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Merge branch 'x86-threadinfo-for-linus' of git://git.kernel.org/pub/s…
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…cm/linux/kernel/git/tip/tip

Pull x86 threadinfo changes from Ingo Molnar:
 "The main change here is the consolidation/unification of 32 and 64 bit
  thread_info handling methods, from Steve Rostedt"

* 'x86-threadinfo-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, threadinfo: Redo "x86: Use inline assembler to get sp"
  x86: Clean up dumpstack_64.c code
  x86: Keep thread_info on thread stack in x86_32
  x86: Prepare removal of previous_esp from i386 thread_info structure
  x86: Nuke GET_THREAD_INFO_WITH_ESP() macro for i386
  x86: Nuke the supervisor_stack field in i386 thread_info
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Linus Torvalds committed Apr 1, 2014
2 parents a21e408 + 6cce16f commit 99f7b02
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Showing 9 changed files with 191 additions and 137 deletions.
9 changes: 9 additions & 0 deletions arch/x86/include/asm/processor.h
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Original file line number Diff line number Diff line change
Expand Up @@ -449,6 +449,15 @@ struct stack_canary {
};
DECLARE_PER_CPU_ALIGNED(struct stack_canary, stack_canary);
#endif
/*
* per-CPU IRQ handling stacks
*/
struct irq_stack {
u32 stack[THREAD_SIZE/sizeof(u32)];
} __aligned(THREAD_SIZE);

DECLARE_PER_CPU(struct irq_stack *, hardirq_stack);
DECLARE_PER_CPU(struct irq_stack *, softirq_stack);
#endif /* X86_64 */

extern unsigned int xstate_size;
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53 changes: 5 additions & 48 deletions arch/x86/include/asm/thread_info.h
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@

#include <linux/compiler.h>
#include <asm/page.h>
#include <asm/percpu.h>
#include <asm/types.h>

/*
Expand All @@ -32,12 +33,6 @@ struct thread_info {
mm_segment_t addr_limit;
struct restart_block restart_block;
void __user *sysenter_return;
#ifdef CONFIG_X86_32
unsigned long previous_esp; /* ESP of the previous stack in
case of nested (IRQ) stacks
*/
__u8 supervisor_stack[0];
#endif
unsigned int sig_on_uaccess_error:1;
unsigned int uaccess_err:1; /* uaccess failed */
};
Expand Down Expand Up @@ -153,52 +148,16 @@ struct thread_info {
#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)

#ifdef CONFIG_X86_32
#define STACK_WARN (THREAD_SIZE/8)
#define KERNEL_STACK_OFFSET (5*(BITS_PER_LONG/8))

#define STACK_WARN (THREAD_SIZE/8)
/*
* macros/functions for gaining access to the thread information structure
*
* preempt_count needs to be 1 initially, until the scheduler is functional.
*/
#ifndef __ASSEMBLY__

#define current_stack_pointer ({ \
unsigned long sp; \
asm("mov %%esp,%0" : "=g" (sp)); \
sp; \
})

/* how to get the thread information struct from C */
static inline struct thread_info *current_thread_info(void)
{
return (struct thread_info *)
(current_stack_pointer & ~(THREAD_SIZE - 1));
}

#else /* !__ASSEMBLY__ */

/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg) \
movl $-THREAD_SIZE, reg; \
andl %esp, reg

/* use this one if reg already contains %esp */
#define GET_THREAD_INFO_WITH_ESP(reg) \
andl $-THREAD_SIZE, reg

#endif

#else /* X86_32 */

#include <asm/percpu.h>
#define KERNEL_STACK_OFFSET (5*8)

/*
* macros/functions for gaining access to the thread information structure
* preempt_count needs to be 1 initially, until the scheduler is functional.
*/
#ifndef __ASSEMBLY__
DECLARE_PER_CPU(unsigned long, kernel_stack);

static inline struct thread_info *current_thread_info(void)
Expand All @@ -213,8 +172,8 @@ static inline struct thread_info *current_thread_info(void)

/* how to get the thread information struct from ASM */
#define GET_THREAD_INFO(reg) \
movq PER_CPU_VAR(kernel_stack),reg ; \
subq $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg
_ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
_ASM_SUB $(THREAD_SIZE-KERNEL_STACK_OFFSET),reg ;

/*
* Same if PER_CPU_VAR(kernel_stack) is, perhaps with some offset, already in
Expand All @@ -224,8 +183,6 @@ static inline struct thread_info *current_thread_info(void)

#endif

#endif /* !X86_32 */

/*
* Thread-synchronous status.
*
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8 changes: 4 additions & 4 deletions arch/x86/kernel/cpu/common.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1079,6 +1079,10 @@ static __init int setup_disablecpuid(char *arg)
}
__setup("clearcpuid=", setup_disablecpuid);

DEFINE_PER_CPU(unsigned long, kernel_stack) =
(unsigned long)&init_thread_union - KERNEL_STACK_OFFSET + THREAD_SIZE;
EXPORT_PER_CPU_SYMBOL(kernel_stack);

#ifdef CONFIG_X86_64
struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1,
Expand All @@ -1095,10 +1099,6 @@ DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
&init_task;
EXPORT_PER_CPU_SYMBOL(current_task);

DEFINE_PER_CPU(unsigned long, kernel_stack) =
(unsigned long)&init_thread_union - KERNEL_STACK_OFFSET + THREAD_SIZE;
EXPORT_PER_CPU_SYMBOL(kernel_stack);

DEFINE_PER_CPU(char *, irq_stack_ptr) =
init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64;

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44 changes: 40 additions & 4 deletions arch/x86/kernel/dumpstack_32.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,12 +16,35 @@

