On 04/16/2013 08:13 AM, Dave Martin wrote: > On Mon, Apr 15, 2013 at 04:50:55PM -0600, Stephen Warren wrote: >> From: Joseph Lo <josephl@xxxxxxxxxx> >> >> When building kernel with CONFIG_THUMB2_KERNEL, the data pointer in the >> assembly may not on the 4 byte alignment. Then causing a data abort when >> accessing the pointer. This patch add a ".align" flag in the head of the >> pointer. And always using 32-bit ADR Thumb instruction to make sure it >> won't build failure. >> >> Signed-off-by: Joseph Lo <josephl@xxxxxxxxxx> >> Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx> >> --- >> arch/arm/mach-tegra/reset-handler.S | 1 + >> arch/arm/mach-tegra/sleep.h | 3 ++- >> 2 files changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm/mach-tegra/reset-handler.S b/arch/arm/mach-tegra/reset-handler.S >> index e6de88a..519a8c5 100644 >> --- a/arch/arm/mach-tegra/reset-handler.S >> +++ b/arch/arm/mach-tegra/reset-handler.S >> @@ -83,6 +83,7 @@ ENDPROC(tegra_resume) >> >> #ifdef CONFIG_CACHE_L2X0 >> .globl l2x0_saved_regs_addr >> + .align >> l2x0_saved_regs_addr: >> .long 0 >> #endif >> diff --git a/arch/arm/mach-tegra/sleep.h b/arch/arm/mach-tegra/sleep.h >> index 4ffae54..8e9b6af 100644 >> --- a/arch/arm/mach-tegra/sleep.h >> +++ b/arch/arm/mach-tegra/sleep.h >> @@ -92,7 +92,8 @@ >> >> #ifdef CONFIG_CACHE_L2X0 >> .macro l2_cache_resume, tmp1, tmp2, tmp3, phys_l2x0_saved_regs >> - adr \tmp1, \phys_l2x0_saved_regs >> + ARM( adr \tmp1, \phys_l2x0_saved_regs ) >> + THUMB( adr.w \tmp1, \phys_l2x0_saved_regs ) > > Can you give an example of the assembler error you get without this? arch/arm/mach-tegra/reset-handler.S: Assembler messages: arch/arm/mach-tegra/reset-handler.S:78: Error: invalid immediate for address calculation (value = 0x00000004) This is with gcc-4.5.3, as: GNU assembler (crosstool-NG hg_unknown@20110628.165246) 2.20.1.20100303 > The target symbol is local and the assembler can see where it is, > so it should choose the correct variant for the adr instruction > with no need for the ".w" suffix. > > If not, it could mean that there is a bug in the version of the > assembler you're using. True. Switching to the Ubuntu-packaged ARM cross-compiler that ships with Ubuntu 12.10, I do not see this problem. Still, many people probably still use older compilers. > If it's definitely needed, you can append a Thumb-only .w suffix with > > W(adr) \tmp1, \phys_l2x0_saved_regs > > ...which is slightly neater. Yes, that certainly works too, even without the .align change in reset-handler.S. Arnd, Olof, I guess let's drop this once patch from this series, but apply the other two, and I'll send an updated version of this one patch. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
