From nobody Mon Feb 9 09:33:57 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4621DC433FE for ; Wed, 8 Dec 2021 11:09:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232194AbhLHLMu (ORCPT ); Wed, 8 Dec 2021 06:12:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232186AbhLHLMp (ORCPT ); Wed, 8 Dec 2021 06:12:45 -0500 Received: from mail-pf1-x431.google.com (mail-pf1-x431.google.com [IPv6:2607:f8b0:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C7444C0617A2 for ; Wed, 8 Dec 2021 03:09:13 -0800 (PST) Received: by mail-pf1-x431.google.com with SMTP id r130so2189621pfc.1 for ; Wed, 08 Dec 2021 03:09:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=4OSMT+TQw2RUHxNW8atVbB9ZMIOeuqyP7ER0LvB+dp8=; b=p9amC8ioLdWqBeAJ4CjkDRZ1SNu2S6IWtNPrQgya84oZpDa9clfN6COADE//h/Kczz kQ+fmFgTFQoLYUpO3SxmFlpuPVleUj1yU37SK/cIZ0B+1mzWQP1bXTdmwTYJqBqgidym s3Qnw3+ezN8X07/YBXDOFJMTCWVdRYuXNtqsZb9MYstubPgHdxVejo3WZ/+NjwbHXH2U 8tjQd71AvCYyeR33oziwHtkT65rxg9yzijXFTi0+rKnlPvNRCFSokL+RsxQRBvOrVIrU w/GkvVUeb2F4qxGFfEyZK3vg73sGRS4uXqjhQZh5lj5xic5xJsV2YQ+0E79kCZaZeBK8 qj8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=4OSMT+TQw2RUHxNW8atVbB9ZMIOeuqyP7ER0LvB+dp8=; b=Kr9AAgHDfS+yIIHkuqBxEjj0/87XYmZ/4LZASYCvzleyPuMwwSTehGi0RC5G50BnXq E4iudaH4tYDr7skoJF1Ohf5cV/zTYGegSivHsSFUWruAM/ElLBYpSbgp+968+AYbnuDf XULyMbDCOw9jph2yR1rZRH0GF64s1HkHw4IYFM+KRa7udkpm8HKTCR451fDWOnFabJQY UhiCmLWHmzgslkBtZM2aN8So1tXDx1NYbPiSn9zgd7pc24BcIl++q3TFZ013CMuQiQL4 4mEMCEo3VPE0SlrBysWz2ToYjMErEyZ+jD+dEZYL5m5mHqK6Zk1G2Sdp1BzqEcvMLlw3 pJ+Q== X-Gm-Message-State: AOAM530VrGJNv37M9YZ0t3i8BIO7oICwAGUxqZpUwW9waLyuIsQrpgEG S4GMLL3x2P2pUBs0OvNNn6y+TMeNSe4= X-Google-Smtp-Source: ABdhPJyXGPiRK3kSpyhR6KL61u0teYkSKfkL2XAKTjzosU2gZ8Lz/nBoNiGVciQ2kf7/fPZtckPd8w== X-Received: by 2002:a63:6a03:: with SMTP id f3mr28895124pgc.618.1638961752671; Wed, 08 Dec 2021 03:09:12 -0800 (PST) Received: from localhost ([47.251.3.230]) by smtp.gmail.com with ESMTPSA id q10sm3232415pfk.180.2021.12.08.03.09.11 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 08 Dec 2021 03:09:12 -0800 (PST) From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, xen-devel@lists.xenproject.org, Lai Jiangshan , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Juergen Gross , "Peter Zijlstra (Intel)" , Joerg Roedel , "Chang S. Bae" , Jan Kiszka Subject: [PATCH 08/11] x86/entry: Use idtentry macro for entry_INT80_compat Date: Wed, 8 Dec 2021 19:08:30 +0800 Message-Id: <20211208110833.65366-9-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20211208110833.65366-1-jiangshanlai@gmail.com> References: <20211208110833.65366-1-jiangshanlai@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Lai Jiangshan entry_INT80_compat is identical to idtentry macro except a special handling for %rax in the prolog. Add the prolog to idtentry and use idtentry for entry_INT80_compat. Signed-off-by: Lai Jiangshan --- arch/x86/entry/entry_64.S | 18 ++++++ arch/x86/entry/entry_64_compat.S | 102 ------------------------------- arch/x86/include/asm/idtentry.h | 47 ++++++++++++++ arch/x86/include/asm/proto.h | 4 -- 4 files changed, 65 insertions(+), 106 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 6100007fd03f..1fd5efaa99b3 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -371,6 +371,24 @@ SYM_CODE_START(\asmsym) pushq $-1 /* ORIG_RAX: no syscall to restart */ .endif =20 + .if \vector =3D=3D IA32_SYSCALL_VECTOR + /* + * User tracing code (ptrace or signal handlers) might assume + * that the saved RAX contains a 32-bit number