diff options
| -rw-r--r-- | arch/x86/include/asm/uaccess_64.h | 18 |
1 files changed, 3 insertions, 15 deletions
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h index 20411e69e67f..e5b23e917f41 100644 --- a/arch/x86/include/asm/uaccess_64.h +++ b/arch/x86/include/asm/uaccess_64.h @@ -15,25 +15,17 @@ #ifdef CONFIG_ADDRESS_MASKING /* * Mask out tag bits from the address. - * - * Magic with the 'sign' allows to untag userspace pointer without any branches - * while leaving kernel addresses intact. */ static inline unsigned long __untagged_addr(unsigned long addr) { - long sign; - /* * Refer tlbstate_untag_mask directly to avoid RIP-relative relocation * in alternative instructions. The relocation gets wrong when gets * copied to the target place. */ asm (ALTERNATIVE("", - "sar $63, %[sign]\n\t" /* user_ptr ? 0 : -1UL */ - "or %%gs:tlbstate_untag_mask, %[sign]\n\t" - "and %[sign], %[addr]\n\t", X86_FEATURE_LAM) - : [addr] "+r" (addr), [sign] "=r" (sign) - : "m" (tlbstate_untag_mask), "[sign]" (addr)); + "and %%gs:tlbstate_untag_mask, %[addr]\n\t", X86_FEATURE_LAM) + : [addr] "+r" (addr) : "m" (tlbstate_untag_mask)); return addr; } @@ -46,12 +38,8 @@ static inline unsigned long __untagged_addr(unsigned long addr) static inline unsigned long __untagged_addr_remote(struct mm_struct *mm, unsigned long addr) { - long sign = addr >> 63; - mmap_assert_locked(mm); - addr &= (mm)->context.untag_mask | sign; - - return addr; + return addr & (mm)->context.untag_mask; } #define untagged_addr_remote(mm, addr) ({ \ |