diff options
author | Sven Schnelle <svens@linux.ibm.com> | 2020-01-21 12:31:47 +0100 |
---|---|---|
committer | Vasily Gorbik <gor@linux.ibm.com> | 2020-01-30 13:07:55 +0100 |
commit | 657480d9c01574d1e11bbb29e725db9907daf782 (patch) | |
tree | fa3de4fc39e350113c3685649d21e56a9ce62517 /arch/s390/kernel/ftrace.c | |
parent | 5f490a520bcb393389a4d44bec90afcb332eb112 (diff) | |
download | linux-657480d9c01574d1e11bbb29e725db9907daf782.tar.bz2 |
s390: support KPROBES_ON_FTRACE
Instead of using our own kprobes-on-ftrace handling convert the
code to support KPROBES_ON_FTRACE.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/kernel/ftrace.c')
-rw-r--r-- | arch/s390/kernel/ftrace.c | 80 |
1 files changed, 46 insertions, 34 deletions
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 1bb85f60c0dd..4cd9b1ada834 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -72,15 +72,6 @@ static inline void ftrace_generate_orig_insn(struct ftrace_insn *insn) #endif } -static inline int is_kprobe_on_ftrace(struct ftrace_insn *insn) -{ -#ifdef CONFIG_KPROBES - if (insn->opc == BREAKPOINT_INSTRUCTION) - return 1; -#endif - return 0; -} - static inline void ftrace_generate_kprobe_nop_insn(struct ftrace_insn *insn) { #ifdef CONFIG_KPROBES @@ -114,16 +105,6 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, /* Initial code replacement */ ftrace_generate_orig_insn(&orig); ftrace_generate_nop_insn(&new); - } else if (is_kprobe_on_ftrace(&old)) { - /* - * If we find a breakpoint instruction, a kprobe has been - * placed at the beginning of the function. We write the - * constant KPROBE_ON_FTRACE_NOP into the remaining four - * bytes of the original instruction so that the kprobes - * handler can execute a nop, if it reaches this breakpoint. - */ - ftrace_generate_kprobe_call_insn(&orig); - ftrace_generate_kprobe_nop_insn(&new); } else { /* Replace ftrace call with a nop. */ ftrace_generate_call_insn(&orig, rec->ip); @@ -142,21 +123,10 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) if (probe_kernel_read(&old, (void *) rec->ip, sizeof(old))) return -EFAULT; - if (is_kprobe_on_ftrace(&old)) { - /* - * If we find a breakpoint instruction, a kprobe has been - * placed at the beginning of the function. We write the - * constant KPROBE_ON_FTRACE_CALL into the remaining four - * bytes of the original instruction so that the kprobes - * handler can execute a brasl if it reaches this breakpoint. - */ - ftrace_generate_kprobe_nop_insn(&orig); - ftrace_generate_kprobe_call_insn(&new); - } else { - /* Replace nop with an ftrace call. */ - ftrace_generate_nop_insn(&orig); - ftrace_generate_call_insn(&new, rec->ip); - } + /* Replace nop with an ftrace call. */ + ftrace_generate_nop_insn(&orig); + ftrace_generate_call_insn(&new, rec->ip); + /* Verify that the to be replaced code matches what we expect. */ if (memcmp(&orig, &old, sizeof(old))) return -EINVAL; @@ -241,3 +211,45 @@ int ftrace_disable_ftrace_graph_caller(void) } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_KPROBES_ON_FTRACE +void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *ops, struct pt_regs *regs) +{ + struct kprobe_ctlblk *kcb; + struct kprobe *p = get_kprobe((kprobe_opcode_t *)ip); + + if (unlikely(!p) || kprobe_disabled(p)) + return; + + if (kprobe_running()) { + kprobes_inc_nmissed_count(p); + return; + } + + __this_cpu_write(current_kprobe, p); + + kcb = get_kprobe_ctlblk(); + kcb->kprobe_status = KPROBE_HIT_ACTIVE; + + instruction_pointer_set(regs, ip); + + if (!p->pre_handler || !p->pre_handler(p, regs)) { + + instruction_pointer_set(regs, ip + MCOUNT_INSN_SIZE); + + if (unlikely(p->post_handler)) { + kcb->kprobe_status = KPROBE_HIT_SSDONE; + p->post_handler(p, regs, 0); + } + } + __this_cpu_write(current_kprobe, NULL); +} +NOKPROBE_SYMBOL(kprobe_ftrace_handler); + +int arch_prepare_kprobe_ftrace(struct kprobe *p) +{ + p->ainsn.insn = NULL; + return 0; +} +#endif |