diff options
| -rw-r--r-- | Documentation/features/debug/kprobes-on-ftrace/arch-support.txt | 2 | ||||
| -rw-r--r-- | arch/s390/Kconfig | 1 | ||||
| -rw-r--r-- | arch/s390/include/asm/kprobes.h | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/ftrace.c | 80 | ||||
| -rw-r--r-- | arch/s390/kernel/kprobes.c | 61 | ||||
| -rw-r--r-- | arch/s390/kernel/mcount.S | 6 |
6 files changed, 59 insertions, 92 deletions
diff --git a/Documentation/features/debug/kprobes-on-ftrace/arch-support.txt b/Documentation/features/debug/kprobes-on-ftrace/arch-support.txt index 4fae0464ddff..32b297295fff 100644 --- a/Documentation/features/debug/kprobes-on-ftrace/arch-support.txt +++ b/Documentation/features/debug/kprobes-on-ftrace/arch-support.txt @@ -24,7 +24,7 @@ | parisc: | ok | | powerpc: | ok | | riscv: | TODO | - | s390: | TODO | + | s390: | ok | | sh: | TODO | | sparc: | TODO | | um: | TODO | diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 287714d51b47..cd84125fe126 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -156,6 +156,7 @@ config S390 select HAVE_KERNEL_UNCOMPRESSED select HAVE_KERNEL_XZ select HAVE_KPROBES + select HAVE_KPROBES_ON_FTRACE select HAVE_KRETPROBES select HAVE_KVM select HAVE_LIVEPATCH diff --git a/arch/s390/include/asm/kprobes.h b/arch/s390/include/asm/kprobes.h index b106aa29bf55..09cdb632a490 100644 --- a/arch/s390/include/asm/kprobes.h +++ b/arch/s390/include/asm/kprobes.h @@ -54,7 +54,6 @@ typedef u16 kprobe_opcode_t; struct arch_specific_insn { /* copy of original instruction */ kprobe_opcode_t *insn; - unsigned int is_ftrace_insn : 1; }; struct prev_kprobe { 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 diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 6f1388391620..548d0ea9808d 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -56,21 +56,10 @@ struct kprobe_insn_cache kprobe_s390_insn_slots = { static void copy_instruction(struct kprobe *p) { - unsigned long ip = (unsigned long) p->addr; s64 disp, new_disp; u64 addr, new_addr; - if (ftrace_location(ip) == ip) { - /* - * If kprobes patches the instruction that is morphed by - * ftrace make sure that kprobes always sees the branch - * "jg .+24" that skips the mcount block or the "brcl 0,0" - * in case of hotpatch. - */ - ftrace_generate_nop_insn((struct ftrace_insn *)p->ainsn.insn); - p->ainsn.is_ftrace_insn = 1; - } else - memcpy(p->ainsn.insn, p->addr, insn_length(*p->addr >> 8)); + memcpy(p->ainsn.insn, p->addr, insn_length(*p->addr >> 8)); p->opcode = p->ainsn.insn[0]; if (!probe_is_insn_relative_long(p->ainsn.insn)) return; @@ -136,11 +125,6 @@ int arch_prepare_kprobe(struct kprobe *p) } NOKPROBE_SYMBOL(arch_prepare_kprobe); -int arch_check_ftrace_location(struct kprobe *p) -{ - return 0; -} - struct swap_insn_args { struct kprobe *p; unsigned int arm_kprobe : 1; @@ -149,28 +133,11 @@ struct swap_insn_args { static int swap_instruction(void *data) { struct swap_insn_args *args = data; - struct ftrace_insn new_insn, *insn; struct kprobe *p = args->p; - size_t len; - - new_insn.opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode; - len = sizeof(new_insn.opc); - if (!p->ainsn.is_ftrace_insn) - goto skip_ftrace; - len = sizeof(new_insn); - insn = (struct ftrace_insn *) p->addr; - if (args->arm_kprobe) { - if (is_ftrace_nop(insn)) - new_insn.disp = KPROBE_ON_FTRACE_NOP; - else - new_insn.disp = KPROBE_ON_FTRACE_CALL; - } else { - ftrace_generate_call_insn(&new_insn, (unsigned long)p->addr); - if (insn->disp == KPROBE_ON_FTRACE_NOP) - ftrace_generate_nop_insn(&new_insn); - } -skip_ftrace: - s390_kernel_write(p->addr, &new_insn, len); + u16 opc; + + opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode; + s390_kernel_write(p->addr, &opc, sizeof(opc)); return 0; } NOKPROBE_SYMBOL(swap_instruction); @@ -464,24 +431,6 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs) unsigned long ip = regs->psw.addr; int fixup = probe_get_fixup_type(p->ainsn.insn); - /* Check if the kprobes location is an enabled ftrace caller */ - if (p->ainsn.is_ftrace_insn) { - struct ftrace_insn *insn = (struct ftrace_insn *) p->addr; - struct ftrace_insn call_insn; - - ftrace_generate_call_insn(&call_insn, (unsigned long) p->addr); - /* - * A kprobe on an enabled ftrace call site actually single - * stepped an unconditional branch (ftrace nop equivalent). - * Now we need to fixup things and pretend that a brasl r0,... - * was executed instead. - */ - if (insn->disp == KPROBE_ON_FTRACE_CALL) { - ip += call_insn.disp * 2 - MCOUNT_INSN_SIZE; - regs->gprs[0] = (unsigned long)p->addr + sizeof(*insn); - } - } - if (fixup & FIXUP_PSW_NORMAL) ip += (unsigned long) p->addr - (unsigned long) p->ainsn.insn; diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S index f942341429b1..7458dcfd6464 100644 --- a/arch/s390/kernel/mcount.S +++ b/arch/s390/kernel/mcount.S @@ -42,6 +42,9 @@ ENTRY(ftrace_caller) .globl ftrace_regs_caller .set ftrace_regs_caller,ftrace_caller stg %r14,(__SF_GPRS+8*8)(%r15) # save traced function caller + lghi %r14,0 # save condition code + ipm %r14 # don't put any instructions + sllg %r14,%r14,16 # clobbering CC before this point lgr %r1,%r15 #if !(defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)) aghi %r0,MCOUNT_RETURN_FIXUP @@ -54,6 +57,9 @@ ENTRY(ftrace_caller) # allocate pt_regs and stack frame for ftrace_trace_function aghi %r15,-STACK_FRAME_SIZE stg %r1,(STACK_PTREGS_GPRS+15*8)(%r15) + stg %r14,(STACK_PTREGS_PSW)(%r15) + lg %r14,(__SF_GPRS+8*8)(%r1) # restore original return address + stosm (STACK_PTREGS_PSW)(%r15),0 aghi %r1,-TRACED_FUNC_FRAME_SIZE stg %r1,__SF_BACKCHAIN(%r15) stg %r0,(STACK_PTREGS_PSW+8)(%r15) |