when we're + * invoking a 32-bit syscall. Just in case the high bits are + * nonzero, zero-extend the syscall number. (This could almost + * certainly be deleted with no ill effects.) + */ + movl %eax, %eax + + /* + * do_int80_syscall_32() expects regs->orig_ax to be user ax, + * and regs->ax to be $-ENOSYS. + */ + movq %rax, (%rsp) + movq $-ENOSYS, %rax + .endif + .if \vector =3D=3D X86_TRAP_BP /* * If coming from kernel space, create a 6-word gap to allow the diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_com= pat.S index 0051cf5c792d..a4fcea0cab14 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -311,105 +311,3 @@ sysret32_from_system_call: swapgs sysretl SYM_CODE_END(entry_SYSCALL_compat) - -/* - * 32-bit legacy system call entry. - * - * 32-bit x86 Linux system calls traditionally used the INT $0x80 - * instruction. INT $0x80 lands here. - * - * This entry point can be used by 32-bit and 64-bit programs to perform - * 32-bit system calls. Instances of INT $0x80 can be found inline in - * various programs and libraries. It is also used by the vDSO's - * __kernel_vsyscall fallback for hardware that doesn't support a faster - * entry method. Restarted 32-bit system calls also fall back to INT - * $0x80 regardless of what instruction was originally used to do the - * system call. - * - * This is considered a slow path. It is not used by most libc - * implementations on modern hardware except during process startup. - * - * Arguments: - * eax system call number - * ebx arg1 - * ecx arg2 - * edx arg3 - * esi arg4 - * edi arg5 - * ebp arg6 - */ -SYM_CODE_START(entry_INT80_compat) - UNWIND_HINT_EMPTY - /* - * Interrupts are off on entry. - */ - ASM_CLAC /* Do this early to minimize exposure */ - SWAPGS - - /* - * User tracing code (ptrace or signal handlers) might assume that - * the saved RAX contains a 32-bit number when we're invoking a 32-bit - * syscall. Just in case the high bits are nonzero, zero-extend - * the syscall number. (This could almost certainly be deleted - * with no ill effects.) - */ - movl %eax, %eax - - /* switch to thread stack expects orig_ax and rdi to be pushed */ - pushq %rax /* pt_regs->orig_ax */ - pushq %rdi /* pt_regs->di */ - - /* Need to switch before accessing the thread stack. */ - SWITCH_TO_KERNEL_CR3 scratch_reg=3D%rdi - - /* In the Xen PV case we already run on the thread stack. */ - ALTERNATIVE "", "jmp .Lint80_keep_stack", X86_FEATURE_XENPV - - movq %rsp, %rdi - movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp - - pushq 6*8(%rdi) /* regs->ss */ - pushq 5*8(%rdi) /* regs->rsp */ - pushq 4*8(%rdi) /* regs->eflags */ - pushq 3*8(%rdi) /* regs->cs */ - pushq 2*8(%rdi) /* regs->ip */ - pushq 1*8(%rdi) /* regs->orig_ax */ - pushq (%rdi) /* pt_regs->di */ -.Lint80_keep_stack: - - pushq %rsi /* pt_regs->si */ - xorl %esi, %esi /* nospec si */ - pushq %rdx /* pt_regs->dx */ - xorl %edx, %edx /* nospec dx */ - pushq %rcx /* pt_regs->cx */ - xorl %ecx, %ecx /* nospec cx */ - pushq $-ENOSYS /* pt_regs->ax */ - pushq %r8 /* pt_regs->r8 */ - xorl %r8d, %r8d /* nospec r8 */ - pushq %r9 /* pt_regs->r9 */ - xorl %r9d, %r9d /* nospec r9 */ - pushq %r10 /* pt_regs->r10*/ - xorl %r10d, %r10d /* nospec r10 */ - pushq %r11 /* pt_regs->r11 */ - xorl %r11d, %r11d /* nospec r11 */ - pushq %rbx /* pt_regs->rbx */ - xorl %ebx, %ebx /* nospec rbx */ - pushq %rbp /* pt_regs->rbp */ - xorl %ebp, %ebp /* nospec rbp */ - pushq %r12 /* pt_regs->r12 */ - xorl %r12d, %r12d /* nospec r12 */ - pushq %r13 /* pt_regs->r13 */ - xorl %r13d, %r13d /* nospec r13 */ - pushq %r14 /* pt_regs->r14 */ - xorl %r14d, %r14d /* nospec r14 */ - pushq %r15 /* pt_regs->r15 */ - xorl %r15d, %r15d /* nospec r15 */ - - UNWIND_HINT_REGS - - cld - - movq %rsp, %rdi - call do_int80_syscall_32 - jmp swapgs_restore_regs_and_return_to_usermode -SYM_CODE_END(entry_INT80_compat) diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentr= y.h index 1345088e9902..38cb2e0dc2c7 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -204,6 +204,20 @@ __visible noinstr void func(struct pt_regs *regs, \ \ static noinline void __##func(struct pt_regs *regs, u32 vector) =20 +/** + * DECLARE_IDTENTRY_IA32_EMULATION - Declare functions for int80 + * @vector: Vector number (ignored for C) + * @asm_func: Function name of the entry point + * @cfunc: The C handler called from the ASM entry point (ignored for C) + * + * Declares two functions: + * - The ASM entry point: asm_func + * - The XEN PV trap entry point: xen_##asm_func (maybe unused) + */ +#define DECLARE_IDTENTRY_IA32_EMULATION(vector, asm_func, cfunc) \ + asmlinkage void asm_func(void); \ + asmlinkage void xen_##asm_func(void) + /** * DECLARE_IDTENTRY_SYSVEC - Declare functions for system vector entry poi= nts * @vector: Vector number (ignored for C) @@ -430,6 +444,35 @@ __visible noinstr void func(struct pt_regs *regs, \ #define DECLARE_IDTENTRY_ERRORCODE(vector, func) \ idtentry vector asm_##func func has_error_code=3D1 =20 +/* + * 32-bit legacy system call entry. + * + * 32-bit x86 Linux system calls traditionally used the INT $0x80 + * instruction. INT $0x80 lands here. + * + * This entry point can be used by 32-bit and 64-bit programs to perform + * 32-bit system calls. Instances of INT $0x80 can be found inline in + * various programs and libraries. It is also used by the vDSO's + * __kernel_vsyscall fallback for hardware that doesn't support a faster + * entry method. Restarted 32-bit system calls also fall back to INT + * $0x80 regardless of what instruction was originally used to do the + * system call. + * + * This is considered a slow path. It is not used by most libc + * implementations on modern hardware except during process startup. + * + * Arguments: + * eax system call number + * ebx arg1 + * ecx arg2 + * edx arg3 + * esi arg4 + * edi arg5 + * ebp arg6 + */ +#define DECLARE_IDTENTRY_IA32_EMULATION(vector, asm_func, cfunc) \ + idtentry vector asm_func cfunc has_error_code=3D0 + /* Special case for 32bit IRET 'trap'. Do not emit ASM code */ #define DECLARE_IDTENTRY_SW(vector, func) =20 @@ -631,6 +674,10 @@ DECLARE_IDTENTRY_IRQ(X86_TRAP_OTHER, common_interrupt); DECLARE_IDTENTRY_IRQ(X86_TRAP_OTHER, spurious_interrupt); #endif =20 +#ifdef CONFIG_IA32_EMULATION +DECLARE_IDTENTRY_IA32_EMULATION(IA32_SYSCALL_VECTOR, entry_INT80_compat, d= o_int80_syscall_32); +#endif + /* System vector entry points */ #ifdef CONFIG_X86_LOCAL_APIC DECLARE_IDTENTRY_SYSVEC(ERROR_APIC_VECTOR, sysvec_error_interrupt); diff --git a/arch/x86/include/asm/proto.h b/arch/x86/include/asm/proto.h index feed36d44d04..c4d331fe65ff 100644 --- a/arch/x86/include/asm/proto.h +++ b/arch/x86/include/asm/proto.h @@ -28,10 +28,6 @@ void entry_SYSENTER_compat(void); void __end_entry_SYSENTER_compat(void); void entry_SYSCALL_compat(void); void entry_SYSCALL_compat_safe_stack(void); -void entry_INT80_compat(void); -#ifdef CONFIG_XEN_PV -void xen_entry_INT80_compat(void); -#endif #endif =20 void x86_configure_nx(void); --=20 2.19.1.6.gb485710b