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ARM: Add support for checking access permissions on prefetch aborts 

ARMv6 introduces non-executable mappings, which can cause prefetch aborts
when an attempt is made to execute from such a mapping.  Currently, this
causes us to loop in the page fault handler since we don't correctly
check for proper permissions.

Fix this by checking that VMAs have VM_EXEC set for prefetch aborts.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
hifive-unleashed-5.1
Russell King 2009-09-20 13:18:47 +01:00
parent d374bf14a5
commit df297bf6c7
1 changed files with 6 additions and 3 deletions
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9
arch/arm/mm/fault.c
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@ -26,8 +26,9 @@
#include "fault.h"
/*
* Fault status register encodings
* Fault status register encodings. We steal bit 31 for our own purposes.
*/
#define FSR_LNX_PF (1 << 31)
#define FSR_WRITE (1 << 11)
#define FSR_FS4 (1 << 10)
#define FSR_FS3_0 (15)
@ -205,6 +206,8 @@ static inline bool access_error(unsigned int fsr, struct vm_area_struct *vma)
if (fsr & FSR_WRITE)
mask = VM_WRITE;
if (fsr & FSR_LNX_PF)
mask = VM_EXEC;
return vma->vm_flags & mask ? false : true;
}
@ -503,7 +506,7 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
const struct fsr_info *inf = fsr_info + fsr_fs(fsr);
struct siginfo info;
if (!inf->fn(addr, fsr, regs))
if (!inf->fn(addr, fsr & ~FSR_LNX_PF, regs))
return;
printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
@ -519,6 +522,6 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
asmlinkage void __exception
do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
{
do_translation_fault(addr, 0, regs);
do_translation_fault(addr, FSR_LNX_PF, regs);
}