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powerpc: ability to create execute-disabled pkeys

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powerpc has hardware support to disable execute on a pkey.
This patch enables the ability to create execute-disabled
keys.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Ram Pai 2018-01-18 17:50:30 -08:00 committed by Michael Ellerman
parent 2ddc53f3a7
commit dcf872956d
2 changed files with 22 additions and 0 deletions
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6
arch/powerpc/include/uapi/asm/mman.h
View File

@ -30,4 +30,10 @@
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x40000 /* create a huge page mapping */
/* Override any generic PKEY permission defines */
#define PKEY_DISABLE_EXECUTE 0x4
#undef PKEY_ACCESS_MASK
#define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\
PKEY_DISABLE_WRITE |\
PKEY_DISABLE_EXECUTE)
#endif /* _UAPI_ASM_POWERPC_MMAN_H */

16
arch/powerpc/mm/pkeys.c
View File

@ -24,6 +24,14 @@ int pkey_initialize(void)
{
int os_reserved, i;
/*
* We define PKEY_DISABLE_EXECUTE in addition to the arch-neutral
* generic defines for PKEY_DISABLE_ACCESS and PKEY_DISABLE_WRITE.
* Ensure that the bits a distinct.
*/
BUILD_BUG_ON(PKEY_DISABLE_EXECUTE &
(PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
/*
* Disable the pkey system till everything is in place. A subsequent
* patch will enable it.
@ -177,10 +185,18 @@ int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
unsigned long init_val)
{
u64 new_amr_bits = 0x0ul;
u64 new_iamr_bits = 0x0ul;
if (!is_pkey_enabled(pkey))
return -EINVAL;
if (init_val & PKEY_DISABLE_EXECUTE) {
if (!pkey_execute_disable_supported)
return -EINVAL;
new_iamr_bits |= IAMR_EX_BIT;
}
init_iamr(pkey, new_iamr_bits);
/* Set the bits we need in AMR: */
if (init_val & PKEY_DISABLE_ACCESS)
new_amr_bits |= AMR_RD_BIT | AMR_WR_BIT;