Hi,
Constructing on Jeremy Fitzhardinge's comments about gcc optimizations, I
rewrote (once more) the markers mechanism so that the optimized mode does not
jump between two different inline asm. Instead, the optimized version uses a
load immediate (in assembly) that will be used by a test to decide of a branch
(in C).
The generic, non optimized version, now does almost the same as the optimized
version, but instead of using an immediate value, it uses a value in memory
which must therefore be loaded before each test.
On x86, the result of the fast path is now (the call is put far from the "hot"
instructions at the end of the function) :
...
70: b0 00 mov $0x0,%al (load 0 in al)
72: 84 c0 test %al,%al
74: 75 57 jne cd <my_open+0x6f> (not taken)
....
Compared to the generic version (the call is also put at the end of the
function) :
...
64: 0f b6 05 07 00 00 00 movzbl 0x7,%eax (load eax from memory)
6b: 84 c0 test %al,%al
6d: 75 4a jne b9 <my_open+0x5b> (not taken)
...
I also added the powerpc optimization (not tested yet though).
Comments are welcome,
Mathieu
---BEGIN---
diff --git a/Makefile b/Makefile
index 1700d3f..78ed30f 100644
--- a/Makefile
+++ b/Makefile
@@ -301,7 +301,8 @@ # Use LINUXINCLUDE when you must referen
# Needed to be compatible with the O= option
LINUXINCLUDE := -Iinclude \
$(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include) \
- -include include/linux/autoconf.h
+ -include include/linux/autoconf.h \
+ -include include/linux/marker.h
CPPFLAGS := -D__KERNEL__ $(LINUXINCLUDE)
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 213c785..95c1d1b 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -630,6 +630,12 @@ source "fs/Kconfig"
source "arch/alpha/oprofile/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/alpha/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 08b7cc9..4c03f09 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -871,6 +871,12 @@ source "fs/Kconfig"
source "arch/arm/oprofile/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/arm/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/arm26/Kconfig b/arch/arm26/Kconfig
index cf4ebf4..f34e157 100644
--- a/arch/arm26/Kconfig
+++ b/arch/arm26/Kconfig
@@ -232,6 +232,12 @@ source "drivers/misc/Kconfig"
source "drivers/usb/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/arm26/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index 856b665..84f8efd 100644
--- a/arch/cris/Kconfig
+++ b/arch/cris/Kconfig
@@ -179,6 +179,12 @@ source "sound/Kconfig"
source "drivers/usb/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/cris/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index 95a3892..8708a75 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -345,6 +345,12 @@ source "drivers/Kconfig"
source "fs/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/frv/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index cabf0bf..bdb67ed 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -197,6 +197,12 @@ endmenu
source "fs/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/h8300/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 8dfa305..e6cc7da 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -1081,6 +1081,9 @@ config KPROBES
a probepoint and specifies the callback. Kprobes is useful
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".
+
+source "kernel/Kconfig.marker"
+
endmenu
source "arch/i386/Kconfig.debug"
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 0f3076a..2342975 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -499,6 +499,9 @@ config KPROBES
a probepoint and specifies the callback. Kprobes is useful
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".
+
+source "kernel/Kconfig.marker"
+
endmenu
source "arch/ia64/Kconfig.debug"
diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig
index 41fd490..50f0a8e 100644
--- a/arch/m32r/Kconfig
+++ b/arch/m32r/Kconfig
@@ -386,6 +386,12 @@ source "fs/Kconfig"
source "arch/m32r/oprofile/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/m32r/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 805b81f..5af9e00 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -652,6 +652,12 @@ endmenu
source "fs/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/m68k/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/m68knommu/Kconfig b/arch/m68knommu/Kconfig
index 3cde682..bd01cc0 100644
--- a/arch/m68knommu/Kconfig
+++ b/arch/m68knommu/Kconfig
@@ -652,6 +652,12 @@ source "drivers/Kconfig"
source "fs/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/m68knommu/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index e8ff09f..4d5dbf9 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1850,6 +1850,12 @@ source "fs/Kconfig"
source "arch/mips/oprofile/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/mips/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 910fb3a..a0a7dd7 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -251,6 +251,12 @@ source "fs/Kconfig"
source "arch/parisc/oprofile/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/parisc/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 6729c98..44f25b5 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -1011,6 +1011,9 @@ config KPROBES
a probepoint and specifies the callback. Kprobes is useful
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".
+
+source "kernel/Kconfig.marker"
+
endmenu
source "arch/powerpc/Kconfig.debug"
diff --git a/arch/ppc/Kconfig b/arch/ppc/Kconfig
index e9a8f5d..ca871ab 100644
--- a/arch/ppc/Kconfig
+++ b/arch/ppc/Kconfig
@@ -1412,6 +1412,12 @@ source "lib/Kconfig"
source "arch/powerpc/oprofile/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/ppc/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 01c5c08..57600b5 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -476,6 +476,12 @@ source "fs/Kconfig"
source "arch/s390/oprofile/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/s390/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 2bcecf4..0fd24d3 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -644,6 +644,12 @@ source "fs/Kconfig"
source "arch/sh/oprofile/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/sh/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/sh64/Kconfig b/arch/sh64/Kconfig
index 58c678e..f4ecb4d 100644
--- a/arch/sh64/Kconfig
+++ b/arch/sh64/Kconfig
@@ -276,6 +276,12 @@ source "fs/Kconfig"
source "arch/sh64/oprofile/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/sh64/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 9431e96..de02311 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -289,6 +289,12 @@ endmenu
source "fs/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/sparc/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
index 43a66f5..971f5e2 100644
--- a/arch/sparc64/Kconfig
+++ b/arch/sparc64/Kconfig
@@ -419,6 +419,9 @@ config KPROBES
a probepoint and specifies the callback. Kprobes is useful
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".
+
+source "kernel/Kconfig.marker"
+
endmenu
source "arch/sparc64/Kconfig.debug"
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 76e85bb..9481883 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -312,4 +312,10 @@ config INPUT
bool
default n
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/um/Kconfig.debug"
diff --git a/arch/v850/Kconfig b/arch/v850/Kconfig
index 37ec644..6ce651f 100644
--- a/arch/v850/Kconfig
+++ b/arch/v850/Kconfig
@@ -324,6 +324,12 @@ source "sound/Kconfig"
source "drivers/usb/Kconfig"
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/v850/Kconfig.debug"
source "security/Kconfig"
diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index 408d44a..6feb011 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -611,6 +611,9 @@ config KPROBES
a probepoint and specifies the callback. Kprobes is useful
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".
+
+source "kernel/Kconfig.marker"
+
endmenu
source "arch/x86_64/Kconfig.debug"
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index dbeb350..413abb8 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -255,6 +255,12 @@ config EMBEDDED_RAMDISK_IMAGE
provide one yourself.
endmenu
+menu "Instrumentation Support"
+
+source "kernel/Kconfig.marker"
+
+endmenu
+
source "arch/xtensa/Kconfig.debug"
source "security/Kconfig"
diff --git a/include/asm-alpha/marker.h b/include/asm-alpha/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-alpha/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-arm/marker.h b/include/asm-arm/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-arm/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-arm26/marker.h b/include/asm-arm26/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-arm26/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-cris/marker.h b/include/asm-cris/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-cris/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-frv/marker.h b/include/asm-frv/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-frv/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-generic/marker.h b/include/asm-generic/marker.h
new file mode 100644
index 0000000..4dd08fa
--- /dev/null
+++ b/include/asm-generic/marker.h
@@ -0,0 +1,42 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Generic header.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#ifdef CONFIG_MARKERS
+
+#define MARK(name, format, args...) \
+ do { \
+ static marker_probe_func *__mark_call_##name = \
+ __mark_empty_function; \
+ volatile static char __marker_enable_##name = 0; \
+ asm volatile( ".section .markers, \"a\";\n\t" \
+ ".long %0, %1, %2, %3;\n\t" \
+ ".previous;\n\t" \
+ : : \
+ "m" (*(#name)), \
+ "m" (__marker_enable_##name), \
+ "m" (__mark_call_##name), \
+ "m" (*format)); \
+ if(unlikely(__marker_enable_##name)) { \
+ preempt_disable(); \
+ (*__mark_call_##name)(format, ## args); \
+ preempt_enable_no_resched(); \
+ } \
+ } while(0)
+
+
+#define MARK_ENABLE_IMMEDIATE_OFFSET 0
+
+struct __mark_marker {
+ const char *name;
+ char *enable;
+ marker_probe_func **call;
+ const char *format;
+} __attribute__((packed));
+
+#endif
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 9d11550..d029043 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -90,6 +90,12 @@ #define RODATA \
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
*(__ksymtab_strings) \
} \
+ /* Kernel markers : pointers */ \
+ .markers : AT(ADDR(.markers) - LOAD_OFFSET) { \
+ VMLINUX_SYMBOL(__start___markers) = .; \
+ *(.markers) \
+ VMLINUX_SYMBOL(__stop___markers) = .; \
+ } \
__end_rodata = .; \
. = ALIGN(4096); \
\
diff --git a/include/asm-h8300/marker.h b/include/asm-h8300/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-h8300/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-i386/marker.h b/include/asm-i386/marker.h
new file mode 100644
index 0000000..bb88767
--- /dev/null
+++ b/include/asm-i386/marker.h
@@ -0,0 +1,48 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. i386 architecture optimisations.
+ *
+ * (C) Copyright 2006 Mathieu Desnoyers <[email protected]>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#ifdef CONFIG_MARKERS
+
+#define MARK(name, format, args...) \
+ do { \
+ static marker_probe_func *__mark_call_##name = \
+ __mark_empty_function; \
+ char condition; \
+ asm volatile( ".section .markers, \"a\";\n\t" \
+ ".long %1, 0f, %2, %3;\n\t" \
+ ".previous;\n\t" \
+ ".align 16;\n\t" \
+ "0:\n\t" \
+ "movb $0,%0;\n\t" \
+ : "=r" (condition) : \
+ "m" (*(#name)), \
+ "m" (__mark_call_##name), \
+ "m" (*format)); \
+ __mark_check_format(format, ## args); \
+ if(unlikely(condition)) { \
+ preempt_disable(); \
+ (*__mark_call_##name)(format, ## args); \
+ preempt_enable_no_resched(); \
+ } \
+ } while(0)
+
+/* Offset of the immediate value from the start of the movb instruction, in
+ * bytes. */
+#define MARK_ENABLE_IMMEDIATE_OFFSET 1
+
+struct __mark_marker {
+ const char *name;
+ char *enable;
+ marker_probe_func **call;
+ const char *format;
+} __attribute__((packed));
+
+#endif
diff --git a/include/asm-ia64/marker.h b/include/asm-ia64/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-ia64/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-m32r/marker.h b/include/asm-m32r/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-m32r/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-m68k/marker.h b/include/asm-m68k/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-m68k/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-m68knommu/marker.h b/include/asm-m68knommu/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-m68knommu/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-mips/marker.h b/include/asm-mips/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-mips/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-parisc/marker.h b/include/asm-parisc/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-parisc/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-powerpc/marker.h b/include/asm-powerpc/marker.h
new file mode 100644
index 0000000..2c76cbe
--- /dev/null
+++ b/include/asm-powerpc/marker.h
@@ -0,0 +1,50 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. PowerPC architecture
+ * optimisations.
+ *
+ * (C) Copyright 2006 Mathieu Desnoyers <[email protected]>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#ifdef CONFIG_MARKERS
+
+#define MARK(name, format, args...) \
+ do { \
+ static marker_probe_func *__mark_call_##name = \
+ __mark_empty_function; \
+ char condition; \
+ asm volatile( ".section .markers, \"a\";\n\t" \
+ ".long %1, 0f, %2, %3;\n\t" \
+ ".previous;\n\t" \
+ ".align 32;\n\t" \
+ "0:\n\t" \
+ "li $0,%0;\n\t" \
+ : "=r" (condition) : \
+ "m" (*(#name)), \
+ "m" (__mark_call_##name), \
+ "m" (*format)); \
+ __mark_check_format(format, ## args); \
+ if(unlikely(condition)) { \
+ preempt_disable(); \
+ (*__mark_call_##name)(format, ## args); \
+ preempt_enable_no_resched(); \
+ } \
+ } while(0)
+
+
+/* Offset of the immediate value from the start of the addi instruction (result
+ * of the li mnemonic), in bytes. */
+#define MARK_ENABLE_IMMEDIATE_OFFSET 2
+
+struct __mark_marker {
+ const char *name;
+ short *enable;
+ marker_probe_func **call;
+ const char *format;
+} __attribute__((packed));
+
+#endif
diff --git a/include/asm-ppc/marker.h b/include/asm-ppc/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-ppc/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-ppc64/marker.h b/include/asm-ppc64/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-ppc64/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-s390/marker.h b/include/asm-s390/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-s390/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-sh/marker.h b/include/asm-sh/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-sh/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-sh64/marker.h b/include/asm-sh64/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-sh64/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-sparc/marker.h b/include/asm-sparc/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-sparc/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-sparc64/marker.h b/include/asm-sparc64/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-sparc64/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-um/marker.h b/include/asm-um/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-um/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-v850/marker.h b/include/asm-v850/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-v850/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-x86_64/marker.h b/include/asm-x86_64/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-x86_64/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/asm-xtensa/marker.h b/include/asm-xtensa/marker.h
new file mode 100644
index 0000000..8d9467f
--- /dev/null
+++ b/include/asm-xtensa/marker.h
@@ -0,0 +1,13 @@
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing. Architecture specific
+ * optimisations.
+ *
+ * No optimisation implemented.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <asm-generic/marker.h>
diff --git a/include/linux/marker.h b/include/linux/marker.h
new file mode 100644
index 0000000..71909f0
--- /dev/null
+++ b/include/linux/marker.h
@@ -0,0 +1,65 @@
+#ifndef _LINUX_MARKER_H
+#define _LINUX_MARKER_H
+
+/*
+ * marker.h
+ *
+ * Code markup for dynamic and static tracing.
+ *
+ * Example :
+ *
+ * MARK(subsystem_event, "%d %s", someint, somestring);
+ * Where :
+ * - Subsystem is the name of your subsystem.
+ * - event is the name of the event to mark.
+ * - "%d %s" is the formatted string for printk.
+ * - someint is an integer.
+ * - somestring is a char *.
+ *
+ * - Dynamically overridable function call based on marker mechanism
+ * from Frank Ch. Eigler <[email protected]>.
+ * - Thanks to Jeremy Fitzhardinge <[email protected]> for his constructive
+ * criticism about gcc optimization related issues.
+ *
+ * The marker mechanism supports multiple instances of the same marker.
+ * Markers can be put in inline functions, inlined static functions and
+ * unrolled loops.
+ *
+ * (C) Copyright 2006 Mathieu Desnoyers <[email protected]>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#ifndef __ASSEMBLY__
+
+typedef void marker_probe_func(const char *fmt, ...);
+
+#ifndef CONFIG_MARKERS_DISABLE_OPTIMIZATION
+#include <asm/marker.h>
+#else
+#include <asm-generic/marker.h>
+#endif
+
+#define MARK_NOARGS " "
+#define MARK_MAX_FORMAT_LEN 1024
+
+#ifndef CONFIG_MARKERS
+#define MARK(name, format, args...) \
+ __mark_check_format(format, ## args)
+#endif
+
+static inline __attribute__ ((format (printf, 1, 2)))
+void __mark_check_format(const char *fmt, ...)
+{ }
+
+extern marker_probe_func __mark_empty_function;
+
+extern int marker_set_probe(const char *name, const char *format,
+ marker_probe_func *probe);
+
+extern int marker_remove_probe(marker_probe_func *probe);
+extern int marker_list_probe(marker_probe_func *probe);
+
+#endif
+#endif
diff --git a/include/linux/module.h b/include/linux/module.h
index eaec13d..5689857 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -254,6 +254,8 @@ struct module
const struct kernel_symbol *syms;
unsigned int num_syms;
const unsigned long *crcs;
+ const struct __mark_marker *markers;
+ unsigned int num_markers;
/* GPL-only exported symbols. */
const struct kernel_symbol *gpl_syms;
diff --git a/kernel/Kconfig.marker b/kernel/Kconfig.marker
new file mode 100644
index 0000000..448e2db
--- /dev/null
+++ b/kernel/Kconfig.marker
@@ -0,0 +1,17 @@
+# Code markers configuration
+
+config MARKERS
+ bool "Activate markers"
+ select MODULES
+ default n
+ help
+ Place an empty function call at each marker site. Can by
+ dynamically changed for a probe function.
+
+config MARKERS_DISABLE_OPTIMIZATION
+ bool "Disable architecture specific marker optimization"
+ depends EMBEDDED
+ default n
+ help
+ Disable code replacement jump optimisations. Especially useful if your
+ code is in a read-only rom/flash.
diff --git a/kernel/module.c b/kernel/module.c
index bbe0486..e451527 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -123,6 +123,8 @@ extern const struct kernel_symbol __stop
extern const unsigned long __start___kcrctab[];
extern const unsigned long __start___kcrctab_gpl[];
extern const unsigned long __start___kcrctab_gpl_future[];
+extern const struct __mark_marker __start___markers[];
+extern const struct __mark_marker __stop___markers[];
#ifndef CONFIG_MODVERSIONS
#define symversion(base, idx) NULL
@@ -236,6 +238,164 @@ static struct module *find_module(const
return NULL;
}
+#ifdef CONFIG_MARKERS
+void __mark_empty_function(const char *fmt, ...)
+{
+}
+EXPORT_SYMBOL(__mark_empty_function);
+
+#define MARK_ENABLE_OFFSET(a) \
+ (typeof(a))((char*)a+MARK_ENABLE_IMMEDIATE_OFFSET)
+
+static int marker_set_probe_range(const char *name,
+ const char *format,
+ marker_probe_func *probe,
+ const struct __mark_marker *begin,
+ const struct __mark_marker *end)
+{
+ const struct __mark_marker *iter;
+ int found = 0;
+
+ for(iter = begin; iter < end; iter++) {
+ if (strcmp(name, iter->name) == 0) {
+ if (format && strcmp(format, iter->format) != 0) {
+ printk(KERN_NOTICE
+ "Format mismatch for probe %s "
+ "(%s), marker (%s)\n",
+ name,
+ format,
+ iter->format);
+ continue;
+ }
+ if (probe == __mark_empty_function) {
+ if (*iter->call != __mark_empty_function) {
+ found++;
+ *MARK_ENABLE_OFFSET(iter->enable) = 0;
+ *iter->call = __mark_empty_function;
+ }
+ } else {
+ if (*iter->call != __mark_empty_function) {
+ if (*iter->call != probe) {
+ printk(KERN_NOTICE
+ "Marker %s busy, "
+ "probe %p already "
+ "installed\n",
+ name,
+ *iter->call);
+ continue;
+ }
+ } else {
+ found++;
+ *iter->call = probe;
+ *MARK_ENABLE_OFFSET(iter->enable) = 1;
+ }
+ }
+ }
+ }
+ return found;
+}
+
+static int marker_remove_probe_range(marker_probe_func *probe,
+ const struct __mark_marker *begin,
+ const struct __mark_marker *end)
+{
+ const struct __mark_marker *iter;
+ int found = 0;
+
+ for(iter = begin; iter < end; iter++) {
+ if (*iter->call == probe) {
+ *MARK_ENABLE_OFFSET(iter->enable) = 0;
+ *iter->call = __mark_empty_function;
+ found++;
+ }
+ }
+ return found;
+}
+
+static int marker_list_probe_range(marker_probe_func *probe,
+ const struct __mark_marker *begin,
+ const struct __mark_marker *end)
+{
+ const struct __mark_marker *iter;
+ int found = 0;
+
+ for(iter = begin; iter < end; iter++) {
+ if (probe)
+ if (probe != *iter->call) continue;
+ printk("name %s \n", iter->name);
+ printk(" enable %u ", *MARK_ENABLE_OFFSET(iter->enable));
+ printk(" func 0x%p format \"%s\"\n",
+ *iter->call, iter->format);
+ found++;
+ }
+ return found;
+}
+/* markers use the modlist_lock to to synchronise */
+int marker_set_probe(const char *name, const char *format,
+ marker_probe_func *probe)
+{
+ struct module *mod;
+ int found = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&modlist_lock, flags);
+ /* Core kernel markers */
+ found += marker_set_probe_range(name, format, probe,
+ __start___markers, __stop___markers);
+ /* Markers in modules. */
+ list_for_each_entry(mod, &modules, list) {
+ found += marker_set_probe_range(name, format, probe,
+ mod->markers, mod->markers+mod->num_markers);
+ }
+ spin_unlock_irqrestore(&modlist_lock, flags);
+ return found;
+}
+EXPORT_SYMBOL(marker_set_probe);
+
+int marker_remove_probe(marker_probe_func *probe)
+{
+ struct module *mod;
+ int found = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&modlist_lock, flags);
+ /* Core kernel markers */
+ found += marker_remove_probe_range(probe,
+ __start___markers, __stop___markers);
+ /* Markers in modules. */
+ list_for_each_entry(mod, &modules, list) {
+ found += marker_remove_probe_range(probe,
+ mod->markers, mod->markers+mod->num_markers);
+ }
+ spin_unlock_irqrestore(&modlist_lock, flags);
+ return found;
+}
+EXPORT_SYMBOL(marker_remove_probe);
+
+int marker_list_probe(marker_probe_func *probe)
+{
+ struct module *mod;
+ int found = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&modlist_lock, flags);
+ /* Core kernel markers */
+ printk("Listing kernel markers\n");
+ found += marker_list_probe_range(probe,
+ __start___markers, __stop___markers);
+ /* Markers in modules. */
+ printk("Listing module markers\n");
+ list_for_each_entry(mod, &modules, list) {
+ printk("Listing markers for module %s\n", mod->name);
+ found += marker_list_probe_range(probe,
+ mod->markers, mod->markers+mod->num_markers);
+ }
+ spin_unlock_irqrestore(&modlist_lock, flags);
+ return found;
+}
+EXPORT_SYMBOL(marker_list_probe);
+#endif
+
#ifdef CONFIG_SMP
/* Number of blocks used and allocated. */
static unsigned int pcpu_num_used, pcpu_num_allocated;
@@ -1412,7 +1572,7 @@ static struct module *load_module(void _
unsigned int i, symindex = 0, strindex = 0, setupindex, exindex,
exportindex, modindex, obsparmindex, infoindex, gplindex,
crcindex, gplcrcindex, versindex, pcpuindex, gplfutureindex,
- gplfuturecrcindex;
+ gplfuturecrcindex, markersindex;
struct module *mod;
long err = 0;
void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
@@ -1502,6 +1662,7 @@ #endif
versindex = find_sec(hdr, sechdrs, secstrings, "__versions");
infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo");
pcpuindex = find_pcpusec(hdr, sechdrs, secstrings);
+ markersindex = find_sec(hdr, sechdrs, secstrings, ".markers");
/* Don't keep modinfo section */
sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
@@ -1510,6 +1671,11 @@ #ifdef CONFIG_KALLSYMS
sechdrs[symindex].sh_flags |= SHF_ALLOC;
sechdrs[strindex].sh_flags |= SHF_ALLOC;
#endif
+#ifdef CONFIG_MARKERS
+ sechdrs[markersindex].sh_flags |= SHF_ALLOC;
+#else
+ sechdrs[markersindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
+#endif
/* Check module struct version now, before we try to use module. */
if (!check_modstruct_version(sechdrs, versindex, mod)) {
@@ -1642,6 +1808,11 @@ #endif
mod->gpl_future_syms = (void *)sechdrs[gplfutureindex].sh_addr;
if (gplfuturecrcindex)
mod->gpl_future_crcs = (void *)sechdrs[gplfuturecrcindex].sh_addr;
+ if (markersindex) {
+ mod->markers = (void *)sechdrs[markersindex].sh_addr;
+ mod->num_markers =
+ sechdrs[markersindex].sh_size / sizeof(*mod->markers);
+ }
#ifdef CONFIG_MODVERSIONS
if ((mod->num_syms && !crcindex) ||
---END---
---BEGIN---
/* probe.c
*
* Loads a function at a marker call site.
