diff options
author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2019-01-28 08:33:08 +0100 |
---|---|---|
committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2019-05-02 13:54:11 +0200 |
commit | 78c98f9074135d3dab4e39544e0a537f92388fce (patch) | |
tree | 6f6d96e8e0911fe2aa27ec89cca52d56d3ed6f7e /arch/s390/include | |
parent | 1c705ad5efae9c712e763a47fbcc95b87b7347d2 (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.h | 72 | ||||
-rw-r--r-- | arch/s390/include/asm/stacktrace.h | 114 | ||||
-rw-r--r-- | arch/s390/include/asm/unwind.h | 101 |
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 */ |