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-rw-r--r--arch/arm64/kernel/stacktrace.c232
1 files changed, 232 insertions, 0 deletions
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
new file mode 100644
index 000000000..83154303e
--- /dev/null
+++ b/arch/arm64/kernel/stacktrace.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Stack tracing support
+ *
+ * Copyright (C) 2012 ARM Ltd.
+ */
+#include <linux/kernel.h>
+#include <linux/efi.h>
+#include <linux/export.h>
+#include <linux/ftrace.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task_stack.h>
+#include <linux/stacktrace.h>
+
+#include <asm/efi.h>
+#include <asm/irq.h>
+#include <asm/stack_pointer.h>
+#include <asm/stacktrace.h>
+
+/*
+ * Start an unwind from a pt_regs.
+ *
+ * The unwind will begin at the PC within the regs.
+ *
+ * The regs must be on a stack currently owned by the calling task.
+ */
+static __always_inline void unwind_init_from_regs(struct unwind_state *state,
+ struct pt_regs *regs)
+{
+ unwind_init_common(state, current);
+
+ state->fp = regs->regs[29];
+ state->pc = regs->pc;
+}
+
+/*
+ * Start an unwind from a caller.
+ *
+ * The unwind will begin at the caller of whichever function this is inlined
+ * into.
+ *
+ * The function which invokes this must be noinline.
+ */
+static __always_inline void unwind_init_from_caller(struct unwind_state *state)
+{
+ unwind_init_common(state, current);
+
+ state->fp = (unsigned long)__builtin_frame_address(1);
+ state->pc = (unsigned long)__builtin_return_address(0);
+}
+
+/*
+ * Start an unwind from a blocked task.
+ *
+ * The unwind will begin at the blocked tasks saved PC (i.e. the caller of
+ * cpu_switch_to()).
+ *
+ * The caller should ensure the task is blocked in cpu_switch_to() for the
+ * duration of the unwind, or the unwind will be bogus. It is never valid to
+ * call this for the current task.
+ */
+static __always_inline void unwind_init_from_task(struct unwind_state *state,
+ struct task_struct *task)
+{
+ unwind_init_common(state, task);
+
+ state->fp = thread_saved_fp(task);
+ state->pc = thread_saved_pc(task);
+}
+
+/*
+ * Unwind from one frame record (A) to the next frame record (B).
+ *
+ * We terminate early if the location of B indicates a malformed chain of frame
+ * records (e.g. a cycle), determined based on the location and fp value of A
+ * and the location (but not the fp value) of B.
+ */
+static int notrace unwind_next(struct unwind_state *state)
+{
+ struct task_struct *tsk = state->task;
+ unsigned long fp = state->fp;
+ int err;
+
+ /* Final frame; nothing to unwind */
+ if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
+ return -ENOENT;
+
+ err = unwind_next_frame_record(state);
+ if (err)
+ return err;
+
+ state->pc = ptrauth_strip_insn_pac(state->pc);
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ if (tsk->ret_stack &&
+ (state->pc == (unsigned long)return_to_handler)) {
+ unsigned long orig_pc;
+ /*
+ * This is a case where function graph tracer has
+ * modified a return address (LR) in a stack frame
+ * to hook a function return.
+ * So replace it to an original value.
+ */
+ orig_pc = ftrace_graph_ret_addr(tsk, NULL, state->pc,
+ (void *)state->fp);
+ if (WARN_ON_ONCE(state->pc == orig_pc))
+ return -EINVAL;
+ state->pc = orig_pc;
+ }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+#ifdef CONFIG_KRETPROBES
+ if (is_kretprobe_trampoline(state->pc))
+ state->pc = kretprobe_find_ret_addr(tsk, (void *)state->fp, &state->kr_cur);
+#endif
+
+ return 0;
+}
+NOKPROBE_SYMBOL(unwind_next);
+
+static void notrace unwind(struct unwind_state *state,
+ stack_trace_consume_fn consume_entry, void *cookie)
+{
+ while (1) {
+ int ret;
+
+ if (!consume_entry(cookie, state->pc))
+ break;
+ ret = unwind_next(state);
+ if (ret < 0)
+ break;
+ }
+}
+NOKPROBE_SYMBOL(unwind);
+
+static bool dump_backtrace_entry(void *arg, unsigned long where)
+{
+ char *loglvl = arg;
+ printk("%s %pSb\n", loglvl, (void *)where);
+ return true;
+}
+
+void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+ const char *loglvl)
+{
+ pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
+
+ if (regs && user_mode(regs))
+ return;
+
+ if (!tsk)
+ tsk = current;
+
+ if (!try_get_task_stack(tsk))
+ return;
+
+ printk("%sCall trace:\n", loglvl);
+ arch_stack_walk(dump_backtrace_entry, (void *)loglvl, tsk, regs);
+
+ put_task_stack(tsk);
+}
+
+void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
+{
+ dump_backtrace(NULL, tsk, loglvl);
+ barrier();
+}
+
+/*
+ * Per-cpu stacks are only accessible when unwinding the current task in a
+ * non-preemptible context.
+ */
+#define STACKINFO_CPU(name) \
+ ({ \
+ ((task == current) && !preemptible()) \
+ ? stackinfo_get_##name() \
+ : stackinfo_get_unknown(); \
+ })
+
+/*
+ * SDEI stacks are only accessible when unwinding the current task in an NMI
+ * context.
+ */
+#define STACKINFO_SDEI(name) \
+ ({ \
+ ((task == current) && in_nmi()) \
+ ? stackinfo_get_sdei_##name() \
+ : stackinfo_get_unknown(); \
+ })
+
+#define STACKINFO_EFI \
+ ({ \
+ ((task == current) && current_in_efi()) \
+ ? stackinfo_get_efi() \
+ : stackinfo_get_unknown(); \
+ })
+
+noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry,
+ void *cookie, struct task_struct *task,
+ struct pt_regs *regs)
+{
+ struct stack_info stacks[] = {
+ stackinfo_get_task(task),
+ STACKINFO_CPU(irq),
+#if defined(CONFIG_VMAP_STACK)
+ STACKINFO_CPU(overflow),
+#endif
+#if defined(CONFIG_VMAP_STACK) && defined(CONFIG_ARM_SDE_INTERFACE)
+ STACKINFO_SDEI(normal),
+ STACKINFO_SDEI(critical),
+#endif
+#ifdef CONFIG_EFI
+ STACKINFO_EFI,
+#endif
+ };
+ struct unwind_state state = {
+ .stacks = stacks,
+ .nr_stacks = ARRAY_SIZE(stacks),
+ };
+
+ if (regs) {
+ if (task != current)
+ return;
+ unwind_init_from_regs(&state, regs);
+ } else if (task == current) {
+ unwind_init_from_caller(&state);
+ } else {
+ unwind_init_from_task(&state, task);
+ }
+
+ unwind(&state, consume_entry, cookie);
+}