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x86: Move thread_info into task_struct

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Now that most of the thread_info users have been cleaned up,
this is straightforward.

Most of this code was written by Linus.

Originally-from: 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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a50eab40abeaec9cb9a9e3cbdeafd32190206654.1473801993.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2016-09-13 14:29:25 -07:00 committed by Ingo Molnar
parent c65eacbe29
commit 15f4eae70d
6 changed files with 10 additions and 57 deletions
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1
arch/x86/Kconfig
View File

@ -157,6 +157,7 @@ config X86
select SPARSE_IRQ
select SRCU
select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK
select USER_STACKTRACE_SUPPORT
select VIRT_TO_BUS
select X86_DEV_DMA_OPS if X86_64

7
arch/x86/entry/entry_64.S
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@ -179,7 +179,8 @@ GLOBAL(entry_SYSCALL_64_after_swapgs)
* If we need to do entry work or if we guess we'll need to do
* exit work, go straight to the slow path.
*/
testl $_TIF_WORK_SYSCALL_ENTRY|_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
movq PER_CPU_VAR(current_task), %r11
testl $_TIF_WORK_SYSCALL_ENTRY|_TIF_ALLWORK_MASK, TASK_TI_flags(%r11)
jnz entry_SYSCALL64_slow_path
entry_SYSCALL_64_fastpath:
@ -217,7 +218,8 @@ entry_SYSCALL_64_fastpath:
*/
DISABLE_INTERRUPTS(CLBR_NONE)
TRACE_IRQS_OFF
testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
movq PER_CPU_VAR(current_task), %r11
testl $_TIF_ALLWORK_MASK, TASK_TI_flags(%r11)
jnz 1f
LOCKDEP_SYS_EXIT
@ -370,6 +372,7 @@ END(ptregs_\func)
/*
* %rdi: prev task
* %rsi: next task
* rsi: task we're switching to
*/
ENTRY(__switch_to_asm)
/*

46
arch/x86/include/asm/thread_info.h
View File

@ -52,20 +52,6 @@ struct task_struct;
#include <asm/cpufeature.h>
#include <linux/atomic.h>
struct thread_info {
struct task_struct *task; /* main task structure */
__u32 flags; /* low level flags */
__u32 cpu; /* current CPU */
};
#define INIT_THREAD_INFO(tsk) \
{ \
.task = &tsk, \
.flags = 0, \
.cpu = 0, \
}
#define init_thread_info (init_thread_union.thread_info)
#define init_stack (init_thread_union.stack)
#else /* !__ASSEMBLY__ */
@ -157,11 +143,6 @@ struct thread_info {
*/
#ifndef __ASSEMBLY__
static inline struct thread_info *current_thread_info(void)
{
return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE);
}
static inline unsigned long current_stack_pointer(void)
{
unsigned long sp;
@ -223,33 +204,6 @@ static inline int arch_within_stack_frames(const void * const stack,
# define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
#endif
/*
* ASM operand which evaluates to a 'thread_info' address of
* the current task, if it is known that "reg" is exactly "off"
* bytes below the top of the stack currently.
*
* ( The kernel stack's size is known at build time, it is usually
* 2 or 4 pages, and the bottom of the kernel stack contains
* the thread_info structure. So to access the thread_info very
* quickly from assembly code we can calculate down from the
* top of the kernel stack to the bottom, using constant,
* build-time calculations only. )
*
* For example, to fetch the current thread_info->flags value into %eax
* on x86-64 defconfig kernels, in syscall entry code where RSP is
* currently at exactly SIZEOF_PTREGS bytes away from the top of the
* stack:
*
* mov ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS), %eax
*
* will translate to:
*
* 8b 84 24 b8 c0 ff ff mov -0x3f48(%rsp), %eax
*
* which is below the current RSP by almost 16K.
*/
#define ASM_THREAD_INFO(field, reg, off) ((field)+(off)-THREAD_SIZE)(reg)
#endif
#ifdef CONFIG_COMPAT

4
arch/x86/kernel/asm-offsets.c
View File

@ -35,9 +35,7 @@ void common(void) {
#endif
BLANK();
OFFSET(TI_flags, thread_info, flags);
BLANK();
OFFSET(TASK_TI_flags, task_struct, thread_info.flags);
OFFSET(TASK_addr_limit, task_struct, thread.addr_limit);
BLANK();

3
arch/x86/kernel/irq_64.c
View File

@ -40,8 +40,7 @@ static inline void stack_overflow_check(struct pt_regs *regs)
if (user_mode(regs))
return;
if (regs->sp >= curbase + sizeof(struct thread_info) +
sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
regs->sp <= curbase + THREAD_SIZE)
return;

6
arch/x86/kernel/process.c
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@ -549,9 +549,7 @@ unsigned long get_wchan(struct task_struct *p)
* PADDING
* ----------- top = topmax - TOP_OF_KERNEL_STACK_PADDING
* stack
* ----------- bottom = start + sizeof(thread_info)
* thread_info
* ----------- start
* ----------- bottom = start
*
* The tasks stack pointer points at the location where the
* framepointer is stored. The data on the stack is:
@ -562,7 +560,7 @@ unsigned long get_wchan(struct task_struct *p)
*/
top = start + THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;
top -= 2 * sizeof(unsigned long);
bottom = start + sizeof(struct thread_info);
bottom = start;
sp = READ_ONCE(p->thread.sp);
if (sp < bottom || sp > top)