lkml.org 
[lkml]   [2022]   [Aug]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4/4] LoongArch: Add USER_STACKTRACE support
Date
To get the best output you can compile your userspace programs with
frame pointers (at least glibc + the app you are tracing export "CC
=gcc -fno-omit-frame-pointer".

...
echo 'p:malloc /usr/lib64/libc.so.6:0x0a4704 size=%r4:u64'
> uprobe_events
echo 'p:free /usr/lib64/libc.so.6:0x0a4d50 ptr=%r4:x64'
>> uprobe_events
echo 'comm == "demo"' > ./events/uprobes/malloc/filter
echo 'comm == "demo"' > ./events/uprobes/free/filter
echo 1 > ./options/userstacktrace
echo 1 > ./options/sym-userobj
...

Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/stacktrace.h | 5 +++
arch/loongarch/kernel/stacktrace.c | 42 +++++++++++++++++++++++++
3 files changed, 48 insertions(+)

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 85d0fa3147cd..05906384d564 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -107,6 +107,7 @@ config LOONGARCH
select SWIOTLB
select TRACE_IRQFLAGS_SUPPORT
select USE_PERCPU_NUMA_NODE_ID
+ select USER_STACKTRACE_SUPPORT
select ZONE_DMA32
select MMU_GATHER_MERGE_VMAS if MMU

diff --git a/arch/loongarch/include/asm/stacktrace.h b/arch/loongarch/include/asm/stacktrace.h
index 49cb89213aeb..77fdb8ad662d 100644
--- a/arch/loongarch/include/asm/stacktrace.h
+++ b/arch/loongarch/include/asm/stacktrace.h
@@ -21,6 +21,11 @@ struct stack_info {
unsigned long begin, end, next_sp;
};

+struct stack_frame {
+ unsigned long fp;
+ unsigned long ra;
+};
+
bool in_task_stack(unsigned long stack, struct task_struct *task,
struct stack_info *info);
bool in_irq_stack(unsigned long stack, struct stack_info *info);
diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
index f4f4b8ad3917..344224c7cb0e 100644
--- a/arch/loongarch/kernel/stacktrace.c
+++ b/arch/loongarch/kernel/stacktrace.c
@@ -6,6 +6,7 @@
*/
#include <linux/sched.h>
#include <linux/stacktrace.h>
+#include <linux/uaccess.h>

#include <asm/stacktrace.h>
#include <asm/unwind.h>
@@ -35,3 +36,44 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
break;
}
}
+
+static int
+copy_stack_frame(unsigned long fp, struct stack_frame *frame)
+{
+ int ret;
+ unsigned long err;
+ unsigned long __user *user_frame_tail;
+
+ user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
+ if (!access_ok(user_frame_tail, sizeof(*frame)))
+ return 0;
+
+ ret = 1;
+ pagefault_disable();
+ err = (__copy_from_user_inatomic(frame, user_frame_tail, sizeof(*frame)));
+ if (err || (unsigned long)user_frame_tail >= frame->fp)
+ ret = 0;
+ pagefault_enable();
+
+ return ret;
+}
+
+void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
+ const struct pt_regs *regs)
+{
+ unsigned long fp = regs->regs[22];
+
+ while (fp && !((unsigned long)fp & 0xf)) {
+ struct stack_frame frame;
+
+ frame.fp = 0;
+ frame.ra = 0;
+ if (!copy_stack_frame(fp, &frame))
+ break;
+ if (!frame.ra)
+ break;
+ if (!consume_entry(cookie, frame.ra))
+ break;
+ fp = frame.fp;
+ }
+}
--
2.20.1
\
 
 \ /
  Last update: 2022-08-01 14:39    [W:0.197 / U:0.460 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site