mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-22 17:33:01 +00:00
22ceaf408f
The function graph tracer used to have a protection against NMI
while entering a function entry tracing. But this is useless now,
the tracer is reentrant and the ring buffer supports NMI tracing.
Same as 07868b086c for x86.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
276 lines
6.2 KiB
C
276 lines
6.2 KiB
C
/*
|
|
* Dynamic function tracer architecture backend.
|
|
*
|
|
* Copyright IBM Corp. 2009
|
|
*
|
|
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
|
|
*
|
|
*/
|
|
|
|
#include <linux/hardirq.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/ftrace.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/types.h>
|
|
#include <trace/syscall.h>
|
|
#include <asm/lowcore.h>
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
|
|
void ftrace_disable_code(void);
|
|
void ftrace_disable_return(void);
|
|
void ftrace_call_code(void);
|
|
void ftrace_nop_code(void);
|
|
|
|
#define FTRACE_INSN_SIZE 4
|
|
|
|
#ifdef CONFIG_64BIT
|
|
|
|
asm(
|
|
" .align 4\n"
|
|
"ftrace_disable_code:\n"
|
|
" j 0f\n"
|
|
" .word 0x0024\n"
|
|
" lg %r1,"__stringify(__LC_FTRACE_FUNC)"\n"
|
|
" basr %r14,%r1\n"
|
|
"ftrace_disable_return:\n"
|
|
" lg %r14,8(15)\n"
|
|
" lgr %r0,%r0\n"
|
|
"0:\n");
|
|
|
|
asm(
|
|
" .align 4\n"
|
|
"ftrace_nop_code:\n"
|
|
" j .+"__stringify(MCOUNT_INSN_SIZE)"\n");
|
|
|
|
asm(
|
|
" .align 4\n"
|
|
"ftrace_call_code:\n"
|
|
" stg %r14,8(%r15)\n");
|
|
|
|
#else /* CONFIG_64BIT */
|
|
|
|
asm(
|
|
" .align 4\n"
|
|
"ftrace_disable_code:\n"
|
|
" j 0f\n"
|
|
" l %r1,"__stringify(__LC_FTRACE_FUNC)"\n"
|
|
" basr %r14,%r1\n"
|
|
"ftrace_disable_return:\n"
|
|
" l %r14,4(%r15)\n"
|
|
" j 0f\n"
|
|
" bcr 0,%r7\n"
|
|
" bcr 0,%r7\n"
|
|
" bcr 0,%r7\n"
|
|
" bcr 0,%r7\n"
|
|
" bcr 0,%r7\n"
|
|
" bcr 0,%r7\n"
|
|
"0:\n");
|
|
|
|
asm(
|
|
" .align 4\n"
|
|
"ftrace_nop_code:\n"
|
|
" j .+"__stringify(MCOUNT_INSN_SIZE)"\n");
|
|
|
|
asm(
|
|
" .align 4\n"
|
|
"ftrace_call_code:\n"
|
|
" st %r14,4(%r15)\n");
|
|
|
|
#endif /* CONFIG_64BIT */
|
|
|
|
static int ftrace_modify_code(unsigned long ip,
|
|
void *old_code, int old_size,
|
|
void *new_code, int new_size)
|
|
{
|
|
unsigned char replaced[MCOUNT_INSN_SIZE];
|
|
|
|
/*
|
|
* Note: Due to modules code can disappear and change.
|
|
* We need to protect against faulting as well as code
|
|
* changing. We do this by using the probe_kernel_*
|
|
* functions.
|
|
* This however is just a simple sanity check.
|
|
*/
|
|
if (probe_kernel_read(replaced, (void *)ip, old_size))
|
|
return -EFAULT;
|
|
if (memcmp(replaced, old_code, old_size) != 0)
|
|
return -EINVAL;
|
|
if (probe_kernel_write((void *)ip, new_code, new_size))
|
|
return -EPERM;
|
|
return 0;
|
|
}
|
|
|
|
static int ftrace_make_initial_nop(struct module *mod, struct dyn_ftrace *rec,
|
|
unsigned long addr)
|
|
{
|
|
return ftrace_modify_code(rec->ip,
|
|
ftrace_call_code, FTRACE_INSN_SIZE,
|
|
ftrace_disable_code, MCOUNT_INSN_SIZE);
|
|
}
|
|
|
|
int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
|
|
unsigned long addr)
|
|
{
|
|
if (addr == MCOUNT_ADDR)
|
|
return ftrace_make_initial_nop(mod, rec, addr);
|
|
return ftrace_modify_code(rec->ip,
|
|
ftrace_call_code, FTRACE_INSN_SIZE,
|
|
ftrace_nop_code, FTRACE_INSN_SIZE);
|
|
}
|
|
|
|
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
|
|
{
|
|
return ftrace_modify_code(rec->ip,
|
|
ftrace_nop_code, FTRACE_INSN_SIZE,
|
|
ftrace_call_code, FTRACE_INSN_SIZE);
|
|
}
|
|
|
|
int ftrace_update_ftrace_func(ftrace_func_t func)
|
|
{
|
|
ftrace_dyn_func = (unsigned long)func;
|
|
return 0;
|
|
}
|
|
|
|
int __init ftrace_dyn_arch_init(void *data)
|
|
{
|
|
*(unsigned long *)data = 0;
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
/*
|
|
* Patch the kernel code at ftrace_graph_caller location:
|
|
* The instruction there is branch relative on condition. The condition mask
|
|
* is either all ones (always branch aka disable ftrace_graph_caller) or all
|
|
* zeroes (nop aka enable ftrace_graph_caller).
