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From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
	Oleg Nesterov <oleg@redhat.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Brian Gerst <brgerst@gmail.com>,
	Andy Lutomirski <luto@kernel.org>
Subject: [PATCH v2 11/12] x86/entry: Remove TIF_SINGLESTEP entry work
Date: Wed,  9 Mar 2016 19:00:34 -0800	[thread overview]
Message-ID: <2d15f24da52dafc9d2f0b8d76f55544f4779c517.1457578375.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1457578375.git.luto@kernel.org>
In-Reply-To: <cover.1457578375.git.luto@kernel.org>

Now that SYSENTER with TF set puts X86_EFLAGS_TF directly into
regs->flags, we don't need a TIF_SINGLESTEP fixup in the syscall
entry code.  Remove it.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/entry/common.c            | 10 ----------
 arch/x86/include/asm/thread_info.h |  2 +-
 2 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index adea12fb7215..e79d93d44ecd 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -163,16 +163,6 @@ long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,
 	if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
 		BUG_ON(regs != task_pt_regs(current));
 
-	/*
-	 * If we stepped into a sysenter/syscall insn, it trapped in
-	 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
-	 * If user-mode had set TF itself, then it's still clear from
-	 * do_debug() and we need to set it again to restore the user
-	 * state.  If we entered on the slow path, TF was already set.
-	 */
-	if (work & _TIF_SINGLESTEP)
-		regs->flags |= X86_EFLAGS_TF;
-
 #ifdef CONFIG_SECCOMP
 	/*
 	 * Call seccomp_phase2 before running the other hooks so that
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index fbdb24e61835..82866697fcf1 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -140,7 +140,7 @@ struct thread_info {
  */
 #define _TIF_WORK_SYSCALL_ENTRY	\
 	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT |	\
-	 _TIF_SECCOMP | _TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT |	\
+	 _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT |	\
 	 _TIF_NOHZ)
 
 /* work to do on any return to user space */
-- 
2.5.0

  parent reply	other threads:[~2016-03-10  3:01 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-10  3:00 [PATCH v2 00/12] x86: Various SYSENTER/SYSEXIT/#DB fixes and cleanups Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 01/12] selftests/x86: In syscall_nt, test NT|TF as well Andy Lutomirski
2016-03-10 11:00   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 02/12] x86/entry/compat: In SYSENTER, sink AC clearing below the existing FLAGS test Andy Lutomirski
2016-03-10 11:01   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 03/12] x86/entry/32: Filter NT and speed up AC filtering in SYSENTER Andy Lutomirski
2016-03-10 11:01   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 04/12] x86/entry/32: Restore FLAGS on SYSEXIT Andy Lutomirski
2016-03-10 11:01   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 05/12] x86/traps: Clear TIF_BLOCKSTEP on all debug exceptions Andy Lutomirski
2016-03-10 11:02   ` [tip:x86/asm] x86/entry/traps: " tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 06/12] x86/traps: Clear DR6 early in do_debug and improve the comment Andy Lutomirski
2016-03-10 11:02   ` [tip:x86/asm] x86/entry/traps: Clear DR6 early in do_debug() " tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 07/12] x86/entry: Vastly simplify SYSENTER TF handling Andy Lutomirski
2016-03-10 11:03   ` [tip:x86/asm] x86/entry: Vastly simplify SYSENTER TF (single-step) handling tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 08/12] x86/entry: Only allocate space for SYSENTER_stack if needed Andy Lutomirski
2016-03-10 11:03   ` [tip:x86/asm] x86/entry: Only allocate space for tss_struct::SYSENTER_stack " tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 09/12] x86/entry/32: Simplify and fix up the SYSENTER stack #DB/NMI fixup Andy Lutomirski
2016-03-10 11:03   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 10/12] x86/entry/32: Add and check a stack canary for the SYSENTER stack Andy Lutomirski
2016-03-10 11:04   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-03-10  3:00 ` Andy Lutomirski [this message]
2016-03-10 11:04   ` [tip:x86/asm] x86/entry: Remove TIF_SINGLESTEP entry work tip-bot for Andy Lutomirski
2016-03-10  3:00 ` [PATCH v2 12/12] x86/entry: Improve system call entry comments Andy Lutomirski
2016-03-10 11:05   ` [tip:x86/asm] " tip-bot for Andy Lutomirski

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