[PATCH v3 0/4] riscv: Add Zicbop & prefetchw support

[PATCH v3 0/4] riscv: Add Zicbop & prefetchw support

[Alexandre Ghiti]

I found this lost series developed by Guo so here is a respin with the
comments on v2 applied.

This patch series adds Zicbop support and then enables the Linux
prefetch features.

Changelog:
V3:
 - Fix typo (Drew)
 - Split first patch (Drew)
 - Ensure that the bits [0:4] of the prefetch insns are zeroed
 - Move PREFETCHW_ASM out of ifdef (Guo)
 - Remove CBO_ prefix for prefetching insn
 - Add prefetch (Drew)

V2: https://lore.kernel.org/linux-riscv/20231231082955.16516-1-guoren@kernel.org/
 - Separate from the qspinlock series
 - Optimize coding convention with last review advice
 - Add DEFINE_INSN_S type in insn-def.h
 - Add CBO_PREFETCH_I/R/W

V1:
https://lore.kernel.org/linux-riscv/20230910082911.3378782-4-guoren@kernel.org/

Alexandre Ghiti (2):
  riscv: Introduce Zicbop instructions
  riscv: Add support for Zicbop

Guo Ren (2):
  riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop
  riscv: xchg: Prefetch the destination word for sc.w

 arch/riscv/Kconfig                  | 15 +++++++
 arch/riscv/include/asm/barrier.h    |  5 ---
 arch/riscv/include/asm/cacheflush.h |  1 +
 arch/riscv/include/asm/cmpxchg.h    |  4 +-
 arch/riscv/include/asm/hwcap.h      |  1 +
 arch/riscv/include/asm/insn-def.h   | 66 +++++++++++++++++++++++++++++
 arch/riscv/include/asm/processor.h  | 25 ++++++++++-
 arch/riscv/kernel/cpufeature.c      | 21 +++++++++
 arch/riscv/mm/cacheflush.c          | 14 ++++--
 9 files changed, 142 insertions(+), 10 deletions(-)

-- 
2.39.2


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[PATCH v3 1/4] riscv: Introduce Zicbop instructions

[Alexandre Ghiti]

The S-type instructions are first introduced and then used to define the
encoding of the Zicbop prefetching instructions.

Co-developed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/include/asm/insn-def.h | 60 +++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/arch/riscv/include/asm/insn-def.h b/arch/riscv/include/asm/insn-def.h
index 71060a2f838e..02c92c1657d2 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)				\
@@ -196,6 +244,18 @@
 	INSN_I(OPCODE_MISC_MEM, FUNC3(2), __RD(0),		\
 	       RS1(base), SIMM12(4))
 
+#define PREFETCH_I(base, offset)				\
+	INSN_S(OPCODE_OP_IMM, FUNC3(6), __RS2(0),		\
+	       SIMM12((offset) & 0xfe0), RS1(base))
+
+#define PREFETCH_R(base, offset)				\
+	INSN_S(OPCODE_OP_IMM, FUNC3(6), __RS2(1),		\
+	       SIMM12((offset) & 0xfe0), RS1(base))
+
+#define PREFETCH_W(base, offset)				\
+	INSN_S(OPCODE_OP_IMM, FUNC3(6), __RS2(3),		\
+	       SIMM12((offset) & 0xfe0), RS1(base))
+
 #define RISCV_PAUSE	".4byte 0x100000f"
 #define ZAWRS_WRS_NTO	".4byte 0x00d00073"
 #define ZAWRS_WRS_STO	".4byte 0x01d00073"
-- 
2.39.2


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[PATCH v3 2/4] riscv: Add support for Zicbop

[Alexandre Ghiti]

Zicbop introduces cache blocks prefetching instructions, add the
necessary support for the kernel to use it in the coming commits.

