sparc64: Allocate sufficient stack space in ftrace stubs.

128 bytes is sufficient for the register window save area, but the
calling conventions allow the callee to save up to 6 incoming argument
registers into the stack frame after the register window save area.

This means a minimal stack frame is 176 bytes (128 + (6 * 8)).

This fixes random crashes when using the function tracer.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/lib/mcount.S b/arch/sparc/lib/mcount.S
index 3753e3c..3ad6cbd 100644 (file)
--- a/arch/sparc/lib/mcount.S
+++ b/arch/sparc/lib/mcount.S
@@ -34,7 +34,7 @@ mcount:
        cmp             %g1, %g2
        be,pn           %icc, 1f
         mov            %i7, %g3
-       save            %sp, -128, %sp
+       save            %sp, -176, %sp
        mov             %g3, %o1
        jmpl            %g1, %o7
         mov            %i7, %o0
@@ -56,7 +56,7 @@ mcount:
         nop
 5:     mov             %i7, %g2
        mov             %fp, %g3
-       save            %sp, -128, %sp
+       save            %sp, -176, %sp
        mov             %g2, %l0
        ba,pt           %xcc, ftrace_graph_caller
         mov            %g3, %l1
@@ -85,7 +85,7 @@ ftrace_caller:
        lduw            [%g1 + %lo(function_trace_stop)], %g1
        brnz,pn         %g1, ftrace_stub
         mov            %fp, %g3
-       save            %sp, -128, %sp
+       save            %sp, -176, %sp
        mov             %g2, %o1
        mov             %g2, %l0
        mov             %g3, %l1
@@ -120,7 +120,7 @@ ENTRY(ftrace_graph_caller)
 END(ftrace_graph_caller)
 
 ENTRY(return_to_handler)
-       save            %sp, -128, %sp
+       save            %sp, -176, %sp
        call            ftrace_return_to_handler
         mov            %fp, %o0
        jmpl            %o0 + 8, %g0