On Mon, Nov 19, 2018 at 06:26:25PM +0100, Andrey Konovalov wrote: > Move the untagged_addr() macro from arch/arm64/include/asm/uaccess.h > to arch/arm64/include/asm/memory.h to be later reused by KASAN. > > Also make the untagged_addr() macro accept all kinds of address types > (void *, unsigned long, etc.). This allows not to specify type casts in > each place where the macro is used. This is done by using __typeof__. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > --- > arch/arm64/include/asm/memory.h | 8 ++++++++ > arch/arm64/include/asm/uaccess.h | 7 ------- > 2 files changed, 8 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 05fbc7ffcd31..deb95be44392 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -73,6 +73,14 @@ > #define KERNEL_START _text > #define KERNEL_END _end > > +/* > + * When dealing with data aborts, watchpoints, or instruction traps we may end > + * up with a tagged userland pointer. Clear the tag to get a sane pointer to > + * pass on to access_ok(), for instance. > + */ > +#define untagged_addr(addr) \ > + (__typeof__(addr))sign_extend64((__u64)(addr), 55) Minor nits: * s/__u64/u64/ (or s/__u64/unsigned long/), since this isn't a UAPI header. * Please move this down into the #ifndef __ASSEMBLY__ block, after we include <linux/bitops.h>, which is necessary for sign_extend64(). With those fixed up, this patch looks sound to me: Acked-by: Mark Rutland <mark.rutland@xxxxxxx> Thanks, Mark. > + > /* > * Generic and tag-based KASAN require 1/8th and 1/16th of the kernel virtual > * address space for the shadow region respectively. They can bloat the stack > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index 07c34087bd5e..281a1e47263d 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -96,13 +96,6 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si > return ret; > } > > -/* > - * When dealing with data aborts, watchpoints, or instruction traps we may end > - * up with a tagged userland pointer. Clear the tag to get a sane pointer to > - * pass on to access_ok(), for instance. > - */ > -#define untagged_addr(addr) sign_extend64(addr, 55) > - > #define access_ok(type, addr, size) __range_ok(addr, size) > #define user_addr_max get_fs > > -- > 2.19.1.1215.g8438c0b245-goog >
