Move the OProfile userspace stack unwinding into
arch/mips/kernel/user_backtrace.c to be shared with the perf
callchain implementation.
Rename struct stackframe to user_stackframe, add a GPLv2 header
to the source with the original author of the code.
Always export the unwind_user_frame symbol to make it easy to
use the OProfile module on an already built kernel.
Signed-off-by: Holger Freyther <holger@xxxxxxxxxxxxxxxx>
---
arch/mips/include/asm/stacktrace.h | 10 +++
arch/mips/kernel/Makefile | 3 +-
arch/mips/kernel/user_backtrace.c | 129 ++++++++++++++++++++++++++++++++++
arch/mips/oprofile/backtrace.c | 133 ++----------------------------------
4 files changed, 146 insertions(+), 129 deletions(-)
create mode 100644 arch/mips/kernel/user_backtrace.c
diff --git a/arch/mips/include/asm/stacktrace.h b/arch/mips/include/asm/stacktrace.h
index 780ee2c..f713da1 100644
--- a/arch/mips/include/asm/stacktrace.h
+++ b/arch/mips/include/asm/stacktrace.h
@@ -49,4 +49,14 @@ static __always_inline void prepare_frametrace(struct pt_regs *regs)
: : "memory");
}
+struct user_stackframe {
+ unsigned long sp;
+ unsigned long pc;
+ unsigned long ra;
+};
+
+int unwind_user_frame(struct user_stackframe *old_frame,
+ const unsigned int max_instr_check);
+
+
#endif /* _ASM_STACKTRACE_H */
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 83bba33..ce82fbf 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -6,7 +6,8 @@ extra-y := head.o init_task.o vmlinux.lds
obj-y += cpu-probe.o branch.o entry.o genex.o irq.o process.o \
ptrace.o reset.o setup.o signal.o syscall.o \
- time.o topology.o traps.o unaligned.o watch.o vdso.o
+ time.o topology.o traps.o unaligned.o watch.o vdso.o \
+ user_backtrace.o
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_ftrace.o = -pg
diff --git a/arch/mips/kernel/user_backtrace.c b/arch/mips/kernel/user_backtrace.c
new file mode 100644
index 0000000..cc1a8be
--- /dev/null
+++ b/arch/mips/kernel/user_backtrace.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2011 Daniel Kalmar
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License..
+ */
+
+#include <linux/uaccess.h>
+#include <linux/module.h>
+
+#include <asm/stacktrace.h>
+#include <asm/sections.h>
+#include <asm/inst.h>
+
+static inline int get_mem(unsigned long addr, unsigned long *result)
+{
+ unsigned long *address = (unsigned long *) addr;
+ if (!access_ok(VERIFY_READ, addr, sizeof(unsigned long)))
+ return -1;
+ if (__copy_from_user_inatomic(result, address, sizeof(unsigned long)))
+ return -3;
+ return 0;
+}
+
+/*
+ * These two instruction helpers were taken from process.c
+ */
+static inline int is_ra_save_ins(union mips_instruction *ip)
+{
+ /* sw / sd $ra, offset($sp) */
+ return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op)
+ && ip->i_format.rs == 29 && ip->i_format.rt == 31;
+}
+
+static inline int is_sp_move_ins(union mips_instruction *ip)
+{
+ /* addiu/daddiu sp,sp,-imm */
+ if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
+ return 0;
+ if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
+ return 1;
+ return 0;
+}
+
+/*
+ * Looks for specific instructions that mark the end of a function.
+ * This usually means we ran into the code area of the previous function.
+ */
+static inline int is_end_of_function_marker(union mips_instruction *ip)
+{
+ /* jr ra */
+ if (ip->r_format.func == jr_op && ip->r_format.rs == 31)
+ return 1;
+ /* lui gp */
+ if (ip->i_format.opcode == lui_op && ip->i_format.rt == 28)
+ return 1;
+ return 0;
+}
+
+/*
+ * TODO for userspace stack unwinding:
+ * - handle cases where the stack is adjusted inside a function
+ * (generally doesn't happen)
+ * - find optimal value for max_instr_check
+ * - try to find a way to handle leaf functions
+ */
+
+int unwind_user_frame(struct user_stackframe *old_frame,
+ const unsigned int max_instr_check)
+{
+ struct user_stackframe new_frame = *old_frame;
+ off_t ra_offset = 0;
+ size_t stack_size = 0;
+ unsigned long addr;
+
+ if (old_frame->pc == 0 || old_frame->sp == 0 || old_frame->ra == 0)
+ return -9;
+
+ for (addr = new_frame.pc; (addr + max_instr_check > new_frame.pc)
+ && (!ra_offset || !stack_size); --addr) {
+ union mips_instruction ip;
+
+ if (get_mem(addr, (unsigned long *) &ip))
+ return -11;
+
+ if (is_sp_move_ins(&ip)) {
+ int stack_adjustment = ip.i_format.simmediate;
+ if (stack_adjustment > 0)
+ /* This marks the end of the previous function,
+ which means we overran. */
+ break;
+ stack_size = (unsigned) stack_adjustment;
+ } else if (is_ra_save_ins(&ip)) {
+ int ra_slot = ip.i_format.simmediate;
+ if (ra_slot < 0)
+ /* This shouldn't happen. */
+ break;
+ ra_offset = ra_slot;
+ } else if (is_end_of_function_marker(&ip))
+ break;
+ }
+
+ if (!ra_offset || !stack_size)
+ return -1;
+
+ if (ra_offset) {
+ new_frame.ra = old_frame->sp + ra_offset;
