Commit 4339e3f3 authored Apr 19, 2013 by Steve Capper Committed by Catalin Marinas Apr 25, 2013

arm64: mm: Correct show_pte behaviour



show_pte makes use of the *_none_or_clear_bad style functions. If a
pgd, pud or pmd is identified as being bad, it will then be cleared.

As show_pte appears to be called from either the user or kernel
fault handlers this side effect can lead to unpredictable behaviour;
especially as TLB entries are not invalidated.

This patch removes the page table sanitisation from show_pte. If a
bad pgd, pud or pmd is encountered it is left unmodified.

Signed-off-by: Steve Capper <steve.capper@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

parent f15a2a12

arch/arm64/mm/fault.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -57,16 +57,16 @@ void show_pte(struct mm_struct *mm, unsigned long addr)
		pmd_t *pmd;
		pte_t *pte;

		if (pgd_none_or_clear_bad(pgd))
		if (pgd_none(pgd) \|\| pgd_bad(pgd))
		break;

		pud = pud_offset(pgd, addr);
		if (pud_none_or_clear_bad(pud))
		if (pud_none(pud) \|\| pud_bad(pud))
		break;

		pmd = pmd_offset(pud, addr);
		printk(", pmd=%016llx", pmd_val(pmd));
		if (pmd_none_or_clear_bad(pmd))
		if (pmd_none(pmd) \|\| pmd_bad(pmd))
		break;

		pte = pte_offset_map(pmd, addr);

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