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Diffstat (limited to 'arch/s390/include/asm/unwind.h')
| -rw-r--r-- | arch/s390/include/asm/unwind.h | 101 |
1 files changed, 101 insertions, 0 deletions
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 */ |