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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2019-01-28 08:33:08 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2019-05-02 13:54:11 +0200
commit78c98f9074135d3dab4e39544e0a537f92388fce (patch)
tree6f6d96e8e0911fe2aa27ec89cca52d56d3ed6f7e /arch/s390/include
parent1c705ad5efae9c712e763a47fbcc95b87b7347d2 (diff)
s390/unwind: introduce stack unwind API
Rework the dump_trace() stack unwinder interface to support different unwinding algorithms. The new interface looks like this: struct unwind_state state; unwind_for_each_frame(&state, task, regs, start_stack) do_something(state.sp, state.ip, state.reliable); The unwind_bc.c file contains the implementation for the classic back-chain unwinder. One positive side effect of the new code is it now handles ftraced functions gracefully. It prints the real name of the return function instead of 'return_to_handler'. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include')
-rw-r--r--arch/s390/include/asm/processor.h72
-rw-r--r--arch/s390/include/asm/stacktrace.h114
-rw-r--r--arch/s390/include/asm/unwind.h101
3 files changed, 215 insertions, 72 deletions
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 8aa85e39f50b..9f2ff4a54aff 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -156,25 +156,6 @@ struct thread_struct {
typedef struct thread_struct thread_struct;
-/*
- * Stack layout of a C stack frame.
- */
-#ifndef __PACK_STACK
-struct stack_frame {
- unsigned long back_chain;
- unsigned long empty1[5];
- unsigned long gprs[10];
- unsigned int empty2[8];
-};
-#else
-struct stack_frame {
- unsigned long empty1[5];
- unsigned int empty2[8];
- unsigned long gprs[10];
- unsigned long back_chain;
-};
-#endif
-
#define ARCH_MIN_TASKALIGN 8
#define INIT_THREAD { \
@@ -206,11 +187,7 @@ struct mm_struct;
struct seq_file;
struct pt_regs;
-typedef int (*dump_trace_func_t)(void *data, unsigned long address, int reliable);
-void dump_trace(dump_trace_func_t func, void *data,
- struct task_struct *task, unsigned long sp);
void show_registers(struct pt_regs *regs);
-
void show_cacheinfo(struct seq_file *m);
/* Free all resources held by a thread. */
@@ -244,55 +221,6 @@ static __no_kasan_or_inline unsigned short stap(void)
return cpu_address;
}
-#define CALL_ARGS_0() \
- register unsigned long r2 asm("2")
-#define CALL_ARGS_1(arg1) \
- register unsigned long r2 asm("2") = (unsigned long)(arg1)
-#define CALL_ARGS_2(arg1, arg2) \
- CALL_ARGS_1(arg1); \
- register unsigned long r3 asm("3") = (unsigned long)(arg2)
-#define CALL_ARGS_3(arg1, arg2, arg3) \
- CALL_ARGS_2(arg1, arg2); \
- register unsigned long r4 asm("4") = (unsigned long)(arg3)
-#define CALL_ARGS_4(arg1, arg2, arg3, arg4) \
- CALL_ARGS_3(arg1, arg2, arg3); \
- register unsigned long r4 asm("5") = (unsigned long)(arg4)
-#define CALL_ARGS_5(arg1, arg2, arg3, arg4, arg5) \
- CALL_ARGS_4(arg1, arg2, arg3, arg4); \
- register unsigned long r4 asm("6") = (unsigned long)(arg5)
-
-#define CALL_FMT_0 "=&d" (r2) :
-#define CALL_FMT_1 "+&d" (r2) :
-#define CALL_FMT_2 CALL_FMT_1 "d" (r3),
-#define CALL_FMT_3 CALL_FMT_2 "d" (r4),
-#define CALL_FMT_4 CALL_FMT_3 "d" (r5),
-#define CALL_FMT_5 CALL_FMT_4 "d" (r6),
-
-#define CALL_CLOBBER_5 "0", "1", "14", "cc", "memory"
-#define CALL_CLOBBER_4 CALL_CLOBBER_5
-#define CALL_CLOBBER_3 CALL_CLOBBER_4, "5"
-#define CALL_CLOBBER_2 CALL_CLOBBER_3, "4"
-#define CALL_CLOBBER_1 CALL_CLOBBER_2, "3"
-#define CALL_CLOBBER_0 CALL_CLOBBER_1
-
-#define CALL_ON_STACK(fn, stack, nr, args...) \
-({ \
- CALL_ARGS_##nr(args); \
- unsigned long prev; \
- \
- asm volatile( \
- " la %[_prev],0(15)\n" \
- " la 15,0(%[_stack])\n" \
- " stg %[_prev],%[_bc](15)\n" \
- " brasl 14,%[_fn]\n" \
- " la 15,0(%[_prev])\n" \
- : [_prev] "=&a" (prev), CALL_FMT_##nr \
- [_stack] "a" (stack), \
- [_bc] "i" (offsetof(struct stack_frame, back_chain)), \
- [_fn] "X" (fn) : CALL_CLOBBER_##nr); \
- r2; \
-})
-
/*
* Give up the time slice of the virtual PU.
