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ppc64: add paranoid warnings for unexpected DSISR_PROTFAULT

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ppc64 should not be depending on DSISR_PROTFAULT and it's unexpected if
they are triggered.  This patch adds warnings just in case they are being
accidentally depended upon.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman 2015-02-12 14:58:25 -08:00 committed by Linus Torvalds
parent 8a0516ed8b
commit 842915f566
2 changed files with 15 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
arch/powerpc/mm/copro_fault.c
View file

@ -64,10 +64,14 @@ int copro_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
if (!(vma->vm_flags & VM_WRITE))
goto out_unlock;
} else {
if (dsisr & DSISR_PROTFAULT)
goto out_unlock;
if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
goto out_unlock;
/*
* protfault should only happen due to us
* mapping a region readonly temporarily. PROT_NONE
* is also covered by the VMA check above.
*/
WARN_ON_ONCE(dsisr & DSISR_PROTFAULT);
}
ret = 0;

20
arch/powerpc/mm/fault.c
View file

@ -389,17 +389,6 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
#endif /* CONFIG_8xx */
if (is_exec) {
#ifdef CONFIG_PPC_STD_MMU
/* Protection fault on exec go straight to failure on
* Hash based MMUs as they either don't support per-page
* execute permission, or if they do, it's handled already
* at the hash level. This test would probably have to
* be removed if we change the way this works to make hash
* processors use the same I/D cache coherency mechanism
* as embedded.
*/
#endif /* CONFIG_PPC_STD_MMU */
/*
* Allow execution from readable areas if the MMU does not
* provide separate controls over reading and executing.
@ -414,6 +403,14 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
(cpu_has_feature(CPU_FTR_NOEXECUTE) ||
!(vma->vm_flags & (VM_READ | VM_WRITE))))
goto bad_area;
#ifdef CONFIG_PPC_STD_MMU
/*
* protfault should only happen due to us
* mapping a region readonly temporarily. PROT_NONE
* is also covered by the VMA check above.
*/
WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
#endif /* CONFIG_PPC_STD_MMU */
/* a write */
} else if (is_write) {
if (!(vma->vm_flags & VM_WRITE))
@ -423,6 +420,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
} else {
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
goto bad_area;
WARN_ON_ONCE(error_code & DSISR_PROTFAULT);
}
/*