[PATCH V2 1/3] riscv: Add Zicbop instruction definitions & cpufeature

guoren
2023-12-31T08:30:29Z

From: Guo Ren <guoren@linux.alibaba.com>

Cache-block prefetch instructions are HINTs to the hardware to
indicate that software intends to perform a particular type of
memory access in the near future. This patch adds prefetch.i,
prefetch.r and prefetch.w instruction definitions by
RISCV_ISA_EXT_ZICBOP cpufeature.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
arch/riscv/Kconfig | 15 ++++++++
arch/riscv/include/asm/hwcap.h | 1 +
arch/riscv/include/asm/insn-def.h | 60 +++++++++++++++++++++++++++++++
arch/riscv/kernel/cpufeature.c | 1 +
4 files changed, 77 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 24c1799e2ec4..fcbd417d65ea 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -579,6 +579,21 @@ config RISCV_ISA_ZICBOZ

If you don't know what to do here, say Y.

+config RISCV_ISA_ZICBOP
+ bool "Zicbop extension support for cache block prefetch"
+ depends on MMU
+ depends on RISCV_ALTERNATIVE
+ default y
+ help
+ Adds support to dynamically detect the presence of the ZICBOP
+ extension (Cache Block Prefetch Operations) and enable its
+ usage.
+
+ The Zicbop extension can be used to prefetch cache block for
+ read/write fetch.
+
+ If you don't know what to do here, say Y.
+
config TOOLCHAIN_HAS_ZIHINTPAUSE
bool
default y
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 06d30526ef3b..77d3b6ee25ab 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -57,6 +57,7 @@
#define RISCV_ISA_EXT_ZIHPM 42
#define RISCV_ISA_EXT_SMSTATEEN 43
#define RISCV_ISA_EXT_ZICOND 44
+#define RISCV_ISA_EXT_ZICBOP 45

#define RISCV_ISA_EXT_MAX 64

diff --git a/arch/riscv/include/asm/insn-def.h b/arch/riscv/include/asm/insn-def.h
index e27179b26086..bbda350a63bf 100644
--- a/arch/riscv/include/asm/insn-def.h
+++ b/arch/riscv/include/asm/insn-def.h
@@ -18,6 +18,13 @@
#define INSN_I_RD_SHIFT 7
#define INSN_I_OPCODE_SHIFT 0

+#define INSN_S_SIMM7_SHIFT 25
+#define INSN_S_RS2_SHIFT 20
+#define INSN_S_RS1_SHIFT 15
+#define INSN_S_FUNC3_SHIFT 12
+#define INSN_S_SIMM5_SHIFT 7
+#define INSN_S_OPCODE_SHIFT 0
+
#ifdef __ASSEMBLY__

#ifdef CONFIG_AS_HAS_INSN
@@ -30,6 +37,10 @@
.insn i \opcode, \func3, \rd, \rs1, \simm12
.endm

+ .macro insn_s, opcode, func3, rs2, simm12, rs1
+ .insn s \opcode, \func3, \rs2, \simm12(\rs1)
+ .endm
+
#else

#include <asm/gpr-num.h>
@@ -51,10 +62,20 @@
(\simm12 << INSN_I_SIMM12_SHIFT))
.endm

+ .macro insn_s, opcode, func3, rs2, simm12, rs1
+ .4byte ((\opcode << INSN_S_OPCODE_SHIFT) | \
+ (\func3 << INSN_S_FUNC3_SHIFT) | \
+ (.L__gpr_num_\rs2 << INSN_S_RS2_SHIFT) | \
+ (.L__gpr_num_\rs1 << INSN_S_RS1_SHIFT) | \
+ ((\simm12 & 0x1f) << INSN_S_SIMM5_SHIFT) | \
+ (((\simm12 >> 5) & 0x7f) << INSN_S_SIMM7_SHIFT))
+ .endm
+
#endif

#define __INSN_R(...) insn_r __VA_ARGS__
#define __INSN_I(...) insn_i __VA_ARGS__
+#define __INSN_S(...) insn_s __VA_ARGS__

#else /* ! __ASSEMBLY__ */

@@ -66,6 +87,9 @@
#define __INSN_I(opcode, func3, rd, rs1, simm12) \
".insn i " opcode ", " func3 ", " rd ", " rs1 ", " simm12 "\n"

+#define __INSN_S(opcode, func3, rs2, simm12, rs1) \
+ ".insn s " opcode ", " func3 ", " rs2 ", " simm12 "(" rs1 ")\n"
+
#else

