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>

1 files changed, 99 insertions, 0 deletions

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;
+}