+ if (get_mem(new_frame.ra, &(new_frame.ra)))
+ return -13;
+ }
+
+ if (stack_size) {
+ new_frame.sp = old_frame->sp + stack_size;
+ if (get_mem(new_frame.sp, &(new_frame.sp)))
+ return -14;
+ }
+
+ if (new_frame.sp > old_frame->sp)
+ return -2;
+
+ new_frame.pc = old_frame->ra;
+ *old_frame = new_frame;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(unwind_user_frame);
+
diff --git a/arch/mips/oprofile/backtrace.c b/arch/mips/oprofile/backtrace.c
index 6854ed5..265d26c 100644
--- a/arch/mips/oprofile/backtrace.c
+++ b/arch/mips/oprofile/backtrace.c
@@ -1,134 +1,11 @@
#include <linux/oprofile.h>
#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/uaccess.h>
+
#include <asm/ptrace.h>
#include <asm/stacktrace.h>
-#include <linux/stacktrace.h>
-#include <linux/kernel.h>
-#include <asm/sections.h>
-#include <asm/inst.h>
-
-struct stackframe {
- unsigned long sp;
- unsigned long pc;
- unsigned long ra;
-};
-
-static inline int get_mem(unsigned long addr, unsigned long *result)
-{
- unsigned long *address = (unsigned long *) addr;
- if (!access_ok(VERIFY_READ, addr, sizeof(unsigned long)))
- return -1;
- if (__copy_from_user_inatomic(result, address, sizeof(unsigned long)))
- return -3;
- return 0;
-}
-
-/*
- * These two instruction helpers were taken from process.c
- */
-static inline int is_ra_save_ins(union mips_instruction *ip)
-{
- /* sw / sd $ra, offset($sp) */
- return (ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op)
- && ip->i_format.rs == 29 && ip->i_format.rt == 31;
-}
-
-static inline int is_sp_move_ins(union mips_instruction *ip)
-{
- /* addiu/daddiu sp,sp,-imm */
- if (ip->i_format.rs != 29 || ip->i_format.rt != 29)
- return 0;
- if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op)
- return 1;
- return 0;
-}
-
-/*
- * Looks for specific instructions that mark the end of a function.
- * This usually means we ran into the code area of the previous function.
- */
-static inline int is_end_of_function_marker(union mips_instruction *ip)
-{
- /* jr ra */
- if (ip->r_format.func == jr_op && ip->r_format.rs == 31)
- return 1;
- /* lui gp */
- if (ip->i_format.opcode == lui_op && ip->i_format.rt == 28)
- return 1;
- return 0;
-}
-
-/*
- * TODO for userspace stack unwinding:
- * - handle cases where the stack is adjusted inside a function
- * (generally doesn't happen)
- * - find optimal value for max_instr_check
- * - try to find a way to handle leaf functions
- */
-
-static inline int unwind_user_frame(struct stackframe *old_frame,
- const unsigned int max_instr_check)
-{
- struct stackframe new_frame = *old_frame;
- off_t ra_offset = 0;
- size_t stack_size = 0;
- unsigned long addr;
-
- if (old_frame->pc == 0 || old_frame->sp == 0 || old_frame->ra == 0)
- return -9;
-
- for (addr = new_frame.pc; (addr + max_instr_check > new_frame.pc)
- && (!ra_offset || !stack_size); --addr) {
- union mips_instruction ip;
-
- if (get_mem(addr, (unsigned long *) &ip))
- return -11;
-
- if (is_sp_move_ins(&ip)) {
- int stack_adjustment = ip.i_format.simmediate;
- if (stack_adjustment > 0)
- /* This marks the end of the previous function,
- which means we overran. */
- break;
- stack_size = (unsigned) stack_adjustment;
- } else if (is_ra_save_ins(&ip)) {
- int ra_slot = ip.i_format.simmediate;
- if (ra_slot < 0)
- /* This shouldn't happen. */
- break;
- ra_offset = ra_slot;
- } else if (is_end_of_function_marker(&ip))
- break;
- }
-
- if (!ra_offset || !stack_size)
- return -1;
-
- if (ra_offset) {
- new_frame.ra = old_frame->sp + ra_offset;
- if (get_mem(new_frame.ra, &(new_frame.ra)))
- return -13;
- }
-
- if (stack_size) {
- new_frame.sp = old_frame->sp + stack_size;
- if (get_mem(new_frame.sp, &(new_frame.sp)))
- return -14;
- }
-
- if (new_frame.sp > old_frame->sp)
- return -2;
-
- new_frame.pc = old_frame->ra;
- *old_frame = new_frame;
-
- return 0;
-}
static inline void do_user_backtrace(unsigned long low_addr,
- struct stackframe *frame,
+ struct user_stackframe *frame,
unsigned int depth)
{
const unsigned int max_instr_check = 512;
@@ -143,11 +20,11 @@ static inline void do_user_backtrace(unsigned long low_addr,
#ifndef CONFIG_KALLSYMS
static inline void do_kernel_backtrace(unsigned long low_addr,
- struct stackframe *frame,
+ struct user_stackframe *frame,
unsigned int depth) { }
#else
static inline void do_kernel_backtrace(unsigned long low_addr,
- struct stackframe *frame,
+ struct user_stackframe *frame,
unsigned int depth)
{
while (depth-- && frame->pc) {
@@ -162,7 +39,7 @@ static inline void do_kernel_backtrace(unsigned long low_addr,
void notrace op_mips_backtrace(struct pt_regs *const regs, unsigned int depth)
{
- struct stackframe frame = { .sp = regs->regs[29],
+ struct user_stackframe frame = { .sp = regs->regs[29],
.pc = regs->cp0_epc,
.ra = regs->regs[31] };
const int userspace = user_mode(regs);
--
1.7.4.1
