[PATCH v4 00/10] riscv: Add Zalasr ISA extension support

[PATCH v4 00/10] riscv: Add Zalasr ISA extension support

[Xu Lu]

This patch adds support for the Zalasr ISA extension, which supplies the
real load acquire/store release instructions.

The specification can be found here:
https://github.com/riscv/riscv-zalasr/blob/main/chapter2.adoc

This patch seires has been tested with ltp on Qemu with Brensan's zalasr
support patch[1].

Some false positive spacing error happens during patch checking. Thus I
CCed maintainers of checkpatch.pl as well.

[1] https://lore.kernel.org/all/CAGPSXwJEdtqW=nx71oufZp64nK6tK=0rytVEcz4F-gfvCOXk2w@mail.gmail.com/

v4:
 - Apply acquire/release semantics to arch_atomic operations. Thanks
 to Andrea.

v3:
 - Apply acquire/release semantics to arch_xchg/arch_cmpxchg operations
 so as to ensure FENCE.TSO ordering between operations which precede the
 UNLOCK+LOCK sequence and operations which follow the sequence. Thanks
 to Andrea.
 - Support hwprobe of Zalasr.
 - Allow Zalasr extensions for Guest/VM.

v2:
 - Adjust the order of Zalasr and Zalrsc in dt-bindings. Thanks to
 Conor.

Xu Lu (10):
  riscv: Add ISA extension parsing for Zalasr
  dt-bindings: riscv: Add Zalasr ISA extension description
  riscv: hwprobe: Export Zalasr extension
  riscv: Introduce Zalasr instructions
  riscv: Apply Zalasr to smp_load_acquire/smp_store_release
  riscv: Apply acquire/release semantics to arch_xchg/arch_cmpxchg
    operations
  riscv: Apply acquire/release semantics to arch_atomic operations
  riscv: Remove arch specific __atomic_acquire/release_fence
  RISC-V: KVM: Allow Zalasr extensions for Guest/VM
  RISC-V: KVM: selftests: Add Zalasr extensions to get-reg-list test

 Documentation/arch/riscv/hwprobe.rst          |   5 +-
 .../devicetree/bindings/riscv/extensions.yaml |   5 +
 arch/riscv/include/asm/atomic.h               |  70 ++++++++-
 arch/riscv/include/asm/barrier.h              |  91 +++++++++--
 arch/riscv/include/asm/cmpxchg.h              | 144 +++++++++---------
 arch/riscv/include/asm/fence.h                |   4 -
 arch/riscv/include/asm/hwcap.h                |   1 +
 arch/riscv/include/asm/insn-def.h             |  79 ++++++++++
 arch/riscv/include/uapi/asm/hwprobe.h         |   1 +
 arch/riscv/include/uapi/asm/kvm.h             |   1 +
 arch/riscv/kernel/cpufeature.c                |   1 +
 arch/riscv/kernel/sys_hwprobe.c               |   1 +
 arch/riscv/kvm/vcpu_onereg.c                  |   2 +
 .../selftests/kvm/riscv/get-reg-list.c        |   4 +
 14 files changed, 314 insertions(+), 95 deletions(-)

-- 
2.20.1

[PATCH v4 01/10] riscv: Add ISA extension parsing for Zalasr

[Xu Lu]

Add parsing for Zalasr ISA extension.

Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
---
 arch/riscv/include/asm/hwcap.h | 1 +
 arch/riscv/kernel/cpufeature.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index affd63e11b0a3..ae3852c4f2ca2 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -106,6 +106,7 @@
 #define RISCV_ISA_EXT_ZAAMO		97
 #define RISCV_ISA_EXT_ZALRSC		98
 #define RISCV_ISA_EXT_ZICBOP		99
+#define RISCV_ISA_EXT_ZALASR		100
 
