On Mon, Oct 16, 2017 at 11:42:05AM +0000, Liuwenliang (Lamb) wrote: > On 10/16/2017 07:03 PM, Abbott Liu wrote: > >arch/arm/kernel/entry-armv.S:348: Error: selected processor does not support `movw r1, > #:lower16:((((0xC0000000-0x01000000)>>3)+((0xC0000000-0x01000000)-(1<<29))))' in ARM mode > >arch/arm/kernel/entry-armv.S:348: Error: selected processor does not support `movt r1, > #:upper16:((((0xC0000000-0x01000000)>>3)+((0xC0000000-0x01000000)-(1<<29))))' in ARM mode > > Thanks for building test. This error can be solved by following code: > --- a/arch/arm/kernel/entry-armv.S > +++ b/arch/arm/kernel/entry-armv.S > @@ -188,8 +188,7 @@ ENDPROC(__und_invalid) > get_thread_info tsk > ldr r0, [tsk, #TI_ADDR_LIMIT] > #ifdef CONFIG_KASAN > - movw r1, #:lower16:TASK_SIZE > - movt r1, #:upper16:TASK_SIZE > + ldr r1, =TASK_SIZE > #else > mov r1, #TASK_SIZE > #endif We can surely do better than this with macros and condition support - we can build-time test in the assembler whether TASK_SIZE can fit in a normal "mov", whether we can use the movw/movt instructions, or fall back to ldr if necessary. I'd rather we avoided "ldr" here where possible. > @@ -446,7 +445,12 @@ ENDPROC(__fiq_abt) > @ if it was interrupted in a critical region. Here we > @ perform a quick test inline since it should be false > @ 99.9999% of the time. The rest is done out of line. > +#if CONFIG_KASAN > + ldr r0, =TASK_SIZE > + cmp r4, r0 > +#else > cmp r4, #TASK_SIZE Same sort of thing goes for here - we can select the instruction at runtime using the assembler's macros and condition support. We know that TASK_SIZE is going to be one of a limited set of values. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
