| Message ID | 40fe1d91c9cd8d78ae952b821185681621f92b10.1567077734.git.viresh.kumar@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | V4.4 backport of arm64 Spectre patches | expand |
On Thu, Aug 29, 2019 at 05:03:53PM +0530, Viresh Kumar wrote: > From: Will Deacon <will.deacon@arm.com> > > commit 84624087dd7e3b482b7b11c170ebc1f329b3a218 upstream. > > access_ok isn't an expensive operation once the addr_limit for the current > thread has been loaded into the cache. Given that the initial access_ok > check preceding a sequence of __{get,put}_user operations will take > the brunt of the miss, we can make the __* variants identical to the > full-fat versions, which brings with it the benefits of address masking. > > The likely cost in these sequences will be from toggling PAN/UAO, which > we can address later by implementing the *_unsafe versions. > > Reviewed-by: Robin Murphy <robin.murphy@arm.com> > Signed-off-by: Will Deacon <will.deacon@arm.com> > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> > [ v4.4: Fixed conflicts around {__get_user|__put_user}_unaligned macros ] > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- Reviewed-by: Mark Rutland <mark.rutland@arm.com> [v4.4 backport] Mark. > arch/arm64/include/asm/uaccess.h | 62 ++++++++++++++++++-------------- > 1 file changed, 36 insertions(+), 26 deletions(-) > > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index fc11c50af558..a34324436ce1 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -200,30 +200,35 @@ do { \ > CONFIG_ARM64_PAN)); \ > } while (0) > > -#define __get_user(x, ptr) \ > +#define __get_user_check(x, ptr, err) \ > ({ \ > - int __gu_err = 0; \ > - __get_user_err((x), (ptr), __gu_err); \ > - __gu_err; \ > + __typeof__(*(ptr)) __user *__p = (ptr); \ > + might_fault(); \ > + if (access_ok(VERIFY_READ, __p, sizeof(*__p))) { \ > + __p = uaccess_mask_ptr(__p); \ > + __get_user_err((x), __p, (err)); \ > + } else { \ > + (x) = 0; (err) = -EFAULT; \ > + } \ > }) > > #define __get_user_error(x, ptr, err) \ > ({ \ > - __get_user_err((x), (ptr), (err)); \ > + __get_user_check((x), (ptr), (err)); \ > (void)0; \ > }) > > -#define __get_user_unaligned __get_user > - > -#define get_user(x, ptr) \ > +#define __get_user(x, ptr) \ > ({ \ > - __typeof__(*(ptr)) __user *__p = (ptr); \ > - might_fault(); \ > - access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \ > - __p = uaccess_mask_ptr(__p), __get_user((x), __p) : \ > - ((x) = 0, -EFAULT); \ > + int __gu_err = 0; \ > + __get_user_check((x), (ptr), __gu_err); \ > + __gu_err; \ > }) > > +#define __get_user_unaligned __get_user > + > +#define get_user __get_user > + > #define __put_user_asm(instr, reg, x, addr, err) \ > asm volatile( \ > "1: " instr " " reg "1, [%2]\n" \ > @@ -266,30 +271,35 @@ do { \ > CONFIG_ARM64_PAN)); \ > } while (0) > > -#define __put_user(x, ptr) \ > +#define __put_user_check(x, ptr, err) \ > ({ \ > - int __pu_err = 0; \ > - __put_user_err((x), (ptr), __pu_err); \ > - __pu_err; \ > + __typeof__(*(ptr)) __user *__p = (ptr); \ > + might_fault(); \ > + if (access_ok(VERIFY_WRITE, __p, sizeof(*__p))) { \ > + __p = uaccess_mask_ptr(__p); \ > + __put_user_err((x), __p, (err)); \ > + } else { \ > + (err) = -EFAULT; \ > + } \ > }) > > #define __put_user_error(x, ptr, err) \ > ({ \ > - __put_user_err((x), (ptr), (err)); \ > + __put_user_check((x), (ptr), (err)); \ > (void)0; \ > }) > > -#define __put_user_unaligned __put_user > - > -#define put_user(x, ptr) \ > +#define __put_user(x, ptr) \ > ({ \ > - __typeof__(*(ptr)) __user *__p = (ptr); \ > - might_fault(); \ > - access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \ > - __p = uaccess_mask_ptr(__p), __put_user((x), __p) : \ > - -EFAULT; \ > + int __pu_err = 0; \ > + __put_user_check((x), (ptr), __pu_err); \ > + __pu_err; \ > }) > > +#define __put_user_unaligned __put_user > + > +#define put_user __put_user > + > extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n); > extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n); > extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n); > -- > 2.21.0.rc0.269.g1a574e7a288b >
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index fc11c50af558..a34324436ce1 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -200,30 +200,35 @@ do { \ CONFIG_ARM64_PAN)); \ } while (0) -#define __get_user(x, ptr) \ +#define __get_user_check(x, ptr, err) \ ({ \ - int __gu_err = 0; \ - __get_user_err((x), (ptr), __gu_err); \ - __gu_err; \ + __typeof__(*(ptr)) __user *__p = (ptr); \ + might_fault(); \ + if (access_ok(VERIFY_READ, __p, sizeof(*__p))) { \ + __p = uaccess_mask_ptr(__p); \ + __get_user_err((x), __p, (err)); \ + } else { \ + (x) = 0; (err) = -EFAULT; \ + } \ }) #define __get_user_error(x, ptr, err) \ ({ \ - __get_user_err((x), (ptr), (err)); \ + __get_user_check((x), (ptr), (err)); \ (void)0; \ }) -#define __get_user_unaligned __get_user - -#define get_user(x, ptr) \ +#define __get_user(x, ptr) \ ({ \ - __typeof__(*(ptr)) __user *__p = (ptr); \ - might_fault(); \ - access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \ - __p = uaccess_mask_ptr(__p), __get_user((x), __p) : \ - ((x) = 0, -EFAULT); \ + int __gu_err = 0; \ + __get_user_check((x), (ptr), __gu_err); \ + __gu_err; \ }) +#define __get_user_unaligned __get_user + +#define get_user __get_user + #define __put_user_asm(instr, reg, x, addr, err) \ asm volatile( \ "1: " instr " " reg "1, [%2]\n" \ @@ -266,30 +271,35 @@ do { \ CONFIG_ARM64_PAN)); \ } while (0) -#define __put_user(x, ptr) \ +#define __put_user_check(x, ptr, err) \ ({ \ - int __pu_err = 0; \ - __put_user_err((x), (ptr), __pu_err); \ - __pu_err; \ + __typeof__(*(ptr)) __user *__p = (ptr); \ + might_fault(); \ + if (access_ok(VERIFY_WRITE, __p, sizeof(*__p))) { \ + __p = uaccess_mask_ptr(__p); \ + __put_user_err((x), __p, (err)); \ + } else { \ + (err) = -EFAULT; \ + } \ }) #define __put_user_error(x, ptr, err) \ ({ \ - __put_user_err((x), (ptr), (err)); \ + __put_user_check((x), (ptr), (err)); \ (void)0; \ }) -#define __put_user_unaligned __put_user - -#define put_user(x, ptr) \ +#define __put_user(x, ptr) \ ({ \ - __typeof__(*(ptr)) __user *__p = (ptr); \ - might_fault(); \ - access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \ - __p = uaccess_mask_ptr(__p), __put_user((x), __p) : \ - -EFAULT; \ + int __pu_err = 0; \ + __put_user_check((x), (ptr), __pu_err); \ + __pu_err; \ }) +#define __put_user_unaligned __put_user + +#define put_user __put_user + extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n); extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n); extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);