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powerpc: Rename STACK_FRAME_MARKER and derive it from frame offset
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This is a count of longs from the stack pointer to the regs marker.
Rename it to make it more distinct from the other byte offsets. It
can be derived from the byte offset definitions just added.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-10-npiggin@gmail.com
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Nicholas Piggin authored and Michael Ellerman committed Dec 2, 2022
1 parent d2e8ff9 commit e856e33
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Showing 5 changed files with 6 additions and 7 deletions.
4 changes: 2 additions & 2 deletions arch/powerpc/include/asm/ptrace.h
Original file line number Diff line number Diff line change
Expand Up @@ -126,7 +126,6 @@ struct pt_regs
STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
#define STACK_INT_FRAME_REGS STACK_FRAME_OVERHEAD
#define STACK_INT_FRAME_MARKER (STACK_FRAME_OVERHEAD - 16)
#define STACK_FRAME_MARKER 12

#ifdef CONFIG_PPC64_ELF_ABI_V2
#define STACK_FRAME_MIN_SIZE 32
Expand All @@ -147,14 +146,15 @@ struct pt_regs
#define STACK_INT_FRAME_SIZE (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
#define STACK_INT_FRAME_REGS STACK_FRAME_OVERHEAD
#define STACK_INT_FRAME_MARKER (STACK_FRAME_OVERHEAD - 8)
#define STACK_FRAME_MARKER 2
#define STACK_FRAME_MIN_SIZE STACK_FRAME_OVERHEAD

/* Size of stack frame allocated when calling signal handler. */
#define __SIGNAL_FRAMESIZE 64

#endif /* __powerpc64__ */

#define STACK_INT_FRAME_MARKER_LONGS (STACK_INT_FRAME_MARKER/sizeof(long))

#ifndef __ASSEMBLY__
#include <asm/paca.h>

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2 changes: 1 addition & 1 deletion arch/powerpc/kernel/process.c
Original file line number Diff line number Diff line change
Expand Up @@ -2263,7 +2263,7 @@ void __no_sanitize_address show_stack(struct task_struct *tsk,
* We look for the "regs" marker in the current frame.
*/
if (validate_sp(sp, tsk, STACK_FRAME_WITH_PT_REGS)
&& stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
&& stack[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) {
struct pt_regs *regs = (struct pt_regs *)
(sp + STACK_INT_FRAME_REGS);

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2 changes: 1 addition & 1 deletion arch/powerpc/kernel/stacktrace.c
Original file line number Diff line number Diff line change
Expand Up @@ -136,7 +136,7 @@ int __no_sanitize_address arch_stack_walk_reliable(stack_trace_consume_fn consum

/* Mark stacktraces with exception frames as unreliable. */
if (sp <= stack_end - STACK_INT_FRAME_SIZE &&
stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
stack[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) {
return -EINVAL;
}

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2 changes: 1 addition & 1 deletion arch/powerpc/perf/callchain.c
Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re

if (next_sp == sp + STACK_INT_FRAME_SIZE &&
validate_sp(sp, current, STACK_INT_FRAME_SIZE) &&
fp[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
fp[STACK_INT_FRAME_MARKER_LONGS] == STACK_FRAME_REGS_MARKER) {
/*
* This looks like an interrupt frame for an
* interrupt that occurred in the kernel
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3 changes: 1 addition & 2 deletions arch/powerpc/xmon/xmon.c
Original file line number Diff line number Diff line change
Expand Up @@ -1721,7 +1721,6 @@ static void get_function_bounds(unsigned long pc, unsigned long *startp,
}

#define LRSAVE_OFFSET (STACK_FRAME_LR_SAVE * sizeof(unsigned long))
#define MARKER_OFFSET (STACK_FRAME_MARKER * sizeof(unsigned long))

static void xmon_show_stack(unsigned long sp, unsigned long lr,
unsigned long pc)
Expand Down Expand Up @@ -1784,7 +1783,7 @@ static void xmon_show_stack(unsigned long sp, unsigned long lr,

/* Look for "regs" marker to see if this is
an exception frame. */
if (mread(sp + MARKER_OFFSET, &marker, sizeof(unsigned long))
if (mread(sp + STACK_INT_FRAME_MARKER, &marker, sizeof(unsigned long))
&& marker == STACK_FRAME_REGS_MARKER) {
if (mread(sp + STACK_INT_FRAME_REGS, &regs, sizeof(regs)) != sizeof(regs)) {
printf("Couldn't read registers at %lx\n",
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