Contributors: 16
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Rabin Vincent |
554 |
46.21% |
7 |
25.00% |
| Ard Biesheuvel |
167 |
13.93% |
5 |
17.86% |
| Abhishek Sagar |
160 |
13.34% |
2 |
7.14% |
| Alexander Sverdlin |
139 |
11.59% |
2 |
7.14% |
| Tim Bird |
85 |
7.09% |
1 |
3.57% |
| Kees Cook |
46 |
3.84% |
1 |
3.57% |
| Abel Vesa |
25 |
2.09% |
1 |
3.57% |
| Catalin Marinas |
7 |
0.58% |
1 |
3.57% |
| Peter Zijlstra |
4 |
0.33% |
1 |
3.57% |
| Laura Abbott |
3 |
0.25% |
1 |
3.57% |
| Josh Poimboeuf |
2 |
0.17% |
1 |
3.57% |
| Li kunyu |
2 |
0.17% |
1 |
3.57% |
| Colin Cross |
2 |
0.17% |
1 |
3.57% |
| Wang Nan |
1 |
0.08% |
1 |
3.57% |
| Christoph Hellwig |
1 |
0.08% |
1 |
3.57% |
| Steven Rostedt |
1 |
0.08% |
1 |
3.57% |
| Total |
1199 |
|
28 |
|
/*
* 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>
#include <asm/stacktrace.h>
#include <asm/patch.h>
/*
* The compiler emitted profiling hook consists of
*
* PUSH {LR}
* BL __gnu_mcount_nc
*
* To turn this combined sequence into a NOP, we need to restore the value of
* SP before the PUSH. Let's use an ADD rather than a POP into LR, as LR is not
* modified anyway, and reloading LR from memory is highly likely to be less
* efficient.
*/
#ifdef CONFIG_THUMB2_KERNEL
#define NOP 0xf10d0d04 /* add.w sp, sp, #4 */
#else
#define NOP 0xe28dd004 /* add sp, sp, #4 */
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
static int __ftrace_modify_code(void *data)
{
int *command = data;
ftrace_modify_all_code(*command);
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;
}
void ftrace_caller_from_init(void);
void ftrace_regs_caller_from_init(void);
static unsigned long __ref adjust_address(struct dyn_ftrace *rec,
unsigned long addr)
{
if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE) ||
system_state >= SYSTEM_FREEING_INITMEM ||
likely(!is_kernel_inittext(rec->ip)))
return addr;
if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) ||
addr == (unsigned long)&ftrace_caller)
return (unsigned long)&ftrace_caller_from_init;
return (unsigned long)&ftrace_regs_caller_from_init;
}
void ftrace_arch_code_modify_prepare(void)
{
}
void ftrace_arch_code_modify_post_process(void)
{
/* Make sure any TLB misses during machine stop are cleared. */
flush_tlb_all();
}
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);
else
old = __opcode_to_mem_arm(old);
if (validate) {
if (copy_from_kernel_nofault(&replaced, (void *)pc,
MCOUNT_INSN_SIZE))
return -EFAULT;
if (replaced != old)
return -EINVAL;
}
__patch_text((void *)pc, new);
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);
/*
* Locations in .init.text may call __gnu_mcount_mc via a linker
* emitted veneer if they are too far away from its implementation, and
* so validation may fail spuriously in such cases. Let's work around
* this by omitting those from validation.
*/
ret = ftrace_modify_code(ip, old, new, !is_kernel_inittext(ip));
return ret;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
asmlinkage
void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
unsigned long frame_pointer,
unsigned long stack_pointer)
{
unsigned long return_hooker = (unsigned long) &return_to_handler;
unsigned long old;
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
err_out:
return;
if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER)) {
/*
* Usually, the stack frames are contiguous in memory but cases
* have been observed where the next stack frame does not live
* at 'frame_pointer + 4' as this code used to assume.
*
* Instead, dereference the field in the stack frame that
* stores the SP of the calling frame: to avoid unbounded
* recursion, this cannot involve any ftrace instrumented
* functions, so use the __get_kernel_nofault() primitive
* directly.
*/
__get_kernel_nofault(&frame_pointer,
(unsigned long *)(frame_pointer - 8),
unsigned long, err_out);
} else {
struct stackframe frame = {
.fp = frame_pointer,
.sp = stack_pointer,
.lr = self_addr,
.pc = self_addr,
};
if (unwind_frame(&frame) < 0)
return;
if (frame.lr != self_addr)
parent = frame.lr_addr;
frame_pointer = frame.sp;
}
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 = arm_gen_nop();
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 */