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arm64: stacktrace: rework stack boundary discovery 

In subsequent patches we'll want to acquire the stack boundaries
ahead-of-time, and we'll need to be able to acquire the relevant
stack_info regardless of whether we have an object the happens to be on
the stack.

This patch replaces the on_XXX_stack() helpers with stackinfo_get_XXX()
helpers, with the caller being responsible for the checking whether an
object is on a relevant stack. For the moment this is moved into the
on_accessible_stack() functions, making these slightly larger;
subsequent patches will remove the on_accessible_stack() functions and
simplify the logic.

The on_irq_stack() and on_task_stack() helpers are kept as these are
used by IRQ entry sequences and stackleak respectively. As they're only
used as predicates, the stack_info pointer parameter is removed in both
cases.

As the on_accessible_stack() functions are always passed a non-NULL info
pointer, these now update info unconditionally. When updating the type
to STACK_TYPE_UNKNOWN, the low/high bounds are also modified, but as
these will not be consumed this should have no adverse affect.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220901130646.1316937-7-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland 2022-09-01 14:06:43 +01:00 committed by Catalin Marinas
parent 36f9a8793c
commit d1f684e46b
7 changed files with 151 additions and 94 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/arm64/include/asm/processor.h
View File

@ -410,7 +410,7 @@ long get_tagged_addr_ctrl(struct task_struct *task);
* The top of the current task's task stack
*/
#define current_top_of_stack() ((unsigned long)current->stack + THREAD_SIZE)
#define on_thread_stack() (on_task_stack(current, current_stack_pointer, 1, NULL))
#define on_thread_stack() (on_task_stack(current, current_stack_pointer, 1))
#endif /* __ASSEMBLY__ */
#endif /* __ASM_PROCESSOR_H */

78
arch/arm64/include/asm/stacktrace.h
View File

@ -22,77 +22,91 @@ extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
static inline bool on_irq_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
static inline struct stack_info stackinfo_get_irq(void)
{
unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
unsigned long high = low + IRQ_STACK_SIZE;
return on_stack(sp, size, low, high, STACK_TYPE_IRQ, info);
return (struct stack_info) {
.low = low,
.high = high,
.type = STACK_TYPE_IRQ,
};
}
static inline bool on_task_stack(const struct task_struct *tsk,
unsigned long sp, unsigned long size,
struct stack_info *info)
static inline bool on_irq_stack(unsigned long sp, unsigned long size)
{
struct stack_info info = stackinfo_get_irq();
return stackinfo_on_stack(&info, sp, size);
}
static inline struct stack_info stackinfo_get_task(const struct task_struct *tsk)
{
unsigned long low = (unsigned long)task_stack_page(tsk);
unsigned long high = low + THREAD_SIZE;
return on_stack(sp, size, low, high, STACK_TYPE_TASK, info);
return (struct stack_info) {
.low = low,
.high = high,
.type = STACK_TYPE_TASK,
};
}
static inline bool on_task_stack(const struct task_struct *tsk,
unsigned long sp, unsigned long size)
{
struct stack_info info = stackinfo_get_task(tsk);
return stackinfo_on_stack(&info, sp, size);
}
#ifdef CONFIG_VMAP_STACK
DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
static inline struct stack_info stackinfo_get_overflow(void)
{
unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
unsigned long high = low + OVERFLOW_STACK_SIZE;
return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info);
return (struct stack_info) {
.low = low,
.high = high,
.type = STACK_TYPE_OVERFLOW,
};
}
#else
static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
{
return false;
}
#define stackinfo_get_overflow() stackinfo_get_unknown()
#endif
#if defined(CONFIG_ARM_SDE_INTERFACE) && defined(CONFIG_VMAP_STACK)
DECLARE_PER_CPU(unsigned long *, sdei_stack_normal_ptr);
DECLARE_PER_CPU(unsigned long *, sdei_stack_critical_ptr);
static inline bool on_sdei_normal_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
static inline struct stack_info stackinfo_get_sdei_normal(void)
{
unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_normal_ptr);
unsigned long high = low + SDEI_STACK_SIZE;
return on_stack(sp, size, low, high, STACK_TYPE_SDEI_NORMAL, info);
return (struct stack_info) {
.low = low,
.high = high,
.type = STACK_TYPE_SDEI_NORMAL,
};
}
static inline bool on_sdei_critical_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
static inline struct stack_info stackinfo_get_sdei_critical(void)
{
unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_critical_ptr);
unsigned long high = low + SDEI_STACK_SIZE;
return on_stack(sp, size, low, high, STACK_TYPE_SDEI_CRITICAL, info);
return (struct stack_info) {
.low = low,
.high = high,
.type = STACK_TYPE_SDEI_CRITICAL,
};
}
#else
static inline bool on_sdei_normal_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
{
return false;
}
static inline bool on_sdei_critical_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
{
return false;
}
#define stackinfo_get_sdei_normal() stackinfo_get_unknown()
#define stackinfo_get_sdei_critical() stackinfo_get_unknown()
#endif
#endif /* __ASM_STACKTRACE_H */

