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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/arm/kernel/stacktrace.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm/kernel/stacktrace.c')
-rw-r--r--arch/arm/kernel/stacktrace.c197
1 files changed, 197 insertions, 0 deletions
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
new file mode 100644
index 0000000000..620aa82e3b
--- /dev/null
+++ b/arch/arm/kernel/stacktrace.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/export.h>
+#include <linux/kprobes.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/stacktrace.h>
+
+#include <asm/sections.h>
+#include <asm/stacktrace.h>
+#include <asm/traps.h>
+
+#include "reboot.h"
+
+#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
+/*
+ * Unwind the current stack frame and store the new register values in the
+ * structure passed as argument. Unwinding is equivalent to a function return,
+ * hence the new PC value rather than LR should be used for backtrace.
+ *
+ * With framepointer enabled, a simple function prologue looks like this:
+ * mov ip, sp
+ * stmdb sp!, {fp, ip, lr, pc}
+ * sub fp, ip, #4
+ *
+ * A simple function epilogue looks like this:
+ * ldm sp, {fp, sp, pc}
+ *
+ * When compiled with clang, pc and sp are not pushed. A simple function
+ * prologue looks like this when built with clang:
+ *
+ * stmdb {..., fp, lr}
+ * add fp, sp, #x
+ * sub sp, sp, #y
+ *
+ * A simple function epilogue looks like this when built with clang:
+ *
+ * sub sp, fp, #x
+ * ldm {..., fp, pc}
+ *
+ *
+ * Note that with framepointer enabled, even the leaf functions have the same
+ * prologue and epilogue, therefore we can ignore the LR value in this case.
+ */
+
+extern unsigned long call_with_stack_end;
+
+static int frame_pointer_check(struct stackframe *frame)
+{
+ unsigned long high, low;
+ unsigned long fp = frame->fp;
+ unsigned long pc = frame->pc;
+
+ /*
+ * call_with_stack() is the only place we allow SP to jump from one
+ * stack to another, with FP and SP pointing to different stacks,
+ * skipping the FP boundary check at this point.
+ */
+ if (pc >= (unsigned long)&call_with_stack &&
+ pc < (unsigned long)&call_with_stack_end)
+ return 0;
+
+ /* only go to a higher address on the stack */
+ low = frame->sp;
+ high = ALIGN(low, THREAD_SIZE);
+
+ /* check current frame pointer is within bounds */
+#ifdef CONFIG_CC_IS_CLANG
+ if (fp < low + 4 || fp > high - 4)
+ return -EINVAL;
+#else
+ if (fp < low + 12 || fp > high - 4)
+ return -EINVAL;
+#endif
+
+ return 0;
+}
+
+int notrace unwind_frame(struct stackframe *frame)
+{
+ unsigned long fp = frame->fp;
+
+ if (frame_pointer_check(frame))
+ return -EINVAL;
+
+ /*
+ * When we unwind through an exception stack, include the saved PC
+ * value into the stack trace.
+ */
+ if (frame->ex_frame) {
+ struct pt_regs *regs = (struct pt_regs *)frame->sp;
+
+ /*
+ * We check that 'regs + sizeof(struct pt_regs)' (that is,
+ * &regs[1]) does not exceed the bottom of the stack to avoid
+ * accessing data outside the task's stack. This may happen
+ * when frame->ex_frame is a false positive.
+ */
+ if ((unsigned long)&regs[1] > ALIGN(frame->sp, THREAD_SIZE))
+ return -EINVAL;
+
+ frame->pc = regs->ARM_pc;
+ frame->ex_frame = false;
+ return 0;
+ }
+
+ /* restore the registers from the stack frame */
+#ifdef CONFIG_CC_IS_CLANG
+ frame->sp = frame->fp;
+ frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
+ frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 4));
+#else
+ frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 12));
+ frame->sp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 8));
+ frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 4));
+#endif
+#ifdef CONFIG_KRETPROBES
+ if (is_kretprobe_trampoline(frame->pc))
+ frame->pc = kretprobe_find_ret_addr(frame->tsk,
+ (void *)frame->fp, &frame->kr_cur);
+#endif
+
+ if (in_entry_text(frame->pc))
+ frame->ex_frame = true;
+
+ return 0;
+}
+#endif
+
+void notrace walk_stackframe(struct stackframe *frame,
+ bool (*fn)(void *, unsigned long), void *data)
+{
+ while (1) {
+ int ret;
+
+ if (!fn(data, frame->pc))
+ break;
+ ret = unwind_frame(frame);
+ if (ret < 0)
+ break;
+ }
+}
+EXPORT_SYMBOL(walk_stackframe);
+
+#ifdef CONFIG_STACKTRACE
+static void start_stack_trace(struct stackframe *frame, struct task_struct *task,
+ unsigned long fp, unsigned long sp,
+ unsigned long lr, unsigned long pc)
+{
+ frame->fp = fp;
+ frame->sp = sp;
+ frame->lr = lr;
+ frame->pc = pc;
+#ifdef CONFIG_KRETPROBES
+ frame->kr_cur = NULL;
+ frame->tsk = task;
+#endif
+#ifdef CONFIG_UNWINDER_FRAME_POINTER
+ frame->ex_frame = in_entry_text(frame->pc);
+#endif
+}
+
+void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
+ struct task_struct *task, struct pt_regs *regs)
+{
+ struct stackframe frame;
+
+ if (regs) {
+ start_stack_trace(&frame, NULL, regs->ARM_fp, regs->ARM_sp,
+ regs->ARM_lr, regs->ARM_pc);
+ } else if (task != current) {
+#ifdef CONFIG_SMP
+ /*
+ * What guarantees do we have here that 'tsk' is not
+ * running on another CPU? For now, ignore it as we
+ * can't guarantee we won't explode.
+ */
+ return;
+#else
+ start_stack_trace(&frame, task, thread_saved_fp(task),
+ thread_saved_sp(task), 0,
+ thread_saved_pc(task));
+#endif
+ } else {
+here:
+ start_stack_trace(&frame, task,
+ (unsigned long)__builtin_frame_address(0),
+ current_stack_pointer,
+ (unsigned long)__builtin_return_address(0),
+ (unsigned long)&&here);
+ /* skip this function */
+ if (unwind_frame(&frame))
+ return;
+ }
+
+ walk_stackframe(&frame, consume_entry, cookie);
+}
+#endif