 #define RISCV_ISA_EXT_XLINUXENVCFG	127
 
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 743d53415572e..bf9d3d92bf372 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -472,6 +472,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA(zaamo, RISCV_ISA_EXT_ZAAMO),
 	__RISCV_ISA_EXT_DATA(zabha, RISCV_ISA_EXT_ZABHA),
 	__RISCV_ISA_EXT_DATA(zacas, RISCV_ISA_EXT_ZACAS),
+	__RISCV_ISA_EXT_DATA(zalasr, RISCV_ISA_EXT_ZALASR),
 	__RISCV_ISA_EXT_DATA(zalrsc, RISCV_ISA_EXT_ZALRSC),
 	__RISCV_ISA_EXT_DATA(zawrs, RISCV_ISA_EXT_ZAWRS),
 	__RISCV_ISA_EXT_DATA(zfa, RISCV_ISA_EXT_ZFA),
-- 
2.20.1

[PATCH v4 02/10] dt-bindings: riscv: Add Zalasr ISA extension description

[Xu Lu]

Add description for the Zalasr ISA extension

Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
---
 Documentation/devicetree/bindings/riscv/extensions.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
index ede6a58ccf534..100fe53fb0731 100644
--- a/Documentation/devicetree/bindings/riscv/extensions.yaml
+++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
@@ -242,6 +242,11 @@ properties:
             is supported as ratified at commit 5059e0ca641c ("update to
             ratified") of the riscv-zacas.
 
+        - const: zalasr
+          description: |
+            The standard Zalasr extension for load-acquire/store-release as frozen
+            at commit 194f0094 ("Version 0.9 for freeze") of riscv-zalasr.
+
         - const: zalrsc
           description: |
             The standard Zalrsc extension for load-reserved/store-conditional as
-- 
2.20.1

[PATCH v4 03/10] riscv: hwprobe: Export Zalasr extension

[Xu Lu]

Export the Zalasr extension to userspace using hwprobe.

Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
---
 Documentation/arch/riscv/hwprobe.rst  | 5 ++++-
 arch/riscv/include/uapi/asm/hwprobe.h | 1 +
 arch/riscv/kernel/sys_hwprobe.c       | 1 +
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
index 2aa9be272d5de..067a3595fb9d5 100644
--- a/Documentation/arch/riscv/hwprobe.rst
+++ b/Documentation/arch/riscv/hwprobe.rst
@@ -249,6 +249,9 @@ The following keys are defined:
        defined in the in the RISC-V ISA manual starting from commit e87412e621f1
        ("integrate Zaamo and Zalrsc text (#1304)").
 
+  * :c:macro:`RISCV_HWPROBE_EXT_ZALASR`: The Zalasr extension is supported as
+       frozen at commit 194f0094 ("Version 0.9 for freeze") of riscv-zalasr.
+
   * :c:macro:`RISCV_HWPROBE_EXT_ZALRSC`: The Zalrsc extension is supported as
        defined in the in the RISC-V ISA manual starting from commit e87412e621f1
        ("integrate Zaamo and Zalrsc text (#1304)").
@@ -360,4 +363,4 @@ The following keys are defined:
 
     * :c:macro:`RISCV_HWPROBE_VENDOR_EXT_XSFVFWMACCQQQ`: The Xsfvfwmaccqqq
         vendor extension is supported in version 1.0 of Matrix Multiply Accumulate
-	Instruction Extensions Specification.
\ No newline at end of file
+	Instruction Extensions Specification.
diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
index aaf6ad9704993..d3a65f8ff7da4 100644
--- a/arch/riscv/include/uapi/asm/hwprobe.h
+++ b/arch/riscv/include/uapi/asm/hwprobe.h
@@ -82,6 +82,7 @@ struct riscv_hwprobe {
 #define		RISCV_HWPROBE_EXT_ZAAMO		(1ULL << 56)
 #define		RISCV_HWPROBE_EXT_ZALRSC	(1ULL << 57)
 #define		RISCV_HWPROBE_EXT_ZABHA		(1ULL << 58)
+#define		RISCV_HWPROBE_EXT_ZALASR	(1ULL << 59)
 #define RISCV_HWPROBE_KEY_CPUPERF_0	5
 #define		RISCV_HWPROBE_MISALIGNED_UNKNOWN	(0 << 0)
 #define		RISCV_HWPROBE_MISALIGNED_EMULATED	(1 << 0)
diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index 0b170e18a2beb..0529e692b1173 100644
--- a/arch/riscv/kernel/sys_hwprobe.c
+++ b/arch/riscv/kernel/sys_hwprobe.c
@@ -99,6 +99,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
 		EXT_KEY(ZAAMO);
 		EXT_KEY(ZABHA);
 		EXT_KEY(ZACAS);
+		EXT_KEY(ZALASR);
 		EXT_KEY(ZALRSC);
 		EXT_KEY(ZAWRS);
 		EXT_KEY(ZBA);
-- 
2.20.1

