Commit 0c416bca authored by Sandipan Das's avatar Sandipan Das Committed by Linus Torvalds
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selftests: vm: pkeys: add helpers for pkey bits 



This introduces some functions that help with setting or clearing bits of
a particular pkey.  This also adds an abstraction for getting a pkey's bit
position in the pkey register as this may vary across architectures.

Signed-off-by: default avatarSandipan Das <sandipan@linux.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarDave Hansen <dave.hansen@intel.com>
Cc: "Desnes A. Nunes do Rosario" <desnesn@linux.vnet.ibm.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Suchanek <msuchanek@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/2ad9705f4f68ca7e72155cc583415e5a979546f1.1585646528.git.sandipan@linux.ibm.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4dbdd947

tools/testing/selftests/vm/pkey-helpers.h

+22 −0
Original line number Diff line number Diff line
@@ -80,6 +80,28 @@ extern void abort_hooks(void); 
#error Architecture not supported

#endif /* arch */



#define PKEY_MASK	(PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE)



static inline u64 set_pkey_bits(u64 reg, int pkey, u64 flags)

{

	u32 shift = pkey_bit_position(pkey);

	/* mask out bits from pkey in old value */

	reg &= ~((u64)PKEY_MASK << shift);

	/* OR in new bits for pkey */

	reg |= (flags & PKEY_MASK) << shift;

	return reg;

}



static inline u64 get_pkey_bits(u64 reg, int pkey)

{

	u32 shift = pkey_bit_position(pkey);

	/*

	 * shift down the relevant bits to the lowest two, then

	 * mask off all the other higher bits

	 */

	return ((reg >> shift) & PKEY_MASK);

}



extern u64 shadow_pkey_reg;



static inline u64 _read_pkey_reg(int line)

tools/testing/selftests/vm/pkey-x86.h

+5 −0
Original line number Diff line number Diff line
@@ -118,6 +118,11 @@ static inline int cpu_has_pku(void) 
	return 1;

}



static inline u32 pkey_bit_position(int pkey)

{

	return pkey * PKEY_BITS_PER_PKEY;

}



#define XSTATE_PKEY_BIT	(9)

#define XSTATE_PKEY	0x200

tools/testing/selftests/vm/protection_keys.c

+9 −23
Original line number Diff line number Diff line
@@ -334,25 +334,13 @@ pid_t fork_lazy_child(void) 


static u32 hw_pkey_get(int pkey, unsigned long flags)

{

	u32 mask = (PKEY_DISABLE_ACCESS|PKEY_DISABLE_WRITE);

	u64 pkey_reg = __read_pkey_reg();

	u64 shifted_pkey_reg;

	u32 masked_pkey_reg;



	dprintf1("%s(pkey=%d, flags=%lx) = %x / %d\n",

			__func__, pkey, flags, 0, 0);

	dprintf2("%s() raw pkey_reg: %016llx\n", __func__, pkey_reg);



	shifted_pkey_reg = (pkey_reg >> (pkey * PKEY_BITS_PER_PKEY));

	dprintf2("%s() shifted_pkey_reg: %016llx\n", __func__,

			shifted_pkey_reg);

	masked_pkey_reg = shifted_pkey_reg & mask;

	dprintf2("%s() masked  pkey_reg: %x\n", __func__, masked_pkey_reg);

	/*

	 * shift down the relevant bits to the lowest two, then

	 * mask off all the other high bits.

	 */

	return masked_pkey_reg;

	return (u32) get_pkey_bits(pkey_reg, pkey);

}



static int hw_pkey_set(int pkey, unsigned long rights, unsigned long flags)
@@ -364,12 +352,8 @@ static int hw_pkey_set(int pkey, unsigned long rights, unsigned long flags) 
	/* make sure that 'rights' only contains the bits we expect: */

	assert(!(rights & ~mask));



	/* copy old pkey_reg */

	new_pkey_reg = old_pkey_reg;

	/* mask out bits from pkey in old value: */

	new_pkey_reg &= ~(mask << (pkey * PKEY_BITS_PER_PKEY));

	/* OR in new bits for pkey: */

	new_pkey_reg |= (rights << (pkey * PKEY_BITS_PER_PKEY));

	/* modify bits accordingly in old pkey_reg and assign it */

	new_pkey_reg = set_pkey_bits(old_pkey_reg, pkey, rights);



	__write_pkey_reg(new_pkey_reg);
@@ -403,7 +387,7 @@ void pkey_disable_set(int pkey, int flags) 
	ret = hw_pkey_set(pkey, pkey_rights, syscall_flags);

	assert(!ret);

	/* pkey_reg and flags have the same format */

	shadow_pkey_reg |= flags << (pkey * 2);

	shadow_pkey_reg = set_pkey_bits(shadow_pkey_reg, pkey, pkey_rights);

	dprintf1("%s(%d) shadow: 0x%016llx\n",

		__func__, pkey, shadow_pkey_reg);
@@ -437,7 +421,7 @@ void pkey_disable_clear(int pkey, int flags) 
	pkey_rights |= flags;



	ret = hw_pkey_set(pkey, pkey_rights, 0);

	shadow_pkey_reg &= ~(flags << (pkey * 2));

	shadow_pkey_reg = set_pkey_bits(shadow_pkey_reg, pkey, pkey_rights);

	pkey_assert(ret >= 0);



	pkey_rights = hw_pkey_get(pkey, syscall_flags);
@@ -513,7 +497,8 @@ int alloc_pkey(void) 
			shadow_pkey_reg);

	if (ret) {

		/* clear both the bits: */

		shadow_pkey_reg &= ~(0x3      << (ret * 2));

		shadow_pkey_reg = set_pkey_bits(shadow_pkey_reg, ret,

						~PKEY_MASK);

		dprintf4("%s()::%d, ret: %d pkey_reg: 0x%016llx"

				" shadow: 0x%016llx\n",

				__func__,
@@ -523,7 +508,8 @@ int alloc_pkey(void) 
		 * move the new state in from init_val

		 * (remember, we cheated and init_val == pkey_reg format)

		 */

		shadow_pkey_reg |=  (init_val << (ret * 2));

		shadow_pkey_reg = set_pkey_bits(shadow_pkey_reg, ret,

						init_val);

	}

	dprintf4("%s()::%d, ret: %d pkey_reg: 0x%016llx"

			" shadow: 0x%016llx\n",