[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>

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 1094787..b674e79 100644 (file)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -82,6 +82,8 @@ config S390
        select USE_GENERIC_SMP_HELPERS if SMP
        select HAVE_SYSCALL_WRAPPERS
        select HAVE_FUNCTION_TRACER
+       select HAVE_FTRACE_MCOUNT_RECORD
+       select HAVE_DYNAMIC_FTRACE
        select HAVE_DEFAULT_NO_SPIN_MUTEXES
        select HAVE_OPROFILE
        select HAVE_KPROBES

diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 5a5bc75..ba23d8f 100644 (file)
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -2,7 +2,26 @@
 #define _ASM_S390_FTRACE_H
 
 #ifndef __ASSEMBLY__
+
 extern void _mcount(void);
+extern unsigned long ftrace_dyn_func;
+
+struct dyn_arch_ftrace { };
+
+#define MCOUNT_ADDR ((long)_mcount)
+
+#ifdef CONFIG_64BIT
+#define MCOUNT_INSN_SIZE 24
+#define MCOUNT_OFFSET   14
+#else
+#define MCOUNT_INSN_SIZE 30
+#define MCOUNT_OFFSET    8
 #endif
 
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+       return addr - MCOUNT_OFFSET;
+}
+
+#endif /* __ASSEMBLY__ */
 #endif /* _ASM_S390_FTRACE_H */

diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h
index 713fe9f..5046ad6 100644 (file)
--- a/arch/s390/include/asm/lowcore.h
+++ b/arch/s390/include/asm/lowcore.h
@@ -68,6 +68,7 @@
 #define __LC_CPUID                     0x02b0
 #define __LC_INT_CLOCK                 0x02c8
 #define __LC_MACHINE_FLAGS             0x02d8
+#define __LC_FTRACE_FUNC               0x02dc
 #define __LC_IRB                       0x0300
 #define __LC_PFAULT_INTPARM            0x0080
 #define __LC_CPU_TIMER_SAVE_AREA       0x00d8
@@ -113,6 +114,7 @@
 #define __LC_INT_CLOCK                 0x0340
 #define __LC_VDSO_PER_CPU              0x0350
 #define __LC_MACHINE_FLAGS             0x0358
+#define __LC_FTRACE_FUNC               0x0360
 #define __LC_IRB                       0x0380
 #define __LC_PASTE                     0x03c0
 #define __LC_PFAULT_INTPARM            0x11b8
@@ -281,7 +283,8 @@ struct _lowcore
        __u64   int_clock;                      /* 0x02c8 */
        __u64   clock_comparator;               /* 0x02d0 */
        __u32   machine_flags;                  /* 0x02d8 */
-       __u8    pad_0x02dc[0x0300-0x02dc];      /* 0x02dc */
+       __u32   ftrace_func;                    /* 0x02dc */
+       __u8    pad_0x02f0[0x0300-0x02f0];      /* 0x02f0 */
 
        /* Interrupt response block */
        __u8    irb[64];                        /* 0x0300 */
@@ -386,7 +389,8 @@ struct _lowcore
        __u64   clock_comparator;               /* 0x0348 */
        __u64   vdso_per_cpu_data;              /* 0x0350 */
        __u64   machine_flags;                  /* 0x0358 */
-       __u8    pad_0x0360[0x0380-0x0360];      /* 0x0360 */
+       __u64   ftrace_func;                    /* 0x0360 */
+       __u8    pad_0x0368[0x0380-0x0368];      /* 0x0368 */
 
        /* Interrupt response block. */
        __u8    irb[64];                        /* 0x0380 */

diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 0657de7..ce172bf 100644 (file)
--- 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 cf09948..fb26373 100644 (file)
--- 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 (file)
index 0000000..0b81a78
--- /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 8064122..de27499 100644 (file)
--- 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 7402b6a..9717717 100644 (file)
--- 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 0af302c..cc8c484 100644 (file)
--- 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)

diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index 0fae7da..91033e6 100755 (executable)
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -185,6 +185,19 @@ if ($arch eq "x86_64") {
     $objcopy .= " -O elf32-i386";
     $cc .= " -m32";
 
+} elsif ($arch eq "s390" && $bits == 32) {
+    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_32\\s+_mcount\$";
+    $alignment = 4;
+    $ld .= " -m elf_s390";
+    $cc .= " -m31";
+
+} elsif ($arch eq "s390" && $bits == 64) {
+    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_390_(PC|PLT)32DBL\\s+_mcount\\+0x2\$";
+    $alignment = 8;
+    $type = ".quad";
+    $ld .= " -m elf64_s390";
+    $cc .= " -m64";
+
 } elsif ($arch eq "sh") {
     $alignment = 2;