[PATCH v4 04/10] riscv: Introduce Zalasr instructions

[Xu Lu]

Introduce l{b|h|w|d}.{aq|aqrl} and s{b|h|w|d}.{rl|aqrl} instruction
encodings.

Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
---
 arch/riscv/include/asm/insn-def.h | 79 +++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/arch/riscv/include/asm/insn-def.h b/arch/riscv/include/asm/insn-def.h
index d5adbaec1d010..3fec7e66ce50f 100644
--- a/arch/riscv/include/asm/insn-def.h
+++ b/arch/riscv/include/asm/insn-def.h
@@ -179,6 +179,7 @@
 #define RV___RS1(v)		__RV_REG(v)
 #define RV___RS2(v)		__RV_REG(v)
 
+#define RV_OPCODE_AMO		RV_OPCODE(47)
 #define RV_OPCODE_MISC_MEM	RV_OPCODE(15)
 #define RV_OPCODE_OP_IMM	RV_OPCODE(19)
 #define RV_OPCODE_SYSTEM	RV_OPCODE(115)
@@ -208,6 +209,84 @@
 	__ASM_STR(.error "hlv.d requires 64-bit support")
 #endif
 
+#define LB_AQ(dest, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(0), FUNC7(26),			\
+	       RD(dest), RS1(addr), __RS2(0))
+
+#define LB_AQRL(dest, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(0), FUNC7(27),			\
+	       RD(dest), RS1(addr), __RS2(0))
+
+#define LH_AQ(dest, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(1), FUNC7(26),			\
+	       RD(dest), RS1(addr), __RS2(0))
+
+#define LH_AQRL(dest, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(1), FUNC7(27),			\
+	       RD(dest), RS1(addr), __RS2(0))
+
+#define LW_AQ(dest, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(2), FUNC7(26),			\
+	       RD(dest), RS1(addr), __RS2(0))
+
+#define LW_AQRL(dest, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(2), FUNC7(27),			\
+	       RD(dest), RS1(addr), __RS2(0))
+
+#define SB_RL(src, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(0), FUNC7(29),			\
+	       __RD(0), RS1(addr), RS2(src))
+
+#define SB_AQRL(src, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(0), FUNC7(31),			\
+	       __RD(0), RS1(addr), RS2(src))
+
+#define SH_RL(src, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(1), FUNC7(29),			\
+	       __RD(0), RS1(addr), RS2(src))
+
+#define SH_AQRL(src, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(1), FUNC7(31),			\
+	       __RD(0), RS1(addr), RS2(src))
+
+#define SW_RL(src, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(2), FUNC7(29),			\
+	       __RD(0), RS1(addr), RS2(src))
+
+#define SW_AQRL(src, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(2), FUNC7(31),			\
+	       __RD(0), RS1(addr), RS2(src))
+
+#ifdef CONFIG_64BIT
+#define LD_AQ(dest, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(3), FUNC7(26),			\
+	       RD(dest), RS1(addr), __RS2(0))
+
+#define LD_AQRL(dest, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(3), FUNC7(27),			\
+	       RD(dest), RS1(addr), __RS2(0))
+
+#define SD_RL(src, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(3), FUNC7(29),			\
+	       __RD(0), RS1(addr), RS2(src))
+
+#define SD_AQRL(src, addr)					\
+	INSN_R(OPCODE_AMO, FUNC3(3), FUNC7(31),			\
+	       __RD(0), RS1(addr), RS2(src))
+#else
+#define LD_AQ(dest, addr)					\
+	__ASM_STR(.error "ld.aq requires 64-bit support")
+
+#define LD_AQRL(dest, addr)					\
+	__ASM_STR(.error "ld.aqrl requires 64-bit support")
+
+#define SD_RL(dest, addr)					\
+	__ASM_STR(.error "sd.rl requires 64-bit support")
+
+#define SD_AQRL(dest, addr)					\
+	__ASM_STR(.error "sd.aqrl requires 64-bit support")
+#endif
+
 #define SINVAL_VMA(vaddr, asid)					\
 	INSN_R(OPCODE_SYSTEM, FUNC3(0), FUNC7(11),		\
 	       __RD(0), RS1(vaddr), RS2(asid))
-- 
2.20.1

