| Message ID | 20201026133156.44186-11-mark.rutland@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: remove set_fs() and friends | expand |
On 2020-10-26 13:31, Mark Rutland wrote: > Currently __copy_user_flushcache() open-codes raw_copy_from_user(), and > doesn't use uaccess_mask_ptr() on the user address. Let's have it call > raw_copy_from_user(), which is both a simplification and ensures that > user pointers are masked under speculation. I think this originally stems from the fact that "raw_*" were merely generic aliases for "__arch_*" at the time. Then whichever chump subsequently implemented uaccess_mask_ptr() for arm64 clearly did a terrible job... ;) > There should be no functional change as a result of this patch. Reviewed-by: Robin Murphy <robin.murphy@arm.com> > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Will Deacon <will@kernel.org> > --- > arch/arm64/lib/uaccess_flushcache.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/arch/arm64/lib/uaccess_flushcache.c b/arch/arm64/lib/uaccess_flushcache.c > index bfa30b75b2b8e..c83bb5a4aad2c 100644 > --- a/arch/arm64/lib/uaccess_flushcache.c > +++ b/arch/arm64/lib/uaccess_flushcache.c > @@ -30,9 +30,7 @@ unsigned long __copy_user_flushcache(void *to, const void __user *from, > { > unsigned long rc; > > - uaccess_enable_not_uao(); > - rc = __arch_copy_from_user(to, from, n); > - uaccess_disable_not_uao(); > + rc = raw_copy_from_user(to, from, n); > > /* See above */ > __clean_dcache_area_pop(to, n - rc); >
On Tue, Oct 27, 2020 at 05:33:31PM +0000, Robin Murphy wrote: > On 2020-10-26 13:31, Mark Rutland wrote: > > Currently __copy_user_flushcache() open-codes raw_copy_from_user(), and > > doesn't use uaccess_mask_ptr() on the user address. Let's have it call > > raw_copy_from_user(), which is both a simplification and ensures that > > user pointers are masked under speculation. > > I think this originally stems from the fact that "raw_*" were merely generic > aliases for "__arch_*" at the time. Then whichever chump subsequently > implemented uaccess_mask_ptr() for arm64 clearly did a terrible job... ;) :) > > There should be no functional change as a result of this patch. > > Reviewed-by: Robin Murphy <robin.murphy@arm.com> Thanks! Mark. > > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Cc: Christoph Hellwig <hch@lst.de> > > Cc: Robin Murphy <robin.murphy@arm.com> > > Cc: Will Deacon <will@kernel.org> > > --- > > arch/arm64/lib/uaccess_flushcache.c | 4 +--- > > 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/arch/arm64/lib/uaccess_flushcache.c b/arch/arm64/lib/uaccess_flushcache.c > > index bfa30b75b2b8e..c83bb5a4aad2c 100644 > > --- a/arch/arm64/lib/uaccess_flushcache.c > > +++ b/arch/arm64/lib/uaccess_flushcache.c > > @@ -30,9 +30,7 @@ unsigned long __copy_user_flushcache(void *to, const void __user *from, > > { > > unsigned long rc; > > - uaccess_enable_not_uao(); > > - rc = __arch_copy_from_user(to, from, n); > > - uaccess_disable_not_uao(); > > + rc = raw_copy_from_user(to, from, n); > > /* See above */ > > __clean_dcache_area_pop(to, n - rc); > >
diff --git a/arch/arm64/lib/uaccess_flushcache.c b/arch/arm64/lib/uaccess_flushcache.c index bfa30b75b2b8e..c83bb5a4aad2c 100644 --- a/arch/arm64/lib/uaccess_flushcache.c +++ b/arch/arm64/lib/uaccess_flushcache.c @@ -30,9 +30,7 @@ unsigned long __copy_user_flushcache(void *to, const void __user *from, { unsigned long rc; - uaccess_enable_not_uao(); - rc = __arch_copy_from_user(to, from, n); - uaccess_disable_not_uao(); + rc = raw_copy_from_user(to, from, n); /* See above */ __clean_dcache_area_pop(to, n - rc);
Currently __copy_user_flushcache() open-codes raw_copy_from_user(), and doesn't use uaccess_mask_ptr() on the user address. Let's have it call raw_copy_from_user(), which is both a simplification and ensures that user pointers are masked under speculation. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Will Deacon <will@kernel.org> --- arch/arm64/lib/uaccess_flushcache.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)