_EXIT) { + const int *br_type =3D brbe_type_to_perf_type_map[brbe_type]; + + entry->type =3D br_type[0]; + entry->new_type =3D br_type[1]; + } +} + +static int brbinf_get_perf_priv(u64 brbinf) +{ + int brbe_el =3D brbinf_get_el(brbinf); + + switch (brbe_el) { + case BRBINFx_EL1_EL_EL0: + return PERF_BR_PRIV_USER; + case BRBINFx_EL1_EL_EL1: + return PERF_BR_PRIV_KERNEL; + case BRBINFx_EL1_EL_EL2: + if (is_kernel_in_hyp_mode()) + return PERF_BR_PRIV_KERNEL; + return PERF_BR_PRIV_HV; + default: + pr_warn_once("%d - unknown branch privilege captured\n", brbe_el); + return PERF_BR_PRIV_UNKNOWN; + } +} + +static bool perf_entry_from_brbe_regset(int index, struct perf_branch_entr= y *entry, + const struct perf_event *event) +{ + struct brbe_regset bregs; + u64 brbinf; + + if (!__read_brbe_regset(&bregs, index)) + return false; + + brbinf =3D bregs.brbinf; + perf_clear_branch_entry_bitfields(entry); + if (brbe_record_is_complete(brbinf)) { + entry->from =3D bregs.brbsrc; + entry->to =3D bregs.brbtgt; + } else if (brbe_record_is_source_only(brbinf)) { + entry->from =3D bregs.brbsrc; + entry->to =3D 0; + } else if (brbe_record_is_target_only(brbinf)) { + entry->from =3D 0; + entry->to =3D bregs.brbtgt; + } + + brbe_set_perf_entry_type(entry, brbinf); + + if (!branch_sample_no_cycles(event)) + entry->cycles =3D brbinf_get_cycles(brbinf); + + if (!branch_sample_no_flags(event)) { + /* Mispredict info is available for source only and complete branch reco= rds. */ + if (!brbe_record_is_target_only(brbinf)) { + entry->mispred =3D brbinf_get_mispredict(brbinf); + entry->predicted =3D !entry->mispred; + } + + /* + * Currently TME feature is neither implemented in any hardware + * nor it is being supported in the kernel. Just warn here once + * if TME related information shows up rather unexpectedly. + */ + if (brbinf_get_lastfailed(brbinf) || brbinf_get_in_tx(brbinf)) + pr_warn_once("Unknown transaction states\n"); + } + + /* + * Branch privilege level is available for target only and complete + * branch records. + */ + if (!brbe_record_is_source_only(brbinf)) + entry->priv =3D brbinf_get_perf_priv(brbinf); + + return true; +} + +#define PERF_BR_ARM64_ALL ( \ + BIT(PERF_BR_COND) | \ + BIT(PERF_BR_UNCOND) | \ + BIT(PERF_BR_IND) | \ + BIT(PERF_BR_CALL) | \ + BIT(PERF_BR_IND_CALL) | \ + BIT(PERF_BR_RET)) + +#define PERF_BR_ARM64_ALL_KERNEL ( \ + BIT(PERF_BR_SYSCALL) | \ + BIT(PERF_BR_IRQ) | \ + BIT(PERF_BR_SERROR) | \ + BIT(PERF_BR_MAX + PERF_BR_NEW_FAULT_ALGN) | \ + BIT(PERF_BR_MAX + PERF_BR_NEW_FAULT_DATA) | \ + BIT(PERF_BR_MAX + PERF_BR_NEW_FAULT_INST)) + +static void prepare_event_branch_type_mask(u64 branch_sample, + unsigned long *event_type_mask) +{ + if (branch_sample & PERF_SAMPLE_BRANCH_ANY) { + if (branch_sample & PERF_SAMPLE_BRANCH_KERNEL) + bitmap_from_u64(event_type_mask, + BIT(PERF_BR_ERET) | PERF_BR_ARM64_ALL | + PERF_BR_ARM64_ALL_KERNEL); + else + bitmap_from_u64(event_type_mask, PERF_BR_ARM64_ALL); + return; + } + + bitmap_zero(event_type_mask, PERF_BR_ARM64_MAX); + + if (branch_sample & PERF_SAMPLE_BRANCH_ANY_CALL) { + if (branch_sample & PERF_SAMPLE_BRANCH_KERNEL) + bitmap_from_u64(event_type_mask, PERF_BR_ARM64_ALL_KERNEL); + + set_bit(PERF_BR_CALL, event_type_mask); + set_bit(PERF_BR_IND_CALL, event_type_mask); + } + + if (branch_sample & PERF_SAMPLE_BRANCH_IND_JUMP) + set_bit(PERF_BR_IND, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_COND) + set_bit(PERF_BR_COND, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_CALL) + set_bit(PERF_BR_CALL, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_IND_CALL) + set_bit(PERF_BR_IND_CALL, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_ANY_RETURN) { + set_bit(PERF_BR_RET, event_type_mask); + + if (branch_sample & PERF_SAMPLE_BRANCH_KERNEL) + set_bit(PERF_BR_ERET, event_type_mask); + } +} + +/* + * BRBE is configured with an OR of permissions from all events, so there = may + * be events which have to be dropped or events where just the source or t= arget + * address has to be zeroed. + */ +static bool filter_branch_privilege(struct perf_branch_entry *entry, u64 b= ranch_sample_type) +{ + /* We can only have a half record if permissions have not been expanded */ + if (!entry->from || !entry->to) + return true; + + bool from_user =3D access_ok((void __user *)(unsigned long)entry->from, 4= ); + bool to_user =3D access_ok((void __user *)(unsigned long)entry->to, 4); + bool exclude_kernel =3D !((branch_sample_type & PERF_SAMPLE_BRANCH_KERNEL= ) || + (is_kernel_in_hyp_mode() && (branch_sample_type & PERF_SAMPLE_BRANCH_HV)= )); + + /* + * If record is within a single exception level, just need to either + * drop or keep the entire record. + */ + if (from_user =3D=3D to_user) + return ((entry->priv =3D=3D PERF_BR_PRIV_KERNEL) && !exclude_kernel) || + ((entry->priv =3D=3D PERF_BR_PRIV_USER) && + (branch_sample_type & PERF_SAMPLE_BRANCH_USER)); + + /* + * Record is across exception levels, mask addresses for the exception + * level we're not capturing. + */ + if (!(branch_sample_type & PERF_SAMPLE_BRANCH_USER)) { + if (from_user) + entry->from =3D 0; + if (to_user) + entry->to =3D 0; + } + + if (exclude_kernel) { + if (!from_user) + entry->from =3D 0; + if (!to_user) + entry->to =3D 0; + } + return true; +} + +static bool filter_branch_type(struct perf_branch_entry *entry, + const unsigned long *event_type_mask) +{ + if (entry->type =3D=3D PERF_BR_EXTEND_ABI) + return test_bit(PERF_BR_MAX + entry->new_type, event_type_mask); + else + return test_bit(entry->type, event_type_mask); +} + +static bool filter_branch_record(struct perf_branch_entry *entry, + u64 branch_sample, + const unsigned long *event_type_mask) +{ + return filter_branch_type(entry, event_type_mask) && + filter_branch_privilege(entry, branch_sample); +} + +void brbe_read_filtered_entries(struct perf_branch_stack *branch_stack, + const struct perf_event *event) +{ + struct arm_pmu *cpu_pmu =3D to_arm_pmu(event->pmu); + int nr_hw =3D brbe_num_branch_records(cpu_pmu); + int nr_banks =3D DIV_ROUND_UP(nr_hw, BRBE_BANK_MAX_ENTRIES); + int nr_filtered =3D 0; + u64 branch_sample_type =3D event->attr.branch_sample_type; + DECLARE_BITMAP(event_type_mask, PERF_BR_ARM64_MAX); + + prepare_event_branch_type_mask(branch_sample_type, event_type_mask); + + for (int bank =3D 0; bank < nr_banks; bank++) { + int nr_remaining =3D nr_hw - (bank * BRBE_BANK_MAX_ENTRIES); + int nr_this_bank =3D min(nr_remaining, BRBE_BANK_MAX_ENTRIES); + + select_brbe_bank(bank); + + for (int i =3D 0; i < nr_this_bank; i++) { + struct perf_branch_entry *pbe =3D &branch_stack->entries[nr_filtered]; + + if (!perf_entry_from_brbe_regset(i, pbe, event)) + goto done; + + if (!filter_branch_record(pbe, branch_sample_type, event_type_mask)) + continue; + + nr_filtered++; + } + } + +done: + brbe_invalidate(); + branch_stack->nr =3D nr_filtered; +} diff --git a/drivers/perf/arm_brbe.h b/drivers/perf/arm_brbe.h new file mode 100644 index 000000000000..b7c7d8796c86 --- /dev/null +++ b/drivers/perf/arm_brbe.h @@ -0,0 +1,47 