From: tip-bot for Linus Torvalds <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: peterz@infradead.org, mingo@kernel.org, jann@thejh.net,
bp@alien8.de, dvlasenk@redhat.com, torvalds@linux-foundation.org,
luto@kernel.org, brgerst@gmail.com, tglx@linutronix.de,
linux-kernel@vger.kernel.org, hpa@zytor.com, jpoimboe@redhat.com
Subject: [tip:x86/asm] x86/entry: Get rid of pt_regs_to_thread_info()
Date: Thu, 15 Sep 2016 03:42:18 -0700 [thread overview]
Message-ID: <tip-97245d00585d82540f4538cf72d92a1e853c7b0e@git.kernel.org> (raw)
In-Reply-To: <6376aa81c68798cc81631673f52bd91a3e078944.1473801993.git.luto@kernel.org>
Commit-ID: 97245d00585d82540f4538cf72d92a1e853c7b0e
Gitweb: http://git.kernel.org/tip/97245d00585d82540f4538cf72d92a1e853c7b0e
Author: Linus Torvalds <torvalds@linux-foundation.org>
AuthorDate: Tue, 13 Sep 2016 14:29:22 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 15 Sep 2016 08:25:12 +0200
x86/entry: Get rid of pt_regs_to_thread_info()
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>
---
arch/x86/entry/common.c | 20 ++++++--------------
1 file changed, 6 insertions(+), 14 deletions(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 871bbf9..bdd9cc5 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
next prev parent reply other threads:[~2016-09-15 10:43 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-13 21:29 [PATCH 00/12] thread_info cleanups and stack caching Andy Lutomirski
2016-09-13 21:29 ` [PATCH 01/12] x86/asm: Move 'status' from struct thread_info to struct thread_struct Andy Lutomirski
2016-09-15 10:41 ` [tip:x86/asm] x86/asm: Move the thread_info::status field to thread_struct tip-bot for Andy Lutomirski
2016-09-13 21:29 ` [PATCH 02/12] x86/entry: Get rid of pt_regs_to_thread_info() Andy Lutomirski
2016-09-15 6:21 ` Ingo Molnar
2016-09-15 10:42 ` tip-bot for Linus Torvalds [this message]
2016-09-13 21:29 ` [PATCH 03/12] um: Stop conflating task_struct::stack with thread_info Andy Lutomirski
2016-09-15 6:21 ` Ingo Molnar
2016-09-15 10:42 ` [tip:x86/asm] um/Stop " tip-bot for Linus Torvalds
2016-09-13 21:29 ` [PATCH 04/12] sched: Allow putting thread_info into task_struct Andy Lutomirski
2016-09-15 10:43 ` [tip:x86/asm] sched/core: " tip-bot for Andy Lutomirski
2016-09-13 21:29 ` [PATCH 05/12] x86: Move " Andy Lutomirski
2016-09-15 10:43 ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2016-09-13 21:29 ` [PATCH 06/12] sched: Add try_get_task_stack() and put_task_stack() Andy Lutomirski
2016-09-13 21:29 ` [PATCH 07/12] kthread: to_live_kthread() needs try_get_task_stack() Andy Lutomirski
2016-09-13 21:29 ` [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() Andy Lutomirski
2016-09-14 14:55 ` Josh Poimboeuf
2016-09-14 18:22 ` Andy Lutomirski
2016-09-14 18:35 ` Josh Poimboeuf
2016-09-15 18:04 ` Andy Lutomirski
2016-09-15 18:37 ` Josh Poimboeuf
2016-09-15 18:41 ` Andy Lutomirski
2016-09-15 19:19 ` Josh Poimboeuf
2016-09-16 7:47 ` Peter Zijlstra
2016-09-16 15:12 ` Andy Lutomirski
2016-09-16 15:31 ` Peter Zijlstra
2016-09-16 15:32 ` Andy Lutomirski
2016-09-16 16:35 ` Peter Zijlstra
2016-09-15 6:37 ` Ingo Molnar
[not found] ` <CA+55aFxt=HLrELBE=BXUrWdh6LYs4gtu9S=yCruiDffq4HN80w@mail.gmail.com>
2016-09-15 9:27 ` Ingo Molnar
2016-09-13 21:29 ` [PATCH 09/12] x86/process: Pin the target stack in get_wchan() Andy Lutomirski
2016-09-17 2:00 ` Jann Horn
2016-09-22 22:44 ` Andy Lutomirski
2016-09-22 22:50 ` Andy Lutomirski
2016-09-23 7:43 ` Jann Horn
2016-09-23 18:28 ` Kees Cook
2016-09-23 18:34 ` Jann Horn
2016-09-26 5:10 ` Tycho Andersen
2016-09-13 21:29 ` [PATCH 10/12] lib/syscall: Pin the task stack in collect_syscall() Andy Lutomirski
2016-09-13 21:29 ` [PATCH 11/12] sched: Free the stack early if CONFIG_THREAD_INFO_IN_TASK Andy Lutomirski
2016-09-13 21:29 ` [PATCH 12/12] fork: Cache two thread stacks per cpu if CONFIG_VMAP_STACK is set Andy Lutomirski
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