Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 242 insertions, 0 deletions

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
new file mode 100644
index 0000000000..17f66a74c7
--- /dev/null
+++ b/arch/arm64/kernel/stacktrace.c
@@ -0,0 +1,242 @@
+// 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);
+}
+
+static __always_inline int
+unwind_recover_return_address(struct unwind_state *state)
+{
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	if (state->task->ret_stack &&
+	    (state->pc == (unsigned long)return_to_handler)) {
+		unsigned long orig_pc;
+		orig_pc = ftrace_graph_ret_addr(state->task, 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(state->task,
+						    (void *)state->fp,
+						    &state->kr_cur);
+	}
+#endif /* CONFIG_KRETPROBES */
+
+	return 0;
+}
+
+/*
+ * 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 __always_inline int
+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_kernel_insn_pac(state->pc);
+
+	return unwind_recover_return_address(state);
+}
+
+static __always_inline void
+unwind(struct unwind_state *state, stack_trace_consume_fn consume_entry,
+       void *cookie)
+{
+	if (unwind_recover_return_address(state))
+		return;
+
+	while (1) {
+		int ret;
+
+		if (!consume_entry(cookie, state->pc))
+			break;
+		ret = unwind_next(state);
+		if (ret < 0)
+			break;
+	}
+}
+
+/*
+ * 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);
+}
+
+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();
+}