Co-developed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/Kconfig                  | 15 +++++++++++++++
 arch/riscv/include/asm/barrier.h    |  5 -----
 arch/riscv/include/asm/cacheflush.h |  1 +
 arch/riscv/include/asm/hwcap.h      |  1 +
 arch/riscv/include/asm/insn-def.h   |  6 ++++++
 arch/riscv/include/asm/processor.h  |  1 -
 arch/riscv/kernel/cpufeature.c      | 21 +++++++++++++++++++++
 arch/riscv/mm/cacheflush.c          | 14 +++++++++++---
 8 files changed, 55 insertions(+), 9 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index bbec87b79309..28765ce563de 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -842,6 +842,21 @@ 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 blocks for
+	  read/write fetch.
+
+	  If you don't know what to do here, say Y.
+
 config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
 	def_bool y
 	# https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
diff --git a/arch/riscv/include/asm/barrier.h b/arch/riscv/include/asm/barrier.h
index e1d9bf1deca6..b8c5726d86ac 100644
--- a/arch/riscv/include/asm/barrier.h
+++ b/arch/riscv/include/asm/barrier.h
@@ -14,11 +14,6 @@
 #include <asm/cmpxchg.h>
 #include <asm/fence.h>
 
-#define nop()		__asm__ __volatile__ ("nop")
-#define __nops(n)	".rept	" #n "\nnop\n.endr\n"
-#define nops(n)		__asm__ __volatile__ (__nops(n))
-
-
 /* These barriers need to enforce ordering on both devices or memory. */
 #define __mb()		RISCV_FENCE(iorw, iorw)
 #define __rmb()		RISCV_FENCE(ir, ir)
diff --git a/arch/riscv/include/asm/cacheflush.h b/arch/riscv/include/asm/cacheflush.h
index 8de73f91bfa3..effa02c2e682 100644
--- a/arch/riscv/include/asm/cacheflush.h
+++ b/arch/riscv/include/asm/cacheflush.h
@@ -80,6 +80,7 @@ void flush_icache_mm(struct mm_struct *mm, bool local);
 
 extern unsigned int riscv_cbom_block_size;
 extern unsigned int riscv_cboz_block_size;
+extern unsigned int riscv_cbop_block_size;
 void riscv_init_cbo_blocksizes(void);
 
 #ifdef CONFIG_RISCV_DMA_NONCOHERENT
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index e3cbf203cdde..affd63e11b0a 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -105,6 +105,7 @@
 #define RISCV_ISA_EXT_ZVFBFWMA		96
 #define RISCV_ISA_EXT_ZAAMO		97
 #define RISCV_ISA_EXT_ZALRSC		98
+#define RISCV_ISA_EXT_ZICBOP		99
 
 #define RISCV_ISA_EXT_XLINUXENVCFG	127
 
diff --git a/arch/riscv/include/asm/insn-def.h b/arch/riscv/include/asm/insn-def.h
index 02c92c1657d2..d5adbaec1d01 100644
--- a/arch/riscv/include/asm/insn-def.h
+++ b/arch/riscv/include/asm/insn-def.h
@@ -263,4 +263,10 @@
 
 #define RISCV_INSN_NOP4	_AC(0x00000013, U)
 
+#ifndef __ASSEMBLY__
+#define nop()           __asm__ __volatile__ ("nop")
+#define __nops(n)       ".rept  " #n "\nnop\n.endr\n"
+#define nops(n)         __asm__ __volatile__ (__nops(n))
+#endif
+
 #endif /* __ASM_INSN_DEF_H */
diff --git a/arch/riscv/include/asm/processor.h b/arch/riscv/include/asm/processor.h
index 5f56eb9d114a..09d4c963399a 100644
--- a/arch/riscv/include/asm/processor.h
+++ b/arch/riscv/include/asm/processor.h
@@ -52,7 +52,6 @@
 #endif
 
 #ifndef __ASSEMBLY__
-#include <linux/cpumask.h>
 
 struct task_struct;
 struct pt_regs;
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 2054f6c4b0ae..743d53415572 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -32,6 +32,7 @@
 #define NUM_ALPHA_EXTS ('z' - 'a' + 1)
 
 static bool any_cpu_has_zicboz;
+static bool any_cpu_has_zicbop;
 static bool any_cpu_has_zicbom;
 
 unsigned long elf_hwcap __read_mostly;
@@ -119,6 +120,21 @@ static int riscv_ext_zicboz_validate(const struct riscv_isa_ext_data *data,
 	return 0;
 }
 
