diff options
| author | Rabin Vincent <rabin@rab.in> | 2010-08-10 20:32:37 +0200 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-09-02 16:24:53 +0200 |
| commit | 09bfafac3e237415cc4b6adde49f9f28b3a42659 (patch) | |
| tree | 980006ad889a1395140dba2a3718ead537975df3 /arch/arm/kernel/entry-common.S | |
| parent | ARM: 6312/1: ftrace: allow building without frame pointers (diff) | |
| download | linux-09bfafac3e237415cc4b6adde49f9f28b3a42659.tar.xz linux-09bfafac3e237415cc4b6adde49f9f28b3a42659.zip | |
ARM: 6314/1: ftrace: allow build without frame pointers on ARM
With a new enough GCC, ARM function tracing can be supported without the
need for frame pointers. This is essential for Thumb-2 support, since
frame pointers aren't available then.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/entry-common.S')
| -rw-r--r-- | arch/arm/kernel/entry-common.S | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index f05a35a59694..6805a7216bf8 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -128,6 +128,13 @@ ENDPROC(ret_from_fork) * allows it to be clobbered in subroutines and doesn't use it to hold * parameters.) */ + +#ifndef CONFIG_OLD_MCOUNT +#if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4)) +#error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0. +#endif +#endif + #ifdef CONFIG_DYNAMIC_FTRACE ENTRY(mcount) stmdb sp!, {r0-r3, lr} @@ -173,6 +180,12 @@ gnu_trace: ldmia sp!, {r0-r3, ip, lr} mov pc, ip +#ifdef CONFIG_OLD_MCOUNT +/* + * This is under an ifdef in order to force link-time errors for people trying + * to build with !FRAME_POINTER with a GCC which doesn't use the new-style + * mcount. + */ ENTRY(mcount) stmdb sp!, {r0-r3, lr} ldr r0, =ftrace_trace_function @@ -191,6 +204,7 @@ trace: mov pc, r2 ldr lr, [fp, #-4] @ restore lr ldmia sp!, {r0-r3, pc} +#endif #endif /* CONFIG_DYNAMIC_FTRACE */ |