sparc64: add ftrace support.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

5 files changed, 156 insertions, 5 deletions

diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
index eb36f3b746b8..a480df6e6012 100644
--- a/arch/sparc64/Kconfig
+++ b/arch/sparc64/Kconfig
@@ -11,6 +11,7 @@ config SPARC
 config SPARC64
         bool
         default y
+        select HAVE_FTRACE
         select HAVE_IDE
         select HAVE_LMB
         select HAVE_ARCH_KGDB
diff --git a/arch/sparc64/Kconfig.debug b/arch/sparc64/Kconfig.debug
index 6a4d28a4076d..d6d32d178fc8 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 ec4f5ebb1ca6..418b5782096e 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 000000000000..f449e6df6c4a
--- /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)
+{
+        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");
+
+        if (replaced != old && replaced != new)
+                faulted = 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 9e4534b485c7..7735a7a60533 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
+#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