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| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2020-11-27 05:44:12 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-03 15:01:25 +0100 |
| commit | 8e560921b58cbc18e192f0ac273d307a37a144f9 (patch) | |
| tree | c31889658923af6daebd988632f9d19a738b98cd /arch/powerpc/kernel/asm-offsets.c | |
| parent | powerpc/exec: Set thread.regs early during exec (diff) | |
| download | linux-8e560921b58cbc18e192f0ac273d307a37a144f9.tar.xz linux-8e560921b58cbc18e192f0ac273d307a37a144f9.zip | |
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/asm-offsets.c')
| -rw-r--r-- | arch/powerpc/kernel/asm-offsets.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index a2e01b7b9eeb..b12d7c049bfe 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -358,11 +358,13 @@ int main(void) #ifdef CONFIG_PPC_PKEY STACK_PT_REGS_OFFSET(STACK_REGS_AMR, amr); + STACK_PT_REGS_OFFSET(STACK_REGS_IAMR, iamr); #endif #ifdef CONFIG_PPC_KUAP STACK_PT_REGS_OFFSET(STACK_REGS_KUAP, kuap); #endif + #if defined(CONFIG_PPC32) #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) DEFINE(EXC_LVL_SIZE, STACK_EXC_LVL_FRAME_SIZE); |