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m68k: Do not set global share for non-kernel shared pages

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If the SG bit is set in MMUTR the page is accessible for all
userspace processes (ignoring the ASID). So a process might randomly
access a page from a different process which had a shared page
(from shared memory) in its context.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
This commit is contained in:
Alexander Stein 2012-01-23 15:45:56 +01:00 committed by Greg Ungerer
parent 57e00098cc
commit 3372f5a7d0
1 changed files with 5 additions and 4 deletions
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9
arch/m68k/mm/mcfmmu.c
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@ -87,7 +87,7 @@ void __init paging_init(void)
int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
{
unsigned long flags, mmuar;
unsigned long flags, mmuar, mmutr;
struct mm_struct *mm;
pgd_t *pgd;
pmd_t *pmd;
@ -137,9 +137,10 @@ int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
if (!pte_dirty(*pte) && !KMAPAREA(mmuar))
set_pte(pte, pte_wrprotect(*pte));
mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) |
(((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK)
>> CF_PAGE_MMUTR_SHIFT) | MMUTR_V);
mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V;
if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE))
mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT;
mmu_write(MMUTR, mmutr);
mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);