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| author | Zeng Chi <zengchi@kylinos.cn> | 2026-09-21 18:24:42 +0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-09-22 08:36:16 -0700 |
| commit | 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d (patch) | |
| tree | 660d50d4139cb750fbde1ae3432452c20726c99d /arch/riscv/lib/memcpy.S | |
| download | linux-stable-119e9db233ad0f4cbd4cfb9f9385a7bca378b37d.tar.gz linux-stable-119e9db233ad0f4cbd4cfb9f9385a7bca378b37d.zip | |
KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted
Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.
Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/riscv/lib/memcpy.S')
| -rw-r--r-- | arch/riscv/lib/memcpy.S | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/arch/riscv/lib/memcpy.S b/arch/riscv/lib/memcpy.S new file mode 100644 index 000000000..44e009ec5 --- /dev/null +++ b/arch/riscv/lib/memcpy.S @@ -0,0 +1,110 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2013 Regents of the University of California + */ + +#include <linux/linkage.h> +#include <asm/asm.h> + +/* void *memcpy(void *, const void *, size_t) */ +SYM_FUNC_START(__memcpy) + move t6, a0 /* Preserve return value */ + + /* Defer to byte-oriented copy for small sizes */ + sltiu a3, a2, 128 + bnez a3, 4f + /* Use word-oriented copy only if low-order bits match */ + andi a3, t6, SZREG-1 + andi a4, a1, SZREG-1 + bne a3, a4, 4f + + beqz a3, 2f /* Skip if already aligned */ + /* + * Round to nearest double word-aligned address + * greater than or equal to start address + */ + andi a3, a1, ~(SZREG-1) + addi a3, a3, SZREG + /* Handle initial misalignment */ + sub a4, a3, a1 +1: + lb a5, 0(a1) + addi a1, a1, 1 + sb a5, 0(t6) + addi t6, t6, 1 + bltu a1, a3, 1b + sub a2, a2, a4 /* Update count */ + +2: + andi a4, a2, ~((16*SZREG)-1) + beqz a4, 4f + add a3, a1, a4 +3: + REG_L a4, 0(a1) + REG_L a5, SZREG(a1) + REG_L a6, 2*SZREG(a1) + REG_L a7, 3*SZREG(a1) + REG_L t0, 4*SZREG(a1) + REG_L t1, 5*SZREG(a1) + REG_L t2, 6*SZREG(a1) + REG_L t3, 7*SZREG(a1) + REG_L t4, 8*SZREG(a1) + REG_L t5, 9*SZREG(a1) + REG_S a4, 0(t6) + REG_S a5, SZREG(t6) + REG_S a6, 2*SZREG(t6) + REG_S a7, 3*SZREG(t6) + REG_S t0, 4*SZREG(t6) + REG_S t1, 5*SZREG(t6) + REG_S t2, 6*SZREG(t6) + REG_S t3, 7*SZREG(t6) + REG_S t4, 8*SZREG(t6) + REG_S t5, 9*SZREG(t6) + REG_L a4, 10*SZREG(a1) + REG_L a5, 11*SZREG(a1) + REG_L a6, 12*SZREG(a1) + REG_L a7, 13*SZREG(a1) + REG_L t0, 14*SZREG(a1) + REG_L t1, 15*SZREG(a1) + addi a1, a1, 16*SZREG + REG_S a4, 10*SZREG(t6) + REG_S a5, 11*SZREG(t6) + REG_S a6, 12*SZREG(t6) + REG_S a7, 13*SZREG(t6) + REG_S t0, 14*SZREG(t6) + REG_S t1, 15*SZREG(t6) + addi t6, t6, 16*SZREG + bltu a1, a3, 3b + andi a2, a2, (16*SZREG)-1 /* Update count */ + +4: + /* Handle trailing misalignment */ + beqz a2, 6f + add a3, a1, a2 + + /* Use word-oriented copy if co-aligned to word boundary */ + or a5, a1, t6 + or a5, a5, a3 + andi a5, a5, 3 + bnez a5, 5f +7: + lw a4, 0(a1) + addi a1, a1, 4 + sw a4, 0(t6) + addi t6, t6, 4 + bltu a1, a3, 7b + + ret + +5: + lb a4, 0(a1) + addi a1, a1, 1 + sb a4, 0(t6) + addi t6, t6, 1 + bltu a1, a3, 5b +6: + ret +SYM_FUNC_END(__memcpy) +SYM_FUNC_ALIAS_WEAK(memcpy, __memcpy) +SYM_FUNC_ALIAS(__pi_memcpy, __memcpy) +SYM_FUNC_ALIAS(__pi___memcpy, __memcpy) |