diff options
| author | Dave Martin <dave.martin@linaro.org> | 2010-11-16 13:13:37 +0000 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2011-04-12 09:48:10 +0200 |
| commit | 0575b4b83edb0a766a9c1518a5da57780f386340 (patch) | |
| tree | dec934c475cd2b9b27a4e93cd7ef8bc08b0dfdee /arch/arm/plat-mxc/ssi-fiq.S | |
| parent | f61b9fc27e5b61dbc330696f040cc66ba1dbcbaa (diff) | |
ARM: mxc: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL
Directives such as .long and .word do not magically cause the
assembler location counter to become aligned in gas. As a
result, using these directives in code sections can result in
misaligned data words when building a Thumb-2 kernel
(CONFIG_THUMB2_KERNEL).
This is a Bad Thing, since the ABI permits the compiler to
assume that fundamental types of word size or above are word-
aligned when accessing them from C. If the data is not really
word-aligned, this can cause impaired performance and stray
alignment faults in some circumstances.
In general, the following rules should be applied when using
data word declaration directives inside code sections:
* .quad and .double:
.align 3
* .long, .word, .single, .float:
.align (or .align 2)
* .short:
No explicit alignment required, since Thumb-2
instructions are always 2 or 4 bytes in size.
immediately after an instruction.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
LAKML-Reference: 1289913217-8672-1-git-send-email-dave.martin@linaro.org
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'arch/arm/plat-mxc/ssi-fiq.S')
| -rw-r--r-- | arch/arm/plat-mxc/ssi-fiq.S | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm/plat-mxc/ssi-fiq.S b/arch/arm/plat-mxc/ssi-fiq.S index 4ddce565b35..8397a2dd19f 100644 --- a/arch/arm/plat-mxc/ssi-fiq.S +++ b/arch/arm/plat-mxc/ssi-fiq.S @@ -124,6 +124,8 @@ imx_ssi_fiq_start: 1: @ return from FIQ subs pc, lr, #4 + + .align imx_ssi_fiq_base: .word 0x0 imx_ssi_fiq_rx_buffer: |