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-rw-r--r--arch/s390/kernel/stacktrace.c108
1 files changed, 94 insertions, 14 deletions
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
index 94f440e383..640363b2a1 100644
--- a/arch/s390/kernel/stacktrace.c
+++ b/arch/s390/kernel/stacktrace.c
@@ -5,6 +5,7 @@
* Copyright IBM Corp. 2006
*/
+#include <linux/perf_event.h>
#include <linux/stacktrace.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
@@ -62,42 +63,121 @@ int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
return 0;
}
-void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
- const struct pt_regs *regs)
+static inline bool store_ip(stack_trace_consume_fn consume_entry, void *cookie,
+ struct perf_callchain_entry_ctx *entry, bool perf,
+ unsigned long ip)
+{
+#ifdef CONFIG_PERF_EVENTS
+ if (perf) {
+ if (perf_callchain_store(entry, ip))
+ return false;
+ return true;
+ }
+#endif
+ return consume_entry(cookie, ip);
+}
+
+static inline bool ip_invalid(unsigned long ip)
+{
+ /*
+ * Perform some basic checks if an instruction address taken
+ * from unreliable source is invalid.
+ */
+ if (ip & 1)
+ return true;
+ if (ip < mmap_min_addr)
+ return true;
+ if (ip >= current->mm->context.asce_limit)
+ return true;
+ return false;
+}
+
+static inline bool ip_within_vdso(unsigned long ip)
{
+ return in_range(ip, current->mm->context.vdso_base, vdso_text_size());
+}
+
+void arch_stack_walk_user_common(stack_trace_consume_fn consume_entry, void *cookie,
+ struct perf_callchain_entry_ctx *entry,
+ const struct pt_regs *regs, bool perf)
+{
+ struct stack_frame_vdso_wrapper __user *sf_vdso;
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)))
+ if (!current->mm)
+ return;
+ ip = instruction_pointer(regs);
+ if (!store_ip(consume_entry, cookie, entry, perf, ip))
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]))
+ /*
+ * VDSO entry code has a non-standard stack frame layout.
+ * See VDSO user wrapper code for details.
+ */
+ if (!sp && ip_within_vdso(ip)) {
+ sf_vdso = (void __user *)sf;
+ if (__get_user(ip, &sf_vdso->return_address))
+ break;
+ sp = (unsigned long)sf + STACK_FRAME_VDSO_OVERHEAD;
+ sf = (void __user *)sp;
+ if (__get_user(sp, &sf->back_chain))
+ break;
+ } else {
+ sf = (void __user *)sp;
+ if (__get_user(ip, &sf->gprs[8]))
+ break;
+ }
+ /* Sanity check: ABI requires SP to be 8 byte aligned. */
+ if (sp & 0x7)
break;
- if (ip & 0x1) {
+ if (ip_invalid(ip)) {
/*
* 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
+ if (!first)
+ break;
+ ip = regs->gprs[14];
+ if (ip_invalid(ip))
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;
+ if (!store_ip(consume_entry, cookie, entry, perf, ip))
+ return;
first = false;
}
pagefault_enable();
}
+
+void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
+ const struct pt_regs *regs)
+{
+ arch_stack_walk_user_common(consume_entry, cookie, NULL, regs, false);
+}
+
+unsigned long return_address(unsigned int n)
+{
+ struct unwind_state state;
+ unsigned long addr;
+
+ /* Increment to skip current stack entry */
+ n++;
+
+ unwind_for_each_frame(&state, NULL, NULL, 0) {
+ addr = unwind_get_return_address(&state);
+ if (!addr)
+ break;
+ if (!n--)
+ return addr;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(return_address);