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ARM: KVM: sanitize freeing of HYP page tables

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Instead of trying to free everything from PAGE_OFFSET to the
top of memory, use the virt_addr_valid macro to check the
upper limit.

Also do the same for the vmalloc region where the IO mappings
are allocated.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
This commit is contained in:
Marc Zyngier 2013-03-05 02:43:17 +00:00 committed by Christoffer Dall
parent 6190920a35
commit 000d399625
1 changed files with 29 additions and 21 deletions
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50
arch/arm/kvm/mmu.c
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@ -85,34 +85,42 @@ static void free_ptes(pmd_t *pmd, unsigned long addr)
}
}
/**
* free_hyp_pmds - free a Hyp-mode level-2 tables and child level-3 tables
*
* Assumes this is a page table used strictly in Hyp-mode and therefore contains
* only mappings in the kernel memory area, which is above PAGE_OFFSET.
*/
void free_hyp_pmds(void)
static void free_hyp_pgd_entry(unsigned long addr)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
unsigned long hyp_addr = KERN_TO_HYP(addr);
pgd = hyp_pgd + pgd_index(hyp_addr);
pud = pud_offset(pgd, hyp_addr);
if (pud_none(*pud))
return;
BUG_ON(pud_bad(*pud));
pmd = pmd_offset(pud, hyp_addr);
free_ptes(pmd, addr);
pmd_free(NULL, pmd);
pud_clear(pud);
}
/**
* free_hyp_pmds - free a Hyp-mode level-2 tables and child level-3 tables
*
* Assumes this is a page table used strictly in Hyp-mode and therefore contains
* either mappings in the kernel memory area (above PAGE_OFFSET), or
* device mappings in the vmalloc range (from VMALLOC_START to VMALLOC_END).
*/
void free_hyp_pmds(void)
{
unsigned long addr;
mutex_lock(&kvm_hyp_pgd_mutex);
for (addr = PAGE_OFFSET; addr != 0; addr += PGDIR_SIZE) {
unsigned long hyp_addr = KERN_TO_HYP(addr);
pgd = hyp_pgd + pgd_index(hyp_addr);
pud = pud_offset(pgd, hyp_addr);
if (pud_none(*pud))
continue;
BUG_ON(pud_bad(*pud));
pmd = pmd_offset(pud, hyp_addr);
free_ptes(pmd, addr);
pmd_free(NULL, pmd);
pud_clear(pud);
}
for (addr = PAGE_OFFSET; virt_addr_valid(addr); addr += PGDIR_SIZE)
free_hyp_pgd_entry(addr);
for (addr = VMALLOC_START; is_vmalloc_addr((void*)addr); addr += PGDIR_SIZE)
free_hyp_pgd_entry(addr);
mutex_unlock(&kvm_hyp_pgd_mutex);
}