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-rw-r--r--arch/s390/include/asm/unwind.h98
1 files changed, 98 insertions, 0 deletions
diff --git a/arch/s390/include/asm/unwind.h b/arch/s390/include/asm/unwind.h
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+++ b/arch/s390/include/asm/unwind.h
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+/* 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 <linux/rethook.h>
+#include <linux/llist.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;
+ struct llist_node *kr_cur;
+ bool reliable;
+ bool error;
+};
+
+/* Recover the return address modified by rethook and ftrace_graph. */
+static inline unsigned long unwind_recover_ret_addr(struct unwind_state *state,
+ unsigned long ip)
+{
+ ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, ip, (void *)state->sp);
+#ifdef CONFIG_RETHOOK
+ if (is_rethook_trampoline(ip))
+ ip = rethook_find_ret_addr(state->task, state->sp, &state->kr_cur);
+#endif
+ return ip;
+}
+
+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 __always_inline void unwind_start(struct unwind_state *state,
+ struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned long first_frame)
+{
+ task = task ?: current;
+ first_frame = first_frame ?: get_stack_pointer(task, regs);
+ __unwind_start(state, task, regs, first_frame);
+}
+
+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) {}
+
+#endif /* _ASM_S390_UNWIND_H */