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s390x/mmu: Add support for read-only regions

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If the "DAT-protection" bit is set in the region table entry and EDAT is
enabled, only read accesses are allowed in the corresponding memory area.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Thomas Huth 2015-02-12 18:09:26 +01:00 committed by Christian Borntraeger
parent 5a123b3c1a
commit 43d49b0115
2 changed files with 5 additions and 3 deletions
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1
target-s390x/cpu.h
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@ -837,6 +837,7 @@ struct sysib_322 {
#define _ASCE_TABLE_LENGTH 0x03 /* region table length */
#define _REGION_ENTRY_ORIGIN ~0xfffULL /* region/segment table origin */
#define _REGION_ENTRY_RO 0x200 /* region/segment protection bit */
#define _REGION_ENTRY_TF 0xc0 /* region/segment table offset */
#define _REGION_ENTRY_INV 0x20 /* invalid region table entry */
#define _REGION_ENTRY_TYPE_MASK 0x0c /* region/segment table type mask */

7
target-s390x/mmu_helper.c
View File

@ -188,9 +188,6 @@ static int mmu_translate_region(CPUS390XState *env, target_ulong vaddr,
return -1;
}
/* XXX region protection flags */
/* *flags &= ~PAGE_WRITE */
if (level == _ASCE_TYPE_SEGMENT) {
return mmu_translate_segment(env, vaddr, asc, new_entry, raddr, flags,
rw, exc);
@ -205,6 +202,10 @@ static int mmu_translate_region(CPUS390XState *env, target_ulong vaddr,
return -1;
}
if ((env->cregs[0] & CR0_EDAT) && (new_entry & _REGION_ENTRY_RO)) {
*flags &= ~PAGE_WRITE;
}
/* yet another region */
return mmu_translate_region(env, vaddr, asc, new_entry, level - 4,
raddr, flags, rw, exc);