Re: [PATCH v4 00/10] riscv: Add Zalasr ISA extension support

[Xu Lu]

This series was automatically blocked by Gmail due to too many
recipients, so I resent it twice, causing the emails to appear
discontinuous. I apologize for any inconvenience this may have caused
to the reviewer.

Best regards,
Xu Lu

On Mon, Oct 20, 2025 at 12:21 PM Xu Lu <luxu.kernel@bytedance.com> wrote:
>
> This patch adds support for the Zalasr ISA extension, which supplies the
> real load acquire/store release instructions.
>
> The specification can be found here:
> https://github.com/riscv/riscv-zalasr/blob/main/chapter2.adoc
>
> This patch seires has been tested with ltp on Qemu with Brensan's zalasr
> support patch[1].
>
> Some false positive spacing error happens during patch checking. Thus I
> CCed maintainers of checkpatch.pl as well.
>
> [1] https://lore.kernel.org/all/CAGPSXwJEdtqW=nx71oufZp64nK6tK=0rytVEcz4F-gfvCOXk2w@mail.gmail.com/
>
> v4:
>  - Apply acquire/release semantics to arch_atomic operations. Thanks
>  to Andrea.
>
> v3:
>  - Apply acquire/release semantics to arch_xchg/arch_cmpxchg operations
>  so as to ensure FENCE.TSO ordering between operations which precede the
>  UNLOCK+LOCK sequence and operations which follow the sequence. Thanks
>  to Andrea.
>  - Support hwprobe of Zalasr.
>  - Allow Zalasr extensions for Guest/VM.
>
> v2:
>  - Adjust the order of Zalasr and Zalrsc in dt-bindings. Thanks to
>  Conor.
>
> Xu Lu (10):
>   riscv: Add ISA extension parsing for Zalasr
>   dt-bindings: riscv: Add Zalasr ISA extension description
>   riscv: hwprobe: Export Zalasr extension
>   riscv: Introduce Zalasr instructions
>   riscv: Apply Zalasr to smp_load_acquire/smp_store_release
>   riscv: Apply acquire/release semantics to arch_xchg/arch_cmpxchg
>     operations
>   riscv: Apply acquire/release semantics to arch_atomic operations
>   riscv: Remove arch specific __atomic_acquire/release_fence
>   RISC-V: KVM: Allow Zalasr extensions for Guest/VM
>   RISC-V: KVM: selftests: Add Zalasr extensions to get-reg-list test
>
>  Documentation/arch/riscv/hwprobe.rst          |   5 +-
>  .../devicetree/bindings/riscv/extensions.yaml |   5 +
>  arch/riscv/include/asm/atomic.h               |  70 ++++++++-
>  arch/riscv/include/asm/barrier.h              |  91 +++++++++--
>  arch/riscv/include/asm/cmpxchg.h              | 144 +++++++++---------
>  arch/riscv/include/asm/fence.h                |   4 -
>  arch/riscv/include/asm/hwcap.h                |   1 +
>  arch/riscv/include/asm/insn-def.h             |  79 ++++++++++
>  arch/riscv/include/uapi/asm/hwprobe.h         |   1 +
>  arch/riscv/include/uapi/asm/kvm.h             |   1 +
>  arch/riscv/kernel/cpufeature.c                |   1 +
>  arch/riscv/kernel/sys_hwprobe.c               |   1 +
>  arch/riscv/kvm/vcpu_onereg.c                  |   2 +
>  .../selftests/kvm/riscv/get-reg-list.c        |   4 +
>  14 files changed, 314 insertions(+), 95 deletions(-)
>
> --
> 2.20.1
>

