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authorQing Zhang <zhangqing@loongson.cn>2022-08-06 16:10:05 +0800
committerHuacai Chen <chenhuacai@loongson.cn>2022-08-12 13:10:11 +0800
commit4d7bf939df08218e682f7a42952eee3bad4dceb7 (patch)
treedce86915387d231ca6d29f3abd71fc1ef99af295
parent93a4fa622eb061f75f87f0cf9609ab4e69c67d01 (diff)
LoongArch: Add USER_STACKTRACE support
To get the best stacktrace output, you can compile your userspace programs with frame pointers (at least glibc + the app you are tracing). 1, export "CC = gcc -fno-omit-frame-pointer"; 2, compile your programs with "CC"; 3, use uprobe to get stacktrace output. ... 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> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
-rw-r--r--arch/loongarch/Kconfig1
-rw-r--r--arch/loongarch/include/asm/stacktrace.h5
-rw-r--r--arch/loongarch/kernel/stacktrace.c41
3 files changed, 47 insertions, 0 deletions
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 947cb633744b..2f110a00a930 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -119,6 +119,7 @@ config LOONGARCH
select SWIOTLB
select TRACE_IRQFLAGS_SUPPORT
select USE_PERCPU_NUMA_NODE_ID
+ select USER_STACKTRACE_SUPPORT
select ZONE_DMA32
config 32BIT
diff --git a/arch/loongarch/include/asm/stacktrace.h b/arch/loongarch/include/asm/stacktrace.h
index 5820a0cabe3a..f23adb15f418 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_irq_stack(unsigned long stack, struct stack_info *info);
bool in_task_stack(unsigned long stack, struct task_struct *task, struct stack_info *info);
int get_stack_info(unsigned long stack, struct task_struct *task, struct stack_info *info);
diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
index e690c1c769f2..3a690f96f00c 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 +36,43 @@ 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 = 1;
+ 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;
+
+ 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;
+ }
+}