Merge git://git.infradead.org/mtd-2.6

[linux-2.6-omap-h63xx.git] / arch / x86 / kernel / ftrace.c

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index d073d981a730306f970aabdf5f7174453c24d226..50ea0ac8c9bf2c27a53323b93b5d473bd7e1d028 100644 (file)
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -21,8 +21,7 @@
 #include <asm/nops.h>
 
 
-/* Long is fine, even if it is only 4 bytes ;-) */
-static unsigned long *ftrace_nop;
+static unsigned char ftrace_nop[MCOUNT_INSN_SIZE];
 
 union ftrace_code_union {
        char code[MCOUNT_INSN_SIZE];
@@ -33,17 +32,17 @@ union ftrace_code_union {
 };
 
 
-static int notrace ftrace_calc_offset(long ip, long addr)
+static int ftrace_calc_offset(long ip, long addr)
 {
        return (int)(addr - ip);
 }
 
-notrace unsigned char *ftrace_nop_replace(void)
+unsigned char *ftrace_nop_replace(void)
 {
-       return (char *)ftrace_nop;
+       return ftrace_nop;
 }
 
-notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
 {
        static union ftrace_code_union calc;
 
@@ -57,7 +56,7 @@ notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
        return calc.code;
 }
 
-notrace int
+int
 ftrace_modify_code(unsigned long ip, unsigned char *old_code,
                   unsigned char *new_code)
 {
@@ -66,26 +65,31 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
        /*
         * Note: Due to modules and __init, code can
         *  disappear and change, we need to protect against faulting
-        *  as well as code changing.
+        *  as well as code changing. We do this by using the
+        *  probe_kernel_* functions.
         *
         * No real locking needed, this code is run through
         * kstop_machine, or before SMP starts.
         */
-       if (__copy_from_user_inatomic(replaced, (char __user *)ip, MCOUNT_INSN_SIZE))
-               return 1;
 
+       /* read the text we want to modify */
+       if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+               return -EFAULT;
+
+       /* Make sure it is what we expect it to be */
        if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
-               return 2;
+               return -EINVAL;
 
-       WARN_ON_ONCE(__copy_to_user_inatomic((char __user *)ip, new_code,
-                                   MCOUNT_INSN_SIZE));
+       /* replace the text with the new text */
+       if (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE))
+               return -EPERM;
 
        sync_core();
 
        return 0;
 }
 
-notrace int ftrace_update_ftrace_func(ftrace_func_t func)
+int ftrace_update_ftrace_func(ftrace_func_t func)
 {
        unsigned long ip = (unsigned long)(&ftrace_call);
        unsigned char old[MCOUNT_INSN_SIZE], *new;
@@ -98,13 +102,6 @@ notrace int ftrace_update_ftrace_func(ftrace_func_t func)
        return ret;
 }
 
-notrace int ftrace_mcount_set(unsigned long *data)
-{
-       /* mcount is initialized as a nop */
-       *data = 0;
-       return 0;
-}
-
 int __init ftrace_dyn_arch_init(void *data)
 {
        extern const unsigned char ftrace_test_p6nop[];
@@ -127,9 +124,6 @@ int __init ftrace_dyn_arch_init(void *data)
         * TODO: check the cpuid to determine the best nop.
         */
        asm volatile (
-               "jmp ftrace_test_jmp\n"
-               /* This code needs to stay around */
-               ".section .text, \"ax\"\n"
                "ftrace_test_jmp:"
                "jmp ftrace_test_p6nop\n"
                "nop\n"
@@ -140,8 +134,6 @@ int __init ftrace_dyn_arch_init(void *data)
                "jmp 1f\n"
                "ftrace_test_nop5:"
                ".byte 0x66,0x66,0x66,0x66,0x90\n"
-               "jmp 1f\n"
-               ".previous\n"
                "1:"
                ".section .fixup, \"ax\"\n"
                "2:     movl $1, %0\n"
@@ -156,15 +148,15 @@ int __init ftrace_dyn_arch_init(void *data)
        switch (faulted) {
        case 0:
                pr_info("ftrace: converting mcount calls to 0f 1f 44 00 00\n");
-               ftrace_nop = (unsigned long *)ftrace_test_p6nop;
+               memcpy(ftrace_nop, ftrace_test_p6nop, MCOUNT_INSN_SIZE);
                break;
        case 1:
                pr_info("ftrace: converting mcount calls to 66 66 66 66 90\n");
-               ftrace_nop = (unsigned long *)ftrace_test_nop5;
+               memcpy(ftrace_nop, ftrace_test_nop5, MCOUNT_INSN_SIZE);
                break;
        case 2:
                pr_info("ftrace: converting mcount calls to jmp . + 5\n");
-               ftrace_nop = (unsigned long *)ftrace_test_jmp;
+               memcpy(ftrace_nop, ftrace_test_jmp, MCOUNT_INSN_SIZE);
                break;
        }