x86/percpu: Move current_top_of_stack next to current_task

Extend the struct pcpu_hot cacheline with current_top_of_stack;
another very frequently used value.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111145.493038635@infradead.org
This commit is contained in:
Thomas Gleixner 2022-09-15 13:11:04 +02:00 committed by Peter Zijlstra
parent 7443b296e6
commit c063a217bc
11 changed files with 19 additions and 28 deletions

View File

@ -1181,7 +1181,7 @@ SYM_CODE_START(asm_exc_nmi)
* is using the thread stack right now, so it's safe for us to use it.
*/
movl %esp, %ebx
movl PER_CPU_VAR(cpu_current_top_of_stack), %esp
movl PER_CPU_VAR(pcpu_hot + X86_top_of_stack), %esp
call exc_nmi
movl %ebx, %esp
@ -1243,7 +1243,7 @@ SYM_CODE_START(rewind_stack_and_make_dead)
/* Prevent any naive code from trying to unwind to our caller. */
xorl %ebp, %ebp
movl PER_CPU_VAR(cpu_current_top_of_stack), %esi
movl PER_CPU_VAR(pcpu_hot + X86_top_of_stack), %esi
leal -TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%esi), %esp
call make_task_dead

View File

@ -92,7 +92,7 @@ SYM_CODE_START(entry_SYSCALL_64)
/* tss.sp2 is scratch space. */
movq %rsp, PER_CPU_VAR(cpu_tss_rw + TSS_sp2)
SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
movq PER_CPU_VAR(pcpu_hot + X86_top_of_stack), %rsp
SYM_INNER_LABEL(entry_SYSCALL_64_safe_stack, SYM_L_GLOBAL)
ANNOTATE_NOENDBR
@ -1209,7 +1209,7 @@ SYM_CODE_START(asm_exc_nmi)
FENCE_SWAPGS_USER_ENTRY
SWITCH_TO_KERNEL_CR3 scratch_reg=%rdx
movq %rsp, %rdx
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
movq PER_CPU_VAR(pcpu_hot + X86_top_of_stack), %rsp
UNWIND_HINT_IRET_REGS base=%rdx offset=8
pushq 5*8(%rdx) /* pt_regs->ss */
pushq 4*8(%rdx) /* pt_regs->rsp */
@ -1525,7 +1525,7 @@ SYM_CODE_START_NOALIGN(rewind_stack_and_make_dead)
/* Prevent any naive code from trying to unwind to our caller. */
xorl %ebp, %ebp
movq PER_CPU_VAR(cpu_current_top_of_stack), %rax
movq PER_CPU_VAR(pcpu_hot + X86_top_of_stack), %rax
leaq -PTREGS_SIZE(%rax), %rsp
UNWIND_HINT_REGS

View File

@ -58,7 +58,7 @@ SYM_CODE_START(entry_SYSENTER_compat)
SWITCH_TO_KERNEL_CR3 scratch_reg=%rax
popq %rax
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
movq PER_CPU_VAR(pcpu_hot + X86_top_of_stack), %rsp
/* Construct struct pt_regs on stack */
pushq $__USER32_DS /* pt_regs->ss */
@ -191,7 +191,7 @@ SYM_CODE_START(entry_SYSCALL_compat)
SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp
/* Switch to the kernel stack */
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
movq PER_CPU_VAR(pcpu_hot + X86_top_of_stack), %rsp
SYM_INNER_LABEL(entry_SYSCALL_compat_safe_stack, SYM_L_GLOBAL)
ANNOTATE_NOENDBR
@ -332,7 +332,7 @@ SYM_CODE_START(entry_INT80_compat)
ALTERNATIVE "", "jmp .Lint80_keep_stack", X86_FEATURE_XENPV
movq %rsp, %rax
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
movq PER_CPU_VAR(pcpu_hot + X86_top_of_stack), %rsp
pushq 5*8(%rax) /* regs->ss */
pushq 4*8(%rax) /* regs->rsp */

View File

@ -17,6 +17,7 @@ struct pcpu_hot {
struct task_struct *current_task;
int preempt_count;
int cpu_number;
unsigned long top_of_stack;
};
u8 pad[64];
};