Re: [PATCH v4 04/10] riscv: Introduce Zalasr instructions

[Guo Ren]

On Mon, Oct 20, 2025 at 12:21 PM Xu Lu <luxu.kernel@bytedance.com> wrote:
>
> Introduce l{b|h|w|d}.{aq|aqrl} and s{b|h|w|d}.{rl|aqrl} instruction
> encodings.
>
> Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
> ---
>  arch/riscv/include/asm/insn-def.h | 79 +++++++++++++++++++++++++++++++
>  1 file changed, 79 insertions(+)
>
> diff --git a/arch/riscv/include/asm/insn-def.h b/arch/riscv/include/asm/insn-def.h
> index d5adbaec1d010..3fec7e66ce50f 100644
> --- a/arch/riscv/include/asm/insn-def.h
> +++ b/arch/riscv/include/asm/insn-def.h
> @@ -179,6 +179,7 @@
>  #define RV___RS1(v)            __RV_REG(v)
>  #define RV___RS2(v)            __RV_REG(v)
>
> +#define RV_OPCODE_AMO          RV_OPCODE(47)
>  #define RV_OPCODE_MISC_MEM     RV_OPCODE(15)
>  #define RV_OPCODE_OP_IMM       RV_OPCODE(19)
>  #define RV_OPCODE_SYSTEM       RV_OPCODE(115)
> @@ -208,6 +209,84 @@
>         __ASM_STR(.error "hlv.d requires 64-bit support")
>  #endif
>
> +#define LB_AQ(dest, addr)                                      \
> +       INSN_R(OPCODE_AMO, FUNC3(0), FUNC7(26),                 \
> +              RD(dest), RS1(addr), __RS2(0))
> +
> +#define LB_AQRL(dest, addr)                                    \
> +       INSN_R(OPCODE_AMO, FUNC3(0), FUNC7(27),                 \
> +              RD(dest), RS1(addr), __RS2(0))
> +
> +#define LH_AQ(dest, addr)                                      \
> +       INSN_R(OPCODE_AMO, FUNC3(1), FUNC7(26),                 \
> +              RD(dest), RS1(addr), __RS2(0))
> +
> +#define LH_AQRL(dest, addr)                                    \
> +       INSN_R(OPCODE_AMO, FUNC3(1), FUNC7(27),                 \
> +              RD(dest), RS1(addr), __RS2(0))
> +
> +#define LW_AQ(dest, addr)                                      \
> +       INSN_R(OPCODE_AMO, FUNC3(2), FUNC7(26),                 \
> +              RD(dest), RS1(addr), __RS2(0))
> +
> +#define LW_AQRL(dest, addr)                                    \
> +       INSN_R(OPCODE_AMO, FUNC3(2), FUNC7(27),                 \
> +              RD(dest), RS1(addr), __RS2(0))
> +
> +#define SB_RL(src, addr)                                       \
> +       INSN_R(OPCODE_AMO, FUNC3(0), FUNC7(29),                 \
> +              __RD(0), RS1(addr), RS2(src))
> +
> +#define SB_AQRL(src, addr)                                     \
> +       INSN_R(OPCODE_AMO, FUNC3(0), FUNC7(31),                 \
> +              __RD(0), RS1(addr), RS2(src))
> +
> +#define SH_RL(src, addr)                                       \
> +       INSN_R(OPCODE_AMO, FUNC3(1), FUNC7(29),                 \
> +              __RD(0), RS1(addr), RS2(src))
> +
> +#define SH_AQRL(src, addr)                                     \
> +       INSN_R(OPCODE_AMO, FUNC3(1), FUNC7(31),                 \
> +              __RD(0), RS1(addr), RS2(src))
> +
> +#define SW_RL(src, addr)                                       \
> +       INSN_R(OPCODE_AMO, FUNC3(2), FUNC7(29),                 \
> +              __RD(0), RS1(addr), RS2(src))
> +
> +#define SW_AQRL(src, addr)                                     \
> +       INSN_R(OPCODE_AMO, FUNC3(2), FUNC7(31),                 \
> +              __RD(0), RS1(addr), RS2(src))
> +
> +#ifdef CONFIG_64BIT
> +#define LD_AQ(dest, addr)                                      \
> +       INSN_R(OPCODE_AMO, FUNC3(3), FUNC7(26),                 \
> +              RD(dest), RS1(addr), __RS2(0))
> +
> +#define LD_AQRL(dest, addr)                                    \
> +       INSN_R(OPCODE_AMO, FUNC3(3), FUNC7(27),                 \
> +              RD(dest), RS1(addr), __RS2(0))
> +
> +#define SD_RL(src, addr)                                       \
> +       INSN_R(OPCODE_AMO, FUNC3(3), FUNC7(29),                 \
> +              __RD(0), RS1(addr), RS2(src))
> +
> +#define SD_AQRL(src, addr)                                     \
> +       INSN_R(OPCODE_AMO, FUNC3(3), FUNC7(31),                 \
> +              __RD(0), RS1(addr), RS2(src))
> +#else
> +#define LD_AQ(dest, addr)                                      \
> +       __ASM_STR(.error "ld.aq requires 64-bit support")
> +
> +#define LD_AQRL(dest, addr)                                    \
> +       __ASM_STR(.error "ld.aqrl requires 64-bit support")
> +
> +#define SD_RL(dest, addr)                                      \
> +       __ASM_STR(.error "sd.rl requires 64-bit support")
> +
> +#define SD_AQRL(dest, addr)                                    \
> +       __ASM_STR(.error "sd.aqrl requires 64-bit support")
> +#endif
> +
>  #define SINVAL_VMA(vaddr, asid)                                        \
>         INSN_R(OPCODE_SYSTEM, FUNC3(0), FUNC7(11),              \
>                __RD(0), RS1(vaddr), RS2(asid))
> --
> 2.20.1
>
I didn't find problem.

