[PATCH v3 37/51] x86/stacktrace: convert save_stack_trace_*() to use the new unwinder

From: Josh Poimboeuf
Date: Fri Aug 12 2016 - 10:32:36 EST


Convert save_stack_trace_*() to use the new unwinder. dump_trace() has
been deprecated.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
arch/x86/kernel/stacktrace.c | 74 +++++++++++++++++---------------------------
1 file changed, 29 insertions(+), 45 deletions(-)

diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index 785aef1..a168e7e 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -8,80 +8,64 @@
#include <linux/export.h>
#include <linux/uaccess.h>
#include <asm/stacktrace.h>
+#include <asm/unwind.h>

-static int save_stack_stack(void *data, const char *name)
+static int save_stack_address(struct stack_trace *trace, unsigned long addr,
+ bool nosched)
{
- return 0;
-}
-
-static int
-__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)
-{
- struct stack_trace *trace = data;
-#ifdef CONFIG_FRAME_POINTER
- if (!reliable)
- return 0;
-#endif
if (nosched && in_sched_functions(addr))
return 0;
+
if (trace->skip > 0) {
trace->skip--;
return 0;
}
- if (trace->nr_entries < trace->max_entries) {
- trace->entries[trace->nr_entries++] = addr;
- return 0;
- } else {
- return -1; /* no more room, stop walking the stack */
- }
-}

-static int save_stack_address(void *data, unsigned long addr, int reliable)
-{
- return __save_stack_address(data, addr, reliable, false);
+ if (trace->nr_entries >= trace->max_entries)
+ return -1;
+
+ trace->entries[trace->nr_entries++] = addr;
+ return 0;
}

-static int
-save_stack_address_nosched(void *data, unsigned long addr, int reliable)
+static void __save_stack_trace(struct stack_trace *trace,
+ struct task_struct *task, struct pt_regs *regs,
+ bool nosched)
{
- return __save_stack_address(data, addr, reliable, true);
-}
+ struct unwind_state state;
+ unsigned long addr;

-static const struct stacktrace_ops save_stack_ops = {
- .stack = save_stack_stack,
- .address = save_stack_address,
- .walk_stack = print_context_stack,
-};
+ if (regs)
+ save_stack_address(trace, regs->ip, nosched);

-static const struct stacktrace_ops save_stack_ops_nosched = {
- .stack = save_stack_stack,
- .address = save_stack_address_nosched,
- .walk_stack = print_context_stack,
-};
+ for (unwind_start(&state, task, regs, NULL); !unwind_done(&state);
+ unwind_next_frame(&state)) {
+ addr = unwind_get_return_address(&state);
+ if (!addr || save_stack_address(trace, addr, nosched))
+ break;
+ }
+
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}

/*
* Save stack-backtrace addresses into a stack_trace buffer.
*/
void save_stack_trace(struct stack_trace *trace)
{
- dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
+ __save_stack_trace(trace, NULL, NULL, false);
}
EXPORT_SYMBOL_GPL(save_stack_trace);

void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
- dump_trace(current, regs, NULL, 0, &save_stack_ops, trace);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
+ __save_stack_trace(trace, NULL, regs, false);
}

void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
- dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = ULONG_MAX;
+ __save_stack_trace(trace, tsk, NULL, true);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);

--
2.7.4