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 3/5] riscv: __asm_to/copy_from_user: Copy until dst is aligned Date: Sat, 19 Jun 2021 20:36:49 +0900 [thread overview] Message-ID: <d2efdd2e-c094-0475-d030-08eaa7efe917@gmail.com> (raw) In-Reply-To: <5a5c07ac-8c11-79d3-46a3-a255d4148f76@gmail.com> First copy in bytes until reaches the first word aligned boundary in destination memory address. For speeding up the copy, trying to avoid both the unaligned memory access and byte access are the key. This is the preparation before the bulk aligned word copy. Signed-off-by: Akira Tsukamoto <akira.tsukamoto@gmail.com> --- arch/riscv/lib/uaccess.S | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S index be1810077f9a..4906b5ca91c3 100644 --- a/arch/riscv/lib/uaccess.S +++ b/arch/riscv/lib/uaccess.S @@ -32,6 +32,34 @@ ENTRY(__asm_copy_from_user) add t0, a0, a2 bgtu a0, t0, 5f + /* + * Use byte copy only if too small. + */ + li a3, 8*SZREG /* size must be larger than size in word_copy */ + bltu a2, a3, .Lbyte_copy_tail + + /* + * Copy first bytes until dst is align to word boundary. + * a0 - start of dst + * t1 - start of aligned dst + */ + addi t1, a0, SZREG-1 + andi t1, t1, ~(SZREG-1) + /* dst is already aligned, skip */ + beq a0, t1, .Lskip_first_bytes +1: + /* a5 - one byte for copying data */ + fixup lb a5, 0(a1), 10f + addi a1, a1, 1 /* src */ + fixup sb a5, 0(a0), 10f + addi a0, a0, 1 /* dst */ + bltu a0, t1, 1b /* t1 - start of aligned dst */ + +.Lskip_first_bytes: + +.Lword_copy: +.Lshift_copy: + .Lbyte_copy_tail: /* * Byte copy anything left. -- 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 3/5] riscv: __asm_to/copy_from_user: Copy until dst is aligned Date: Sat, 19 Jun 2021 20:36:49 +0900 [thread overview] Message-ID: <d2efdd2e-c094-0475-d030-08eaa7efe917@gmail.com> (raw) In-Reply-To: <5a5c07ac-8c11-79d3-46a3-a255d4148f76@gmail.com> First copy in bytes until reaches the first word aligned boundary in destination memory address. For speeding up the copy, trying to avoid both the unaligned memory access and byte access are the key. This is the preparation before the bulk aligned word copy. Signed-off-by: Akira Tsukamoto <akira.tsukamoto@gmail.com> --- arch/riscv/lib/uaccess.S | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/arch/riscv/lib/uaccess.S b/arch/riscv/lib/uaccess.S index be1810077f9a..4906b5ca91c3 100644 --- a/arch/riscv/lib/uaccess.S +++ b/arch/riscv/lib/uaccess.S @@ -32,6 +32,34 @@ ENTRY(__asm_copy_from_user) add t0, a0, a2 bgtu a0, t0, 5f + /* + * Use byte copy only if too small. + */ + li a3, 8*SZREG /* size must be larger than size in word_copy */ + bltu a2, a3, .Lbyte_copy_tail + + /* + * Copy first bytes until dst is align to word boundary. + * a0 - start of dst + * t1 - start of aligned dst + */ + addi t1, a0, SZREG-1 + andi t1, t1, ~(SZREG-1) + /* dst is already aligned, skip */ + beq a0, t1, .Lskip_first_bytes +1: + /* a5 - one byte for copying data */ + fixup lb a5, 0(a1), 10f + addi a1, a1, 1 /* src */ + fixup sb a5, 0(a0), 10f + addi a0, a0, 1 /* dst */ + bltu a0, t1, 1b /* t1 - start of aligned dst */ + +.Lskip_first_bytes: + +.Lword_copy: +.Lshift_copy: + .Lbyte_copy_tail: /* * Byte copy anything left. -- 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 11:36 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 ` [PATCH 2/5] riscv: __asm_to/copy_from_user: Adding byte copy first Akira Tsukamoto 2021-06-19 11:35 ` Akira Tsukamoto 2021-06-19 11:36 ` Akira Tsukamoto [this message] 2021-06-19 11:36 ` [PATCH 3/5] riscv: __asm_to/copy_from_user: Copy until dst is aligned Akira Tsukamoto 2021-06-19 11:37 ` [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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