[tip: x86/core] x86/percpu: Move irq_stack variables next to current_task

From: tip-bot2 for Thomas Gleixner
Date: Mon Oct 17 2022 - 10:56:59 EST

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The following commit has been merged into the x86/core branch of tip:

Commit-ID: d7b6d709a76a4f4ef3108ac41e1b39eb80f5c084
Gitweb: https://git.kernel.org/tip/d7b6d709a76a4f4ef3108ac41e1b39eb80f5c084
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 15 Sep 2022 13:11:05 +02:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Mon, 17 Oct 2022 16:41:05 +02:00

x86/percpu: Move irq_stack variables next to current_task

Further extend struct pcpu_hot with the hard and soft irq stack
pointers.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220915111145.599170752@xxxxxxxxxxxxx
---
arch/x86/include/asm/current.h | 6 ++++++
arch/x86/include/asm/irq_stack.h | 12 ++++++------
arch/x86/include/asm/processor.h | 4 ----
arch/x86/kernel/cpu/common.c | 3 ---
arch/x86/kernel/dumpstack_32.c | 4 ++--
arch/x86/kernel/dumpstack_64.c | 2 +-
arch/x86/kernel/irq_32.c | 13 +++++--------
arch/x86/kernel/irq_64.c | 6 +++---
arch/x86/kernel/process_64.c | 2 +-
9 files changed, 24 insertions(+), 28 deletions(-)

diff --git a/arch/x86/include/asm/current.h b/arch/x86/include/asm/current.h
index 2dd0131..ac3090d 100644
--- a/arch/x86/include/asm/current.h
+++ b/arch/x86/include/asm/current.h
@@ -18,6 +18,12 @@ struct pcpu_hot {
int preempt_count;
int cpu_number;
unsigned long top_of_stack;
+ void *hardirq_stack_ptr;
+#ifdef CONFIG_X86_64
+ bool hardirq_stack_inuse;
+#else
+ void *softirq_stack_ptr;
+#endif
};
u8 pad[64];
};
diff --git a/arch/x86/include/asm/irq_stack.h b/arch/x86/include/asm/irq_stack.h
index 147cb8f..7981838 100644
--- a/arch/x86/include/asm/irq_stack.h
+++ b/arch/x86/include/asm/irq_stack.h
@@ -116,7 +116,7 @@
ASM_CALL_ARG2

#define call_on_irqstack(func, asm_call, argconstr...) \
- call_on_stack(__this_cpu_read(hardirq_stack_ptr), \
+ call_on_stack(__this_cpu_read(pcpu_hot.hardirq_stack_ptr), \
func, asm_call, argconstr)

/* Macros to assert type correctness for run_*_on_irqstack macros */
@@ -135,7 +135,7 @@
* User mode entry and interrupt on the irq stack do not \
* switch stacks. If from user mode the task stack is empty. \
*/ \
- if (user_mode(regs) || __this_cpu_read(hardirq_stack_inuse)) { \
+ if (user_mode(regs) || __this_cpu_read(pcpu_hot.hardirq_stack_inuse)) { \
irq_enter_rcu(); \
func(c_args); \
irq_exit_rcu(); \
@@ -146,9 +146,9 @@
* places. Invoke the stack switch macro with the call \
* sequence which matches the above direct invocation. \
*/ \
- __this_cpu_write(hardirq_stack_inuse, true); \
+ __this_cpu_write(pcpu_hot.hardirq_stack_inuse, true); \
call_on_irqstack(func, asm_call, constr); \
- __this_cpu_write(hardirq_stack_inuse, false); \
+ __this_cpu_write(pcpu_hot.hardirq_stack_inuse, false); \
} \
}

@@ -212,9 +212,9 @@
*/
#define do_softirq_own_stack() \
{ \
- __this_cpu_write(hardirq_stack_inuse, true); \
+ __this_cpu_write(pcpu_hot.hardirq_stack_inuse, true); \
call_on_irqstack(__do_softirq, ASM_CALL_ARG0); \
- __this_cpu_write(hardirq_stack_inuse, false); \
+ __this_cpu_write(pcpu_hot.hardirq_stack_inuse, false); \
}

#endif
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index c345f30..bdde687 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -448,8 +448,6 @@ static inline unsigned long cpu_kernelmode_gs_base(int cpu)
return (unsigned long)per_cpu(fixed_percpu_data.gs_base, cpu);
}

-DECLARE_PER_CPU(void *, hardirq_stack_ptr);
-DECLARE_PER_CPU(bool, hardirq_stack_inuse);
extern asmlinkage void ignore_sysret(void);

/* Save actual FS/GS selectors and bases to current->thread */
@@ -458,8 +456,6 @@ void current_save_fsgs(void);
#ifdef CONFIG_STACKPROTECTOR
DECLARE_PER_CPU(unsigned long, __stack_chk_guard);
#endif
-DECLARE_PER_CPU(struct irq_stack *, hardirq_stack_ptr);
-DECLARE_PER_CPU(struct irq_stack *, softirq_stack_ptr);
#endif /* !X86_64 */

struct perf_event;
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 408245c..2bec4b4 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2024,9 +2024,6 @@ DEFINE_PER_CPU_FIRST(struct fixed_percpu_data,
fixed_percpu_data) __aligned(PAGE_SIZE) __visible;
EXPORT_PER_CPU_SYMBOL_GPL(fixed_percpu_data);

