5bb7d5086b
Commit cafa0010cd ("Raise the minimum required gcc version to 4.6")
raised the minimum GCC version to 4.6. Old mcount is only required for
GCC versions older than 4.4.0. Hence old mcount support can be dropped
too.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
(cherry picked from commit d3c61619568c88d48eccd5e74b4f84faa1440652)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I036c04a6d06c8e8afb954d02f222047af838803d
278 lines
6.1 KiB
C
278 lines
6.1 KiB
C
/*
|
|
* Dynamic function tracing support.
|
|
*
|
|
* Copyright (C) 2008 Abhishek Sagar <sagar.abhishek@gmail.com>
|
|
* Copyright (C) 2010 Rabin Vincent <rabin@rab.in>
|
|
*
|
|
* For licencing details, see COPYING.
|
|
*
|
|
* Defines low-level handling of mcount calls when the kernel
|
|
* is compiled with the -pg flag. When using dynamic ftrace, the
|
|
* mcount call-sites get patched with NOP till they are enabled.
|
|
* All code mutation routines here are called under stop_machine().
|
|
*/
|
|
|
|
#include <linux/ftrace.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/module.h>
|
|
#include <linux/stop_machine.h>
|
|
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/opcodes.h>
|
|
#include <asm/ftrace.h>
|
|
#include <asm/insn.h>
|
|
#include <asm/set_memory.h>
|
|
|
|
#ifdef CONFIG_THUMB2_KERNEL
|
|
#define NOP 0xf85deb04 /* pop.w {lr} */
|
|
#else
|
|
#define NOP 0xe8bd4000 /* pop {lr} */
|
|
#endif
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
|
|
static int __ftrace_modify_code(void *data)
|
|
{
|
|
int *command = data;
|
|
|
|
set_kernel_text_rw();
|
|
ftrace_modify_all_code(*command);
|
|
set_kernel_text_ro();
|
|
|
|
return 0;
|
|
}
|
|
|
|
void arch_ftrace_update_code(int command)
|
|
{
|
|
stop_machine(__ftrace_modify_code, &command, NULL);
|
|
}
|
|
|
|
static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
|
|
{
|
|
return NOP;
|
|
}
|
|
|
|
static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
|
|
{
|
|
return addr;
|
|
}
|
|
|
|
int ftrace_arch_code_modify_prepare(void)
|
|
{
|
|
set_all_modules_text_rw();
|
|
return 0;
|
|
}
|
|
|
|
int ftrace_arch_code_modify_post_process(void)
|
|
{
|
|
set_all_modules_text_ro();
|
|
/* Make sure any TLB misses during machine stop are cleared. */
|
|
flush_tlb_all();
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr,
|
|
bool warn)
|
|
{
|
|
return arm_gen_branch_link(pc, addr, warn);
|
|
}
|
|
|
|
static int ftrace_modify_code(unsigned long pc, unsigned long old,
|
|
unsigned long new, bool validate)
|
|
{
|
|
unsigned long replaced;
|
|
|
|
if (IS_ENABLED(CONFIG_THUMB2_KERNEL)) {
|
|
old = __opcode_to_mem_thumb32(old);
|
|
new = __opcode_to_mem_thumb32(new);
|
|
} else {
|
|
old = __opcode_to_mem_arm(old);
|
|
new = __opcode_to_mem_arm(new);
|
|
}
|
|
|
|
if (validate) {
|
|
if (probe_kernel_read(&replaced, (void *)pc, MCOUNT_INSN_SIZE))
|
|
return -EFAULT;
|
|
|
|
if (replaced != old)
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (probe_kernel_write((void *)pc, &new, MCOUNT_INSN_SIZE))
|
|
return -EPERM;
|
|
|
|
flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int ftrace_update_ftrace_func(ftrace_func_t func)
|
|
{
|
|
unsigned long pc;
|
|
unsigned long new;
|
|
int ret;
|
|
|
|
pc = (unsigned long)&ftrace_call;
|
|
new = ftrace_call_replace(pc, (unsigned long)func, true);
|
|
|
|
ret = ftrace_modify_code(pc, 0, new, false);
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
if (!ret) {
|
|
pc = (unsigned long)&ftrace_regs_call;
|
|
new = ftrace_call_replace(pc, (unsigned long)func, true);
|
|
|
|
ret = ftrace_modify_code(pc, 0, new, false);
|
|
}
|
|
#endif
|
|
|
|
return ret;
|
|
}
|
|
|
|
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