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Branch Record Buffer Extension Helpers. + * + * Copyright (C) 2022-2025 ARM Limited + * + * Author: Anshuman Khandual + */ + +struct arm_pmu; +struct perf_branch_stack; +struct perf_event; + +#ifdef CONFIG_ARM64_BRBE +void brbe_probe(struct arm_pmu *arm_pmu); +unsigned int brbe_num_branch_records(const struct arm_pmu *armpmu); +void brbe_invalidate(void); + +void brbe_enable(const struct arm_pmu *arm_pmu); +void brbe_disable(void); + +bool brbe_branch_attr_valid(struct perf_event *event); +void brbe_read_filtered_entries(struct perf_branch_stack *branch_stack, + const struct perf_event *event); +#else +static inline void brbe_probe(struct arm_pmu *arm_pmu) { } +static inline unsigned int brbe_num_branch_records(const struct arm_pmu *a= rmpmu) +{ + return 0; +} + +static inline void brbe_invalidate(void) { } + +static inline void brbe_enable(const struct arm_pmu *arm_pmu) { }; +static inline void brbe_disable(void) { }; + +static inline bool brbe_branch_attr_valid(struct perf_event *event) +{ + WARN_ON_ONCE(!has_branch_stack(event)); + return false; +} + +static void brbe_read_filtered_entries(struct perf_branch_stack *branch_st= ack, + const struct perf_event *event) +{ +} +#endif diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 2f33e69a8caf..5c310e803dd7 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -99,7 +99,7 @@ static const struct pmu_irq_ops percpu_pmunmi_ops =3D { .free_pmuirq =3D armpmu_free_percpu_pmunmi }; =20 -static DEFINE_PER_CPU(struct arm_pmu *, cpu_armpmu); +DEFINE_PER_CPU(struct arm_pmu *, cpu_armpmu); static DEFINE_PER_CPU(int, cpu_irq); static DEFINE_PER_CPU(const struct pmu_irq_ops *, cpu_irq_ops); =20 @@ -318,6 +318,12 @@ armpmu_del(struct perf_event *event, int flags) int idx =3D hwc->idx; =20 armpmu_stop(event, PERF_EF_UPDATE); + + if (has_branch_stack(event)) { + hw_events->branch_users--; + perf_sched_cb_dec(event->pmu); + } + hw_events->events[idx] =3D NULL; armpmu->clear_event_idx(hw_events, event); perf_event_update_userpage(event); @@ -345,6 +351,11 @@ armpmu_add(struct perf_event *event, int flags) /* The newly-allocated counter should be empty */ WARN_ON_ONCE(hw_events->events[idx]); =20 + if (has_branch_stack(event)) { + hw_events->branch_users++; + perf_sched_cb_inc(event->pmu); + } + event->hw.idx =3D idx; hw_events->events[idx] =3D event; =20 @@ -509,8 +520,7 @@ static int armpmu_event_init(struct perf_event *event) !cpumask_test_cpu(event->cpu, &armpmu->supported_cpus)) return -ENOENT; =20 - /* does not support taken branch sampling */ - if (has_branch_stack(event)) + if (has_branch_stack(event) && !armpmu->reg_brbidr) return -EOPNOTSUPP; =20 return __hw_perf_event_init(event); diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c index 3db9f4ed17e8..256c5ee8709c 100644 --- a/drivers/perf/arm_pmuv3.c +++ b/drivers/perf/arm_pmuv3.c @@ -25,6 +25,8 @@ #include #include =20 +#include "arm_brbe.h" + /* ARMv8 Cortex-A53 specific event types. */ #define ARMV8_A53_PERFCTR_PREF_LINEFILL 0xC2 =20 @@ -438,7 +440,19 @@ static ssize_t threshold_max_show(struct device *dev, =20 static DEVICE_ATTR_RO(threshold_max); =20 +static ssize_t branches_show(struct device *dev, + struct device_attribute *attr, char *page) +{ + struct pmu *pmu =3D dev_get_drvdata(dev); + struct arm_pmu *cpu_pmu =3D container_of(pmu, struct arm_pmu, pmu); + + return sysfs_emit(page, "%d\n", brbe_num_branch_records(cpu_pmu)); +} + +static DEVICE_ATTR_RO(branches); + static struct attribute *armv8_pmuv3_caps_attrs[] =3D { + &dev_attr_branches.attr, &dev_attr_slots.attr, &dev_attr_bus_slots.attr, &dev_attr_bus_width.attr, @@ -446,9 +460,22 @@ static struct attribute *armv8_pmuv3_caps_attrs[] =3D { NULL, }; =20 +static umode_t caps_is_visible(struct kobject *kobj, struct attribute *att= r, int i) +{ + struct device *dev =3D kobj_to_dev(kobj); + struct pmu *pmu =3D dev_get_drvdata(dev); + struct arm_pmu *cpu_pmu =3D container_of(pmu, struct arm_pmu, pmu); + + if (i =3D=3D 0) + return brbe_num_branch_records(cpu_pmu) ? attr->mode : 0; + + return attr->mode; +} + static const struct attribute_group armv8_pmuv3_caps_attr_group =3D { .name =3D "caps", .attrs =3D armv8_pmuv3_caps_attrs, + .is_visible =3D caps_is_visible, }; =20 /* @@ -806,9 +833,10 @@ static void armv8pmu_disable_event(struct perf_event *= event) armv8pmu_disable_event_irq(event); } =20 -static void armv8pmu_start(struct arm_pmu *cpu_pmu) +static void armv8pmu_restart(struct arm_pmu *cpu_pmu) { struct perf_event_context *ctx; + struct pmu_hw_events *hw_events =3D this_cpu_ptr(cpu_pmu->hw_events); int nr_user =3D 0; =20 ctx =3D perf_cpu_task_ctx(); @@ -822,16 +850,44 @@ static void armv8pmu_start(struct arm_pmu *cpu_pmu) =20 kvm_vcpu_pmu_resync_el0(); =20 + if (hw_events->branch_users) + brbe_enable(cpu_pmu); + /* Enable all counters */ armv8pmu_pmcr_write(armv8pmu_pmcr_read() | ARMV8_PMU_PMCR_E); } =20 +static void armv8pmu_start(struct arm_pmu *cpu_pmu) +{ + struct pmu_hw_events *hw_events =3D this_cpu_ptr(cpu_pmu->hw_events); + + if (hw_events->branch_users) + brbe_invalidate(); + + armv8pmu_restart(cpu_pmu); +} + static void armv8pmu_stop(struct arm_pmu *cpu_pmu) { + struct pmu_hw_events *hw_events =3D this_cpu_ptr(cpu_pmu->hw_events); + + if (hw_events->branch_users) + brbe_disable(); + /* Disable all counters */ armv8pmu_pmcr_write(armv8pmu_pmcr_read() & ~ARMV8_PMU_PMCR_E); } =20 +static void read_branch_records(struct pmu_hw_events *cpuc, + struct perf_event *event, + struct perf_sample_data *data) +{ + struct perf_branch_stack *branch_stack =3D cpuc->branch_stack; + + brbe_read_filtered_entries(branch_stack, event); + perf_sample_save_brstack(data, event, branch_stack, NULL); +} + static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu) { u64 pmovsr; @@ -882,6 +938,13 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu = *cpu_pmu) if (!armpmu_event_set_period(event)) continue; =20 + /* + * PMU IRQ should remain asserted until all branch records + * are captured and processed into struct perf_sample_data. + */ + if (has_branch_stack(event)) + read_branch_records(cpuc, event, &data); + /* * Perf event overflow will queue the processing of the event as * an irq_work which will be taken care of in the handling of @@ -889,7 +952,7 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *= cpu_pmu) */ perf_event_overflow(event, &data, regs); } - armv8pmu_start(cpu_pmu); + armv8pmu_restart(cpu_pmu); =20 return IRQ_HANDLED; } @@ -938,7 +1001,7 @@ static int armv8pmu_get_event_idx(struct pmu_hw_events= *cpuc, =20 /* Always prefer to place a cycle counter into the cycle counter. */ if ((evtype =3D=3D ARMV8_PMUV3_PERFCTR_CPU_CYCLES) && - !armv8pmu_event_get_threshold(&event->attr)) { + !armv8pmu_event_get_threshold(&event->attr) && !has_branch_stack(even= t)) { if (!test_and_set_bit(ARMV8_PMU_CYCLE_IDX, cpuc->used_mask)) return ARMV8_PMU_CYCLE_IDX; else if (armv8pmu_event_is_64bit(event) && @@ -987,6 +1050,19 @@ static int armv8pmu_user_event_idx(struct perf_event = *event) return event->hw.idx + 