diff options
| author | Peter Collingbourne <pcc@google.com> | 2021-03-18 20:10:54 -0700 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-04-13 17:31:44 +0100 |
| commit | b90e483938ce387c256e03fb144f82f64551847b (patch) | |
| tree | 142877923b78d506be4812ecacc65fb8718adf29 /arch/arm64/include/asm/asm_pointer_auth.h | |
| parent | 201698626fbca1cf1a3b686ba14cf2a056500716 (diff) | |
arm64: pac: Optimize kernel entry/exit key installation code paths
The kernel does not use any keys besides IA so we don't need to
install IB/DA/DB/GA on kernel exit if we arrange to install them
on task switch instead, which we can expect to happen an order of
magnitude less often.
Furthermore we can avoid installing the user IA in the case where the
user task has IA disabled and just leave the kernel IA installed. This
also lets us avoid needing to install IA on kernel entry.
On an Apple M1 under a hypervisor, the overhead of kernel entry/exit
has been measured to be reduced by 15.6ns in the case where IA is
enabled, and 31.9ns in the case where IA is disabled.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/Ieddf6b580d23c9e0bed45a822dabe72d2ffc9a8e
Link: https://lore.kernel.org/r/2d653d055f38f779937f2b92f8ddd5cf9e4af4f4.1616123271.git.pcc@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/asm_pointer_auth.h')
| -rw-r--r-- | arch/arm64/include/asm/asm_pointer_auth.h | 20 |
1 files changed, 1 insertions, 19 deletions
diff --git a/arch/arm64/include/asm/asm_pointer_auth.h b/arch/arm64/include/asm/asm_pointer_auth.h index 52dead2a8640..8ca2dc0661ee 100644 --- a/arch/arm64/include/asm/asm_pointer_auth.h +++ b/arch/arm64/include/asm/asm_pointer_auth.h @@ -13,30 +13,12 @@ * so use the base value of ldp as thread.keys_user and offset as * thread.keys_user.ap*. */ - .macro ptrauth_keys_install_user tsk, tmp1, tmp2, tmp3 + .macro __ptrauth_keys_install_user tsk, tmp1, tmp2, tmp3 mov \tmp1, #THREAD_KEYS_USER add \tmp1, \tsk, \tmp1 -alternative_if_not ARM64_HAS_ADDRESS_AUTH - b .Laddr_auth_skip_\@ -alternative_else_nop_endif ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APIA] msr_s SYS_APIAKEYLO_EL1, \tmp2 msr_s SYS_APIAKEYHI_EL1, \tmp3 - ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APIB] - msr_s SYS_APIBKEYLO_EL1, \tmp2 - msr_s SYS_APIBKEYHI_EL1, \tmp3 - ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APDA] - msr_s SYS_APDAKEYLO_EL1, \tmp2 - msr_s SYS_APDAKEYHI_EL1, \tmp3 - ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APDB] - msr_s SYS_APDBKEYLO_EL1, \tmp2 - msr_s SYS_APDBKEYHI_EL1, \tmp3 -.Laddr_auth_skip_\@: -alternative_if ARM64_HAS_GENERIC_AUTH - ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APGA] - msr_s SYS_APGAKEYLO_EL1, \tmp2 - msr_s SYS_APGAKEYHI_EL1, \tmp3 -alternative_else_nop_endif .endm .macro __ptrauth_keys_install_kernel_nosync tsk, tmp1, tmp2, tmp3 |