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

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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: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Tyler Baker <tyler.baker@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Lucas Stach 2015-10-19 13:38:09 +01:00 committed by Russell King
parent c8d46ece44
commit 9254970cbb
3 changed files with 25 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

22
arch/arm/mm/fault.c
View file

@ -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)
{

1
arch/arm/mm/fault.h
View file

@ -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 */

3
arch/arm/mm/mmu.c
View file

@ -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)