View File

@ -426,8 +426,6 @@ struct irq_stack {
char stack[IRQ_STACK_SIZE];
} __aligned(IRQ_STACK_SIZE);
DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack);
#ifdef CONFIG_X86_64
struct fixed_percpu_data {
/*
@ -566,7 +564,7 @@ static __always_inline unsigned long current_top_of_stack(void)
* and around vm86 mode and sp0 on x86_64 is special because of the
* entry trampoline.
*/
return this_cpu_read_stable(cpu_current_top_of_stack);
return this_cpu_read_stable(pcpu_hot.top_of_stack);
}
static __always_inline bool on_thread_stack(void)

View File

@ -109,6 +109,8 @@ static void __used common(void)
OFFSET(TSS_sp1, tss_struct, x86_tss.sp1);
OFFSET(TSS_sp2, tss_struct, x86_tss.sp2);
OFFSET(X86_top_of_stack, pcpu_hot, top_of_stack);
if (IS_ENABLED(CONFIG_KVM_INTEL)) {
BLANK();
OFFSET(VMX_spec_ctrl, vcpu_vmx, spec_ctrl);

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@ -2015,6 +2015,7 @@ __setup("clearcpuid=", setup_clearcpuid);
DEFINE_PER_CPU_ALIGNED(struct pcpu_hot, pcpu_hot) = {
.current_task = &init_task,
.preempt_count = INIT_PREEMPT_COUNT,
.top_of_stack = TOP_OF_INIT_STACK,
};
EXPORT_PER_CPU_SYMBOL(pcpu_hot);
@ -2026,8 +2027,6 @@ EXPORT_PER_CPU_SYMBOL_GPL(fixed_percpu_data);
DEFINE_PER_CPU(void *, hardirq_stack_ptr);
DEFINE_PER_CPU(bool, hardirq_stack_inuse);
DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) = TOP_OF_INIT_STACK;
static void wrmsrl_cstar(unsigned long val)
{
/*
@ -2078,15 +2077,6 @@ void syscall_init(void)
#else /* CONFIG_X86_64 */
/*
* On x86_32, vm86 modifies tss.sp0, so sp0 isn't a reliable way to find
* the top of the kernel stack. Use an extra percpu variable to track the
* top of the kernel stack directly.
*/
DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) =
(unsigned long)&init_thread_union + THREAD_SIZE;
EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack);
#ifdef CONFIG_STACKPROTECTOR
DEFINE_PER_CPU(unsigned long, __stack_chk_guard);
EXPORT_PER_CPU_SYMBOL(__stack_chk_guard);

View File

@ -191,13 +191,13 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
arch_end_context_switch(next_p);
/*
* Reload esp0 and cpu_current_top_of_stack. This changes
* Reload esp0 and pcpu_hot.top_of_stack. This changes
* current_thread_info(). Refresh the SYSENTER configuration in
* case prev or next is vm86.
*/
update_task_stack(next_p);
refresh_sysenter_cs(next);
this_cpu_write(cpu_current_top_of_stack,
this_cpu_write(pcpu_hot.top_of_stack,
(unsigned long)task_stack_page(next_p) +
THREAD_SIZE);

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@ -618,7 +618,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* Switch the PDA and FPU contexts.
*/
raw_cpu_write(pcpu_hot.current_task, next_p);
this_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p));
raw_cpu_write(pcpu_hot.top_of_stack, task_top_of_stack(next_p));
switch_fpu_finish();

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@ -1056,7 +1056,7 @@ int common_cpu_up(unsigned int cpu, struct task_struct *idle)
#ifdef CONFIG_X86_32
/* Stack for startup_32 can be just as for start_secondary onwards */
per_cpu(cpu_current_top_of_stack, cpu) = task_top_of_stack(idle);
per_cpu(pcpu_hot.top_of_stack, cpu) = task_top_of_stack(idle);
#else
initial_gs = per_cpu_offset(cpu);
#endif

View File

@ -851,7 +851,7 @@ DEFINE_IDTENTRY_RAW(exc_int3)
*/
asmlinkage __visible noinstr struct pt_regs *sync_regs(struct pt_regs *eregs)
{
struct pt_regs *regs = (struct pt_regs *)this_cpu_read(cpu_current_top_of_stack) - 1;
struct pt_regs *regs = (struct pt_regs *)this_cpu_read(pcpu_hot.top_of_stack) - 1;
if (regs != eregs)
*regs = *eregs;
return regs;
@ -869,7 +869,7 @@ asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *r
* trust it and switch to the current kernel stack
*/
if (ip_within_syscall_gap(regs)) {
sp = this_cpu_read(cpu_current_top_of_stack);
sp = this_cpu_read(pcpu_hot.top_of_stack);
goto sync;
}