+static int riscv_ext_zicbop_validate(const struct riscv_isa_ext_data *data,
+				     const unsigned long *isa_bitmap)
+{
+	if (!riscv_cbop_block_size) {
+		pr_err("Zicbop detected in ISA string, disabling as no cbop-block-size found\n");
+		return -EINVAL;
+	}
+	if (!is_power_of_2(riscv_cbop_block_size)) {
+		pr_err("Zicbop disabled as cbop-block-size present, but is not a power-of-2\n");
+		return -EINVAL;
+	}
+	any_cpu_has_zicbop = true;
+	return 0;
+}
+
 static int riscv_ext_f_validate(const struct riscv_isa_ext_data *data,
 				const unsigned long *isa_bitmap)
 {
@@ -442,6 +458,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_SUPERSET_VALIDATE(v, RISCV_ISA_EXT_v, riscv_v_exts, riscv_ext_vector_float_validate),
 	__RISCV_ISA_EXT_DATA(h, RISCV_ISA_EXT_h),
 	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicbom, RISCV_ISA_EXT_ZICBOM, riscv_xlinuxenvcfg_exts, riscv_ext_zicbom_validate),
+	__RISCV_ISA_EXT_DATA_VALIDATE(zicbop, RISCV_ISA_EXT_ZICBOP, riscv_ext_zicbop_validate),
 	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicboz, RISCV_ISA_EXT_ZICBOZ, riscv_xlinuxenvcfg_exts, riscv_ext_zicboz_validate),
 	__RISCV_ISA_EXT_DATA(ziccrse, RISCV_ISA_EXT_ZICCRSE),
 	__RISCV_ISA_EXT_DATA(zicntr, RISCV_ISA_EXT_ZICNTR),
@@ -1112,6 +1129,10 @@ void __init riscv_user_isa_enable(void)
 		current->thread.envcfg |= ENVCFG_CBCFE;
 	else if (any_cpu_has_zicbom)
 		pr_warn("Zicbom disabled as it is unavailable on some harts\n");
+
+	if (!riscv_has_extension_unlikely(RISCV_ISA_EXT_ZICBOP) &&
+	    any_cpu_has_zicbop)
+		pr_warn("Zicbop disabled as it is unavailable on some harts\n");
 }
 
 #ifdef CONFIG_RISCV_ALTERNATIVE
diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index b81672729887..6265052ef8b6 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -101,6 +101,9 @@ EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
 unsigned int riscv_cboz_block_size;
 EXPORT_SYMBOL_GPL(riscv_cboz_block_size);
 
+unsigned int riscv_cbop_block_size;
+EXPORT_SYMBOL_GPL(riscv_cbop_block_size);
+
 static void __init cbo_get_block_size(struct device_node *node,
 				      const char *name, u32 *block_size,
 				      unsigned long *first_hartid)
@@ -125,8 +128,8 @@ static void __init cbo_get_block_size(struct device_node *node,
 
 void __init riscv_init_cbo_blocksizes(void)
 {
-	unsigned long cbom_hartid, cboz_hartid;
-	u32 cbom_block_size = 0, cboz_block_size = 0;
+	unsigned long cbom_hartid, cboz_hartid, cbop_hartid;
+	u32 cbom_block_size = 0, cboz_block_size = 0, cbop_block_size = 0;
 	struct device_node *node;
 	struct acpi_table_header *rhct;
 	acpi_status status;
@@ -138,13 +141,15 @@ void __init riscv_init_cbo_blocksizes(void)
 					   &cbom_block_size, &cbom_hartid);
 			cbo_get_block_size(node, "riscv,cboz-block-size",
 					   &cboz_block_size, &cboz_hartid);
+			cbo_get_block_size(node, "riscv,cbop-block-size",
+					   &cbop_block_size, &cbop_hartid);
 		}
 	} else {
 		status = acpi_get_table(ACPI_SIG_RHCT, 0, &rhct);
 		if (ACPI_FAILURE(status))
 			return;
 
-		acpi_get_cbo_block_size(rhct, &cbom_block_size, &cboz_block_size, NULL);
+		acpi_get_cbo_block_size(rhct, &cbom_block_size, &cboz_block_size, &cbop_block_size);
 		acpi_put_table((struct acpi_table_header *)rhct);
 	}
 
@@ -153,6 +158,9 @@ void __init riscv_init_cbo_blocksizes(void)
 
 	if (cboz_block_size)
 		riscv_cboz_block_size = cboz_block_size;
+
+	if (cbop_block_size)
+		riscv_cbop_block_size = cbop_block_size;
 }
 
 #ifdef CONFIG_SMP
-- 
2.39.2


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[PATCH v3 3/4] riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop

[Alexandre Ghiti]

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

Enable Linux prefetch and prefetchw primitives using Zicbop.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20231231082955.16516-3-guoren@kernel.org
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 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 <vdso/processor.h>
 
 #include <asm/ptrace.h>
+#include <asm/insn-def.h>
+#include <asm/alternative-macros.h>
+#include <asm/hwcap.h>
 
 #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,
-- 
2.39.2


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[PATCH v3 4/4] riscv: xchg: Prefetch the destination word for sc.w

[Alexandre Ghiti]

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

The cost of changing a cacheline from shared to exclusive state can be
significant, especially when this is triggered by an exclusive store,
since it may result in having to retry the transaction.

