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| author | Rabin Vincent <rabin@rab.in> | 2010-08-10 19:37:21 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-09-02 15:26:12 +0100 |
| commit | a3ba87a614992500cf2c47e6f788e74a971ce91f (patch) | |
| tree | 5b644570cf2d93e6216a0c308e1fbf72efda2913 /arch/arm/kernel/entry-common.S | |
| parent | 72fa62fa5dff0e2e06491dd99c429adb137f299b (diff) | |
| download | linux-a3ba87a614992500cf2c47e6f788e74a971ce91f.tar.gz linux-a3ba87a614992500cf2c47e6f788e74a971ce91f.tar.bz2 linux-a3ba87a614992500cf2c47e6f788e74a971ce91f.zip | |
ARM: 6316/1: ftrace: add Thumb-2 support
Fix the mcount routines to build and run on a kernel built with the
Thumb-2 instruction set by correcting the following errors using the
fixes suggested by Catalin Marinas:
- Problem: The following assembler errors appear at the "adr r0,
ftrace_stub" instruction:
entry-common.S: Assembler messages:
entry-common.S:179: Error: invalid immediate for address calculation (value = 0x00000004)
Fix: The errors don't occur with a non-global symbol, so use one.
- Problem: The "mov lr, pc" does not set the lsb when storing the pc in
lr. The called function returns with "bx lr", and the mode changes
to ARM.
Fix: Add a label on the return address and use "adr lr, BSYM(label)".
We don't modify the old mcount because it won't be built when using
Thumb-2.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
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 | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index c7a8c208a45c..f5e75de0203e 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -167,7 +167,7 @@ ENTRY(__gnu_mcount_nc) stmdb sp!, {r0-r3, lr} ldr r0, =ftrace_trace_function ldr r2, [r0] - adr r0, ftrace_stub + adr r0, .Lftrace_stub cmp r0, r2 bne gnu_trace ldmia sp!, {r0-r3, ip, lr} @@ -177,8 +177,9 @@ gnu_trace: ldr r1, [sp, #20] @ lr of instrumented routine mov r0, lr sub r0, r0, #MCOUNT_INSN_SIZE - mov lr, pc + adr lr, BSYM(1f) mov pc, r2 +1: ldmia sp!, {r0-r3, ip, lr} mov pc, ip ENDPROC(__gnu_mcount_nc) @@ -213,6 +214,7 @@ ENDPROC(mcount) #endif /* CONFIG_DYNAMIC_FTRACE */ ENTRY(ftrace_stub) +.Lftrace_stub: mov pc, lr ENDPROC(ftrace_stub) |