[patch V3 29/29] x86/stacktrace: Use common infrastructure

Thomas Gleixner
2019-04-25T09:45:22Z

Replace the stack_trace_save*() functions with the new arch_stack_walk()
interfaces.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
---
arch/x86/Kconfig | 1
arch/x86/kernel/stacktrace.c | 116 +++++++------------------------------------
2 files changed, 20 insertions(+), 97 deletions(-)

--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -74,6 +74,7 @@ config X86
select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
+ select ARCH_STACKWALK
select ARCH_SUPPORTS_ACPI
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -12,75 +12,31 @@
#include <asm/stacktrace.h>
#include <asm/unwind.h>

-static int save_stack_address(struct stack_trace *trace, unsigned long addr,
- bool nosched)
-{
- if (nosched && in_sched_functions(addr))
- return 0;
-
- if (trace->skip > 0) {
- trace->skip--;
- return 0;
- }
-
- if (trace->nr_entries >= trace->max_entries)
- return -1;
-
- trace->entries[trace->nr_entries++] = addr;
- return 0;
-}
-
-static void noinline __save_stack_trace(struct stack_trace *trace,
- struct task_struct *task, struct pt_regs *regs,
- bool nosched)
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+ struct task_struct *task, struct pt_regs *regs)
{
struct unwind_state state;
unsigned long addr;

- if (regs)
- save_stack_address(trace, regs->ip, nosched);
+ if (regs && !consume_entry(cookie, regs->ip, false))
+ return;

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))
+ if (!addr || !consume_entry(cookie, addr, false))
break;
}
}

/*
- * Save stack-backtrace addresses into a stack_trace buffer.
+ * This function returns an error if it detects any unreliable features of the
+ * stack. Otherwise it guarantees that the stack trace is reliable.
+ *
+ * If the task is not 'current', the caller *must* ensure the task is inactive.
*/
-void save_stack_trace(struct stack_trace *trace)
-{
- trace->skip++;
- __save_stack_trace(trace, current, NULL, false);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace);
-
-void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
-{
- __save_stack_trace(trace, current, regs, false);
-}
-
-void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
-{
- if (!try_get_task_stack(tsk))
- return;
-
- if (tsk == current)
- trace->skip++;
- __save_stack_trace(trace, tsk, NULL, true);
-
- put_task_stack(tsk);
-}
-EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
-
-#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
-
-static int __always_inline
-__save_stack_trace_reliable(struct stack_trace *trace,
- struct task_struct *task)
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+ void *cookie, struct task_struct *task)
{
struct unwind_state state;
struct pt_regs *regs;
@@ -117,7 +73,7 @@ static int __always_inline
if (!addr)
return -EINVAL;

- if (save_stack_address(trace, addr, false))
+ if (!consume_entry(cookie, addr, false))
return -EINVAL;
}

@@ -132,32 +88,6 @@ static int __always_inline
return 0;
}

-/*
- * This function returns an error if it detects any unreliable features of the
- * stack. Otherwise it guarantees that the stack trace is reliable.
- *
- * If the task is not 'current', the caller *must* ensure the task is inactive.
- */
-int save_stack_trace_tsk_reliable(struct task_struct *tsk,
- struct stack_trace *trace)
-{
- int ret;
-
- /*
- * If the task doesn't have a stack (e.g., a zombie), the stack is
- * "reliably" empty.
- */
- if (!try_get_task_stack(tsk))
- return 0;
-
- ret = __save_stack_trace_reliable(trace, tsk);
-
- put_task_stack(tsk);
-
- return ret;
-}
-#endif /* CONFIG_HAVE_RELIABLE_STACKTRACE */
-
/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */

struct stack_frame_user {
@@ -182,15 +112,15 @@ copy_stack_frame(const void __user *fp,
return ret;
}

-static inline void __save_stack_trace_user(struct stack_trace *trace)
+void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
+ const struct pt_regs *regs)
{
- const struct pt_regs *regs = task_pt_regs(current);
const void __user *fp = (const void __user *)regs->bp;

- if (trace->nr_entries < trace->max_entries)
- trace->entries[trace->nr_entries++] = regs->ip;
+ if (!consume_entry(cookie, regs->ip, false))
+ return;

- while (trace->nr_entries < trace->max_entries) {
+ while (1) {
struct stack_frame_user frame;

frame.next_fp = NULL;
@@ -200,8 +130,8 @@ static inline void __save_stack_trace_us
if ((unsigned long)fp < regs->sp)
break;
if (frame.ret_addr) {
- trace->entries[trace->nr_entries++] =
- frame.ret_addr;
+ if (!consume_entry(cookie, frame.ret_addr, false))
+ return;
}
if (fp == frame.next_fp)
break;
@@ -209,11 +139,3 @@ static inline void __save_stack_trace_us
}
}

-void save_stack_trace_user(struct stack_trace *trace)
-{
- /*
- * Trace user stack if we are not a kernel thread
- */
- if (current->mm)
- __save_stack_trace_user(trace);
-}