File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
new file mode 100644
index 0000000..fdd0c64
--- /dev/null
+++ b/arch/x86/kernel/stacktrace.c
@@ -0,0 +1,146 @@
+/*
+ * Stack trace management functions
+ *
+ * Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ */
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <asm/stacktrace.h>
+
+static int save_stack_stack(void *data, char *name)
+{
+ return 0;
+}
+
+static void
+__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)
+{
+ struct stack_trace *trace = data;
+#ifdef CONFIG_FRAME_POINTER
+ if (!reliable)
+ return;
+#endif
+ if (nosched && in_sched_functions(addr))
+ return;
+ if (trace->skip > 0) {
+ trace->skip--;
+ return;
+ }
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = addr;
+}
+
+static void save_stack_address(void *data, unsigned long addr, int reliable)
+{
+ return __save_stack_address(data, addr, reliable, false);
+}
+
+static void
+save_stack_address_nosched(void *data, unsigned long addr, int reliable)
+{
+ return __save_stack_address(data, addr, reliable, true);
+}
+
+static const struct stacktrace_ops save_stack_ops = {
+ .stack = save_stack_stack,
+ .address = save_stack_address,
+ .walk_stack = print_context_stack,
+};
+
+static const struct stacktrace_ops save_stack_ops_nosched = {
+ .stack = save_stack_stack,
+ .address = save_stack_address_nosched,
+ .walk_stack = print_context_stack,
+};
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer.
+ */
+void save_stack_trace(struct stack_trace *trace)
+{
+ dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+
+void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
+{
+ dump_trace(current, regs, NULL, 0, &save_stack_ops, trace);
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+ dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
+
+/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
+
+struct stack_frame_user {
+ const void __user *next_fp;
+ unsigned long ret_addr;
+};
+
+static int
+copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
+{
+ int ret;
+
+ if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
+ return 0;
+
+ ret = 1;
+ pagefault_disable();
+ if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
+ ret = 0;
+ pagefault_enable();
+
+ return ret;
+}
+
+static inline void __save_stack_trace_user(struct stack_trace *trace)
+{
+ const struct pt_regs *regs = task_pt_regs(current);
+ const void __user *fp = (const void __user *)regs->bp;
+
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = regs->ip;
+
+ while (trace->nr_entries < trace->max_entries) {
+ struct stack_frame_user frame;
+
+ frame.next_fp = NULL;
+ frame.ret_addr = 0;
+ if (!copy_stack_frame(fp, &frame))
+ break;
+ if ((unsigned long)fp < regs->sp)
+ break;
+ if (frame.ret_addr) {
+ trace->entries[trace->nr_entries++] =
+ frame.ret_addr;
+ }
+ if (fp == frame.next_fp)
+ break;
+ fp = frame.next_fp;
+ }
+}
+
+void save_stack_trace_user(struct stack_trace *trace)
+{
+ /*
+ * Trace user stack if we are not a kernel thread
+ */
+ if (current->mm) {
+ __save_stack_trace_user(trace);
+ }
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+