| Message ID | 20200615154642.3579-1-will@kernel.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 034aa9cd698e315c767af1bac3fd1ff8898d2cd7 |
| Headers | show |
| Series | arm64: pgtable: Clear the GP bit for non-executable kernel pages | expand |
On Mon, Jun 15, 2020 at 04:46:42PM +0100, Will Deacon wrote: > Commit cca98e9f8b5e ("mm: enforce that vmap can't map pages executable") > introduced 'pgprot_nx(prot)' for arm64 but colliding silently with the > BTI support during the merge window, which endeavours to clear the GP > bit for non-executable kernel mappings in set_memory_nx(). Reviewed-by: Mark Brown <broonie@kernel.org>
On Mon, Jun 15, 2020 at 04:46:42PM +0100, Will Deacon wrote: > Commit cca98e9f8b5e ("mm: enforce that vmap can't map pages executable") > introduced 'pgprot_nx(prot)' for arm64 but colliding silently with the > BTI support during the merge window, which endeavours to clear the GP > bit for non-executable kernel mappings in set_memory_nx(). > > For consistency between the two APIs, clear the GP bit in pgprot_nx(). > > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Mark Brown <broonie@kernel.org> > Signed-off-by: Will Deacon <will@kernel.org> > --- > arch/arm64/include/asm/pgtable.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index 6dbd267ab931..758e2d1577d0 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -416,7 +416,7 @@ static inline pmd_t pmd_mkdevmap(pmd_t pmd) > __pgprot((pgprot_val(prot) & ~(mask)) | (bits)) > > #define pgprot_nx(prot) \ > - __pgprot_modify(prot, 0, PTE_PXN) > + __pgprot_modify(prot, PTE_MAYBE_GP, PTE_PXN) Since this is just used to clear the bit, we could use PTE_GP directly and allow the compiler to constant fold this. Either way: Acked-by: Mark Rutland <mark.rutland@arm.com> Mark. > > /* > * Mark the prot value as uncacheable and unbufferable. > -- > 2.27.0.290.gba653c62da-goog >
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 6dbd267ab931..758e2d1577d0 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -416,7 +416,7 @@ static inline pmd_t pmd_mkdevmap(pmd_t pmd) __pgprot((pgprot_val(prot) & ~(mask)) | (bits)) #define pgprot_nx(prot) \ - __pgprot_modify(prot, 0, PTE_PXN) + __pgprot_modify(prot, PTE_MAYBE_GP, PTE_PXN) /* * Mark the prot value as uncacheable and unbufferable.
Commit cca98e9f8b5e ("mm: enforce that vmap can't map pages executable") introduced 'pgprot_nx(prot)' for arm64 but colliding silently with the BTI support during the merge window, which endeavours to clear the GP bit for non-executable kernel mappings in set_memory_nx(). For consistency between the two APIs, clear the GP bit in pgprot_nx(). Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/pgtable.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)