1; } =20 +static void armv8pmu_sched_task(struct perf_event_pmu_context *pmu_ctx, + struct task_struct *task, bool sched_in) +{ + struct arm_pmu *armpmu =3D *this_cpu_ptr(&cpu_armpmu); + struct pmu_hw_events *hw_events =3D this_cpu_ptr(armpmu->hw_events); + + if (!hw_events->branch_users) + return; + + if (sched_in) + brbe_invalidate(); +} + /* * Add an event filter to a given event. */ @@ -1004,6 +1080,13 @@ static int armv8pmu_set_event_filter(struct hw_perf_= event *event, return -EOPNOTSUPP; } =20 + if (has_branch_stack(perf_event)) { + if (!brbe_num_branch_records(cpu_pmu) || !brbe_branch_attr_valid(perf_ev= ent)) + return -EOPNOTSUPP; + + perf_event->attach_state |=3D PERF_ATTACH_SCHED_CB; + } + /* * If we're running in hyp mode, then we *are* the hypervisor. * Therefore we ignore exclude_hv in this configuration, since @@ -1070,6 +1153,11 @@ static void armv8pmu_reset(void *info) /* Clear the counters we flip at guest entry/exit */ kvm_clr_pmu_events(mask); =20 + if (brbe_num_branch_records(cpu_pmu)) { + brbe_disable(); + brbe_invalidate(); + } + /* * Initialize & Reset PMNC. Request overflow interrupt for * 64 bit cycle counter but cheat in armv8pmu_write_counter(). @@ -1238,6 +1326,25 @@ static void __armv8pmu_probe_pmu(void *info) cpu_pmu->reg_pmmir =3D read_pmmir(); else cpu_pmu->reg_pmmir =3D 0; + + brbe_probe(cpu_pmu); +} + +static int branch_records_alloc(struct arm_pmu *armpmu) +{ + size_t size =3D struct_size_t(struct perf_branch_stack, entries, + brbe_num_branch_records(armpmu)); + int cpu; + + for_each_cpu(cpu, &armpmu->supported_cpus) { + struct pmu_hw_events *events_cpu; + + events_cpu =3D per_cpu_ptr(armpmu->hw_events, cpu); + events_cpu->branch_stack =3D kmalloc(size, GFP_KERNEL); + if (!events_cpu->branch_stack) + return -ENOMEM; + } + return 0; } =20 static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pmu) @@ -1254,7 +1361,15 @@ static int armv8pmu_probe_pmu(struct arm_pmu *cpu_pm= u) if (ret) return ret; =20 - return probe.present ? 0 : -ENODEV; + if (!probe.present) + return -ENODEV; + + if (brbe_num_branch_records(cpu_pmu)) { + ret =3D branch_records_alloc(cpu_pmu); + if (ret) + return ret; + } + return 0; } =20 static void armv8pmu_disable_user_access_ipi(void *unused) @@ -1313,6 +1428,8 @@ static int armv8_pmu_init(struct arm_pmu *cpu_pmu, ch= ar *name, cpu_pmu->set_event_filter =3D armv8pmu_set_event_filter; =20 cpu_pmu->pmu.event_idx =3D armv8pmu_user_event_idx; + if (brbe_num_branch_records(cpu_pmu)) + cpu_pmu->pmu.sched_task =3D armv8pmu_sched_task; =20 cpu_pmu->name =3D name; cpu_pmu->map_event =3D map_event; diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 6dc5e0cd76ca..93c9a26492fc 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h @@ -70,6 +70,11 @@ struct pmu_hw_events { struct arm_pmu *percpu_pmu; =20 int irq; + + struct perf_branch_stack *branch_stack; + + /* Active events requesting branch records */ + unsigned int branch_users; }; =20 enum armpmu_attr_groups { @@ -115,6 +120,7 @@ struct arm_pmu { /* PMUv3 only */ int pmuver; u64 reg_pmmir; + u64 reg_brbidr; #define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40 DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS); #define ARMV8_PMUV3_EXT_COMMON_EVENT_BASE 0x4000 @@ -126,6 +132,8 @@ struct arm_pmu { =20 #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu)) =20 +DECLARE_PER_CPU(struct arm_pmu *, cpu_armpmu); + u64 armpmu_event_update(struct perf_event *event); =20 int armpmu_event_set_period(struct perf_event *event); --=20 2.47.2