*/
diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h
new file mode 100644
index 000000000000..49634bfbecdd
--- /dev/null
+++ b/arch/s390/include/asm/stacktrace.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_STACKTRACE_H
+#define _ASM_S390_STACKTRACE_H
+
+#include <linux/uaccess.h>
+#include <linux/ptrace.h>
+#include <asm/switch_to.h>
+
+enum stack_type {
+ STACK_TYPE_UNKNOWN,
+ STACK_TYPE_TASK,
+ STACK_TYPE_IRQ,
+ STACK_TYPE_NODAT,
+ STACK_TYPE_RESTART,
+};
+
+struct stack_info {
+ enum stack_type type;
+ unsigned long begin, end;
+};
+
+const char *stack_type_name(enum stack_type type);
+int get_stack_info(unsigned long sp, struct task_struct *task,
+ struct stack_info *info, unsigned long *visit_mask);
+
+static inline bool on_stack(struct stack_info *info,
+ unsigned long addr, size_t len)
+{
+ if (info->type == STACK_TYPE_UNKNOWN)
+ return false;
+ if (addr + len < addr)
+ return false;
+ return addr >= info->begin && addr + len < info->end;
+}
+
+static inline unsigned long get_stack_pointer(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ if (regs)
+ return (unsigned long) kernel_stack_pointer(regs);
+ if (task == current)
+ return current_stack_pointer();
+ return (unsigned long) task->thread.ksp;
+}
+
+/*
+ * Stack layout of a C stack frame.
+ */
+#ifndef __PACK_STACK
+struct stack_frame {
+ unsigned long back_chain;
+ unsigned long empty1[5];
+ unsigned long gprs[10];
+ unsigned int empty2[8];
+};
+#else
+struct stack_frame {
+ unsigned long empty1[5];
+ unsigned int empty2[8];
+ unsigned long gprs[10];
+ unsigned long back_chain;
+};
+#endif
+
+#define CALL_ARGS_0() \
+ register unsigned long r2 asm("2")
+#define CALL_ARGS_1(arg1) \
+ register unsigned long r2 asm("2") = (unsigned long)(arg1)
+#define CALL_ARGS_2(arg1, arg2) \
+ CALL_ARGS_1(arg1); \
+ register unsigned long r3 asm("3") = (unsigned long)(arg2)
+#define CALL_ARGS_3(arg1, arg2, arg3) \
+ CALL_ARGS_2(arg1, arg2); \
+ register unsigned long r4 asm("4") = (unsigned long)(arg3)
+#define CALL_ARGS_4(arg1, arg2, arg3, arg4) \
+ CALL_ARGS_3(arg1, arg2, arg3); \
+ register unsigned long r4 asm("5") = (unsigned long)(arg4)
+#define CALL_ARGS_5(arg1, arg2, arg3, arg4, arg5) \
+ CALL_ARGS_4(arg1, arg2, arg3, arg4); \
+ register unsigned long r4 asm("6") = (unsigned long)(arg5)
+
+#define CALL_FMT_0 "=&d" (r2) :
+#define CALL_FMT_1 "+&d" (r2) :
+#define CALL_FMT_2 CALL_FMT_1 "d" (r3),
+#define CALL_FMT_3 CALL_FMT_2 "d" (r4),
+#define CALL_FMT_4 CALL_FMT_3 "d" (r5),
+#define CALL_FMT_5 CALL_FMT_4 "d" (r6),
+
+#define CALL_CLOBBER_5 "0", "1", "14", "cc", "memory"
+#define CALL_CLOBBER_4 CALL_CLOBBER_5
+#define CALL_CLOBBER_3 CALL_CLOBBER_4, "5"
+#define CALL_CLOBBER_2 CALL_CLOBBER_3, "4"
+#define CALL_CLOBBER_1 CALL_CLOBBER_2, "3"
+#define CALL_CLOBBER_0 CALL_CLOBBER_1
+
+#define CALL_ON_STACK(fn, stack, nr, args...) \
+({ \
+ CALL_ARGS_##nr(args); \
+ unsigned long prev; \
+ \
+ asm volatile( \
+ " la %[_prev],0(15)\n" \
+ " la 15,0(%[_stack])\n" \
+ " stg %[_prev],%[_bc](15)\n" \
+ " brasl 14,%[_fn]\n" \
+ " la 15,0(%[_prev])\n" \
+ : [_prev] "=&a" (prev), CALL_FMT_##nr \
+ [_stack] "a" (stack), \
+ [_bc] "i" (offsetof(struct stack_frame, back_chain)), \
+ [_fn] "X" (fn) : CALL_CLOBBER_##nr); \
+ r2; \
+})
+
+#endif /* _ASM_S390_STACKTRACE_H */
diff --git a/arch/s390/include/asm/unwind.h b/arch/s390/include/asm/unwind.h
new file mode 100644
index 000000000000..6eb2ef105d87
--- /dev/null
+++ b/arch/s390/include/asm/unwind.h
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_UNWIND_H
+#define _ASM_S390_UNWIND_H
+
+#include <linux/sched.h>
+#include <linux/ftrace.h>
+#include <asm/ptrace.h>
+#include <asm/stacktrace.h>
+
+/*
+ * To use the stack unwinder it has to be initialized with unwind_start.
