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arm64: stacktrace: Factor out unwind_next_common() 

Move common unwind_next logic to stacktrace/common.h. This allows
reusing the code in the implementation the nVHE hypervisor stack
unwinder, later in this series.

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-4-kaleshsingh@google.com
This commit is contained in:
Kalesh Singh 2022-07-26 00:37:36 -07:00 committed by Marc Zyngier
parent 15a59f19a0
commit be63c647fd
2 changed files with 54 additions and 37 deletions
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50
arch/arm64/include/asm/stacktrace/common.h
View File

@ -65,6 +65,10 @@ struct unwind_state {
static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
struct stack_info *info);
static inline bool on_accessible_stack(const struct task_struct *tsk,
unsigned long sp, unsigned long size,
struct stack_info *info);
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)
@ -120,4 +124,50 @@ static inline void unwind_init_common(struct unwind_state *state,
state->prev_type = STACK_TYPE_UNKNOWN;
}
static inline int unwind_next_common(struct unwind_state *state,
struct stack_info *info)
{
struct task_struct *tsk = state->task;
unsigned long fp = state->fp;
if (fp & 0x7)
return -EINVAL;
if (!on_accessible_stack(tsk, fp, 16, info))
return -EINVAL;
if (test_bit(info->type, state->stacks_done))
return -EINVAL;
/*
* As stacks grow downward, any valid record on the same stack must be
* at a strictly higher address than the prior record.
*
* Stacks can nest in several valid orders, e.g.
*
* TASK -> IRQ -> OVERFLOW -> SDEI_NORMAL
* TASK -> SDEI_NORMAL -> SDEI_CRITICAL -> OVERFLOW
*
* ... but the nesting itself is strict. Once we transition from one
* stack to another, it's never valid to unwind back to that first
* stack.
*/
if (info->type == state->prev_type) {
if (fp <= state->prev_fp)
return -EINVAL;
} else {
__set_bit(state->prev_type, state->stacks_done);
}
/*
* Record this frame record's values and location. The prev_fp and
* prev_type are only meaningful to the next unwind_next() invocation.
*/
state->fp = READ_ONCE(*(unsigned long *)(fp));
state->pc = READ_ONCE(*(unsigned long *)(fp + 8));
state->prev_fp = fp;
state->prev_type = info->type;
return 0;
}
#endif /* __ASM_STACKTRACE_COMMON_H */

41
arch/arm64/kernel/stacktrace.c
View File

@ -81,48 +81,15 @@ static int notrace unwind_next(struct unwind_state *state)
struct task_struct *tsk = state->task;
unsigned long fp = state->fp;
struct stack_info info;
int err;
/* Final frame; nothing to unwind */
if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
return -ENOENT;
if (fp & 0x7)
return -EINVAL;
if (!on_accessible_stack(tsk, fp, 16, &info))
return -EINVAL;
if (test_bit(info.type, state->stacks_done))
return -EINVAL;
/*
* As stacks grow downward, any valid record on the same stack must be
* at a strictly higher address than the prior record.
*
* Stacks can nest in several valid orders, e.g.
*
* TASK -> IRQ -> OVERFLOW -> SDEI_NORMAL
* TASK -> SDEI_NORMAL -> SDEI_CRITICAL -> OVERFLOW
*
* ... but the nesting itself is strict. Once we transition from one
* stack to another, it's never valid to unwind back to that first
* stack.
*/
if (info.type == state->prev_type) {
if (fp <= state->prev_fp)
return -EINVAL;
} else {
__set_bit(state->prev_type, state->stacks_done);
}
/*
* Record this frame record's values and location. The prev_fp and
* prev_type are only meaningful to the next unwind_next() invocation.
*/
state->fp = READ_ONCE(*(unsigned long *)(fp));
state->pc = READ_ONCE(*(unsigned long *)(fp + 8));
state->prev_fp = fp;
state->prev_type = info.type;
err = unwind_next_common(state, &info);
if (err)
return err;
state->pc = ptrauth_strip_insn_pac(state->pc);