diff options
Diffstat (limited to 'arch/s390/kernel')
| -rw-r--r-- | arch/s390/kernel/Makefile | 4 | ||||
| -rw-r--r-- | arch/s390/kernel/ftrace.c | 15 | ||||
| -rw-r--r-- | arch/s390/kernel/kprobes.c | 3 | ||||
| -rw-r--r-- | arch/s390/kernel/mcount.S | 2 |
4 files changed, 20 insertions, 4 deletions
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile index 204c43a4c245..31fab2676fe9 100644 --- a/arch/s390/kernel/Makefile +++ b/arch/s390/kernel/Makefile @@ -4,8 +4,8 @@ ifdef CONFIG_FUNCTION_TRACER # Don't trace early setup code and tracing code -CFLAGS_REMOVE_early.o = -pg -CFLAGS_REMOVE_ftrace.o = -pg +CFLAGS_REMOVE_early.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) endif # diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 3dabcae40e04..82c19899574f 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -46,6 +46,13 @@ * lg %r14,8(%r15) # offset 18 * The jg instruction branches to offset 24 to skip as many instructions * as possible. + * In case we use gcc's hotpatch feature the original and also the disabled + * function prologue contains only a single six byte instruction and looks + * like this: + * > brcl 0,0 # offset 0 + * To enable ftrace the code gets patched like above and afterwards looks + * like this: + * > brasl %r0,ftrace_caller # offset 0 */ unsigned long ftrace_plt; @@ -64,9 +71,15 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, if (probe_kernel_read(&old, (void *) rec->ip, sizeof(old))) return -EFAULT; if (addr == MCOUNT_ADDR) { - /* Initial code replacement; we expect to see stg r14,8(r15) */ + /* Initial code replacement */ +#ifdef CC_USING_HOTPATCH + /* We expect to see brcl 0,0 */ + ftrace_generate_nop_insn(&orig); +#else + /* We expect to see stg r14,8(r15) */ orig.opc = 0xe3e0; orig.disp = 0xf0080024; +#endif ftrace_generate_nop_insn(&new); } else if (old.opc == BREAKPOINT_INSTRUCTION) { /* diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 1e4c710dfb92..f516edc1fbe3 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -69,7 +69,8 @@ static void copy_instruction(struct kprobe *p) /* * 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 + * "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; diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S index b6dfc5bfcb89..e499370fbccb 100644 --- a/arch/s390/kernel/mcount.S +++ b/arch/s390/kernel/mcount.S @@ -27,7 +27,9 @@ ENTRY(ftrace_caller) .globl ftrace_regs_caller .set ftrace_regs_caller,ftrace_caller lgr %r1,%r15 +#ifndef CC_USING_HOTPATCH aghi %r0,MCOUNT_RETURN_FIXUP +#endif aghi %r15,-STACK_FRAME_SIZE stg %r1,__SF_BACKCHAIN(%r15) stg %r1,(STACK_PTREGS_GPRS+15*8)(%r15) |