-DEFINE_PER_CPU(void *, hardirq_stack_ptr);
-DEFINE_PER_CPU(bool, hardirq_stack_inuse);
-
static void wrmsrl_cstar(unsigned long val)
{
/*
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 722fd71..b4905d5 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -37,7 +37,7 @@ const char *stack_type_name(enum stack_type type)

static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
{
- unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack_ptr);
+ unsigned long *begin = (unsigned long *)this_cpu_read(pcpu_hot.hardirq_stack_ptr);
unsigned long *end = begin + (THREAD_SIZE / sizeof(long));

/*
@@ -62,7 +62,7 @@ static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)

static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
{
- unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack_ptr);
+ unsigned long *begin = (unsigned long *)this_cpu_read(pcpu_hot.softirq_stack_ptr);
unsigned long *end = begin + (THREAD_SIZE / sizeof(long));

/*
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 6c5defd..f05339f 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -134,7 +134,7 @@ static __always_inline bool in_exception_stack(unsigned long *stack, struct stac

static __always_inline bool in_irq_stack(unsigned long *stack, struct stack_info *info)
{
- unsigned long *end = (unsigned long *)this_cpu_read(hardirq_stack_ptr);
+ unsigned long *end = (unsigned long *)this_cpu_read(pcpu_hot.hardirq_stack_ptr);
unsigned long *begin;

/*
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 01833eb..dc1049c 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -52,9 +52,6 @@ static inline int check_stack_overflow(void) { return 0; }
static inline void print_stack_overflow(void) { }
#endif

-DEFINE_PER_CPU(struct irq_stack *, hardirq_stack_ptr);
-DEFINE_PER_CPU(struct irq_stack *, softirq_stack_ptr);
-
static void call_on_stack(void *func, void *stack)
{
asm volatile("xchgl %%ebx,%%esp \n"
@@ -77,7 +74,7 @@ static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
u32 *isp, *prev_esp, arg1;

curstk = (struct irq_stack *) current_stack();
- irqstk = __this_cpu_read(hardirq_stack_ptr);
+ irqstk = __this_cpu_read(pcpu_hot.hardirq_stack_ptr);

/*
* this is where we switch to the IRQ stack. However, if we are
@@ -115,7 +112,7 @@ int irq_init_percpu_irqstack(unsigned int cpu)
int node = cpu_to_node(cpu);
struct page *ph, *ps;

- if (per_cpu(hardirq_stack_ptr, cpu))
+ if (per_cpu(pcpu_hot.hardirq_stack_ptr, cpu))
return 0;

ph = alloc_pages_node(node, THREADINFO_GFP, THREAD_SIZE_ORDER);
@@ -127,8 +124,8 @@ int irq_init_percpu_irqstack(unsigned int cpu)
return -ENOMEM;
}

- per_cpu(hardirq_stack_ptr, cpu) = page_address(ph);
- per_cpu(softirq_stack_ptr, cpu) = page_address(ps);
+ per_cpu(pcpu_hot.hardirq_stack_ptr, cpu) = page_address(ph);
+ per_cpu(pcpu_hot.softirq_stack_ptr, cpu) = page_address(ps);
return 0;
}

@@ -138,7 +135,7 @@ void do_softirq_own_stack(void)
struct irq_stack *irqstk;
u32 *isp, *prev_esp;

- irqstk = __this_cpu_read(softirq_stack_ptr);
+ irqstk = __this_cpu_read(pcpu_hot.softirq_stack_ptr);

/* build the stack frame on the softirq stack */
isp = (u32 *) ((char *)irqstk + sizeof(*irqstk));
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 1c0fb96..fe0c859 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -50,7 +50,7 @@ static int map_irq_stack(unsigned int cpu)
return -ENOMEM;

/* Store actual TOS to avoid adjustment in the hotpath */
- per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
+ per_cpu(pcpu_hot.hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
return 0;
}
#else
@@ -63,14 +63,14 @@ static int map_irq_stack(unsigned int cpu)
void *va = per_cpu_ptr(&irq_stack_backing_store, cpu);

/* Store actual TOS to avoid adjustment in the hotpath */
- per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
+ per_cpu(pcpu_hot.hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE - 8;
return 0;
}
#endif

int irq_init_percpu_irqstack(unsigned int cpu)
{
- if (per_cpu(hardirq_stack_ptr, cpu))
+ if (per_cpu(pcpu_hot.hardirq_stack_ptr, cpu))
return 0;
return map_irq_stack(cpu);
}
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 7f807e8..1312de5 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -563,7 +563,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
int cpu = smp_processor_id();

WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_ENTRY) &&
- this_cpu_read(hardirq_stack_inuse));
+ this_cpu_read(pcpu_hot.hardirq_stack_inuse));

if (!test_thread_flag(TIF_NEED_FPU_LOAD))
switch_fpu_prepare(prev_fpu, cpu);

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