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[76.210.143.223]) by smtp.gmail.com with ESMTPSA id z18sm1034026pfn.186.2020.09.08.21.59.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Sep 2020 21:59:25 -0700 (PDT) Date: Tue, 08 Sep 2020 21:59:25 -0700 (PDT) X-Google-Original-Date: Tue, 08 Sep 2020 21:43:09 PDT (-0700) Subject: Re: [PATCH 6/8] riscv: refactor __get_user and __put_user In-Reply-To: <20200907055825.1917151-7-hch@lst.de> CC: Paul Walmsley , Arnd Bergmann , viro@zeniv.linux.org.uk, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org From: Palmer Dabbelt To: Christoph Hellwig Message-ID: Mime-Version: 1.0 (MHng) Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 06 Sep 2020 22:58:23 PDT (-0700), Christoph Hellwig wrote: > Add new __get_user_nocheck and __put_user_nocheck that switch on the size > and call the actual inline assembly helpers, and move the uaccess enable > / disable into the actual __get_user and __put_user. This prepares for > natively implementing __get_kernel_nofault and __put_kernel_nofault. > > Also don't bother with the deprecated register keyword for the error > return. > > Signed-off-by: Christoph Hellwig > --- > arch/riscv/include/asm/uaccess.h | 94 ++++++++++++++++++-------------- > 1 file changed, 52 insertions(+), 42 deletions(-) > > diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h > index e8eedf22e90747..b67d1c616ec348 100644 > --- a/arch/riscv/include/asm/uaccess.h > +++ b/arch/riscv/include/asm/uaccess.h > @@ -107,7 +107,6 @@ static inline int __access_ok(unsigned long addr, unsigned long size) > do { \ > uintptr_t __tmp; \ > __typeof__(x) __x; \ > - __enable_user_access(); \ > __asm__ __volatile__ ( \ > "1:\n" \ > " " insn " %1, %3\n" \ > @@ -125,7 +124,6 @@ do { \ > " .previous" \ > : "+r" (err), "=&r" (__x), "=r" (__tmp) \ > : "m" (*(ptr)), "i" (-EFAULT)); \ > - __disable_user_access(); \ > (x) = __x; \ > } while (0) > > @@ -138,7 +136,6 @@ do { \ > u32 __user *__ptr = (u32 __user *)(ptr); \ > u32 __lo, __hi; \ > uintptr_t __tmp; \ > - __enable_user_access(); \ > __asm__ __volatile__ ( \ > "1:\n" \ > " lw %1, %4\n" \ > @@ -162,12 +159,30 @@ do { \ > "=r" (__tmp) \ > : "m" (__ptr[__LSW]), "m" (__ptr[__MSW]), \ > "i" (-EFAULT)); \ > - __disable_user_access(); \ > (x) = (__typeof__(x))((__typeof__((x)-(x)))( \ > (((u64)__hi << 32) | __lo))); \ > } while (0) > #endif /* CONFIG_64BIT */ > > +#define __get_user_nocheck(x, __gu_ptr, __gu_err) \ > +do { \ > + switch (sizeof(*__gu_ptr)) { \ > + case 1: \ > + __get_user_asm("lb", (x), __gu_ptr, __gu_err); \ > + break; \ > + case 2: \ > + __get_user_asm("lh", (x), __gu_ptr, __gu_err); \ > + break; \ > + case 4: \ > + __get_user_asm("lw", (x), __gu_ptr, __gu_err); \ > + break; \ > + case 8: \ > + __get_user_8((x), __gu_ptr, __gu_err); \ > + break; \ > + default: \ > + BUILD_BUG(); \ > + } \ > +} while (0) > > /** > * __get_user: - Get a simple variable from user space, with less checking. > @@ -191,25 +206,15 @@ do { \ > */ > #define __get_user(x, ptr) \ > ({ \ > - register long __gu_err = 0; \ > const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ > + long __gu_err = 0; \ > + \ > __chk_user_ptr(__gu_ptr); \ > - switch (sizeof(*__gu_ptr)) { \ > - case 1: \ > - __get_user_asm("lb", (x), __gu_ptr, __gu_err); \ > - break; \ > - case 2: \ > - __get_user_asm("lh", (x), __gu_ptr, __gu_err); \ > - break; \ > - case 4: \ > - __get_user_asm("lw", (x), __gu_ptr, __gu_err); \ > - break; \ > - case 8: \ > - __get_user_8((x), __gu_ptr, __gu_err); \ > - break; \ > - default: \ > - BUILD_BUG(); \ > - } \ > + \ > + __enable_user_access(); \ > + __get_user_nocheck(x, __gu_ptr, __gu_err); \ > + __disable_user_access(); \ > + \ > __gu_err; \ > }) > > @@ -243,7 +248,6 @@ do { \ > do { \ > uintptr_t __tmp; \ > __typeof__(*(ptr)) __x = x; \ > - __enable_user_access(); \ > __asm__ __volatile__ ( \ > "1:\n" \ > " " insn " %z3, %2\n" \ > @@ -260,7 +264,6 @@ do { \ > " .previous" \ > : "+r" (err), "=r" (__tmp), "=m" (*(ptr)) \ > : "rJ" (__x), "i" (-EFAULT)); \ > - __disable_user_access(); \ > } while (0) > > #ifdef CONFIG_64BIT > @@ -272,7 +275,6 @@ do { \ > u32 __user *__ptr = (u32 __user *)(ptr); \ > u64 __x = (__typeof__((x)-(x)))(x); \ > uintptr_t __tmp; \ > - __enable_user_access(); \ > __asm__ __volatile__ ( \ > "1:\n" \ > " sw %z4, %2\n" \ > @@ -294,10 +296,28 @@ do { \ > "=m" (__ptr[__LSW]), \ > "=m" (__ptr[__MSW]) \ > : "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT)); \ > - __disable_user_access(); \ > } while (0) > #endif /* CONFIG_64BIT */ > > +#define __put_user_nocheck(x, __gu_ptr, __pu_err) \ > +do { \ > + switch (sizeof(*__gu_ptr)) { \ > + case 1: \ > + __put_user_asm("sb", (x), __gu_ptr, __pu_err); \ > + break; \ > + case 2: \ > + __put_user_asm("sh", (x), __gu_ptr, __pu_err); \ > + break; \ > + case 4: \ > + __put_user_asm("sw", (x), __gu_ptr, __pu_err); \ > + break; \ > + case 8: \ > + __put_user_8((x), __gu_ptr, __pu_err); \ > + break; \ > + default: \ > + BUILD_BUG(); \ > + } \ > +} while (0) > > /** > * __put_user: - Write a simple value into user space, with less checking. > @@ -320,25 +340,15 @@ do { \ > */ > #define __put_user(x, ptr) \ > ({ \ > - register long __pu_err = 0; \ > __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \ > + long __pu_err = 0; \ > + \ > __chk_user_ptr(__gu_ptr); \ > - switch (sizeof(*__gu_ptr)) { \ > - case 1: \ > - __put_user_asm("sb", (x), __gu_ptr, __pu_err); \ > - break; \ > - case 2: \ > - __put_user_asm("sh", (x), __gu_ptr, __pu_err); \ > - break; \ > - case 4: \ > - __put_user_asm("sw", (x), __gu_ptr, __pu_err); \ > - break; \ > - case 8: \ > - __put_user_8((x), __gu_ptr, __pu_err); \ > - break; \ > - default: \ > - BUILD_BUG(); \ > - } \ > + \ > + __enable_user_access(); \ > + __put_user_nocheck(x, __gu_ptr, __pu_err); \ > + __disable_user_access(); \ > + \ > __pu_err; \ > }) Reviewed-by: Palmer Dabbelt Acked-by: Palmer Dabbelt