#include <linux/stringify.h>
@@ -92,12 +116,26 @@
" (\\simm12 << " __stringify(INSN_I_SIMM12_SHIFT) "))\n" \
" .endm\n"

+#define DEFINE_INSN_S \
+ __DEFINE_ASM_GPR_NUMS \
+" .macro insn_s, opcode, func3, rs2, simm12, rs1\n" \
+" .4byte ((\\opcode << " __stringify(INSN_S_OPCODE_SHIFT) ") |" \
+" (\\func3 << " __stringify(INSN_S_FUNC3_SHIFT) ") |" \
+" (.L__gpr_num_\\rs2 << " __stringify(INSN_S_RS2_SHIFT) ") |" \
+" (.L__gpr_num_\\rs1 << " __stringify(INSN_S_RS1_SHIFT) ") |" \
+" ((\\simm12 & 0x1f) << " __stringify(INSN_S_SIMM5_SHIFT) ") |" \
+" (((\\simm12 >> 5) & 0x7f) << " __stringify(INSN_S_SIMM7_SHIFT) "))\n" \
+" .endm\n"
+
#define UNDEFINE_INSN_R \
" .purgem insn_r\n"

#define UNDEFINE_INSN_I \
" .purgem insn_i\n"

+#define UNDEFINE_INSN_S \
+" .purgem insn_s\n"
+
#define __INSN_R(opcode, func3, func7, rd, rs1, rs2) \
DEFINE_INSN_R \
"insn_r " opcode ", " func3 ", " func7 ", " rd ", " rs1 ", " rs2 "\n" \
@@ -108,6 +146,11 @@
"insn_i " opcode ", " func3 ", " rd ", " rs1 ", " simm12 "\n" \
UNDEFINE_INSN_I

+#define __INSN_S(opcode, func3, rs2, simm12, rs1) \
+ DEFINE_INSN_S \
+ "insn_s " opcode ", " func3 ", " rs2 ", " simm12 ", " rs1 "\n" \
+ UNDEFINE_INSN_S
+
#endif

#endif /* ! __ASSEMBLY__ */
@@ -120,6 +163,10 @@
__INSN_I(RV_##opcode, RV_##func3, RV_##rd, \
RV_##rs1, RV_##simm12)

+#define INSN_S(opcode, func3, rs2, simm12, rs1) \
+ __INSN_S(RV_##opcode, RV_##func3, RV_##rs2, \
+ RV_##simm12, RV_##rs1)
+
#define RV_OPCODE(v) __ASM_STR(v)
#define RV_FUNC3(v) __ASM_STR(v)
#define RV_FUNC7(v) __ASM_STR(v)
@@ -133,6 +180,7 @@
#define RV___RS2(v) __RV_REG(v)

#define RV_OPCODE_MISC_MEM RV_OPCODE(15)
+#define RV_OPCODE_OP_IMM RV_OPCODE(19)
#define RV_OPCODE_SYSTEM RV_OPCODE(115)

#define HFENCE_VVMA(vaddr, asid) \
@@ -196,4 +244,16 @@
INSN_I(OPCODE_MISC_MEM, FUNC3(2), __RD(0), \
RS1(base), SIMM12(4))

+#define CBO_PREFETCH_I(base, offset) \
+ INSN_S(OPCODE_OP_IMM, FUNC3(6), __RS2(0), \
+ SIMM12(offset), RS1(base))
+
+#define CBO_PREFETCH_R(base, offset) \
+ INSN_S(OPCODE_OP_IMM, FUNC3(6), __RS2(1), \
+ SIMM12(offset), RS1(base))
+
+#define CBO_PREFETCH_W(base, offset) \
+ INSN_S(OPCODE_OP_IMM, FUNC3(6), __RS2(3), \
+ SIMM12(offset), RS1(base))
+
#endif /* __ASM_INSN_DEF_H */
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index b3785ffc1570..bdb02b066041 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -168,6 +168,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
__RISCV_ISA_EXT_DATA(h, RISCV_ISA_EXT_h),
__RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
__RISCV_ISA_EXT_DATA(zicboz, RISCV_ISA_EXT_ZICBOZ),
+ __RISCV_ISA_EXT_DATA(zicbop, RISCV_ISA_EXT_ZICBOP),
__RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR),
__RISCV_ISA_EXT_DATA(zicond, RISCV_ISA_EXT_ZICOND),
__RISCV_ISA_EXT_DATA(zicsr, RISCV_ISA_EXT_ZICSR),
--
2.40.1