+ * There four combinations for task and regs:
+ * 1) task==NULL, regs==NULL: the unwind starts for the task that is currently
+ * running, sp/ip picked up from the CPU registers
+ * 2) task==NULL, regs!=NULL: the unwind starts from the sp/ip found in
+ * the struct pt_regs of an interrupt frame for the current task
+ * 3) task!=NULL, regs==NULL: the unwind starts for an inactive task with
+ * the sp picked up from task->thread.ksp and the ip picked up from the
+ * return address stored by __switch_to
+ * 4) task!=NULL, regs!=NULL: the sp/ip are picked up from the interrupt
+ * frame 'regs' of a inactive task
+ * If 'first_frame' is not zero unwind_start skips unwind frames until it
+ * reaches the specified stack pointer.
+ * The end of the unwinding is indicated with unwind_done, this can be true
+ * right after unwind_start, e.g. with first_frame!=0 that can not be found.
+ * unwind_next_frame skips to the next frame.
+ * Once the unwind is completed unwind_error() can be used to check if there
+ * has been a situation where the unwinder could not correctly understand
+ * the tasks call chain.
+ */
+
+struct unwind_state {
+ struct stack_info stack_info;
+ unsigned long stack_mask;
+ struct task_struct *task;
+ struct pt_regs *regs;
+ unsigned long sp, ip;
+ int graph_idx;
+ bool reliable;
+ bool error;
+};
+
+void __unwind_start(struct unwind_state *state, struct task_struct *task,
+ struct pt_regs *regs, unsigned long first_frame);
+bool unwind_next_frame(struct unwind_state *state);
+unsigned long unwind_get_return_address(struct unwind_state *state);
+
+static inline bool unwind_done(struct unwind_state *state)
+{
+ return state->stack_info.type == STACK_TYPE_UNKNOWN;
+}
+
+static inline bool unwind_error(struct unwind_state *state)
+{
+ return state->error;
+}
+
+static inline void unwind_start(struct unwind_state *state,
+ struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned long sp)
+{
+ sp = sp ? : get_stack_pointer(task, regs);
+ __unwind_start(state, task, regs, sp);
+}
+
+static inline struct pt_regs *unwind_get_entry_regs(struct unwind_state *state)
+{
+ return unwind_done(state) ? NULL : state->regs;
+}
+
+#define unwind_for_each_frame(state, task, regs, first_frame) \
+ for (unwind_start(state, task, regs, first_frame); \
+ !unwind_done(state); \
+ unwind_next_frame(state))
+
+static inline void unwind_init(void) {}
+static inline void unwind_module_init(struct module *mod, void *orc_ip,
+ size_t orc_ip_size, void *orc,
+ size_t orc_size) {}
+
+#ifdef CONFIG_KASAN
+/*
+ * This disables KASAN checking when reading a value from another task's stack,
+ * since the other task could be running on another CPU and could have poisoned
+ * the stack in the meantime.
+ */
+#define READ_ONCE_TASK_STACK(task, x) \
+({ \
+ unsigned long val; \
+ if (task == current) \
+ val = READ_ONCE(x); \
+ else \
+ val = READ_ONCE_NOCHECK(x); \
+ val; \
+})
+#else
+#define READ_ONCE_TASK_STACK(task, x) READ_ONCE(x)
+#endif
+
+#endif /* _ASM_S390_UNWIND_H */