|
|
* Instruction format for brc is a7m4xxxx where m is the condition mask.
|
|
*/
|
|
int ftrace_enable_ftrace_graph_caller(void)
|
|
{
|
|
unsigned short opcode = 0xa704;
|
|
|
|
return probe_kernel_write(ftrace_graph_caller, &opcode, sizeof(opcode));
|
|
}
|
|
|
|
int ftrace_disable_ftrace_graph_caller(void)
|
|
{
|
|
unsigned short opcode = 0xa7f4;
|
|
|
|
return probe_kernel_write(ftrace_graph_caller, &opcode, sizeof(opcode));
|
|
}
|
|
|
|
static inline unsigned long ftrace_mcount_call_adjust(unsigned long addr)
|
|
{
|
|
return addr - (ftrace_disable_return - ftrace_disable_code);
|
|
}
|
|
|
|
#else /* CONFIG_DYNAMIC_FTRACE */
|
|
|
|
static inline unsigned long ftrace_mcount_call_adjust(unsigned long addr)
|
|
{
|
|
return addr - MCOUNT_OFFSET_RET;
|
|
}
|
|
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
|
|
/*
|
|
* Hook the return address and push it in the stack of return addresses
|
|
* in current thread info.
|
|
*/
|
|
unsigned long prepare_ftrace_return(unsigned long ip, unsigned long parent)
|
|
{
|
|
struct ftrace_graph_ent trace;
|
|
|
|
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
|
|
goto out;
|
|
if (ftrace_push_return_trace(parent, ip, &trace.depth, 0) == -EBUSY)
|
|
goto out;
|
|
trace.func = ftrace_mcount_call_adjust(ip) & PSW_ADDR_INSN;
|
|
/* Only trace if the calling function expects to. */
|
|
if (!ftrace_graph_entry(&trace)) {
|
|
current->curr_ret_stack--;
|
|
goto out;
|
|
}
|
|
parent = (unsigned long)return_to_handler;
|
|
out:
|
|
return parent;
|
|
}
|
|
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
|
|
|
#ifdef CONFIG_FTRACE_SYSCALLS
|
|
|
|
extern unsigned long __start_syscalls_metadata[];
|
|
extern unsigned long __stop_syscalls_metadata[];
|
|
extern unsigned int sys_call_table[];
|
|
|
|
static struct syscall_metadata **syscalls_metadata;
|
|
|
|
struct syscall_metadata *syscall_nr_to_meta(int nr)
|
|
{
|
|
if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
|
|
return NULL;
|
|
|
|
return syscalls_metadata[nr];
|
|
}
|
|
|
|
int syscall_name_to_nr(char *name)
|
|
{
|
|
int i;
|
|
|
|
if (!syscalls_metadata)
|
|
return -1;
|
|
for (i = 0; i < NR_syscalls; i++)
|
|
if (syscalls_metadata[i])
|
|
if (!strcmp(syscalls_metadata[i]->name, name))
|
|
return i;
|
|
return -1;
|
|
}
|
|
|
|
void set_syscall_enter_id(int num, int id)
|
|
{
|
|
syscalls_metadata[num]->enter_id = id;
|
|
}
|
|
|
|
void set_syscall_exit_id(int num, int id)
|
|
{
|
|
syscalls_metadata[num]->exit_id = id;
|
|
}
|
|
|
|
static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
|
|
{
|
|
struct syscall_metadata *start;
|
|
struct syscall_metadata *stop;
|
|
char str[KSYM_SYMBOL_LEN];
|
|
|
|
start = (struct syscall_metadata *)__start_syscalls_metadata;
|
|
stop = (struct syscall_metadata *)__stop_syscalls_metadata;
|
|
kallsyms_lookup(syscall, NULL, NULL, NULL, str);
|
|
|
|
for ( ; start < stop; start++) {
|
|
if (start->name && !strcmp(start->name + 3, str + 3))
|
|
return start;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static int __init arch_init_ftrace_syscalls(void)
|
|
{
|
|
struct syscall_metadata *meta;
|
|
int i;
|
|
syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) * NR_syscalls,
|
|
GFP_KERNEL);
|
|
if (!syscalls_metadata)
|
|
return -ENOMEM;
|
|
for (i = 0; i < NR_syscalls; i++) {
|
|
meta = find_syscall_meta((unsigned long)sys_call_table[i]);
|
|
syscalls_metadata[i] = meta;
|
|
}
|
|
return 0;
|
|
}
|
|
arch_initcall(arch_init_ftrace_syscalls);
|
|
#endif
|