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Mon, 18 Nov 2024 15:01:31 -0800 (PST) Received: from aus-ird.local.tenstorrent.com ([38.104.49.66]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7b37a897eebsm35344185a.94.2024.11.18.15.01.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Nov 2024 15:01:31 -0800 (PST) From: Cyril Bur To: palmer@dabbelt.com, aou@eecs.berkeley.edu, paul.walmsley@sifive.com Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Jisheng Zhang Subject: [PATCH v2 3/4] riscv: uaccess: use 'asm goto' for put_user() Date: Mon, 18 Nov 2024 23:01:11 +0000 Message-Id: <20241118230112.2872978-4-cyrilbur@tenstorrent.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241118230112.2872978-1-cyrilbur@tenstorrent.com> References: <20241118230112.2872978-1-cyrilbur@tenstorrent.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241118_150133_028548_51FEACC8 X-CRM114-Status: GOOD ( 11.35 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: Jisheng Zhang 'asm goto' generates noticeably better code since we don't need to test the error etc, the exception just jumps to the error handling directly. Signed-off-by: Jisheng Zhang Signed-off-by: Cyril Bur --- arch/riscv/include/asm/uaccess.h | 70 +++++++++++++++----------------- 1 file changed, 33 insertions(+), 37 deletions(-) diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h index 84b084e388a7..916df594ef3c 100644 --- a/arch/riscv/include/asm/uaccess.h +++ b/arch/riscv/include/asm/uaccess.h @@ -181,61 +181,66 @@ do { \ ((x) = (__force __typeof__(x))0, -EFAULT); \ }) -#define __put_user_asm(insn, x, ptr, err) \ +#define __put_user_asm(insn, x, ptr, label) \ do { \ __typeof__(*(ptr)) __x = x; \ - __asm__ __volatile__ ( \ + asm goto( \ "1:\n" \ - " " insn " %z1, %2\n" \ - "2:\n" \ - _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %0) \ - : "+r" (err) \ - : "rJ" (__x), "m"(*(ptr))); \ + " " insn " %z0, %1\n" \ + _ASM_EXTABLE(1b, %l2) \ + : : "rJ" (__x), "m"(*(ptr)) : : label); \ } while (0) #ifdef CONFIG_64BIT -#define __put_user_8(x, ptr, err) \ - __put_user_asm("sd", x, ptr, err) +#define __put_user_8(x, ptr, label) \ + __put_user_asm("sd", x, ptr, label) #else /* !CONFIG_64BIT */ -#define __put_user_8(x, ptr, err) \ +#define __put_user_8(x, ptr, label) \ do { \ u32 __user *__ptr = (u32 __user *)(ptr); \ u64 __x = (__typeof__((x)-(x)))(x); \ - __asm__ __volatile__ ( \ + asm goto( \ "1:\n" \ - " sw %z1, %3\n" \ + " sw %z0, %2\n" \ "2:\n" \ - " sw %z2, %4\n" \ - "3:\n" \ - _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %0) \ - _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %0) \ - : "+r" (err) \ - : "rJ" (__x), "rJ" (__x >> 32), \ + " sw %z1, %3\n" \ + _ASM_EXTABLE(1b, %l4) \ + _ASM_EXTABLE(2b, %l4) \ + : : "rJ" (__x), "rJ" (__x >> 32), \ "m" (__ptr[__LSW]), \ - "m" (__ptr[__MSW])); \ + "m" (__ptr[__MSW]) : : label); \ } while (0) #endif /* CONFIG_64BIT */ -#define __put_user_nocheck(x, __gu_ptr, __pu_err) \ +#define __put_user_nocheck(x, __gu_ptr, label) \ do { \ switch (sizeof(*__gu_ptr)) { \ case 1: \ - __put_user_asm("sb", (x), __gu_ptr, __pu_err); \ + __put_user_asm("sb", (x), __gu_ptr, label); \ break; \ case 2: \ - __put_user_asm("sh", (x), __gu_ptr, __pu_err); \ + __put_user_asm("sh", (x), __gu_ptr, label); \ break; \ case 4: \ - __put_user_asm("sw", (x), __gu_ptr, __pu_err); \ + __put_user_asm("sw", (x), __gu_ptr, label); \ break; \ case 8: \ - __put_user_8((x), __gu_ptr, __pu_err); \ + __put_user_8((x), __gu_ptr, label); \ break; \ default: \ BUILD_BUG(); \ } \ } while (0) +#define __put_user_error(x, ptr, err) \ +do { \ + __label__ err_label; \ + __put_user_nocheck(x, ptr, err_label); \ + break; \ +err_label: \ + (err) = -EFAULT; \ +} while (0) + /** * __put_user: - Write a simple value into user space, with less checking. * @x: Value to copy to user space. @@ -266,7 +271,7 @@ do { \ __chk_user_ptr(__gu_ptr); \ \ __enable_user_access(); \ - __put_user_nocheck(__val, __gu_ptr, __pu_err); \ + __put_user_error(__val, __gu_ptr, __pu_err); \ __disable_user_access(); \ \ __pu_err; \ @@ -340,13 +345,7 @@ do { \ } while (0) #define __put_kernel_nofault(dst, src, type, err_label) \ -do { \ - long __kr_err = 0; \ - \ - __put_user_nocheck(*((type *)(src)), (type *)(dst), __kr_err); \ - if (unlikely(__kr_err)) \ - goto err_label; \ -} while (0) + __put_user_nocheck(*((type *)(src)), (type *)(dst), err_label); static __must_check __always_inline bool user_access_begin(const void __user *ptr, size_t len) { @@ -361,11 +360,8 @@ static __must_check __always_inline bool user_access_begin(const void __user *pt static inline unsigned long user_access_save(void) { return 0UL; } static inline void user_access_restore(unsigned long enabled) { } -#define unsafe_put_user(x, ptr, label) do { \ - long __kr_err = 0; \ - __put_user_nocheck(x, (ptr), __kr_err); \ - if (__kr_err) goto label; \ -} while (0) +#define unsafe_put_user(x, ptr, label) \ + __put_user_nocheck(x, (ptr), label); #define unsafe_get_user(x, ptr, label) do { \ long __kr_err = 0; \