diff options
Diffstat (limited to 'arch/x86/kernel/ftrace.c')
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 67 |
1 files changed, 33 insertions, 34 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 8257a59704ae..0caf8122d680 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -49,7 +49,7 @@ int ftrace_arch_code_modify_post_process(void) union ftrace_code_union { char code[MCOUNT_INSN_SIZE]; struct { - unsigned char e8; + unsigned char op; int offset; } __attribute__((packed)); }; @@ -59,20 +59,23 @@ static int ftrace_calc_offset(long ip, long addr) return (int)(addr - ip); } -static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr) +static unsigned char * +ftrace_text_replace(unsigned char op, unsigned long ip, unsigned long addr) { static union ftrace_code_union calc; - calc.e8 = 0xe8; + calc.op = op; calc.offset = ftrace_calc_offset(ip + MCOUNT_INSN_SIZE, addr); - /* - * No locking needed, this must be called via kstop_machine - * which in essence is like running on a uniprocessor machine. - */ return calc.code; } +static unsigned char * +ftrace_call_replace(unsigned long ip, unsigned long addr) +{ + return ftrace_text_replace(0xe8, ip, addr); +} + static inline int within(unsigned long addr, unsigned long start, unsigned long end) { @@ -269,7 +272,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func) return ret; } -static int is_ftrace_caller(unsigned long ip) +static nokprobe_inline int is_ftrace_caller(unsigned long ip) { if (ip == ftrace_update_func) return 1; @@ -299,6 +302,7 @@ int ftrace_int3_handler(struct pt_regs *regs) return 1; } +NOKPROBE_SYMBOL(ftrace_int3_handler); static int ftrace_write(unsigned long ip, const char *val, int size) { @@ -664,22 +668,6 @@ int __init ftrace_dyn_arch_init(void) return 0; } -#if defined(CONFIG_X86_64) || defined(CONFIG_FUNCTION_GRAPH_TRACER) -static unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr) -{ - static union ftrace_code_union calc; - - /* Jmp not a call (ignore the .e8) */ - calc.e8 = 0xe9; - calc.offset = ftrace_calc_offset(ip + MCOUNT_INSN_SIZE, addr); - - /* - * ftrace external locks synchronize the access to the static variable. - */ - return calc.code; -} -#endif - /* Currently only x86_64 supports dynamic trampolines */ #ifdef CONFIG_X86_64 @@ -690,12 +678,8 @@ static inline void *alloc_tramp(unsigned long size) { return module_alloc(size); } -static inline void tramp_free(void *tramp, int size) +static inline void tramp_free(void *tramp) { - int npages = PAGE_ALIGN(size) >> PAGE_SHIFT; - - set_memory_nx((unsigned long)tramp, npages); - set_memory_rw((unsigned long)tramp, npages); module_memfree(tramp); } #else @@ -704,7 +688,7 @@ static inline void *alloc_tramp(unsigned long size) { return NULL; } -static inline void tramp_free(void *tramp, int size) { } +static inline void tramp_free(void *tramp) { } #endif /* Defined as markers to the end of the ftrace default trampolines */ @@ -742,6 +726,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) unsigned long end_offset; unsigned long op_offset; unsigned long offset; + unsigned long npages; unsigned long size; unsigned long retq; unsigned long *ptr; @@ -774,6 +759,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) return 0; *tramp_size = size + RET_SIZE + sizeof(void *); + npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE); /* Copy ftrace_caller onto the trampoline memory */ ret = probe_kernel_read(trampoline, (void *)start_offset, size); @@ -818,9 +804,17 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) /* ALLOC_TRAMP flags lets us know we created it */ ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP; + set_vm_flush_reset_perms(trampoline); + + /* + * Module allocation needs to be completed by making the page + * executable. The page is still writable, which is a security hazard, + * but anyhow ftrace breaks W^X completely. + */ + set_memory_x((unsigned long)trampoline, npages); return (unsigned long)trampoline; fail: - tramp_free(trampoline, *tramp_size); + tramp_free(trampoline); return 0; } @@ -891,8 +885,8 @@ static void *addr_from_call(void *ptr) return NULL; /* Make sure this is a call */ - if (WARN_ON_ONCE(calc.e8 != 0xe8)) { - pr_warn("Expected e8, got %x\n", calc.e8); + if (WARN_ON_ONCE(calc.op != 0xe8)) { + pr_warn("Expected e8, got %x\n", calc.op); return NULL; } @@ -951,7 +945,7 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops) if (!ops || !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) return; - tramp_free((void *)ops->trampoline, ops->trampoline_size); + tramp_free((void *)ops->trampoline); ops->trampoline = 0; } @@ -963,6 +957,11 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops) #ifdef CONFIG_DYNAMIC_FTRACE extern void ftrace_graph_call(void); +static unsigned char *ftrace_jmp_replace(unsigned long ip, unsigned long addr) +{ + return ftrace_text_replace(0xe9, ip, addr); +} + static int ftrace_mod_jmp(unsigned long ip, void *func) { unsigned char *new; |