#include <asm/stacktrace.h>

static void *is_irq_stack(void *p, void *irq)
{
if (p < irq || p >= (irq + THREAD_SIZE))
return NULL;
return irq + THREAD_SIZE;
}


static void *is_hardirq_stack(unsigned long *stack, int cpu)
{
void *irq = per_cpu(hardirq_stack, cpu);

return is_irq_stack(stack, irq);
}

static void *is_softirq_stack(unsigned long *stack, int cpu)
{
void *irq = per_cpu(softirq_stack, cpu);

return is_irq_stack(stack, irq);
}

void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
const unsigned cpu = get_cpu();
int graph = 0;
u32 *prev_esp;

if (!task)
task = current;
Expand All @@ -39,18 +62,31 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,

for (;;) {
struct thread_info *context;
void *end_stack;

end_stack = is_hardirq_stack(stack, cpu);
if (!end_stack)
end_stack = is_softirq_stack(stack, cpu);

context = (struct thread_info *)
((unsigned long)stack & (~(THREAD_SIZE - 1)));
bp = ops->walk_stack(context, stack, bp, ops, data, NULL, &graph);
context = task_thread_info(task);
bp = ops->walk_stack(context, stack, bp, ops, data,
end_stack, &graph);

stack = (unsigned long *)context->previous_esp;
/* Stop if not on irq stack */
if (!end_stack)
break;

/* The previous esp is saved on the bottom of the stack */
prev_esp = (u32 *)(end_stack - THREAD_SIZE);
stack = (unsigned long *)*prev_esp;
if (!stack)
break;

if (ops->stack(data, "IRQ") < 0)
break;
touch_nmi_watchdog();
}
put_cpu();
}
EXPORT_SYMBOL(dump_trace);

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117 changes: 83 additions & 34 deletions arch/x86/kernel/dumpstack_64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,45 @@ in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
return (stack >= irq_stack && stack < irq_stack_end);
}

static const unsigned long irq_stack_size =
(IRQ_STACK_SIZE - 64) / sizeof(unsigned long);

enum stack_type {
STACK_IS_UNKNOWN,
STACK_IS_NORMAL,
STACK_IS_EXCEPTION,
STACK_IS_IRQ,
};

static enum stack_type
analyze_stack(int cpu, struct task_struct *task,
unsigned long *stack, unsigned long **stack_end, char **id)
{
unsigned long *irq_stack;
unsigned long addr;
unsigned used = 0;

addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
if ((unsigned long)task_stack_page(task) == addr)
return STACK_IS_NORMAL;

*stack_end = in_exception_stack(cpu, (unsigned long)stack,
&used, id);
if (*stack_end)
return STACK_IS_EXCEPTION;

*stack_end = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
if (!*stack_end)
return STACK_IS_UNKNOWN;

irq_stack = *stack_end - irq_stack_size;

if (in_irq_stack(stack, irq_stack, *stack_end))
return STACK_IS_IRQ;

return STACK_IS_UNKNOWN;
}

/*
* x86-64 can have up to three kernel stacks:
* process stack
Expand All @@ -116,12 +155,11 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
const struct stacktrace_ops *ops, void *data)
{
const unsigned cpu = get_cpu();
unsigned long *irq_stack_end =
(unsigned long *)per_cpu(irq_stack_ptr, cpu);
unsigned used = 0;
struct thread_info *tinfo;
int graph = 0;
unsigned long *irq_stack;
unsigned long dummy;
int graph = 0;
int done = 0;

if (!task)
task = current;
Expand All @@ -143,49 +181,60 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
* exceptions
*/
tinfo = task_thread_info(task);
for (;;) {
while (!done) {
unsigned long *stack_end;
enum stack_type stype;
char *id;
unsigned long *estack_end;
estack_end = in_exception_stack(cpu, (unsigned long)stack,
&used, &id);

if (estack_end) {
stype = analyze_stack(cpu, task, stack, &stack_end, &id);

/* Default finish unless specified to continue */
done = 1;

switch (stype) {

/* Break out early if we are on the thread stack */
case STACK_IS_NORMAL:
break;

case STACK_IS_EXCEPTION:

if (ops->stack(data, id) < 0)
break;

bp = ops->walk_stack(tinfo, stack, bp, ops,
data, estack_end, &graph);
data, stack_end, &graph);
ops->stack(data, "<EOE>");
/*
* We link to the next stack via the
* second-to-last pointer (index -2 to end) in the
* exception stack:
*/
stack = (unsigned long *) estack_end[-2];
continue;
}
if (irq_stack_end) {
unsigned long *irq_stack;
irq_stack = irq_stack_end -
(IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);

if (in_irq_stack(stack, irq_stack, irq_stack_end)) {
if (ops->stack(data, "IRQ") < 0)
break;
bp = ops->walk_stack(tinfo, stack, bp,
ops, data, irq_stack_end, &graph);
/*
* We link to the next stack (which would be
* the process stack normally) the last
* pointer (index -1 to end) in the IRQ stack:
*/
stack = (unsigned long *) (irq_stack_end[-1]);
irq_stack_end = NULL;
ops->stack(data, "EOI");
continue;
}
stack = (unsigned long *) stack_end[-2];
done = 0;
break;

case STACK_IS_IRQ:

if (ops->stack(data, "IRQ") < 0)
break;
bp = ops->walk_stack(tinfo, stack, bp,
ops, data, stack_end, &graph);
/*
* We link to the next stack (which would be
* the process stack normally) the last
* pointer (index -1 to end) in the IRQ stack:
*/
stack = (unsigned long *) (stack_end[-1]);
irq_stack = stack_end - irq_stack_size;
ops->stack(data, "EOI");
done = 0;
break;

case STACK_IS_UNKNOWN:
ops->stack(data, "UNK");
break;
}
break;
}

/*
Expand Down
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