diff options
Diffstat (limited to 'arch/arm64/kernel/ftrace.c')
| -rw-r--r-- | arch/arm64/kernel/ftrace.c | 27 |
1 files changed, 13 insertions, 14 deletions
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index ebecf9aa33d1..c851be795080 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -29,11 +29,12 @@ static int ftrace_modify_code(unsigned long pc, u32 old, u32 new, /* * Note: - * We are paranoid about modifying text, as if a bug were to happen, it - * could cause us to read or write to someplace that could cause harm. - * Carefully read and modify the code with aarch64_insn_*() which uses - * probe_kernel_*(), and make sure what we read is what we expected it - * to be before modifying it. + * Due to modules and __init, code can disappear and change, + * we need to protect against faulting as well as code changing. + * We do this by aarch64_insn_*() which use the probe_kernel_*(). + * + * No lock is held here because all the modifications are run + * through stop_machine(). */ if (validate) { if (aarch64_insn_read((void *)pc, &replaced)) @@ -92,11 +93,6 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, return ftrace_modify_code(pc, old, new, true); } -void arch_ftrace_update_code(int command) -{ - ftrace_modify_all_code(command); -} - int __init ftrace_dyn_arch_init(void) { return 0; @@ -129,20 +125,23 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, * on other archs. It's unlikely on AArch64. */ old = *parent; + *parent = return_hooker; trace.func = self_addr; trace.depth = current->curr_ret_stack + 1; /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) + if (!ftrace_graph_entry(&trace)) { + *parent = old; return; + } err = ftrace_push_return_trace(old, self_addr, &trace.depth, frame_pointer); - if (err == -EBUSY) + if (err == -EBUSY) { + *parent = old; return; - else - *parent = return_hooker; + } } #ifdef CONFIG_DYNAMIC_FTRACE |