diff options
Diffstat (limited to 'arch/x86/kernel/ftrace.c')
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 145 |
1 files changed, 83 insertions, 62 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 37a0aeaf89e7..bd165004776d 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -37,7 +37,7 @@ static int ftrace_poke_late = 0; -int ftrace_arch_code_modify_prepare(void) +void ftrace_arch_code_modify_prepare(void) __acquires(&text_mutex) { /* @@ -47,10 +47,9 @@ int ftrace_arch_code_modify_prepare(void) */ mutex_lock(&text_mutex); ftrace_poke_late = 1; - return 0; } -int ftrace_arch_code_modify_post_process(void) +void ftrace_arch_code_modify_post_process(void) __releases(&text_mutex) { /* @@ -61,12 +60,11 @@ int ftrace_arch_code_modify_post_process(void) text_poke_finish(); ftrace_poke_late = 0; mutex_unlock(&text_mutex); - return 0; } static const char *ftrace_nop_replace(void) { - return ideal_nops[NOP_ATOMIC5]; + return x86_nops[5]; } static const char *ftrace_call_replace(unsigned long ip, unsigned long addr) @@ -86,13 +84,14 @@ static int ftrace_verify_code(unsigned long ip, const char *old_code) * sure what we read is what we expected it to be before modifying it. */ /* read the text we want to modify */ - if (probe_kernel_read(cur_code, (void *)ip, MCOUNT_INSN_SIZE)) { + if (copy_from_kernel_nofault(cur_code, (void *)ip, MCOUNT_INSN_SIZE)) { WARN_ON(1); return -EFAULT; } /* Make sure it is what we expect it to be */ if (memcmp(cur_code, old_code, MCOUNT_INSN_SIZE) != 0) { + ftrace_expected = old_code; WARN_ON(1); return -EINVAL; } @@ -252,11 +251,6 @@ void arch_ftrace_update_code(int command) ftrace_modify_all_code(command); } -int __init ftrace_dyn_arch_init(void) -{ - return 0; -} - /* Currently only x86_64 supports dynamic trampolines */ #ifdef CONFIG_X86_64 @@ -282,9 +276,11 @@ static inline void tramp_free(void *tramp) { } /* Defined as markers to the end of the ftrace default trampolines */ extern void ftrace_regs_caller_end(void); -extern void ftrace_epilogue(void); +extern void ftrace_regs_caller_ret(void); +extern void ftrace_caller_end(void); extern void ftrace_caller_op_ptr(void); extern void ftrace_regs_caller_op_ptr(void); +extern void ftrace_regs_caller_jmp(void); /* movq function_trace_op(%rip), %rdx */ /* 0x48 0x8b 0x15 <offset-to-ftrace_trace_op (4 bytes)> */ @@ -306,7 +302,7 @@ union ftrace_op_code_union { } __attribute__((packed)); }; -#define RET_SIZE 1 +#define RET_SIZE (IS_ENABLED(CONFIG_RETPOLINE) ? 5 : 1 + IS_ENABLED(CONFIG_SLS)) static unsigned long create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) @@ -315,15 +311,16 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) unsigned long end_offset; unsigned long op_offset; unsigned long call_offset; + unsigned long jmp_offset; unsigned long offset; unsigned long npages; unsigned long size; - unsigned long retq; unsigned long *ptr; void *trampoline; void *ip; /* 48 8b 15 <offset> is movq <offset>(%rip), %rdx */ unsigned const char op_ref[] = { 0x48, 0x8b, 0x15 }; + unsigned const char retq[] = { RET_INSN_OPCODE, INT3_INSN_OPCODE }; union ftrace_op_code_union op_ptr; int ret; @@ -332,11 +329,13 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) end_offset = (unsigned long)ftrace_regs_caller_end; op_offset = (unsigned long)ftrace_regs_caller_op_ptr; call_offset = (unsigned long)ftrace_regs_call; + jmp_offset = (unsigned long)ftrace_regs_caller_jmp; } else { start_offset = (unsigned long)ftrace_caller; - end_offset = (unsigned long)ftrace_epilogue; + end_offset = (unsigned long)ftrace_caller_end; op_offset = (unsigned long)ftrace_caller_op_ptr; call_offset = (unsigned long)ftrace_call; + jmp_offset = 0; } size = end_offset - start_offset; @@ -354,17 +353,26 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE); /* Copy ftrace_caller onto the trampoline memory */ - ret = probe_kernel_read(trampoline, (void *)start_offset, size); + ret = copy_from_kernel_nofault(trampoline, (void *)start_offset, size); if (WARN_ON(ret < 0)) goto fail; ip = trampoline + size; + if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) + __text_gen_insn(ip, JMP32_INSN_OPCODE, ip, &__x86_return_thunk, JMP32_INSN_SIZE); + else + memcpy(ip, retq, sizeof(retq)); - /* The trampoline ends with ret(q) */ - retq = (unsigned long)ftrace_stub; - ret = probe_kernel_read(ip, (void *)retq, RET_SIZE); - if (WARN_ON(ret < 0)) - goto fail; + /* No need to test direct calls on created trampolines */ + if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) { + /* NOP the jnz 1f; but make sure it's a 2 byte jnz */ + ip = trampoline + (jmp_offset - start_offset); + if (WARN_ON(*(char *)ip != 0x75)) + goto fail; + ret = copy_from_kernel_nofault(ip, x86_nops[2], 