28
arch/arm64/include/asm/stacktrace/common.h
View File

@ -65,6 +65,15 @@ struct unwind_state {
struct task_struct *task;
};
static inline struct stack_info stackinfo_get_unknown(void)
{
return (struct stack_info) {
.low = 0,
.high = 0,
.type = STACK_TYPE_UNKNOWN,
};
}
static inline bool stackinfo_on_stack(const struct stack_info *info,
unsigned long sp, unsigned long size)
{
@ -77,25 +86,6 @@ static inline bool stackinfo_on_stack(const struct stack_info *info,
return true;
}
static inline bool on_stack(unsigned long sp, unsigned long size,
unsigned long low, unsigned long high,
enum stack_type type, struct stack_info *info)
{
struct stack_info tmp = {
.low = low,
.high = high,
.type = type,
};
if (!stackinfo_on_stack(&tmp, sp, size))
return false;
if (info)
*info = tmp;
return true;
}
static inline void unwind_init_common(struct unwind_state *state,
struct task_struct *task)
{

2
arch/arm64/kernel/ptrace.c
View File

@ -121,7 +121,7 @@ static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
{
return ((addr & ~(THREAD_SIZE - 1)) ==
(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))) ||
on_irq_stack(addr, sizeof(unsigned long), NULL);
on_irq_stack(addr, sizeof(unsigned long));
}
/**

61
arch/arm64/kernel/stacktrace.c
View File

@ -67,36 +67,55 @@ static inline void unwind_init_from_task(struct unwind_state *state,
state->pc = thread_saved_pc(task);
}
/*
* We can only safely access per-cpu stacks from current in a non-preemptible
* context.
*/
static bool on_accessible_stack(const struct task_struct *tsk,
unsigned long sp, unsigned long size,
struct stack_info *info)
{
if (info)
info->type = STACK_TYPE_UNKNOWN;
struct stack_info tmp;
if (on_task_stack(tsk, sp, size, info))
return true;
tmp = stackinfo_get_task(tsk);
if (stackinfo_on_stack(&tmp, sp, size))
goto found;
/*
* We can only safely access per-cpu stacks when unwinding the current
* task in a non-preemptible context.
*/
if (tsk != current || preemptible())
return false;
if (on_irq_stack(sp, size, info))
return true;
if (on_overflow_stack(sp, size, info))
return true;
goto not_found;
if (IS_ENABLED(CONFIG_VMAP_STACK) &&
IS_ENABLED(CONFIG_ARM_SDE_INTERFACE) &&
in_nmi()) {
if (on_sdei_critical_stack(sp, size, info))
return true;
if (on_sdei_normal_stack(sp, size, info))
return true;
}
tmp = stackinfo_get_irq();
if (stackinfo_on_stack(&tmp, sp, size))
goto found;
tmp = stackinfo_get_overflow();
if (stackinfo_on_stack(&tmp, sp, size))
goto found;
/*
* We can only safely access SDEI stacks which unwinding the current
* task in an NMI context.
*/
if (!IS_ENABLED(CONFIG_VMAP_STACK) ||
!IS_ENABLED(CONFIG_ARM_SDE_INTERFACE) ||
!in_nmi())
goto not_found;
tmp = stackinfo_get_sdei_normal();
if (stackinfo_on_stack(&tmp, sp, size))
goto found;
tmp = stackinfo_get_sdei_critical();
if (stackinfo_on_stack(&tmp, sp, size))
goto found;
not_found:
*info = stackinfo_get_unknown();
return false;
found:
*info = tmp;
return true;
}
/*

