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powerpc: split validate_sp into two functions 

Most callers just want to validate an arbitrary kernel stack pointer,
some need a particular size. Make the size case the exceptional one
with an extra function.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-15-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2022-11-27 22:49:39 +10:00 committed by Michael Ellerman
parent edbd0387f3
commit 4cefb0f6c5
4 changed files with 30 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
arch/powerpc/include/asm/processor.h
View File

@ -374,9 +374,18 @@ static inline unsigned long __pack_fe01(unsigned int fpmode)
#endif
/* Check that a certain kernel stack pointer is valid in task_struct p */
int validate_sp(unsigned long sp, struct task_struct *p,
unsigned long nbytes);
/*
* Check that a certain kernel stack pointer is a valid (minimum sized)
* stack frame in task_struct p.
*/
int validate_sp(unsigned long sp, struct task_struct *p);
/*
* validate the stack frame of a particular minimum size, used for when we are
* looking at a certain object in the stack beyond the minimum.
*/
int validate_sp_size(unsigned long sp, struct task_struct *p,
unsigned long nbytes);
/*
* Prefetch macros.

23
arch/powerpc/kernel/process.c
View File

@ -2157,9 +2157,12 @@ static inline int valid_emergency_stack(unsigned long sp, struct task_struct *p,
return 0;
}
int validate_sp(unsigned long sp, struct task_struct *p,
unsigned long nbytes)
/*
* validate the stack frame of a particular minimum size, used for when we are
* looking at a certain object in the stack beyond the minimum.
*/
int validate_sp_size(unsigned long sp, struct task_struct *p,
unsigned long nbytes)
{
unsigned long stack_page = (unsigned long)task_stack_page(p);
@ -2175,7 +2178,10 @@ int validate_sp(unsigned long sp, struct task_struct *p,
return valid_emergency_stack(sp, p, nbytes);
}
EXPORT_SYMBOL(validate_sp);
int validate_sp(unsigned long sp, struct task_struct *p)
{
return validate_sp_size(sp, p, STACK_FRAME_OVERHEAD);
}
static unsigned long ___get_wchan(struct task_struct *p)
{
@ -2183,13 +2189,12 @@ static unsigned long ___get_wchan(struct task_struct *p)
int count = 0;
sp = p->thread.ksp;
if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
if (!validate_sp(sp, p))
return 0;
do {
sp = READ_ONCE_NOCHECK(*(unsigned long *)sp);
if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD) ||
task_is_running(p))
if (!validate_sp(sp, p) || task_is_running(p))
return 0;
if (count > 0) {
ip = READ_ONCE_NOCHECK(((unsigned long *)sp)[STACK_FRAME_LR_SAVE]);
@ -2243,7 +2248,7 @@ void __no_sanitize_address show_stack(struct task_struct *tsk,
lr = 0;
printk("%sCall Trace:\n", loglvl);
do {
if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
if (!validate_sp(sp, tsk))
break;
stack = (unsigned long *) sp;
@ -2270,7 +2275,7 @@ void __no_sanitize_address show_stack(struct task_struct *tsk,
* could hold a pt_regs, if that does not fit then it can't
* have regs.
*/
if (validate_sp(sp, tsk, STACK_SWITCH_FRAME_SIZE)
if (validate_sp_size(sp, tsk, STACK_SWITCH_FRAME_SIZE)
&& stack[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) {
struct pt_regs *regs = (struct pt_regs *)
(sp + STACK_INT_FRAME_REGS);

2
arch/powerpc/kernel/stacktrace.c
View File

@ -43,7 +43,7 @@ void __no_sanitize_address arch_stack_walk(stack_trace_consume_fn consume_entry,
unsigned long *stack = (unsigned long *) sp;
unsigned long newsp, ip;
if (!validate_sp(sp, task, STACK_FRAME_OVERHEAD))
if (!validate_sp(sp, task))
return;
newsp = stack[0];

6
arch/powerpc/perf/callchain.c
View File

@ -27,7 +27,7 @@ static int valid_next_sp(unsigned long sp, unsigned long prev_sp)
{
if (sp & 0xf)
return 0; /* must be 16-byte aligned */
if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
if (!validate_sp(sp, current))
return 0;
if (sp >= prev_sp + STACK_FRAME_MIN_SIZE)
return 1;
@ -53,7 +53,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
sp = regs->gpr[1];
perf_callchain_store(entry, perf_instruction_pointer(regs));
if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
if (!validate_sp(sp, current))
return;
for (;;) {
@ -61,7 +61,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
next_sp = fp[0];
if (next_sp == sp + STACK_INT_FRAME_SIZE &&
validate_sp(sp, current, STACK_INT_FRAME_SIZE) &&
validate_sp_size(sp, current, STACK_INT_FRAME_SIZE) &&
fp[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) {
/*
* This looks like an interrupt frame for an