1 files changed, 61 insertions, 0 deletions

diff --git a/arch/sparc64/lib/mcount.S b/arch/sparc64/lib/mcount.S
new file mode 100644
index 000000000000..2ef2e268bdcf
--- /dev/null
+++ b/arch/sparc64/lib/mcount.S
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com)
+ *
+ * This file implements mcount(), which is used to collect profiling data.
+ * This can also be tweaked for kernel stack overflow detection.
+ */
+
+#include <linux/config.h>
+#include <linux/linkage.h>
+
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+/*
+ * This is the main variant and is called by C code.  GCC's -pg option
+ * automatically instruments every C function with a call to this.
+ */
+
+#ifdef CONFIG_STACK_DEBUG
+
+#define OVSTACKSIZE     4096            /* lets hope this is enough */
+
+        .data
+        .align          8
+panicstring:
+        .asciz          "Stack overflow\n"
+        .align          8
+ovstack:
+        .skip           OVSTACKSIZE
+#endif
+        .text
+        .align 32
+        .globl mcount, _mcount
+mcount:
+_mcount:
+#ifdef CONFIG_STACK_DEBUG
+        /*
+         * Check whether %sp is dangerously low.
+         */
+        ldub            [%g6 + TI_FPDEPTH], %g1
+        srl             %g1, 1, %g3
+        add             %g3, 1, %g3
+        sllx            %g3, 8, %g3                     ! each fpregs frame is 256b
+        add             %g3, 192, %g3
+        add             %g6, %g3, %g3                   ! where does task_struct+frame end?
+        sub             %g3, STACK_BIAS, %g3
+        cmp             %sp, %g3
+        bg,pt           %xcc, 1f
+         sethi          %hi(panicstring), %g3
+        sethi           %hi(ovstack), %g7               ! cant move to panic stack fast enough
+         or             %g7, %lo(ovstack), %g7
+        add             %g7, OVSTACKSIZE, %g7
+        sub             %g7, STACK_BIAS, %g7
+        mov             %g7, %sp
+        call            prom_printf
+         or             %g3, %lo(panicstring), %o0
+        call            prom_halt
+         nop
+#endif
+1:      retl
+         nop