diff options
| -rw-r--r-- | arch/s390/Kconfig | 1 | ||||
| -rw-r--r-- | arch/s390/Makefile | 10 | ||||
| -rw-r--r-- | arch/s390/include/asm/ftrace.h | 15 | ||||
| -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 | ||||
| -rwxr-xr-x | scripts/recordmcount.pl | 9 |
8 files changed, 52 insertions, 7 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 7eba5b5723e9..8d11babf9aa5 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -117,7 +117,6 @@ config S390 select HAVE_BPF_JIT if 64BIT && PACK_STACK select HAVE_CMPXCHG_DOUBLE select HAVE_CMPXCHG_LOCAL - select HAVE_C_RECORDMCOUNT select HAVE_DEBUG_KMEMLEAK select HAVE_DYNAMIC_FTRACE if 64BIT select HAVE_DYNAMIC_FTRACE_WITH_REGS if 64BIT diff --git a/arch/s390/Makefile b/arch/s390/Makefile index e742ec5de9a7..acb6859c6a95 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -87,6 +87,16 @@ ifeq ($(call cc-option-yn,-mwarn-dynamicstack),y) cflags-$(CONFIG_WARN_DYNAMIC_STACK) += -mwarn-dynamicstack endif +ifdef CONFIG_FUNCTION_TRACER +# make use of hotpatch feature if the compiler supports it +cc_hotpatch := -mhotpatch=0,3 +ifeq ($(call cc-option-yn,$(cc_hotpatch)),y) +CC_FLAGS_FTRACE := $(cc_hotpatch) +KBUILD_AFLAGS += -DCC_USING_HOTPATCH +KBUILD_CFLAGS += -DCC_USING_HOTPATCH +endif +endif + KBUILD_CFLAGS += -mbackchain -msoft-float $(cflags-y) KBUILD_CFLAGS += -pipe -fno-strength-reduce -Wno-sign-compare KBUILD_AFLAGS += $(aflags-y) diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h index abb618f1ead2..836c56290499 100644 --- a/arch/s390/include/asm/ftrace.h +++ b/arch/s390/include/asm/ftrace.h @@ -3,8 +3,12 @@ #define ARCH_SUPPORTS_FTRACE_OPS 1 +#ifdef CC_USING_HOTPATCH +#define MCOUNT_INSN_SIZE 6 +#else #define MCOUNT_INSN_SIZE 24 #define MCOUNT_RETURN_FIXUP 18 +#endif #ifndef __ASSEMBLY__ @@ -37,18 +41,29 @@ struct ftrace_insn { static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn) { #ifdef CONFIG_FUNCTION_TRACER +#ifdef CC_USING_HOTPATCH + /* brcl 0,0 */ + insn->opc = 0xc004; + insn->disp = 0; +#else /* jg .+24 */ insn->opc = 0xc0f4; insn->disp = MCOUNT_INSN_SIZE / 2; #endif +#endif } static inline int is_ftrace_nop(struct ftrace_insn *insn) { #ifdef CONFIG_FUNCTION_TRACER +#ifdef CC_USING_HOTPATCH + if (insn->disp == 0) + return 1; +#else if (insn->disp == MCOUNT_INSN_SIZE / 2) return 1; #endif +#endif return 0; } 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) diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl index 56ea99a12ab7..be39be0abefc 100755 --- a/scripts/recordmcount.pl +++ b/scripts/recordmcount.pl @@ -242,8 +242,13 @@ if ($arch eq "x86_64") { $cc .= " -m32"; } elsif ($arch eq "s390" && $bits == 64) { - $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_(PC|PLT)32DBL\\s+_mcount\\+0x2\$"; - $mcount_adjust = -14; + if ($cc =~ /-DCC_USING_HOTPATCH/) { + $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*c0 04 00 00 00 00\\s*brcl\\s*0,[0-9a-f]+ <([^\+]*)>\$"; + $mcount_adjust = 0; + } else { + $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_(PC|PLT)32DBL\\s+_mcount\\+0x2\$"; + $mcount_adjust = -14; + } $alignment = 8; $type = ".quad"; $ld .= " -m elf64_s390"; |