2); + if (ret < 0) + goto fail; + } /* * The address of the ftrace_ops that is used for this trampoline @@ -407,7 +415,8 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) set_vm_flush_reset_perms(trampoline); - set_memory_ro((unsigned long)trampoline, npages); + if (likely(system_state != SYSTEM_BOOTING)) + set_memory_ro((unsigned long)trampoline, npages); set_memory_x((unsigned long)trampoline, npages); return (unsigned long)trampoline; fail: @@ -415,6 +424,32 @@ fail: return 0; } +void set_ftrace_ops_ro(void) +{ + struct ftrace_ops *ops; + unsigned long start_offset; + unsigned long end_offset; + unsigned long npages; + unsigned long size; + + do_for_each_ftrace_op(ops, ftrace_ops_list) { + if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) + continue; + + if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) { + start_offset = (unsigned long)ftrace_regs_caller; + end_offset = (unsigned long)ftrace_regs_caller_end; + } else { + start_offset = (unsigned long)ftrace_caller; + end_offset = (unsigned long)ftrace_caller_end; + } + size = end_offset - start_offset; + size = size + RET_SIZE + sizeof(void *); + npages = DIV_ROUND_UP(size, PAGE_SIZE); + set_memory_ro((unsigned long)ops->trampoline, npages); + } while_for_each_ftrace_op(ops); +} + static unsigned long calc_trampoline_call_offset(bool save_regs) { unsigned long start_offset; @@ -471,7 +506,7 @@ static void *addr_from_call(void *ptr) union text_poke_insn call; int ret; - ret = probe_kernel_read(&call, ptr, CALL_INSN_SIZE); + ret = copy_from_kernel_nofault(&call, ptr, CALL_INSN_SIZE); if (WARN_ON_ONCE(ret < 0)) return NULL; @@ -484,7 +519,7 @@ static void *addr_from_call(void *ptr) return ptr + CALL_INSN_SIZE + call.disp; } -void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, +void prepare_ftrace_return(unsigned long ip, unsigned long *parent, unsigned long frame_pointer); /* @@ -498,7 +533,8 @@ static void *static_tramp_func(struct ftrace_ops *ops, struct dyn_ftrace *rec) void *ptr; if (ops && ops->trampoline) { -#ifdef CONFIG_FUNCTION_GRAPH_TRACER +#if !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS) && \ + defined(CONFIG_FUNCTION_GRAPH_TRACER) /* * We only know about function graph tracer setting as static * trampoline. @@ -545,9 +581,8 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops) #ifdef CONFIG_FUNCTION_GRAPH_TRACER -#ifdef CONFIG_DYNAMIC_FTRACE +#if defined(CONFIG_DYNAMIC_FTRACE) && !defined(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS) extern void ftrace_graph_call(void); - static const char *ftrace_jmp_replace(unsigned long ip, unsigned long addr) { return text_gen_insn(JMP32_INSN_OPCODE, (void *)ip, (void *)addr); @@ -575,19 +610,17 @@ int ftrace_disable_ftrace_graph_caller(void) return ftrace_mod_jmp(ip, &ftrace_stub); } - -#endif /* !CONFIG_DYNAMIC_FTRACE */ +#endif /* CONFIG_DYNAMIC_FTRACE && !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */ /* * Hook the return address and push it in the stack of return addrs * in current thread info. */ -void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, +void prepare_ftrace_return(unsigned long ip, unsigned long *parent, unsigned long frame_pointer) { unsigned long return_hooker = (unsigned long)&return_to_handler; - unsigned long old; - int faulted; + int bit; /* * When resuming from suspend-to-ram, this function can be indirectly @@ -607,37 +640,25 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, if (unlikely(atomic_read(¤t->tracing_graph_pause))) return; - /* - * Protect against fault, even if it shouldn't - * happen. This tool is too much intrusive to - * ignore such a protection. - */ - asm volatile( - "1: " _ASM_MOV " (%[parent]), %[old]\n" - "2: " _ASM_MOV " %[return_hooker], (%[parent])\n" - " movl $0, %[faulted]\n" - "3:\n" - - ".section .fixup, \"ax\"\n" - "4: movl $1, %[faulted]\n" - " jmp 3b\n" - ".previous\n" - - _ASM_EXTABLE(1b, 4b) - _ASM_EXTABLE(2b, 4b) - - : [old] "=&r" (old), [faulted] "=r" (faulted) - : [parent] "r" (parent), [return_hooker] "r" (return_hooker) - : "memory" - ); - - if (unlikely(faulted)) { - ftrace_graph_stop(); - WARN_ON(1); + bit = ftrace_test_recursion_trylock(ip, *parent); + if (bit < 0) return; - } - if (function_graph_enter(old, self_addr, frame_pointer, parent)) - *parent = old; + if (!function_graph_enter(*parent, ip, frame_pointer, parent)) + *parent = return_hooker; + + ftrace_test_recursion_unlock(bit); } + +#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs) +{ + struct pt_regs *regs = &fregs->regs; + unsigned long *stack = (unsigned long *)kernel_stack_pointer(regs); + + prepare_ftrace_return(ip, (unsigned long *)stack, 0); +} +#endif + #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |