Re: [PATCH 2/2]: sparc64: Add ftrace support.
From: Steven Rostedt
Date: Wed May 14 2008 - 09:32:48 EST
David Miller wrote:
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
---
arch/sparc64/Kconfig | 1 +
arch/sparc64/Kconfig.debug | 2 +-
arch/sparc64/kernel/Makefile | 1 +
arch/sparc64/kernel/ftrace.c | 99 ++++++++++++++++++++++++++++++++++++++++++
arch/sparc64/lib/mcount.S | 58 +++++++++++++++++++++++--
5 files changed, 156 insertions(+), 5 deletions(-)
create mode 100644 arch/sparc64/kernel/ftrace.c
diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
index 4c40862..56344b1 100644
--- a/arch/sparc64/Kconfig
+++ b/arch/sparc64/Kconfig
@@ -15,6 +15,7 @@ config SPARC64
select HAVE_LMB
select HAVE_ARCH_KGDB
select HAVE_IMMEDIATE
+ select HAVE_FTRACE
config GENERIC_TIME
bool
diff --git a/arch/sparc64/Kconfig.debug b/arch/sparc64/Kconfig.debug
index 6a4d28a..d6d32d1 100644
--- a/arch/sparc64/Kconfig.debug
+++ b/arch/sparc64/Kconfig.debug
@@ -33,7 +33,7 @@ config DEBUG_PAGEALLOC
config MCOUNT
bool
- depends on STACK_DEBUG
+ depends on STACK_DEBUG || FTRACE
default y
config FRAME_POINTER
diff --git a/arch/sparc64/kernel/Makefile b/arch/sparc64/kernel/Makefile
index 311c797..52e933f 100644
--- a/arch/sparc64/kernel/Makefile
+++ b/arch/sparc64/kernel/Makefile
@@ -14,6 +14,7 @@ obj-y := process.o setup.o cpu.o idprom.o \
power.o sbus.o sparc64_ksyms.o chmc.o \
visemul.o prom.o of_device.o hvapi.o sstate.o mdesc.o
+obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_PCI) += ebus.o pci_common.o \
pci_psycho.o pci_sabre.o pci_schizo.o \
diff --git a/arch/sparc64/kernel/ftrace.c b/arch/sparc64/kernel/ftrace.c
new file mode 100644
index 0000000..f449e6d
--- /dev/null
+++ b/arch/sparc64/kernel/ftrace.c
@@ -0,0 +1,99 @@
+#include <linux/spinlock.h>
+#include <linux/hardirq.h>
+#include <linux/ftrace.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/list.h>
+
+static const u32 ftrace_nop = 0x01000000;
+
+notrace int ftrace_ip_converted(unsigned long ip)
FYI,
If you look in the kernel/Makefile you will see a way to have the whole
file not be traced. This will eliminate the need for the "notrace"
annotation on all functions. I haven't update the x86 version of ftrace
to do this so you probably just copied the old method from us.
If you add the following in arch/sparc64/kernel/Makefile
ifdef CONFIG_DYNAMIC_FTRACE
obj-y += ftrace.o
# Do not trace the ftrace code itself
ORIG_CFLAGS := $(KBUILD_CFLAGS)
KBUILD_CFLAGS = $(if $(filter-out ftrace, $(basename $(notdir $@))), \
$(ORIG_CFLAGS), \
$(subst -pg,,$(ORIG_CFLAGS)))
endif
Then you wont need the "notrace" annotations on the functions.
/me needs to send Ingo a patch to do this for x86 as well.
+{
+ u32 insn = *(u32 *) ip;
+
+ return (insn == ftrace_nop);
+}
+
+notrace unsigned char *ftrace_nop_replace(void)
+{
+ return (char *)&ftrace_nop;
+}
+
+notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+{
+ static u32 call;
+ s32 off;
+
+ off = ((s32)addr - (s32)ip);
+ call = 0x40000000 | ((u32)off >> 2);
+
+ return (unsigned char *) &call;
+}
+
+notrace int
+ftrace_modify_code(unsigned long ip, unsigned char *old_code,
+ unsigned char *new_code)
+{
+ u32 old = *(u32 *)old_code;
+ u32 new = *(u32 *)new_code;
+ u32 replaced;
+ int faulted;
+
+ __asm__ __volatile__(
+ "1: cas [%[ip]], %[old], %[new]\n"
+ " flush %[ip]\n"
+ " mov 0, %[faulted]\n"
+ "2:\n"
+ " .section .fixup,#alloc,#execinstr\n"
+ " .align 4\n"
+ "3: sethi %%hi(2b), %[faulted]\n"
+ " jmpl %[faulted] + %%lo(2b), %%g0\n"
+ " mov 1, %[faulted]\n"
+ " .previous\n"
+ " .section __ex_table,\"a\"\n"
+ " .align 4\n"
+ " .word 1b, 3b\n"
+ " .previous\n"
+ : "=r" (replaced), [faulted] "=r" (faulted)
+ : [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
+ : "memory");
I'm so use to the %1 %2 and %3's I should update the x86 code to use the
names as well. (nice)
+
+ if (replaced != old && replaced != new)
+ faulted = 2;
Thanks for putting in the "2", I may plan on doing something different
later if the code didn't "fault" but something else happened. I should
also make MACROS out of that and not uses 1 and 2.
+
+ return faulted;
+}
+
+notrace int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+ unsigned long ip = (unsigned long)(&ftrace_call);
+ unsigned char old[4], *new;
+
+ memcpy(old, &ftrace_call, 4);
+ new = ftrace_call_replace(ip, (unsigned long)func);
+ return ftrace_modify_code(ip, old, new);
+}
+
+notrace int ftrace_mcount_set(unsigned long *data)
+{
+ unsigned long ip = (long)(&mcount_call);
+ unsigned long *addr = data;
+ unsigned char old[4], *new;
+
+ /*
+ * Replace the mcount stub with a pointer to the
+ * ip recorder function.
+ */
+ memcpy(old, &mcount_call, 4);
+ new = ftrace_call_replace(ip, *addr);
+ *addr = ftrace_modify_code(ip, old, new);
+
+ return 0;
+}
+
+
+int __init ftrace_dyn_arch_init(void *data)
+{
+ ftrace_mcount_set(data);
+ return 0;
+}
diff --git a/arch/sparc64/lib/mcount.S b/arch/sparc64/lib/mcount.S
index 9e4534b..7735a7a 100644
--- a/arch/sparc64/lib/mcount.S
+++ b/arch/sparc64/lib/mcount.S
@@ -28,10 +28,13 @@ ovstack:
.skip OVSTACKSIZE
#endif
.text
- .align 32
- .globl mcount, _mcount
-mcount:
+ .align 32
+ .globl _mcount
+ .type _mcount,#function
+ .globl mcount
+ .type mcount,#function
_mcount:
+mcount:
#ifdef CONFIG_STACK_DEBUG
/*
* Check whether %sp is dangerously low.
@@ -55,6 +58,53 @@ _mcount:
or %g3, %lo(panicstring), %o0
call prom_halt
nop
+1:
+#endif
+#ifdef CONFIG_FTRACE
+#ifdef CONFIG_DYNAMIC_FTRACE
+ mov %o7, %o0
+ .globl mcount_call
+mcount_call:
+ call ftrace_stub
+ mov %o0, %o7
WOW! Sparc64 has some really efficient context saving!
+#else
+ sethi %hi(ftrace_trace_function), %g1
+ sethi %hi(ftrace_stub), %g2
+ ldx [%g1 + %lo(ftrace_trace_function)], %g1
+ or %g2, %lo(ftrace_stub), %g2
+ cmp %g1, %g2
+ be,pn %icc, 1f
+ mov %i7, %o1
+ jmpl %g1, %g0
+ mov %o7, %o0
+ /* not reached */
+1:
#endif
-1: retl
+#endif
+ retl
nop
+ .size _mcount,.-_mcount
+ .size mcount,.-mcount
+
+#ifdef CONFIG_FTRACE
+ .globl ftrace_stub
+ .type ftrace_stub,#function
+ftrace_stub:
+ retl
+ nop
+ .size ftrace_stub,.-ftrace_stub
+#ifdef CONFIG_DYNAMIC_FTRACE
+ .globl ftrace_caller
+ .type ftrace_caller,#function
+ftrace_caller:
+ mov %i7, %o1
+ mov %o7, %o0
+ .globl ftrace_call
+ftrace_call:
+ call ftrace_stub
+ mov %o0, %o7
+ retl
+ nop
+ .size ftrace_caller,.-ftrace_caller
+#endif
+#endif
Looks great!
Acked-by: Steven Rostedt <srostedt@xxxxxxxxxx>
-- Steve
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