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x86/dumpstack/64: Add noinstr version of get_stack_info()

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The get_stack_info() functionality is needed in the entry code for the
#VC exception handler. Provide a version of it in the .text.noinstr
section which can be called safely from there.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-45-joro@8bytes.org
This commit is contained in:
Joerg Roedel 2020-09-07 15:15:45 +02:00 committed by Borislav Petkov
parent 315562c9af
commit 6b27edd74a
4 changed files with 34 additions and 24 deletions
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2
arch/x86/include/asm/stacktrace.h
View File

@ -35,6 +35,8 @@ bool in_entry_stack(unsigned long *stack, struct stack_info *info);
int get_stack_info(unsigned long *stack, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask);
bool get_stack_info_noinstr(unsigned long *stack, struct task_struct *task,
struct stack_info *info);
const char *stack_type_name(enum stack_type type);

7
arch/x86/kernel/dumpstack.c
View File

@ -29,8 +29,8 @@ static int die_counter;
static struct pt_regs exec_summary_regs;
bool in_task_stack(unsigned long *stack, struct task_struct *task,
struct stack_info *info)
bool noinstr in_task_stack(unsigned long *stack, struct task_struct *task,
struct stack_info *info)
{
unsigned long *begin = task_stack_page(task);
unsigned long *end = task_stack_page(task) + THREAD_SIZE;
@ -46,7 +46,8 @@ bool in_task_stack(unsigned long *stack, struct task_struct *task,
return true;
}
bool in_entry_stack(unsigned long *stack, struct stack_info *info)
/* Called from get_stack_info_noinstr - so must be noinstr too */
bool noinstr in_entry_stack(unsigned long *stack, struct stack_info *info)
{
struct entry_stack *ss = cpu_entry_stack(smp_processor_id());

46
arch/x86/kernel/dumpstack_64.c
View File

@ -85,7 +85,7 @@ struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = {
EPAGERANGE(VC2),
};
static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
static __always_inline bool in_exception_stack(unsigned long *stack, struct stack_info *info)
{
unsigned long begin, end, stk = (unsigned long)stack;
const struct estack_pages *ep;
@ -126,7 +126,7 @@ static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
return true;
}
static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
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 *begin = end - (IRQ_STACK_SIZE / sizeof(long));
@ -151,32 +151,38 @@ static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
return true;
}
bool noinstr get_stack_info_noinstr(unsigned long *stack, struct task_struct *task,
struct stack_info *info)
{
if (in_task_stack(stack, task, info))
return true;
if (task != current)
return false;
if (in_exception_stack(stack, info))
return true;
if (in_irq_stack(stack, info))
return true;
if (in_entry_stack(stack, info))
return true;
return false;
}
int get_stack_info(unsigned long *stack, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask)
{
task = task ? : current;
if (!stack)
goto unknown;
task = task ? : current;
if (in_task_stack(stack, task, info))
goto recursion_check;
if (task != current)
if (!get_stack_info_noinstr(stack, task, info))
goto unknown;
if (in_exception_stack(stack, info))
goto recursion_check;
if (in_irq_stack(stack, info))
goto recursion_check;
if (in_entry_stack(stack, info))
goto recursion_check;
goto unknown;
recursion_check:
/*
* Make sure we don't iterate through any given stack more than once.
* If it comes up a second time then there's something wrong going on:

3
arch/x86/mm/cpu_entry_area.c
View File

@ -21,7 +21,8 @@ DEFINE_PER_CPU(struct cea_exception_stacks*, cea_exception_stacks);
DECLARE_PER_CPU_PAGE_ALIGNED(struct doublefault_stack, doublefault_stack);
#endif
struct cpu_entry_area *get_cpu_entry_area(int cpu)
/* Is called from entry code, so must be noinstr */
noinstr struct cpu_entry_area *get_cpu_entry_area(int cpu)
{
unsigned long va = CPU_ENTRY_AREA_PER_CPU + cpu * CPU_ENTRY_AREA_SIZE;
BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE != 0);