From: Akira Tsukamoto <akira.tsukamoto@gmail.com> To: Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: [PATCH 2/5] riscv: __asm_to/copy_from_user: Adding byte copy first Date: Sat, 19 Jun 2021 20:35:39 +0900 [thread overview] Message-ID: <98088fde-cdb2-6410-8d11-7c8ca984d3c3@gmail.com> (raw) In-Reply-To: <5a5c07ac-8c11-79d3-46a3-a255d4148f76@gmail.com> Typical load and store loop. It is used for mainly copying the remainder in one byte at a time. Signed-off-by: Akira Tsukamoto <akira.tsukamoto@gmail.com> --- arch/riscv/lib/uaccess.S | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S index da9536e1e9cb..be1810077f9a 100644 --- a/arch/riscv/lib/uaccess.S +++ b/arch/riscv/lib/uaccess.S @@ -19,9 +19,39 @@ ENTRY(__asm_copy_from_user) li t6, SR_SUM csrs CSR_STATUS, t6 + /* Save for return value */ + mv t5, a2 + + /* + * Register allocation for code below: + * a0 - start of uncopied dst + * a1 - start of uncopied src + * a2 - size + * t0 - end of uncopied dst + */ + add t0, a0, a2 + bgtu a0, t0, 5f + +.Lbyte_copy_tail: + /* + * Byte copy anything left. + * + * a0 - start of remaining dst + * a1 - start of remaining src + * t0 - end of remaining dst + */ + bgeu a0, t0, 5f +4: + fixup lb a5, 0(a1), 10f + addi a1, a1, 1 /* src */ + fixup sb a5, 0(a0), 10f + addi a0, a0, 1 /* dst */ + bltu a0, t0, 4b /* t0 - end of dst */ + +5: /* Disable access to user memory */ csrc CSR_STATUS, t6 - li a0, 0 + li a0, 0 ret ENDPROC(__asm_copy_to_user) ENDPROC(__asm_copy_from_user) @@ -77,7 +107,7 @@ EXPORT_SYMBOL(__clear_user) 10: /* Disable access to user memory */ csrs CSR_STATUS, t6 - mv a0, a2 + mv a0, t5 ret 11: csrs CSR_STATUS, t6 -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Akira Tsukamoto <akira.tsukamoto@gmail.com> To: Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: [PATCH 2/5] riscv: __asm_to/copy_from_user: Adding byte copy first Date: Sat, 19 Jun 2021 20:35:39 +0900 [thread overview] Message-ID: <98088fde-cdb2-6410-8d11-7c8ca984d3c3@gmail.com> (raw) In-Reply-To: <5a5c07ac-8c11-79d3-46a3-a255d4148f76@gmail.com> Typical load and store loop. It is used for mainly copying the remainder in one byte at a time. Signed-off-by: Akira Tsukamoto <akira.tsukamoto@gmail.com> --- arch/riscv/lib/uaccess.S | 34 ++++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S index da9536e1e9cb..be1810077f9a 100644 --- a/arch/riscv/lib/uaccess.S +++ b/arch/riscv/lib/uaccess.S @@ -19,9 +19,39 @@ ENTRY(__asm_copy_from_user) li t6, SR_SUM csrs CSR_STATUS, t6 + /* Save for return value */ + mv t5, a2 + + /* + * Register allocation for code below: + * a0 - start of uncopied dst + * a1 - start of uncopied src + * a2 - size + * t0 - end of uncopied dst + */ + add t0, a0, a2 + bgtu a0, t0, 5f + +.Lbyte_copy_tail: + /* + * Byte copy anything left. + * + * a0 - start of remaining dst + * a1 - start of remaining src + * t0 - end of remaining dst + */ + bgeu a0, t0, 5f +4: + fixup lb a5, 0(a1), 10f + addi a1, a1, 1 /* src */ + fixup sb a5, 0(a0), 10f + addi a0, a0, 1 /* dst */ + bltu a0, t0, 4b /* t0 - end of dst */ + +5: /* Disable access to user memory */ csrc CSR_STATUS, t6 - li a0, 0 + li a0, 0 ret ENDPROC(__asm_copy_to_user) ENDPROC(__asm_copy_from_user) @@ -77,7 +107,7 @@ EXPORT_SYMBOL(__clear_user) 10: /* Disable access to user memory */ csrs CSR_STATUS, t6 - mv a0, a2 + mv a0, t5 ret 11: csrs CSR_STATUS, t6 -- 2.17.1 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2021-06-19 11:35 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-19 11:21 [PATCH v2 0/5] riscv: improving uaccess with logs from network bench Akira Tsukamoto 2021-06-19 11:21 ` Akira Tsukamoto 2021-06-19 11:34 ` [PATCH 1/5] riscv: __asm_to/copy_from_user: delete existing code Akira Tsukamoto 2021-06-19 11:34 ` Akira Tsukamoto 2021-06-21 11:45 ` David Laight 2021-06-21 11:45 ` David Laight 2021-06-21 13:55 ` Akira Tsukamoto 2021-06-21 13:55 ` Akira Tsukamoto 2021-06-19 11:35 ` Akira Tsukamoto [this message] 2021-06-19 11:35 ` [PATCH 2/5] riscv: __asm_to/copy_from_user: Adding byte copy first Akira Tsukamoto 2021-06-19 11:36 ` [PATCH 3/5] riscv: __asm_to/copy_from_user: Copy until dst is aligned Akira Tsukamoto 2021-06-19 11:36 ` Akira Tsukamoto 2021-06-19 11:37 ` [PATCH 4/5] riscv: __asm_to/copy_from_user: Bulk copy while shifting Akira Tsukamoto 2021-06-19 11:37 ` Akira Tsukamoto 2021-06-19 11:43 ` [PATCH 5/5] riscv: __asm_to/copy_from_user: Bulk copy when both src, dst are aligned Akira Tsukamoto 2021-06-19 11:43 ` Akira Tsukamoto 2021-06-21 11:55 ` David Laight 2021-06-21 11:55 ` David Laight 2021-06-21 14:13 ` Akira Tsukamoto 2021-06-21 14:13 ` Akira Tsukamoto 2021-06-20 10:02 ` [PATCH v2 0/5] riscv: improving uaccess with logs from network bench Ben Dooks 2021-06-20 10:02 ` Ben Dooks 2021-06-20 16:36 ` Akira Tsukamoto 2021-06-20 16:36 ` Akira Tsukamoto 2021-06-22 8:30 ` Ben Dooks 2021-06-22 8:30 ` Ben Dooks 2021-06-22 12:05 ` Akira Tsukamoto 2021-06-22 12:05 ` Akira Tsukamoto 2021-06-22 17:45 ` Ben Dooks 2021-06-22 17:45 ` Ben Dooks 2021-07-12 21:24 ` Ben Dooks 2021-07-12 21:24 ` Ben Dooks
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