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Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1tgNTA-00000007nBw-0W3v; Fri, 07 Feb 2025 12:28:28 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 0) id 451F930615B; Fri, 7 Feb 2025 13:28:25 +0100 (CET) Message-ID: <20250207122547.022463564@infradead.org> User-Agent: quilt/0.66 Date: Fri, 07 Feb 2025 13:15:39 +0100 From: Peter Zijlstra To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, alyssa.milburn@intel.com, scott.d.constable@intel.com, joao@overdrivepizza.com, andrew.cooper3@citrix.com, jpoimboe@kernel.org, jose.marchesi@oracle.com, hjl.tools@gmail.com, ndesaulniers@google.com, samitolvanen@google.com, nathan@kernel.org, ojeda@kernel.org, kees@kernel.org, alexei.starovoitov@gmail.com, mhiramat@kernel.org Subject: [PATCH 10/11] x86: BHI stubs References: <20250207121529.222723073@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/cfi.h | 3 + arch/x86/lib/Makefile | 3 - arch/x86/lib/bhi.S | 130 ++++++++++++++++++++++++++++++++++++++++= +++++ 3 files changed, 135 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/cfi.h +++ b/arch/x86/include/asm/cfi.h @@ -101,6 +101,9 @@ enum cfi_mode { =20 extern enum cfi_mode cfi_mode; =20 +typedef u8 bhi_thunk[32]; +extern bhi_thunk __bhi_args[]; + struct pt_regs; =20 #ifdef CONFIG_CFI_CLANG --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -66,5 +66,6 @@ endif lib-y +=3D clear_page_64.o copy_page_64.o lib-y +=3D memmove_64.o memset_64.o lib-y +=3D copy_user_64.o copy_user_uncached_64.o - lib-y +=3D cmpxchg16b_emu.o + lib-y +=3D cmpxchg16b_emu.o + lib-y +=3D bhi.o endif --- /dev/null +++ b/arch/x86/lib/bhi.S @@ -0,0 +1,130 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include +#include +#include + +/* + * Notably, the FineIBT preamble calling these will have ZF set and r10 ze= ro. + * + * The very last element is in fact larger than 32 bytes, but since its the + * last element, this does not matter, + */ + +.pushsection .noinstr.text, "ax" + + .align 32 +SYM_CODE_START(__bhi_args) + + .align 32 +SYM_INNER_LABEL(__bhi_args_0, SYM_L_LOCAL) + ANNOTATE_NOENDBR + UNWIND_HINT_FUNC + jz 1f + ud2 +1: ANNOTATE_UNRET_SAFE + ret + int3 + + .align 32 +SYM_INNER_LABEL(__bhi_args_1, SYM_L_LOCAL) + ANNOTATE_NOENDBR + UNWIND_HINT_FUNC + jz 1f + ud2 +1: cmovne %r10, %rdi + ANNOTATE_UNRET_SAFE + ret + int3 + + .align 32 +SYM_INNER_LABEL(__bhi_args_2, SYM_L_LOCAL) + ANNOTATE_NOENDBR + UNWIND_HINT_FUNC + jz 1f + ud2 +1: cmovne %r10, %rdi + cmovne %r10, %rsi + ANNOTATE_UNRET_SAFE + ret + int3 + + .align 32 +SYM_INNER_LABEL(__bhi_args_3, SYM_L_LOCAL) + ANNOTATE_NOENDBR + UNWIND_HINT_FUNC + jz 1f + ud2 +1: cmovne %r10, %rdi + cmovne %r10, %rsi + cmovne %r10, %rdx + ANNOTATE_UNRET_SAFE + ret + int3 + + .align 32 +SYM_INNER_LABEL(__bhi_args_4, SYM_L_LOCAL) + ANNOTATE_NOENDBR + UNWIND_HINT_FUNC + jz 1f + ud2 +1: cmovne %r10, %rdi + cmovne %r10, %rsi + cmovne %r10, %rdx + cmovne %r10, %rcx + ANNOTATE_UNRET_SAFE + ret + int3 + + .align 32 +SYM_INNER_LABEL(__bhi_args_5, SYM_L_LOCAL) + ANNOTATE_NOENDBR + UNWIND_HINT_FUNC + jz 1f + ud2 +1: cmovne %r10, %rdi + cmovne %r10, %rsi + cmovne %r10, %rdx + cmovne %r10, %rcx + cmovne %r10, %r8 + ANNOTATE_UNRET_SAFE + ret + int3 + + .align 32 +SYM_INNER_LABEL(__bhi_args_6, SYM_L_LOCAL) + ANNOTATE_NOENDBR + UNWIND_HINT_FUNC + jz 1f + ud2 +1: cmovne %r10, %rdi + cmovne %r10, %rsi + cmovne %r10, %rdx + cmovne %r10, %rcx + cmovne %r10, %r8 + cmovne %r10, %r9 + ANNOTATE_UNRET_SAFE + ret + int3 + + .align 32 +SYM_INNER_LABEL(__bhi_args_7, SYM_L_LOCAL) + ANNOTATE_NOENDBR + UNWIND_HINT_FUNC + jz 1f + ud2 +1: cmovne %r10, %rdi + cmovne %r10, %rsi + cmovne %r10, %rdx + cmovne %r10, %rcx + cmovne %r10, %r8 + cmovne %r10, %r9 + cmovne %r10, %rsp + ANNOTATE_UNRET_SAFE + ret + int3 + + .align 32 +SYM_CODE_END(__bhi_args) + +.popsection