diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2020-11-27 10:14:12 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-04 01:01:25 +1100 |
| commit | 8e560921b58cbc18e192f0ac273d307a37a144f9 (patch) | |
| tree | c31889658923af6daebd988632f9d19a738b98cd /arch/powerpc/kernel/exceptions-64s.S | |
| parent | d7df77e89039623ededf0ece7b4358f7c9ecbaae (diff) | |
powerpc/book3s64/pkeys: Store/restore userspace AMR/IAMR correctly on entry and exit from kernel
This prepare kernel to operate with a different value than userspace AMR/IAMR.
For this, AMR/IAMR need to be saved and restored on entry and return from the
kernel.
With KUAP we modify kernel AMR when accessing user address from the kernel
via copy_to/from_user interfaces. We don't need to modify IAMR value in
similar fashion.
If MMU_FTR_PKEY is enabled we need to save AMR/IAMR in pt_regs on entering
kernel from userspace. If not we can assume that AMR/IAMR is not modified
from userspace.
We need to save AMR if we have MMU_FTR_BOOK3S_KUAP feature enabled and we are
interrupted within kernel. This is required so that if we get interrupted
within copy_to/from_user we continue with the right AMR value.
If we hae MMU_FTR_BOOK3S_KUEP enabled we need to restore IAMR on
return to userspace beause kernel will be running with a different
IAMR value.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-11-aneesh.kumar@linux.ibm.com
Diffstat (limited to 'arch/powerpc/kernel/exceptions-64s.S')
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 4d01f09ecf80..1c8f1b90e174 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1059,7 +1059,7 @@ EXC_COMMON_BEGIN(system_reset_common) ld r10,SOFTE(r1) stb r10,PACAIRQSOFTMASK(r13) - kuap_restore_amr r9, r10 + kuap_kernel_restore r9, r10 EXCEPTION_RESTORE_REGS RFI_TO_USER_OR_KERNEL @@ -2875,7 +2875,7 @@ EXC_COMMON_BEGIN(soft_nmi_common) ld r10,SOFTE(r1) stb r10,PACAIRQSOFTMASK(r13) - kuap_restore_amr r9, r10 + kuap_kernel_restore r9, r10 EXCEPTION_RESTORE_REGS hsrr=0 RFI_TO_KERNEL |