diff options
Diffstat (limited to 'arch/x86/kernel/ftrace.c')
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 5a1b9758fd6..30968924543 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -189,9 +189,26 @@ static void wait_for_nmi(void) nmi_wait_count++; } +static inline int +within(unsigned long addr, unsigned long start, unsigned long end) +{ + return addr >= start && addr < end; +} + static int do_ftrace_mod_code(unsigned long ip, void *new_code) { + /* + * On x86_64, kernel text mappings are mapped read-only with + * CONFIG_DEBUG_RODATA. So we use the kernel identity mapping instead + * of the kernel text mapping to modify the kernel text. + * + * For 32bit kernels, these mappings are same and we can use + * kernel identity mapping to modify code. + */ + if (within(ip, (unsigned long)_text, (unsigned long)_etext)) + ip = (unsigned long)__va(__pa(ip)); + mod_code_ip = (void *)ip; mod_code_newcode = new_code; |