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Commit dcf87295 authored by Ram Pai's avatar Ram Pai Committed by Michael Ellerman
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powerpc: ability to create execute-disabled pkeys 



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

Signed-off-by: default avatarRam Pai <linuxram@us.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 2ddc53f3

arch/powerpc/include/uapi/asm/mman.h

+6 −0
Original line number Diff line number Diff line
@@ -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 */

arch/powerpc/mm/pkeys.c

+16 −0
Original line number Diff line number Diff line
@@ -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;