Author: markj Date: Mon Jan 21 19:38:53 2019 New Revision: 343275 URL: https://svnweb.freebsd.org/changeset/base/343275
Log: Optimize RISC-V copyin(9)/copyout(9) routines. The existing copyin(9) and copyout(9) routines on RISC-V perform only a simple byte-by-byte copy. Improve their performance by performing word-sized copies where possible. Submitted by: Mitchell Horne <mhorne...@gmail.com> MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D18851 Modified: head/sys/riscv/include/riscvreg.h head/sys/riscv/riscv/copyinout.S Modified: head/sys/riscv/include/riscvreg.h ============================================================================== --- head/sys/riscv/include/riscvreg.h Mon Jan 21 19:37:12 2019 (r343274) +++ head/sys/riscv/include/riscvreg.h Mon Jan 21 19:38:53 2019 (r343275) @@ -155,7 +155,8 @@ #define SATP_MODE_SV39 (8ULL << SATP_MODE_S) #define SATP_MODE_SV48 (9ULL << SATP_MODE_S) -#define XLEN 8 +#define XLEN __riscv_xlen +#define XLEN_BYTES (XLEN / 8) #define INSN_SIZE 4 #define INSN_C_SIZE 2 Modified: head/sys/riscv/riscv/copyinout.S ============================================================================== --- head/sys/riscv/riscv/copyinout.S Mon Jan 21 19:37:12 2019 (r343274) +++ head/sys/riscv/riscv/copyinout.S Mon Jan 21 19:38:53 2019 (r343275) @@ -1,5 +1,6 @@ /*- * Copyright (c) 2015-2018 Ruslan Bukin <b...@bsdpad.com> + * Copyright (c) 2019 Mitchell Horne * All rights reserved. * * Portions of this software were developed by SRI International and the @@ -59,19 +60,52 @@ END(copyio_fault) * a2 - Size of copy */ .macro copycommon - la a6, copyio_fault /* Get the handler address */ - SET_FAULT_HANDLER(a6, a7) /* Set the handler */ + la a6, copyio_fault /* Get the handler address */ + SET_FAULT_HANDLER(a6, a7) /* Set the handler */ ENTER_USER_ACCESS(a7) -1: lb a4, 0(a0) /* Load from src */ + li t2, XLEN_BYTES + blt a2, t2, 3f /* Byte-copy if len < XLEN_BYTES */ + + /* + * Compare lower bits of src and dest. + * If they are aligned with each other, we can do word copy. + */ + andi t0, a0, (XLEN_BYTES-1) /* Low bits of src */ + andi t1, a1, (XLEN_BYTES-1) /* Low bits of dest */ + bne t0, t1, 3f /* Misaligned. Go to byte copy */ + beqz t0, 2f /* Already word-aligned, skip ahead */ + + /* Byte copy until the first word-aligned address */ +1: lb a4, 0(a0) /* Load byte from src */ addi a0, a0, 1 - sb a4, 0(a1) /* Store in dest */ + sb a4, 0(a1) /* Store byte in dest */ addi a1, a1, 1 - addi a2, a2, -1 /* len-- */ - bnez a2, 1b + addi a2, a2, -1 /* len-- */ + andi t0, a0, (XLEN_BYTES-1) + bnez t0, 1b - EXIT_USER_ACCESS(a7) - SET_FAULT_HANDLER(x0, a7) /* Clear the handler */ + /* Copy words */ +2: ld a4, 0(a0) /* Load word from src */ + addi a0, a0, XLEN_BYTES + sd a4, 0(a1) /* Store word in dest */ + addi a1, a1, XLEN_BYTES + addi a2, a2, -XLEN_BYTES /* len -= XLEN_BYTES */ + bgeu a2, t2, 2b /* Again if len >= XLEN_BYTES */ + + /* Check if we're finished */ + beqz a2, 4f + + /* Copy any remaining bytes */ +3: lb a4, 0(a0) /* Load byte from src */ + addi a0, a0, 1 + sb a4, 0(a1) /* Store byte in dest */ + addi a1, a1, 1 + addi a2, a2, -1 /* len-- */ + bnez a2, 3b + +4: EXIT_USER_ACCESS(a7) + SET_FAULT_HANDLER(x0, a7) /* Clear the handler */ .endm /* _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
