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Commit 9254970c authored by Lucas Stach's avatar Lucas Stach Committed by Russell King
Browse files

ARM: 8447/1: catch pending imprecise abort on unmask 



Install a non-faulting handler just before unmasking imprecise aborts
and switch back to the regular one after unmasking is done.

This catches any pending imprecise abort that the firmware/bootloader
may have left behind that would normally crash the kernel at that point.
As there are apparently a lot of bootlaoders out there that do such a
thing it makes sense to handle it in the common startup code.

Signed-off-by: default avatarLucas Stach <l.stach@pengutronix.de>
Tested-by: default avatarTyler Baker <tyler.baker@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent c8d46ece

arch/arm/mm/fault.c

+22 −0
Original line number Diff line number Diff line
@@ -593,6 +593,28 @@ do_PrefetchAbort(unsigned long addr, unsigned int ifsr, struct pt_regs *regs) 
	arm_notify_die("", regs, &info, ifsr, 0);

}



/*

 * Abort handler to be used only during first unmasking of asynchronous aborts

 * on the boot CPU. This makes sure that the machine will not die if the

 * firmware/bootloader left an imprecise abort pending for us to trip over.

 */

static int __init early_abort_handler(unsigned long addr, unsigned int fsr,

				      struct pt_regs *regs)

{

	pr_warn("Hit pending asynchronous external abort (FSR=0x%08x) during "

		"first unmask, this is most likely caused by a "

		"firmware/bootloader bug.\n", fsr);



	return 0;

}



void __init early_abt_enable(void)

{

	fsr_info[22].fn = early_abort_handler;

	local_abt_enable();

	fsr_info[22].fn = do_bad;

}



#ifndef CONFIG_ARM_LPAE

static int __init exceptions_init(void)

{

arch/arm/mm/fault.h

+1 −0
Original line number Diff line number Diff line
@@ -24,5 +24,6 @@ static inline int fsr_fs(unsigned int fsr) 


void do_bad_area(unsigned long addr, unsigned int fsr, struct pt_regs *regs);

unsigned long search_exception_table(unsigned long addr);

void early_abt_enable(void);



#endif	/* __ARCH_ARM_FAULT_H */

arch/arm/mm/mmu.c

+2 −1
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <asm/mach/pci.h>

#include <asm/fixmap.h>



#include "fault.h"

#include "mm.h"

#include "tcm.h"
@@ -1365,7 +1366,7 @@ static void __init devicemaps_init(const struct machine_desc *mdesc) 
	flush_cache_all();



	/* Enable asynchronous aborts */

	local_abt_enable();

	early_abt_enable();

}



static void __init kmap_init(void)