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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: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Dave 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: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sandipan Das 2020-06-04 16:51:54 -07:00 committed by Linus Torvalds
parent 4dbdd947cb
commit 0c416bcaef
3 changed files with 36 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
tools/testing/selftests/vm/pkey-helpers.h
View File

@ -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)

5
tools/testing/selftests/vm/pkey-x86.h
View File

@ -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

32
tools/testing/selftests/vm/protection_keys.c
View File

@ -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",