diff options
| author | Heiko Stuebner <heiko.stuebner@vrull.eu> | 2023-01-13 22:23:00 +0100 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2023-01-31 11:43:23 -0800 |
| commit | 56e0790c7f9e59ba6a0f4b59981d1d6fbf43efb0 (patch) | |
| tree | 8ce7a6332c962e62f84c6fcffc7faa88c31b617f /arch/riscv/include/asm/string.h | |
| parent | 61a9b7129070e07c207d89fffbce577223507327 (diff) | |
RISC-V: add infrastructure to allow different str* implementations
Depending on supported extensions on specific RISC-V cores,
optimized str* functions might make sense.
This adds basic infrastructure to allow patching the function calls
via alternatives later on.
The Linux kernel provides standard implementations for string functions
but when architectures want to extend them, they need to provide their
own.
The added generic string functions are done in assembler (taken from
disassembling the main-kernel functions for now) to allow us to control
the used registers and extend them with optimized variants.
This doesn't override the compiler's use of builtin replacements. So still
first of all the compiler will select if a builtin will be better suitable
i.e. for known strings. For all regular cases we will want to later
select possible optimized variants and in the worst case fall back to the
generic implemention added with this change.
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230113212301.3534711-2-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv/include/asm/string.h')
| -rw-r--r-- | arch/riscv/include/asm/string.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/string.h b/arch/riscv/include/asm/string.h index 909049366555..a96b1fea24fe 100644 --- a/arch/riscv/include/asm/string.h +++ b/arch/riscv/include/asm/string.h @@ -18,6 +18,16 @@ extern asmlinkage void *__memcpy(void *, const void *, size_t); #define __HAVE_ARCH_MEMMOVE extern asmlinkage void *memmove(void *, const void *, size_t); extern asmlinkage void *__memmove(void *, const void *, size_t); + +#define __HAVE_ARCH_STRCMP +extern asmlinkage int strcmp(const char *cs, const char *ct); + +#define __HAVE_ARCH_STRLEN +extern asmlinkage __kernel_size_t strlen(const char *); + +#define __HAVE_ARCH_STRNCMP +extern asmlinkage int strncmp(const char *cs, const char *ct, size_t count); + /* For those files which don't want to check by kasan. */ #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__) #define memcpy(dst, src, len) __memcpy(dst, src, len) |