diff options
Diffstat (limited to 'arch/riscv/lib/clear_page.S')
| -rw-r--r-- | arch/riscv/lib/clear_page.S | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/arch/riscv/lib/clear_page.S b/arch/riscv/lib/clear_page.S new file mode 100644 index 000000000000..20ff03f5b0f2 --- /dev/null +++ b/arch/riscv/lib/clear_page.S @@ -0,0 +1,74 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2023 Ventana Micro Systems Inc. + */ + +#include <linux/linkage.h> +#include <linux/export.h> +#include <asm/asm.h> +#include <asm/alternative-macros.h> +#include <asm/hwcap.h> +#include <asm/insn-def.h> +#include <asm/page.h> + +#define CBOZ_ALT(order, old, new) \ + ALTERNATIVE(old, new, 0, \ + ((order) << 16) | RISCV_ISA_EXT_ZICBOZ, \ + CONFIG_RISCV_ISA_ZICBOZ) + +/* void clear_page(void *page) */ +SYM_FUNC_START(clear_page) + li a2, PAGE_SIZE + + /* + * If Zicboz isn't present, or somehow has a block + * size larger than 4K, then fallback to memset. + */ + CBOZ_ALT(12, "j .Lno_zicboz", "nop") + + lw a1, riscv_cboz_block_size + add a2, a0, a2 +.Lzero_loop: + CBO_ZERO(a0) + add a0, a0, a1 + CBOZ_ALT(11, "bltu a0, a2, .Lzero_loop; ret", "nop; nop") + CBO_ZERO(a0) + add a0, a0, a1 + CBOZ_ALT(10, "bltu a0, a2, .Lzero_loop; ret", "nop; nop") + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBOZ_ALT(9, "bltu a0, a2, .Lzero_loop; ret", "nop; nop") + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBOZ_ALT(8, "bltu a0, a2, .Lzero_loop; ret", "nop; nop") + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + CBO_ZERO(a0) + add a0, a0, a1 + bltu a0, a2, .Lzero_loop + ret +.Lno_zicboz: + li a1, 0 + tail __memset +SYM_FUNC_END(clear_page) +EXPORT_SYMBOL(clear_page) |