diff options
| -rw-r--r-- | arch/powerpc/kernel/trace/ftrace.c | 161 |
1 files changed, 21 insertions, 140 deletions
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 6ea8b90246a5..c37e22c6c265 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -89,33 +89,11 @@ static inline int ftrace_modify_code(unsigned long ip, ppc_inst_t old, ppc_inst_ return ret; } -/* - * Helper functions that are the same for both PPC64 and PPC32. - */ -static int test_24bit_addr(unsigned long ip, unsigned long addr) -{ - addr = ppc_function_entry((void *)addr); - - return is_offset_in_branch_range(addr - ip); -} - static int is_bl_op(ppc_inst_t op) { return (ppc_inst_val(op) & ~PPC_LI_MASK) == PPC_RAW_BL(0); } -static unsigned long find_bl_target(unsigned long ip, ppc_inst_t op) -{ - int offset; - - offset = PPC_LI(ppc_inst_val(op)); - /* make it signed */ - if (offset & 0x02000000) - offset |= 0xfe000000; - - return ip + (long)offset; -} - static unsigned long find_ftrace_tramp(unsigned long ip) { int i; @@ -130,115 +108,16 @@ static unsigned long find_ftrace_tramp(unsigned long ip) } #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS -#ifdef CONFIG_MODULES -static int -__ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, - unsigned long addr) +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) { - ppc_inst_t op; - unsigned long ip = rec->ip; - unsigned long entry, ptr, tramp; - struct module *mod = rec->arch.mod; - - /* If we never set up ftrace trampolines, then bail */ - if (!mod->arch.tramp || !mod->arch.tramp_regs) { - pr_err("No ftrace trampoline\n"); - return -EINVAL; - } - - /* read where this goes */ - if (copy_inst_from_kernel_nofault(&op, (void *)ip)) { - pr_err("Fetching opcode failed.\n"); - return -EFAULT; - } - - /* Make sure that this is still a 24bit jump */ - if (!is_bl_op(op)) { - pr_err("Not expected bl: opcode is %08lx\n", ppc_inst_as_ulong(op)); - return -EINVAL; - } - - /* lets find where the pointer goes */ - tramp = find_bl_target(ip, op); - entry = ppc_global_function_entry((void *)old_addr); - - pr_devel("ip:%lx jumps to %lx", ip, tramp); - - if (tramp != entry) { - /* old_addr is not within range, so we must have used a trampoline */ - if (module_trampoline_target(mod, tramp, &ptr)) { - pr_err("Failed to get trampoline target\n"); - return -EFAULT; - } - - pr_devel("trampoline target %lx", ptr); - - /* This should match what was called */ - if (ptr != entry) { - pr_err("addr %lx does not match expected %lx\n", ptr, entry); - return -EINVAL; - } - } - - /* The new target may be within range */ - if (test_24bit_addr(ip, addr)) { - /* within range */ - if (patch_branch((u32 *)ip, addr, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } - - return 0; - } - - if (rec->flags & FTRACE_FL_REGS) - tramp = mod->arch.tramp_regs; - else - tramp = mod->arch.tramp; - - if (module_trampoline_target(mod, tramp, &ptr)) { - pr_err("Failed to get trampoline target\n"); - return -EFAULT; - } - - pr_devel("trampoline target %lx", ptr); - - entry = ppc_global_function_entry((void *)addr); - /* This should match what was called */ - if (ptr != entry) { - pr_err("addr %lx does not match expected %lx\n", ptr, entry); - return -EINVAL; - } - - if (patch_branch((u32 *)ip, tramp, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } - - return 0; -} -#else -static int __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) -{ - return 0; -} -#endif - -int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, - unsigned long addr) -{ - unsigned long ip = rec->ip; + unsigned long tramp, tramp_old, ip = rec->ip; ppc_inst_t old, new; + struct module *mod; - /* - * If the calling address is more that 24 bits away, - * then we had to use a trampoline to make the call. - * Otherwise just update the call site. - */ - if (test_24bit_addr(ip, addr) && test_24bit_addr(ip, old_addr)) { - /* within range */ - old = ftrace_call_replace(ip, old_addr, 1); - new = ftrace_call_replace(ip, addr, 1); + if (is_offset_in_branch_range(old_addr - ip) && is_offset_in_branch_range(addr - ip)) { + /* Within range */ + old = ftrace_create_branch_inst(ip, old_addr, 1); + new = ftrace_create_branch_inst(ip, addr, 1); return ftrace_modify_code(ip, old, new); } else if (core_kernel_text(ip)) { /* @@ -246,20 +125,22 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, * variant, so there is nothing to do here */ return 0; - } else if (!IS_ENABLED(CONFIG_MODULES)) { - /* We should not get here without modules */ - return -EINVAL; - } - - /* - * Out of range jumps are called from modules. - */ - if (!rec->arch.mod) { - pr_err("No module loaded\n"); - return -EINVAL; + } else if (IS_ENABLED(CONFIG_MODULES)) { + /* Module code would be going to one of the module stubs */ + mod = rec->arch.mod; + if (addr == (unsigned long)ftrace_caller) { + tramp_old = mod->arch.tramp_regs; + tramp = mod->arch.tramp; + } else { + tramp_old = mod->arch.tramp; + tramp = mod->arch.tramp_regs; + } + old = ftrace_create_branch_inst(ip, tramp_old, 1); + new = ftrace_create_branch_inst(ip, tramp, 1); + return ftrace_modify_code(ip, old, new); } - return __ftrace_modify_call(rec, old_addr, addr); + return -EINVAL; } #endif |