[ARM] support tracing when using newer compilers

Since gcc 4.4 the name and calling convention for function profiling
on ARM changed.  With this patch both types are supported.

See http://sourceware.org/ml/libc-ports/2008-04/msg00009.html for some
details.

Lightly-Tested-by: Anand Gadiyar <gadiyar@ti.com>
Tested-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

1 files changed, 19 insertions, 0 deletions

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 366e5097a41a..99208728d48f 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -132,6 +132,25 @@ ftrace_call:
 
 #else
 
+ENTRY(__gnu_mcount_nc)
+        stmdb sp!, {r0-r3, lr}
+        ldr r0, =ftrace_trace_function
+        ldr r2, [r0]
+        adr r0, ftrace_stub
+        cmp r0, r2
+        bne gnu_trace
+        ldmia sp!, {r0-r3, ip, lr}
+        bx ip
+
+gnu_trace:
+        ldr r1, [sp, #20]                       @ lr of instrumented routine
+        mov r0, lr
+        sub r0, r0, #MCOUNT_INSN_SIZE
+        mov lr, pc
+        mov pc, r2
+        ldmia sp!, {r0-r3, ip, lr}
+        bx ip
+
 ENTRY(mcount)
         stmdb sp!, {r0-r3, lr}
         ldr r0, =ftrace_trace_function