|
|
{
|
|
unsigned long new, old;
|
|
unsigned long ip = rec->ip;
|
|
unsigned long aaddr = adjust_address(rec, addr);
|
|
struct module *mod = NULL;
|
|
|
|
#ifdef CONFIG_ARM_MODULE_PLTS
|
|
mod = rec->arch.mod;
|
|
#endif
|
|
|
|
old = ftrace_nop_replace(rec);
|
|
|
|
new = ftrace_call_replace(ip, aaddr, !mod);
|
|
#ifdef CONFIG_ARM_MODULE_PLTS
|
|
if (!new && mod) {
|
|
aaddr = get_module_plt(mod, ip, aaddr);
|
|
new = ftrace_call_replace(ip, aaddr, true);
|
|
}
|
|
#endif
|
|
|
|
return ftrace_modify_code(rec->ip, old, new, true);
|
|
}
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
|
|
int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
|
|
unsigned long addr)
|
|
{
|
|
unsigned long new, old;
|
|
unsigned long ip = rec->ip;
|
|
|
|
old = ftrace_call_replace(ip, adjust_address(rec, old_addr), true);
|
|
|
|
new = ftrace_call_replace(ip, adjust_address(rec, addr), true);
|
|
|
|
return ftrace_modify_code(rec->ip, old, new, true);
|
|
}
|
|
|
|
#endif
|
|
|
|
int ftrace_make_nop(struct module *mod,
|
|
struct dyn_ftrace *rec, unsigned long addr)
|
|
{
|
|
unsigned long aaddr = adjust_address(rec, addr);
|
|
unsigned long ip = rec->ip;
|
|
unsigned long old;
|
|
unsigned long new;
|
|
int ret;
|
|
|
|
#ifdef CONFIG_ARM_MODULE_PLTS
|
|
/* mod is only supplied during module loading */
|
|
if (!mod)
|
|
mod = rec->arch.mod;
|
|
else
|
|
rec->arch.mod = mod;
|
|
#endif
|
|
|
|
old = ftrace_call_replace(ip, aaddr,
|
|
!IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || !mod);
|
|
#ifdef CONFIG_ARM_MODULE_PLTS
|
|
if (!old && mod) {
|
|
aaddr = get_module_plt(mod, ip, aaddr);
|
|
old = ftrace_call_replace(ip, aaddr, true);
|
|
}
|
|
#endif
|
|
|
|
new = ftrace_nop_replace(rec);
|
|
ret = ftrace_modify_code(ip, old, new, true);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int __init ftrace_dyn_arch_init(void)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
|
|
unsigned long frame_pointer)
|
|
{
|
|
unsigned long return_hooker = (unsigned long) &return_to_handler;
|
|
unsigned long old;
|
|
|
|
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
|
|
return;
|
|
|
|
old = *parent;
|
|
*parent = return_hooker;
|
|
|
|
if (function_graph_enter(old, self_addr, frame_pointer, NULL))
|
|
*parent = old;
|
|
}
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
extern unsigned long ftrace_graph_call;
|
|
extern unsigned long ftrace_graph_call_old;
|
|
extern void ftrace_graph_caller_old(void);
|
|
extern unsigned long ftrace_graph_regs_call;
|
|
extern void ftrace_graph_regs_caller(void);
|
|
|
|
static int __ftrace_modify_caller(unsigned long *callsite,
|
|
void (*func) (void), bool enable)
|
|
{
|
|
unsigned long caller_fn = (unsigned long) func;
|
|
unsigned long pc = (unsigned long) callsite;
|
|
unsigned long branch = arm_gen_branch(pc, caller_fn);
|
|
unsigned long nop = 0xe1a00000; /* mov r0, r0 */
|
|
unsigned long old = enable ? nop : branch;
|
|
unsigned long new = enable ? branch : nop;
|
|
|
|
return ftrace_modify_code(pc, old, new, true);
|
|
}
|
|
|
|
static int ftrace_modify_graph_caller(bool enable)
|
|
{
|
|
int ret;
|
|
|
|
ret = __ftrace_modify_caller(&ftrace_graph_call,
|
|
ftrace_graph_caller,
|
|
enable);
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
if (!ret)
|
|
ret = __ftrace_modify_caller(&ftrace_graph_regs_call,
|
|
ftrace_graph_regs_caller,
|
|
enable);
|
|
#endif
|
|
|
|
|
|
return ret;
|
|
}
|
|
|
|
int ftrace_enable_ftrace_graph_caller(void)
|
|
{
|
|
return ftrace_modify_graph_caller(true);
|
|
}
|
|
|
|
int ftrace_disable_ftrace_graph_caller(void)
|
|
{
|
|
return ftrace_modify_graph_caller(false);
|
|
}
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|