This patch makes use of prefetch.w to prefetch cachelines for write
prior to lr/sc loops when using the xchg_small atomic routine.

This patch is inspired by commit 0ea366f5e1b6 ("arm64: atomics:
prefetch the destination word for write prior to stxr").

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20231231082955.16516-4-guoren@kernel.org
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 arch/riscv/include/asm/cmpxchg.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h
index 2ec119eb147b..0b749e710216 100644
--- a/arch/riscv/include/asm/cmpxchg.h
+++ b/arch/riscv/include/asm/cmpxchg.h
@@ -13,6 +13,7 @@
 #include <asm/hwcap.h>
 #include <asm/insn-def.h>
 #include <asm/cpufeature-macros.h>
+#include <asm/processor.h>
 
 #define __arch_xchg_masked(sc_sfx, swap_sfx, prepend, sc_append,		\
 			   swap_append, r, p, n)				\
@@ -37,6 +38,7 @@
 										\
 		__asm__ __volatile__ (						\
 		       prepend							\
+		       PREFETCHW_ASM(%5)					\
 		       "0:	lr.w %0, %2\n"					\
 		       "	and  %1, %0, %z4\n"				\
 		       "	or   %1, %1, %z3\n"				\
@@ -44,7 +46,7 @@
 		       "	bnez %1, 0b\n"					\
 		       sc_append						\
 		       : "=&r" (__retx), "=&r" (__rc), "+A" (*(__ptr32b))	\
-		       : "rJ" (__newx), "rJ" (~__mask)				\
+		       : "rJ" (__newx), "rJ" (~__mask), "rJ" (__ptr32b)		\
 		       : "memory");						\
 										\
 		r = (__typeof__(*(p)))((__retx & __mask) >> __s);		\
-- 
2.39.2


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Re: [PATCH v3 0/4] riscv: Add Zicbop & prefetchw support

[Andrea Parri]

> Alexandre Ghiti (2):
>   riscv: Introduce Zicbop instructions
>   riscv: Add support for Zicbop
> 
> Guo Ren (2):
>   riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop
>   riscv: xchg: Prefetch the destination word for sc.w

For this series,

Tested-by: Andrea Parri <parri.andrea@gmail.com>

  Andrea

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Re: [PATCH v3 0/4] riscv: Add Zicbop & prefetchw support

[patchwork-bot+linux-riscv]

Hello:

This series was applied to riscv/linux.git (for-next)
by Alexandre Ghiti <alexghiti@rivosinc.com>:

On Mon, 21 Apr 2025 16:24:37 +0200 you wrote:
> I found this lost series developed by Guo so here is a respin with the
> comments on v2 applied.
> 
> This patch series adds Zicbop support and then enables the Linux
> prefetch features.
> 
> Changelog:
> V3:
>  - Fix typo (Drew)
>  - Split first patch (Drew)
>  - Ensure that the bits [0:4] of the prefetch insns are zeroed
>  - Move PREFETCHW_ASM out of ifdef (Guo)
>  - Remove CBO_ prefix for prefetching insn
>  - Add prefetch (Drew)
> 
> [...]

Here is the summary with links:
  - [v3,1/4] riscv: Introduce Zicbop instructions
    https://git.kernel.org/riscv/c/b81f148e583b
  - [v3,2/4] riscv: Add support for Zicbop
    https://git.kernel.org/riscv/c/120068a68961
  - [v3,3/4] riscv: Add ARCH_HAS_PREFETCH[W] support with Zicbop
    https://git.kernel.org/riscv/c/46a47d7a42bb
  - [v3,4/4] riscv: xchg: Prefetch the destination word for sc.w
    https://git.kernel.org/riscv/c/993d2e054b05

You are awesome, thank you!
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