diff options
Diffstat (limited to 'arch/arm64/kernel/ftrace.c')
| -rw-r--r-- | arch/arm64/kernel/ftrace.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 26789865748c..8745175f4a75 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -217,11 +217,26 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long pc = rec->ip; u32 old = 0, new; + new = aarch64_insn_gen_nop(); + + /* + * When using mcount, callsites in modules may have been initalized to + * call an arbitrary module PLT (which redirects to the _mcount stub) + * rather than the ftrace PLT we'll use at runtime (which redirects to + * the ftrace trampoline). We can ignore the old PLT when initializing + * the callsite. + * + * Note: 'mod' is only set at module load time. + */ + if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS) && + IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) && mod) { + return aarch64_insn_patch_text_nosync((void *)pc, new); + } + if (!ftrace_find_callable_addr(rec, mod, &addr)) return -EINVAL; old = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK); - new = aarch64_insn_gen_nop(); return ftrace_modify_code(pc, old, new, true); } |