There are some features which need this string operation for compilation, like KASAN. So the purpose of this porting is for the features like KASAN which cannot be compiled without it.
KASAN's string operations would replace the original string operations and call for the architecture defined string operations. Since we don't have this in current kernel, this patch provides the implementation. This porting refers to the 'arch/nds32/lib/memmove.S'. Signed-off-by: Nick Hu <nic...@andestech.com> --- arch/riscv/include/asm/string.h | 3 ++ arch/riscv/kernel/riscv_ksyms.c | 1 + arch/riscv/lib/Makefile | 1 + arch/riscv/lib/memmove.S | 63 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 68 insertions(+), 0 deletions(-) create mode 100644 arch/riscv/lib/memmove.S diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h index 1b5d445..11210f1 100644 --- a/arch/riscv/include/asm/string.h +++ b/arch/riscv/include/asm/string.h @@ -15,4 +15,7 @@ #define __HAVE_ARCH_MEMCPY extern asmlinkage void *memcpy(void *, const void *, size_t); +#define __HAVE_ARCH_MEMMOVE +extern asmlinkage void *memmove(void *, const void *, size_t); + #endif /* _ASM_RISCV_STRING_H */ diff --git a/arch/riscv/kernel/riscv_ksyms.c b/arch/riscv/kernel/riscv_ksyms.c index 4800cf7..ffabaf1 100644 --- a/arch/riscv/kernel/riscv_ksyms.c +++ b/arch/riscv/kernel/riscv_ksyms.c @@ -14,3 +14,4 @@ EXPORT_SYMBOL(__asm_copy_from_user); EXPORT_SYMBOL(memset); EXPORT_SYMBOL(memcpy); +EXPORT_SYMBOL(memmove); diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile index 8e364eb..9a4d5b3 100644 --- a/arch/riscv/lib/Makefile +++ b/arch/riscv/lib/Makefile @@ -2,6 +2,7 @@ lib-y += delay.o lib-y += memcpy.o lib-y += memset.o +lib-y += memmove.o lib-y += uaccess.o lib-$(CONFIG_64BIT) += tishift.o diff --git a/arch/riscv/lib/memmove.S b/arch/riscv/lib/memmove.S new file mode 100644 index 0000000..3657a06 --- /dev/null +++ b/arch/riscv/lib/memmove.S @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include <linux/linkage.h> +#include <asm/asm.h> + +ENTRY(memmove) + move t0, a0 + move t1, a1 + + beq a0, a1, exit_memcpy + beqz a2, exit_memcpy + srli t2, a2, 0x2 + + slt t3, a0, a1 + beqz t3, do_reverse + + andi a2, a2, 0x3 + li t4, 1 + beqz t2, byte_copy + +word_copy: + lw t3, 0(a1) + addi t2, t2, -1 + addi a1, a1, 4 + sw t3, 0(a0) + addi a0, a0, 4 + bnez t2, word_copy + beqz a2, exit_memcpy + j byte_copy + +do_reverse: + add a0, a0, a2 + add a1, a1, a2 + andi a2, a2, 0x3 + li t4, -1 + beqz t2, reverse_byte_copy + +reverse_word_copy: + addi a1, a1, -4 + addi t2, t2, -1 + lw t3, 0(a1) + addi a0, a0, -4 + sw t3, 0(a0) + bnez t2, reverse_word_copy + beqz a2, exit_memcpy + +reverse_byte_copy: + addi a0, a0, -1 + addi a1, a1, -1 +byte_copy: + lb t3, 0(a1) + addi a2, a2, -1 + sb t3, 0(a0) + add a1, a1, t4 + add a0, a0, t4 + bnez a2, byte_copy + +exit_memcpy: + move a0, t0 + move a1, t1 + ret + +END(memmove) -- 1.7.1
