From a5f947c73115efb6fb0d9579e71ce1ee5cf706aa Mon Sep 17 00:00:00 2001 From: Guo Ren Date: Mon, 21 Apr 2025 16:24:40 +0200 Subject: [PATCH] riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop Enable Linux prefetch and prefetchw primitives using Zicbop. Signed-off-by: Guo Ren Signed-off-by: Guo Ren Link: https://lore.kernel.org/r/20231231082955.16516-3-guoren@kernel.org Tested-by: Andrea Parri Link: https://lore.kernel.org/r/20250421142441.395849-4-alexghiti@rivosinc.com Signed-off-by: Alexandre Ghiti Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/processor.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h index 09d4c963399a..39dfab495a4c 100644 --- a/arch/riscv/include/asm/processor.h +++ b/arch/riscv/include/asm/processor.h @@ -13,6 +13,9 @@ #include #include +#include +#include +#include #define arch_get_mmap_end(addr, len, flags) \ ({ \ @@ -135,6 +138,27 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset, #define KSTK_EIP(tsk) (task_pt_regs(tsk)->epc) #define KSTK_ESP(tsk) (task_pt_regs(tsk)->sp) +#define PREFETCH_ASM(x) \ + ALTERNATIVE(__nops(1), PREFETCH_R(x, 0), 0, \ + RISCV_ISA_EXT_ZICBOP, CONFIG_RISCV_ISA_ZICBOP) + +#define PREFETCHW_ASM(x) \ + ALTERNATIVE(__nops(1), PREFETCH_W(x, 0), 0, \ + RISCV_ISA_EXT_ZICBOP, CONFIG_RISCV_ISA_ZICBOP) + +#ifdef CONFIG_RISCV_ISA_ZICBOP +#define ARCH_HAS_PREFETCH +static inline void prefetch(const void *x) +{ + __asm__ __volatile__(PREFETCH_ASM(%0) : : "r" (x) : "memory"); +} + +#define ARCH_HAS_PREFETCHW +static inline void prefetchw(const void *x) +{ + __asm__ __volatile__(PREFETCHW_ASM(%0) : : "r" (x) : "memory"); +} +#endif /* CONFIG_RISCV_ISA_ZICBOP */ /* Do necessary setup to start up a newly executed thread. */ extern void start_thread(struct pt_regs *regs, -- 2.20.1