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-rw-r--r--arch/powerpc/oprofile/backtrace.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/arch/powerpc/oprofile/backtrace.c b/arch/powerpc/oprofile/backtrace.c
new file mode 100644
index 000000000..9db7ada79
--- /dev/null
+++ b/arch/powerpc/oprofile/backtrace.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/**
+ * Copyright (C) 2005 Brian Rogan <bcr6@cornell.edu>, IBM
+ *
+**/
+
+#include <linux/time.h>
+#include <linux/oprofile.h>
+#include <linux/sched.h>
+#include <asm/processor.h>
+#include <linux/uaccess.h>
+#include <linux/compat.h>
+#include <asm/oprofile_impl.h>
+
+#define STACK_SP(STACK) *(STACK)
+
+#define STACK_LR64(STACK) *((unsigned long *)(STACK) + 2)
+#define STACK_LR32(STACK) *((unsigned int *)(STACK) + 1)
+
+#ifdef CONFIG_PPC64
+#define STACK_LR(STACK) STACK_LR64(STACK)
+#else
+#define STACK_LR(STACK) STACK_LR32(STACK)
+#endif
+
+static unsigned int user_getsp32(unsigned int sp, int is_first)
+{
+ unsigned int stack_frame[2];
+ void __user *p = compat_ptr(sp);
+
+ /*
+ * The most likely reason for this is that we returned -EFAULT,
+ * which means that we've done all that we can do from
+ * interrupt context.
+ */
+ if (copy_from_user_nofault(stack_frame, (void __user *)p,
+ sizeof(stack_frame)))
+ return 0;
+
+ if (!is_first)
+ oprofile_add_trace(STACK_LR32(stack_frame));
+
+ /*
+ * We do not enforce increasing stack addresses here because
+ * we may transition to a different stack, eg a signal handler.
+ */
+ return STACK_SP(stack_frame);
+}
+
+#ifdef CONFIG_PPC64
+static unsigned long user_getsp64(unsigned long sp, int is_first)
+{
+ unsigned long stack_frame[3];
+
+ if (copy_from_user_nofault(stack_frame, (void __user *)sp,
+ sizeof(stack_frame)))
+ return 0;
+
+ if (!is_first)
+ oprofile_add_trace(STACK_LR64(stack_frame));
+
+ return STACK_SP(stack_frame);
+}
+#endif
+
+static unsigned long kernel_getsp(unsigned long sp, int is_first)
+{
+ unsigned long *stack_frame = (unsigned long *)sp;
+
+ if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
+ return 0;
+
+ if (!is_first)
+ oprofile_add_trace(STACK_LR(stack_frame));
+
+ /*
+ * We do not enforce increasing stack addresses here because
+ * we might be transitioning from an interrupt stack to a kernel
+ * stack. validate_sp() is designed to understand this, so just
+ * use it.
+ */
+ return STACK_SP(stack_frame);
+}
+
+void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+ unsigned long sp = regs->gpr[1];
+ int first_frame = 1;
+
+ /* We ditch the top stackframe so need to loop through an extra time */
+ depth += 1;
+
+ if (!user_mode(regs)) {
+ while (depth--) {
+ sp = kernel_getsp(sp, first_frame);
+ if (!sp)
+ break;
+ first_frame = 0;
+ }
+ } else {
+#ifdef CONFIG_PPC64
+ if (!is_32bit_task()) {
+ while (depth--) {
+ sp = user_getsp64(sp, first_frame);
+ if (!sp)
+ break;
+ first_frame = 0;
+ }
+ return;
+ }
+#endif
+
+ while (depth--) {
+ sp = user_getsp32(sp, first_frame);
+ if (!sp)
+ break;
+ first_frame = 0;
+ }
+ }
+}