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| author | Michael Ellerman <mpe@ellerman.id.au> | 2020-12-17 01:53:06 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-01-30 01:39:25 +0100 |
| commit | 7613f5a66becfd0e43a0f34de8518695888f5458 (patch) | |
| tree | 79cd8aeccdf14be69adf62f05fce5b3238ffffa4 /arch/powerpc | |
| parent | ocxl: use DEFINE_MUTEX() for mutex lock (diff) | |
| download | linux-7613f5a66becfd0e43a0f34de8518695888f5458.tar.xz linux-7613f5a66becfd0e43a0f34de8518695888f5458.zip | |
powerpc/64s/kuap: Use mmu_has_feature()
In commit 8150a153c013 ("powerpc/64s: Use early_mmu_has_feature() in
set_kuap()") we switched the KUAP code to use early_mmu_has_feature(),
to avoid a bug where we called set_kuap() before feature patching had
been done, leading to recursion and crashes.
That path, which called probe_kernel_read() from printk(), has since
been removed, see commit 2ac5a3bf7042 ("vsprintf: Do not break early
boot with probing addresses").
Additionally probe_kernel_read() no longer invokes any KUAP routines,
since commit fe557319aa06 ("maccess: rename probe_kernel_{read,write}
to copy_{from,to}_kernel_nofault") and c33165253492 ("powerpc: use
non-set_fs based maccess routines").
So it should now be safe to use mmu_has_feature() in the KUAP
routines, because we shouldn't invoke them prior to feature patching.
This is essentially a revert of commit 8150a153c013 ("powerpc/64s: Use
early_mmu_has_feature() in set_kuap()"), but we've since added a
second usage of early_mmu_has_feature() in get_kuap(), so we convert
that to use mmu_has_feature() as well.
Reported-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Depends-on: c33165253492 ("powerpc: use non-set_fs based maccess routines").
Link: https://lore.kernel.org/r/20201217005306.895685-1-mpe@ellerman.id.au
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/include/asm/book3s/64/kup.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h index f50f72e535aa..2298eac49763 100644 --- a/arch/powerpc/include/asm/book3s/64/kup.h +++ b/arch/powerpc/include/asm/book3s/64/kup.h @@ -333,7 +333,7 @@ static inline unsigned long get_kuap(void) * This has no effect in terms of actually blocking things on hash, * so it doesn't break anything. */ - if (!early_mmu_has_feature(MMU_FTR_BOOK3S_KUAP)) + if (!mmu_has_feature(MMU_FTR_BOOK3S_KUAP)) return AMR_KUAP_BLOCKED; return mfspr(SPRN_AMR); @@ -341,7 +341,7 @@ static inline unsigned long get_kuap(void) static inline void set_kuap(unsigned long value) { - if (!early_mmu_has_feature(MMU_FTR_BOOK3S_KUAP)) + if (!mmu_has_feature(MMU_FTR_BOOK3S_KUAP)) return; /* |