diff options
author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2009-06-12 10:26:44 +0200 |
---|---|---|
committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2009-06-12 10:27:38 +0200 |
commit | dfd9f7abc0fb67b5781f340d982384cea53b2884 (patch) | |
tree | 850baae88167699f45ba1dea1765b9156373db72 /arch/s390/kernel | |
parent | a2b53673fae14601bb520acf6a6f154463994565 (diff) |
[S390] ftrace: add dynamic ftrace support
Dynamic ftrace support for s390.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel')
-rw-r--r-- | arch/s390/kernel/Makefile | 5 | ||||
-rw-r--r-- | arch/s390/kernel/early.c | 4 | ||||
-rw-r--r-- | arch/s390/kernel/ftrace.c | 132 | ||||
-rw-r--r-- | arch/s390/kernel/mcount.S | 119 | ||||
-rw-r--r-- | arch/s390/kernel/setup.c | 2 | ||||
-rw-r--r-- | arch/s390/kernel/smp.c | 1 |
6 files changed, 236 insertions, 27 deletions
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile index 0657de7944fe..ce172bfaab8a 100644 --- a/arch/s390/kernel/Makefile +++ b/arch/s390/kernel/Makefile @@ -7,6 +7,10 @@ ifdef CONFIG_FUNCTION_TRACER CFLAGS_REMOVE_early.o = -pg endif +ifdef CONFIG_DYNAMIC_FTRACE +CFLAGS_REMOVE_ftrace.o = -pg +endif + # # Passing null pointers is ok for smp code, since we access the lowcore here. # @@ -41,6 +45,7 @@ obj-$(CONFIG_COMPAT) += compat_linux.o compat_signal.o \ obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_FUNCTION_TRACER) += mcount.o +obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o # Kexec part S390_KEXEC_OBJS := machine_kexec.o crash.o diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c index cf09948faad6..fb263736826c 100644 --- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -11,6 +11,7 @@ #include <linux/errno.h> #include <linux/string.h> #include <linux/ctype.h> +#include <linux/ftrace.h> #include <linux/lockdep.h> #include <linux/module.h> #include <linux/pfn.h> @@ -410,5 +411,8 @@ void __init startup_init(void) sclp_facilities_detect(); detect_memory_layout(memory_chunk); S390_lowcore.machine_flags = machine_flags; +#ifdef CONFIG_DYNAMIC_FTRACE + S390_lowcore.ftrace_func = (unsigned long)ftrace_caller; +#endif lockdep_on(); } diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c new file mode 100644 index 000000000000..0b81a784e039 --- /dev/null +++ b/arch/s390/kernel/ftrace.c @@ -0,0 +1,132 @@ +/* + * Dynamic function tracer architecture backend. + * + * Copyright IBM Corp. 2009 + * + * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>, + * + */ + +#include <linux/uaccess.h> +#include <linux/ftrace.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <asm/lowcore.h> + +void ftrace_disable_code(void); +void ftrace_call_code(void); +void ftrace_nop_code(void); + +#define FTRACE_INSN_SIZE 4 + +#ifdef CONFIG_64BIT + +asm( + " .align 4\n" + "ftrace_disable_code:\n" + " j 0f\n" + " .word 0x0024\n" + " lg %r1,"__stringify(__LC_FTRACE_FUNC)"\n" + " basr %r14,%r1\n" + " lg %r14,8(15)\n" + " lgr %r0,%r0\n" + "0:\n"); + +asm( + " .align 4\n" + "ftrace_nop_code:\n" + " j .+"__stringify(MCOUNT_INSN_SIZE)"\n"); + +asm( + " .align 4\n" + "ftrace_call_code:\n" + " stg %r14,8(%r15)\n"); + +#else /* CONFIG_64BIT */ + +asm( + " .align 4\n" + "ftrace_disable_code:\n" + " j 0f\n" + " l %r1,"__stringify(__LC_FTRACE_FUNC)"\n" + " basr %r14,%r1\n" + " l %r14,4(%r15)\n" + " j 0f\n" + " bcr 0,%r7\n" + " bcr 0,%r7\n" + " bcr 0,%r7\n" + " bcr 0,%r7\n" + " bcr 0,%r7\n" + " bcr 0,%r7\n" + "0:\n"); + +asm( + " .align 4\n" + "ftrace_nop_code:\n" + " j .+"__stringify(MCOUNT_INSN_SIZE)"\n"); + +asm( + " .align 4\n" + "ftrace_call_code:\n" + " st %r14,4(%r15)\n"); + +#endif /* CONFIG_64BIT */ + +static int ftrace_modify_code(unsigned long ip, + void *old_code, int old_size, + void *new_code, int new_size) +{ + unsigned char replaced[MCOUNT_INSN_SIZE]; + + /* + * Note: Due to modules code can disappear and change. + * We need to protect against faulting as well as code + * changing. We do this by using the probe_kernel_* + * functions. + * This however is just a simple sanity check. + */ + if (probe_kernel_read(replaced, (void *)ip, old_size)) + return -EFAULT; + if (memcmp(replaced, old_code, old_size) != 0) + return -EINVAL; + if (probe_kernel_write((void *)ip, new_code, new_size)) + return -EPERM; + return 0; +} + +static int ftrace_make_initial_nop(struct module *mod, struct dyn_ftrace *rec, + unsigned long addr) +{ + return