From: Sandipan Das <sandipan@xxxxxxxxxxxxx> Subject: 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. Link: http://lkml.kernel.org/r/2ad9705f4f68ca7e72155cc583415e5a979546f1.1585646528.git.sandipan@xxxxxxxxxxxxx Signed-off-by: Sandipan Das <sandipan@xxxxxxxxxxxxx> Acked-by: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: "Desnes A. Nunes do Rosario" <desnesn@xxxxxxxxxxxxxxxxxx> Cc: Florian Weimer <fweimer@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Ram Pai <linuxram@xxxxxxxxxx> Cc: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx> Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Michal Suchanek <msuchanek@xxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/vm/pkey-helpers.h | 22 +++++++++++ tools/testing/selftests/vm/pkey-x86.h | 5 ++ tools/testing/selftests/vm/protection_keys.c | 32 ++++------------- 3 files changed, 36 insertions(+), 23 deletions(-) --- a/tools/testing/selftests/vm/pkey-helpers.h~selftests-vm-pkeys-add-helpers-for-pkey-bits +++ a/tools/testing/selftests/vm/pkey-helpers.h @@ -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) --- a/tools/testing/selftests/vm/pkey-x86.h~selftests-vm-pkeys-add-helpers-for-pkey-bits +++ a/tools/testing/selftests/vm/pkey-x86.h @@ -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 --- a/tools/testing/selftests/vm/protection_keys.c~selftests-vm-pkeys-add-helpers-for-pkey-bits +++ a/tools/testing/selftests/vm/protection_keys.c @@ -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, unsigne /* 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 flag 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 fl 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", _
