projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| d05f5f99 DM |
1 | #include <linux/spinlock.h> |
| 2 | #include <linux/hardirq.h> | |
| 3 | #include <linux/ftrace.h> | |
| 4 | #include <linux/percpu.h> | |
| 5 | #include <linux/init.h> | |
| 6 | #include <linux/list.h> | |
| 7 | ||
| 8 | static const u32 ftrace_nop = 0x01000000; | |
| 9 | ||
| d05f5f99 DM |
10 | notrace unsigned char *ftrace_nop_replace(void) |
| 11 | { | |
| 12 | return (char *)&ftrace_nop; | |
| 13 | } | |
| 14 | ||
| 15 | notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr) | |
| 16 | { | |
| 17 | static u32 call; | |
| 18 | s32 off; | |
| 19 | ||
| 20 | off = ((s32)addr - (s32)ip); | |
| 21 | call = 0x40000000 | ((u32)off >> 2); | |
| 22 | ||
| 23 | return (unsigned char *) &call; | |
| 24 | } | |
| 25 | ||
| 26 | notrace int | |
| 27 | ftrace_modify_code(unsigned long ip, unsigned char *old_code, | |
| 28 | unsigned char *new_code) | |
| 29 | { | |
| 30 | u32 old = *(u32 *)old_code; | |
| 31 | u32 new = *(u32 *)new_code; | |
| 32 | u32 replaced; | |
| 33 | int faulted; | |
| 34 | ||
| 35 | __asm__ __volatile__( | |
| 36 | "1: cas [%[ip]], %[old], %[new]\n" | |
| 37 | " flush %[ip]\n" | |
| 38 | " mov 0, %[faulted]\n" | |
| 39 | "2:\n" | |
| 40 | " .section .fixup,#alloc,#execinstr\n" | |
| 41 | " .align 4\n" | |
| 42 | "3: sethi %%hi(2b), %[faulted]\n" | |
| 43 | " jmpl %[faulted] + %%lo(2b), %%g0\n" | |
| 44 | " mov 1, %[faulted]\n" | |
| 45 | " .previous\n" | |
| 46 | " .section __ex_table,\"a\"\n" | |
| 47 | " .align 4\n" | |
| 48 | " .word 1b, 3b\n" | |
| 49 | " .previous\n" | |
| 50 | : "=r" (replaced), [faulted] "=r" (faulted) | |
| 51 | : [new] "0" (new), [old] "r" (old), [ip] "r" (ip) | |
| 52 | : "memory"); | |
| 53 | ||
| 54 | if (replaced != old && replaced != new) | |
| 55 | faulted = 2; | |
| 56 | ||
| 57 | return faulted; | |
| 58 | } | |
| 59 | ||
| 60 | notrace int ftrace_update_ftrace_func(ftrace_func_t func) | |
| 61 | { | |
| 62 | unsigned long ip = (unsigned long)(&ftrace_call); | |
| 63 | unsigned char old[4], *new; | |
| 64 | ||
| 65 | memcpy(old, &ftrace_call, 4); | |
| 66 | new = ftrace_call_replace(ip, (unsigned long)func); | |
| 67 | return ftrace_modify_code(ip, old, new); | |
| 68 | } | |
| 69 | ||
| 70 | notrace int ftrace_mcount_set(unsigned long *data) | |
| 71 | { | |
| 72 | unsigned long ip = (long)(&mcount_call); | |
| 73 | unsigned long *addr = data; | |
| 74 | unsigned char old[4], *new; | |
| 75 | ||
| 76 | /* | |
| 77 | * Replace the mcount stub with a pointer to the | |
| 78 | * ip recorder function. | |
| 79 | */ | |
| 80 | memcpy(old, &mcount_call, 4); | |
| 81 | new = ftrace_call_replace(ip, *addr); | |
| 82 | *addr = ftrace_modify_code(ip, old, new); | |
| 83 | ||
| 84 | return 0; | |
| 85 | } | |
| 86 | ||
| 87 | ||
| 88 | int __init ftrace_dyn_arch_init(void *data) | |
| 89 | { | |
| 90 | ftrace_mcount_set(data); | |
| 91 | return 0; | |
| 92 | } |