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authorHeiko Carstens2023-10-30 16:50:47 +0100
committerVasily Gorbik2023-11-05 22:34:57 +0100
commitaa44433ac4ee2ae59b4b11e01eddb6241ae24ef5 (patch)
tree75fec215f6dd53e54fa2116e6d0a9f3240b3b1fb /arch
parent504b73d00a55a68c0d1bb0e7c12e56e5f908e906 (diff)
s390: add USER_STACKTRACE support
Use the perf_callchain_user() code as blueprint to also add support for USER_STACKTRACE. To describe how to use this cite the commit message of the LoongArch implementation which came with commit 4d7bf939df08 ("LoongArch: Add USER_STACKTRACE support"), but replace -fno-omit-frame-pointer option with the s390 specific -mbackchain option: ====================================================================== 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 -mbackchain"; 2, compile your programs with "CC"; 3, use uprobe to get stacktrace output. ... echo 'p:malloc /usr/lib64/libc.so.6:0x0a4704 size=%r2:u64' > uprobe_events echo 'p:free /usr/lib64/libc.so.6:0x0a4d50 ptr=%r2:u64' >> 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: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/s390/Kconfig1
-rw-r--r--arch/s390/kernel/stacktrace.c43
2 files changed, 44 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index b0d67ac8695f..3bec98d20283 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -236,6 +236,7 @@ config S390
select THREAD_INFO_IN_TASK
select TRACE_IRQFLAGS_SUPPORT
select TTY
+ select USER_STACKTRACE_SUPPORT
select VIRT_CPU_ACCOUNTING
select ZONE_DMA
# Note: keep the above list sorted alphabetically
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 0787010139f7..94f440e38303 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -6,9 +6,12 @@
*/
#include <linux/stacktrace.h>
+#include <linux/uaccess.h>
+#include <linux/compat.h>
#include <asm/stacktrace.h>
#include <asm/unwind.h>
#include <asm/kprobes.h>
+#include <asm/ptrace.h>
void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
struct task_struct *task, struct pt_regs *regs)
@@ -58,3 +61,43 @@ int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
return -EINVAL;
return 0;
}
+
+void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
+ const struct pt_regs *regs)
+{
+ struct stack_frame_user __user *sf;
+ unsigned long ip, sp;
+ bool first = true;
+
+ if (is_compat_task())
+ return;
+ if (!consume_entry(cookie, instruction_pointer(regs)))
+ return;
+ sf = (void __user *)user_stack_pointer(regs);
+ pagefault_disable();
+ while (1) {
+ if (__get_user(sp, &sf->back_chain))
+ break;
+ if (__get_user(ip, &sf->gprs[8]))
+ break;
+ if (ip & 0x1) {
+ /*
+ * If the instruction address is invalid, and this
+ * is the first stack frame, assume r14 has not
+ * been written to the stack yet. Otherwise exit.
+ */
+ if (first && !(regs->gprs[14] & 0x1))
+ ip = regs->gprs[14];
+ else
+ break;
+ }
+ if (!consume_entry(cookie, ip))
+ break;
+ /* Sanity check: ABI requires SP to be aligned 8 bytes. */
+ if (!sp || sp & 0x7)
+ break;
+ sf = (void __user *)sp;
+ first = false;
+ }
+ pagefault_enable();
+}