ftrace_modify_code(rec->ip, + ftrace_call_code, FTRACE_INSN_SIZE, + ftrace_disable_code, MCOUNT_INSN_SIZE); +} + +int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, + unsigned long addr) +{ + if (addr == MCOUNT_ADDR) + return ftrace_make_initial_nop(mod, rec, addr); + return ftrace_modify_code(rec->ip, + ftrace_call_code, FTRACE_INSN_SIZE, + ftrace_nop_code, FTRACE_INSN_SIZE); +} + +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + return ftrace_modify_code(rec->ip, + ftrace_nop_code, FTRACE_INSN_SIZE, + ftrace_call_code, FTRACE_INSN_SIZE); +} + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + ftrace_dyn_func = (unsigned long)func; + return 0; +} + +int __init ftrace_dyn_arch_init(void *data) +{ + *(unsigned long *)data = 0; + return 0; +} diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S index 80641224a095..de274996f640 100644 --- a/arch/s390/kernel/mcount.S +++ b/arch/s390/kernel/mcount.S @@ -1,5 +1,5 @@ /* - * Copyright IBM Corp. 2008 + * Copyright IBM Corp. 2008,2009 * * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>, * @@ -7,36 +7,46 @@ #include <asm/asm-offsets.h> -#ifndef CONFIG_64BIT -.globl _mcount + .globl ftrace_stub +ftrace_stub: + br %r14 + +#ifdef CONFIG_64BIT + +#ifdef CONFIG_DYNAMIC_FTRACE + + .globl _mcount _mcount: - stm %r0,%r5,8(%r15) - st %r14,56(%r15) - lr %r1,%r15 - ahi %r15,-96 - l %r3,100(%r15) - la %r2,0(%r14) - st %r1,__SF_BACKCHAIN(%r15) - la %r3,0(%r3) - bras %r14,0f - .long ftrace_trace_function -0: l %r14,0(%r14) - l %r14,0(%r14) - basr %r14,%r14 - ahi %r15,96 - lm %r0,%r5,8(%r15) - l %r14,56(%r15) br %r14 -.globl ftrace_stub -ftrace_stub: + .globl ftrace_caller +ftrace_caller: + stmg %r2,%r5,32(%r15) + stg %r14,112(%r15) + lgr %r1,%r15 + aghi %r15,-160 + stg %r1,__SF_BACKCHAIN(%r15) + lgr %r2,%r14 + lg %r3,168(%r15) + larl %r14,ftrace_dyn_func + lg %r14,0(%r14) + basr %r14,%r14 + aghi %r15,160 + lmg %r2,%r5,32(%r15) + lg %r14,112(%r15) br %r14 -#else /* CONFIG_64BIT */ + .data + .globl ftrace_dyn_func +ftrace_dyn_func: + .quad ftrace_stub + .previous + +#else /* CONFIG_DYNAMIC_FTRACE */ -.globl _mcount + .globl _mcount _mcount: - stmg %r0,%r5,16(%r15) + stmg %r2,%r5,32(%r15) stg %r14,112(%r15) lgr %r1,%r15 aghi %r15,-160 @@ -47,12 +57,67 @@ _mcount: lg %r14,0(%r14) basr %r14,%r14 aghi %r15,160 - lmg %r0,%r5,16(%r15) + lmg %r2,%r5,32(%r15) lg %r14,112(%r15) br %r14 -.globl ftrace_stub -ftrace_stub: +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#else /* CONFIG_64BIT */ + +#ifdef CONFIG_DYNAMIC_FTRACE + + .globl _mcount +_mcount: + br %r14 + + .globl ftrace_caller +ftrace_caller: + stm %r2,%r5,16(%r15) + st %r14,56(%r15) + lr %r1,%r15 + ahi %r15,-96 + l %r3,100(%r15) + la %r2,0(%r14) + st %r1,__SF_BACKCHAIN(%r15) + la %r3,0(%r3) + bras %r14,0f + .long ftrace_dyn_func +0: l %r14,0(%r14) + l %r14,0(%r14) + basr %r14,%r14 + ahi %r15,96 + lm %r2,%r5,16(%r15) + l %r14,56(%r15) + br %r14 + + .data + .globl ftrace_dyn_func +ftrace_dyn_func: + .long ftrace_stub + .previous + +#else /* CONFIG_DYNAMIC_FTRACE */ + + .globl _mcount +_mcount: + stm %r2,%r5,16(%r15) + st %r14,56(%r15) + lr %r1,%r15 + ahi %r15,-96 + l %r3,100(%r15) + la %r2,0(%r14) + st %r1,__SF_BACKCHAIN(%r15) + la %r3,0(%r3) + bras %r14,0f + .long ftrace_trace_function +0: l %r14,0(%r14) + l %r14,0(%r14) + basr %r14,%r14 + ahi %r15,96 + lm %r2,%r5,16(%r15) + l %r14,56(%r15) br %r14 +#endif /* CONFIG_DYNAMIC_FTRACE */ #endif /* CONFIG_64BIT */ diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 7402b6a39ead..9717717c6fea 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -42,6 +42,7 @@ #include <linux/ctype.h> #include <linux/reboot.h> #include <linux/topology.h> +#include <linux/ftrace.h> #include <asm/ipl.h> #include <asm/uaccess.h> @@ -442,6 +443,7 @@ setup_lowcore(void) lc->steal_timer = S390_lowcore.steal_timer; lc->last_update_timer = S390_lowcore.last_update_timer; lc->last_update_clock = S390_lowcore.last_update_clock; + lc->ftrace_func = S390_lowcore.ftrace_func; set_prefix((u32)(unsigned long) lc); lowcore_ptr[0] = lc; } diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 0af302ceac2d..cc8c484984e3 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -572,6 +572,7 @@ int __cpuinit __cpu_up(unsigned int cpu) cpu_lowcore->cpu_nr = cpu; cpu_lowcore->kernel_asce = S390_lowcore.kernel_asce; cpu_lowcore->machine_flags = S390_lowcore.machine_flags; + cpu_lowcore->ftrace_func = S390_lowcore.ftrace_func; eieio(); while (signal_processor(cpu, sigp_restart) == sigp_busy) |