Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752633AbbFGIcy (ORCPT ); Sun, 7 Jun 2015 04:32:54 -0400 Received: from terminus.zytor.com ([198.137.202.10]:53027 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932707AbbFGIcl (ORCPT ); Sun, 7 Jun 2015 04:32:41 -0400 Date: Sun, 7 Jun 2015 01:31:37 -0700 From: tip-bot for Denys Vlasenko Message-ID: Cc: tglx@linutronix.de, brgerst@gmail.com, linux-kernel@vger.kernel.org, fweisbec@gmail.com, ast@plumgrid.com, keescook@chromium.org, akpm@linux-foundation.org, rostedt@goodmis.org, hpa@zytor.com, luto@amacapital.net, peterz@infradead.org, torvalds@linux-foundation.org, oleg@redhat.com, wad@chromium.org, dvlasenk@redhat.com, bp@alien8.de, mingo@kernel.org Reply-To: hpa@zytor.com, luto@amacapital.net, rostedt@goodmis.org, oleg@redhat.com, torvalds@linux-foundation.org, wad@chromium.org, peterz@infradead.org, bp@alien8.de, dvlasenk@redhat.com, mingo@kernel.org, brgerst@gmail.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, fweisbec@gmail.com, ast@plumgrid.com, keescook@chromium.org, akpm@linux-foundation.org In-Reply-To: <1433271842-9139-2-git-send-email-dvlasenk@redhat.com> References: <1433271842-9139-2-git-send-email-dvlasenk@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/asm/entry/32: Open-code LOAD_ARGS32 Git-Commit-ID: 73cbf687914fd5f4ef88a42a55784fd28b7450cf X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4352 Lines: 128 Commit-ID: 73cbf687914fd5f4ef88a42a55784fd28b7450cf Gitweb: http://git.kernel.org/tip/73cbf687914fd5f4ef88a42a55784fd28b7450cf Author: Denys Vlasenko AuthorDate: Tue, 2 Jun 2015 21:04:02 +0200 Committer: Ingo Molnar CommitDate: Fri, 5 Jun 2015 13:22:22 +0200 x86/asm/entry/32: Open-code LOAD_ARGS32 This macro is small, has only three callsites, and one of them is slightly different using a conditional parameter. A few saved lines aren't worth the resulting obfuscation. Generated machine code is identical. Signed-off-by: Denys Vlasenko Cc: Alexei Starovoitov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Will Drewry Link: http://lkml.kernel.org/r/1433271842-9139-2-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/entry/ia32entry.S | 54 +++++++++++++++++++++++++--------------------- 1 file changed, 29 insertions(+), 25 deletions(-) diff --git a/arch/x86/entry/ia32entry.S b/arch/x86/entry/ia32entry.S index 8a45d2c..56f819e 100644 --- a/arch/x86/entry/ia32entry.S +++ b/arch/x86/entry/ia32entry.S @@ -29,28 +29,6 @@ .section .entry.text, "ax" - /* - * Reload arg registers from stack in case ptrace changed them. - * We don't reload %eax because syscall_trace_enter() returned - * the %rax value we should see. Instead, we just truncate that - * value to 32 bits again as we did on entry from user mode. - * If it's a new value set by user_regset during entry tracing, - * this matches the normal truncation of the user-mode value. - * If it's -1 to make us punt the syscall, then (u32)-1 is still - * an appropriately invalid value. - */ - .macro LOAD_ARGS32 _r9=0 - .if \_r9 - movl R9(%rsp),%r9d - .endif - movl RCX(%rsp),%ecx - movl RDX(%rsp),%edx - movl RSI(%rsp),%esi - movl RDI(%rsp),%edi - movl %eax,%eax /* zero extension */ - .endm - - #ifdef CONFIG_PARAVIRT ENTRY(native_usergs_sysret32) swapgs @@ -269,7 +247,14 @@ sysenter_tracesys: movq %rax, R8(%rsp) movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS32 /* reload args from stack in case ptrace changed it */ + + /* Reload arg registers from stack. (see sysenter_tracesys) */ + movl RCX(%rsp), %ecx + movl RDX(%rsp), %edx + movl RSI(%rsp), %esi + movl RDI(%rsp), %edi + movl %eax, %eax /* zero extension */ + RESTORE_EXTRA_REGS jmp sysenter_do_call ENDPROC(ia32_sysenter_target) @@ -413,7 +398,15 @@ cstar_tracesys: movq %rax, R8(%rsp) movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS32 1 /* reload args from stack in case ptrace changed it */ + movl R9(%rsp),%r9d + + /* Reload arg registers from stack. (see sysenter_tracesys) */ + movl RCX(%rsp), %ecx + movl RDX(%rsp), %edx + movl RSI(%rsp), %esi + movl RDI(%rsp), %edi + movl %eax, %eax /* zero extension */ + RESTORE_EXTRA_REGS xchgl %ebp,%r9d jmp cstar_do_call @@ -502,7 +495,18 @@ ia32_tracesys: SAVE_EXTRA_REGS movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS32 /* reload args from stack in case ptrace changed it */ + /* + * Reload arg registers from stack in case ptrace changed them. + * Don't reload %eax because syscall_trace_enter() returned + * the %rax value we should see. But do truncate it to 32 bits. + * If it's -1 to make us punt the syscall, then (u32)-1 is still + * an appropriately invalid value. + */ + movl RCX(%rsp), %ecx + movl RDX(%rsp), %edx + movl RSI(%rsp), %esi + movl RDI(%rsp), %edi + movl %eax, %eax /* zero extension */ RESTORE_EXTRA_REGS jmp ia32_do_call END(ia32_syscall) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/