blob: 5b70330869172be1961f696d3425a186116965fa [file] [log] [blame]
From 97245d00585d82540f4538cf72d92a1e853c7b0e Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 13 Sep 2016 14:29:22 -0700
Subject: [PATCH] x86/entry: Get rid of pt_regs_to_thread_info()
commit 97245d00585d82540f4538cf72d92a1e853c7b0e upstream.
It was a nice optimization while it lasted, but thread_info is moving
and this optimization will no longer work.
Quoting Linus:
Oh Gods, Andy. That pt_regs_to_thread_info() thing made me want
to do unspeakable acts on a poor innocent wax figure that looked
_exactly_ like you.
[ Changelog written by Andy. ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/6376aa81c68798cc81631673f52bd91a3e078944.1473801993.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 871bbf975d4c..bdd9cc59d20f 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -31,13 +31,6 @@
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
-static struct thread_info *pt_regs_to_thread_info(struct pt_regs *regs)
-{
- unsigned long top_of_stack =
- (unsigned long)(regs + 1) + TOP_OF_KERNEL_STACK_PADDING;
- return (struct thread_info *)(top_of_stack - THREAD_SIZE);
-}
-
#ifdef CONFIG_CONTEXT_TRACKING
/* Called on entry from user mode with IRQs off. */
__visible inline void enter_from_user_mode(void)
@@ -71,7 +64,7 @@ static long syscall_trace_enter(struct pt_regs *regs)
{
u32 arch = in_ia32_syscall() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
- struct thread_info *ti = pt_regs_to_thread_info(regs);
+ struct thread_info *ti = current_thread_info();
unsigned long ret = 0;
bool emulated = false;
u32 work;
@@ -173,18 +166,17 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
/* Disable IRQs and retry */
local_irq_disable();
- cached_flags = READ_ONCE(pt_regs_to_thread_info(regs)->flags);
+ cached_flags = READ_ONCE(current_thread_info()->flags);
if (!(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS))
break;
-
}
}
/* Called with IRQs disabled. */
__visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
{
- struct thread_info *ti = pt_regs_to_thread_info(regs);
+ struct thread_info *ti = current_thread_info();
u32 cached_flags;
if (IS_ENABLED(CONFIG_PROVE_LOCKING) && WARN_ON(!irqs_disabled()))
@@ -247,7 +239,7 @@ static void syscall_slow_exit_work(struct pt_regs *regs, u32 cached_flags)
*/
__visible inline void syscall_return_slowpath(struct pt_regs *regs)
{
- struct thread_info *ti = pt_regs_to_thread_info(regs);
+ struct thread_info *ti = current_thread_info();
u32 cached_flags = READ_ONCE(ti->flags);
CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
@@ -270,7 +262,7 @@ __visible inline void syscall_return_slowpath(struct pt_regs *regs)
#ifdef CONFIG_X86_64
__visible void do_syscall_64(struct pt_regs *regs)
{
- struct thread_info *ti = pt_regs_to_thread_info(regs);
+ struct thread_info *ti = current_thread_info();
unsigned long nr = regs->orig_ax;
enter_from_user_mode();
@@ -303,7 +295,7 @@ __visible void do_syscall_64(struct pt_regs *regs)
*/
static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
{
- struct thread_info *ti = pt_regs_to_thread_info(regs);
+ struct thread_info *ti = current_thread_info();
unsigned int nr = (unsigned int)regs->orig_ax;
#ifdef CONFIG_IA32_EMULATION
--
2.15.0