37
arch/arm64/kvm/hyp/nvhe/stacktrace.c
View File

@ -39,34 +39,51 @@ static void hyp_prepare_backtrace(unsigned long fp, unsigned long pc)
DEFINE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)], pkvm_stacktrace);
static bool on_overflow_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
static struct stack_info stackinfo_get_overflow(void)
{
unsigned long low = (unsigned long)this_cpu_ptr(overflow_stack);
unsigned long high = low + OVERFLOW_STACK_SIZE;
return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info);
return (struct stack_info) {
.low = low,
.high = high,
.type = STACK_TYPE_OVERFLOW,
};
}
static bool on_hyp_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
static struct stack_info stackinfo_get_hyp(void)
{
struct kvm_nvhe_init_params *params = this_cpu_ptr(&kvm_init_params);
unsigned long high = params->stack_hyp_va;
unsigned long low = high - PAGE_SIZE;
return on_stack(sp, size, low, high, STACK_TYPE_HYP, info);
return (struct stack_info) {
.low = low,
.high = high,
.type = STACK_TYPE_HYP,
};
}
static bool on_accessible_stack(const struct task_struct *tsk,
unsigned long sp, unsigned long size,
struct stack_info *info)
{
if (info)
info->type = STACK_TYPE_UNKNOWN;
struct stack_info tmp;
return (on_overflow_stack(sp, size, info) ||
on_hyp_stack(sp, size, info));
tmp = stackinfo_get_overflow();
if (stackinfo_on_stack(&tmp, sp, size))
goto found;
tmp = stackinfo_get_hyp();
if (stackinfo_on_stack(&tmp, sp, size))
goto found;
*info = stackinfo_get_unknown();
return false;
found:
*info = tmp;
return true;
}
static int unwind_next(struct unwind_state *state)

37
arch/arm64/kvm/stacktrace.c
View File

@ -62,37 +62,54 @@ static bool kvm_nvhe_stack_kern_va(unsigned long *addr,
return true;
}
static bool on_overflow_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
static struct stack_info stackinfo_get_overflow(void)
{
struct kvm_nvhe_stacktrace_info *stacktrace_info
= this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
unsigned long low = (unsigned long)stacktrace_info->overflow_stack_base;
unsigned long high = low + OVERFLOW_STACK_SIZE;
return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info);
return (struct stack_info) {
.low = low,
.high = high,
.type = STACK_TYPE_OVERFLOW,
};
}
static bool on_hyp_stack(unsigned long sp, unsigned long size,
struct stack_info *info)
static struct stack_info stackinfo_get_hyp(void)
{
struct kvm_nvhe_stacktrace_info *stacktrace_info
= this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
unsigned long low = (unsigned long)stacktrace_info->stack_base;
unsigned long high = low + PAGE_SIZE;
return on_stack(sp, size, low, high, STACK_TYPE_HYP, info);
return (struct stack_info) {
.low = low,
.high = high,
.type = STACK_TYPE_HYP,
};
}
static bool on_accessible_stack(const struct task_struct *tsk,
unsigned long sp, unsigned long size,
struct stack_info *info)
{
if (info)
info->type = STACK_TYPE_UNKNOWN;
struct stack_info tmp;
return (on_overflow_stack(sp, size, info) ||
on_hyp_stack(sp, size, info));
tmp = stackinfo_get_overflow();
if (stackinfo_on_stack(&tmp, sp, size))
goto found;
tmp = stackinfo_get_hyp();
if (stackinfo_on_stack(&tmp, sp, size))
goto found;
*info = stackinfo_get_unknown();
return false;
found:
*info = tmp;
return true;
}
static int unwind_next(struct unwind_state *state)