Messages in this thread Patch in this message | | | Date | Mon, 10 Feb 2014 14:12:07 +0000 | From | Will Deacon <> | Subject | Re: [RFC PATCH] ARM: Add imprecise abort enable/disable macro |
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On Mon, Feb 10, 2014 at 01:56:59PM +0000, Russell King - ARM Linux wrote: > On Mon, Feb 10, 2014 at 11:17:10AM +0000, Will Deacon wrote: > > On Mon, Feb 10, 2014 at 08:50:16AM +0000, Fabrice Gasnier wrote: > > > On 02/07/2014 06:09 PM, Will Deacon wrote: > > > > On Fri, Feb 07, 2014 at 04:19:15PM +0000, Fabrice GASNIER wrote: > > > >> diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c > > > >> index 4636d56..ef15709 100644 > > > >> --- a/arch/arm/kernel/traps.c > > > >> +++ b/arch/arm/kernel/traps.c > > > >> @@ -900,6 +900,10 @@ void __init early_trap_init(void *vectors_base) > > > >> > > > >> flush_icache_range(vectors, vectors + PAGE_SIZE * 2); > > > >> modify_domain(DOMAIN_USER, DOMAIN_CLIENT); > > > >> + > > > >> + /* Enable imprecise aborts */ > > > >> + local_abt_enable(); > > > > Surely we want to enable this as early as possible? Now, putting this into > > > > head.S is ugly, as it duplicating it across all the proc*.S files, so why > > > > not setup_arch? > > > Sorry, I'm not sure to understand your last comment. > > > At least, I need it enabled before probing drivers (PCIe bus) > > > I've added imprecise abort enable code in traps.c, following Russel > > > King's advice, please see: > > > http://archive.arm.linux.org.uk/lurker/message/20140131.170827.d752a1cc.en.html > > > As abort bit is local to a cpu, i've also added it in smp.c, but this > > > may not be the right place ? > > > > > > Please elaborate, > > > > I was just suggesting that we move your local_abt_enable() call to > > setup_arch, since that's called before early_trap_init on the primary CPU. > > Why would we want to enable aborts before we've setup the vectors page > to handle an abort? That's akin to enabling interrupts and hoping there > isn't one pending...
I figured we'd want to fall over as quickly as possible if the bootloader had left a pending exception for us, but you're right in that it's not very helpful if we can't print out a diagnostic.
Fabrice, please ignore my suggestion and keep the unmasking where it is.
Will
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