[PATCH] ARM: vfp: Fix up exception location in Thumb mode

Catalin Marinas catalin.marinas at arm.com
Sun Jan 16 06:51:47 EST 2011


On Saturday, 15 January 2011, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Sat, Jan 15, 2011 at 03:38:16PM +0000, Catalin Marinas wrote:
>> On 14 January 2011 18:47, Russell King - ARM Linux
>> <linux at arm.linux.org.uk> wrote:
>> > diff -u b/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
>> > --- b/arch/arm/kernel/entry-armv.S
>> > +++ b/arch/arm/kernel/entry-armv.S
>> > @@ -499,10 +499,11 @@
>> >        blo     __und_usr_unknown
>> >  3:     ldrht   r0, [r4]
>> >        add     r2, r2, #2                      @ r2 is PC + 2, make it PC + 4
>> > -       orr     r0, r0, r5, lsl #16
>> > +       str     r2, [sp, #S_PC]                 @ it's a 2x16bit instr, update
>> > +       orr     r0, r0, r5, lsl #16             @  regs->ARM_pc
>> >        @
>> >        @ r0 = the two 16-bit Thumb instructions which caused the exception
>> > -       @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc+2)
>> > +       @ r2 = PC value for the following Thumb instruction (:= regs->ARM_pc)
>> >        @ r4 = PC value for the first 16-bit Thumb instruction
>> >        @
>> >  #else
>>
>> Do we need to modify the VFP entry code to avoit the store to ARM_pc?
>
> The one after the sub #4 instruction?

No, I misread the code, we still need the one after sub #4.


-- 
Catalin



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