*
* (C) Copyright 2006 Mathieu Desnoyers <[email protected]>
*
* This file is released under the GPLv2.
* See the file COPYING for more details.
*/
#include <linux/marker.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
/* function to install */
#define DO_MARK1_FORMAT "%d"
void do_mark1(const char *format, ...)
{
va_list ap;
int value;
va_start(ap, format);
value = va_arg(ap, int);
printk("value is %d\n", value);
va_end(ap);
}
void do_mark2(const char *format, ...)
{
va_list ap;
va_start(ap, format);
vprintk(format, ap);
va_end(ap);
printk("\n");
}
#define DO_MARK3_FORMAT "%d %s %s"
void do_mark3(const char *format, ...)
{
va_list ap;
int value;
const char *s1, *s2;
va_start(ap, format);
value = va_arg(ap, int);
s1 = va_arg(ap, const char*);
s2 = va_arg(ap, const char *);
printk("value is %d %s %s\n",
value, s1, s2);
va_end(ap);
}
int init_module(void)
{
int result;
result = marker_set_probe("subsys_mark1", DO_MARK1_FORMAT,
(marker_probe_func*)do_mark1);
if(!result) goto end;
result = marker_set_probe("subsys_mark2", NULL,
(marker_probe_func*)do_mark2);
if(!result) goto cleanup1;
result = marker_set_probe("subsys_mark3", DO_MARK3_FORMAT,
(marker_probe_func*)do_mark3);
if(!result) goto cleanup2;
return 0;
cleanup2:
marker_remove_probe((marker_probe_func*)do_mark2);
cleanup1:
marker_remove_probe((marker_probe_func*)do_mark1);
end:
return -EPERM;
}
void cleanup_module(void)
{
marker_remove_probe((marker_probe_func*)do_mark1);
marker_remove_probe((marker_probe_func*)do_mark2);
marker_remove_probe((marker_probe_func*)do_mark3);
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Probe");
---END---
---BEGIN---
/* test-mark.c
*
*/
#include <linux/marker.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <asm/ptrace.h>
volatile int x = 7;
struct proc_dir_entry *pentry = NULL;
static inline void test(struct pt_regs * regs)
{
MARK(kernel_debug_test, "%d %ld %p", 2, regs->eip, regs);
}
static int my_open(struct inode *inode, struct file *file)
{
unsigned int i;
for(i=0; i<2; i++) {
MARK(subsys_mark1, "%d", 1);
}
MARK(subsys_mark2, "%d %s %s", 2, "blah2", "blahx");
MARK(subsys_mark3, "%d %s %s", x, "blah3", "blah5");
test(NULL);
test(NULL);
return -EPERM;
}
static struct file_operations my_operations = {
.open = my_open,
};
int init_module(void)
{
pentry = create_proc_entry("testmark", 0444, NULL);
if (pentry)
pentry->proc_fops = &my_operations;
marker_list_probe(NULL);
return 0;
}
void cleanup_module(void)
{
remove_proc_entry("testmark", NULL);
}
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Marker Test");
---END---
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