Reviewed-by: Guo Ren <guoren@kernel.org>

-- 
Best Regards
 Guo Ren

Re: [PATCH v4 03/10] riscv: hwprobe: Export Zalasr extension

[Guo Ren]

On Mon, Oct 20, 2025 at 12:21 PM Xu Lu <luxu.kernel@bytedance.com> wrote:
>
> Export the Zalasr extension to userspace using hwprobe.
>
> Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
> ---
>  Documentation/arch/riscv/hwprobe.rst  | 5 ++++-
>  arch/riscv/include/uapi/asm/hwprobe.h | 1 +
>  arch/riscv/kernel/sys_hwprobe.c       | 1 +
>  3 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
> index 2aa9be272d5de..067a3595fb9d5 100644
> --- a/Documentation/arch/riscv/hwprobe.rst
> +++ b/Documentation/arch/riscv/hwprobe.rst
> @@ -249,6 +249,9 @@ The following keys are defined:
>         defined in the in the RISC-V ISA manual starting from commit e87412e621f1
>         ("integrate Zaamo and Zalrsc text (#1304)").
>
> +  * :c:macro:`RISCV_HWPROBE_EXT_ZALASR`: The Zalasr extension is supported as
> +       frozen at commit 194f0094 ("Version 0.9 for freeze") of riscv-zalasr.
"Frozen Version 0.9" might not be proper; it denotes the current
temporary state, not the goal of the patch.

> +
>    * :c:macro:`RISCV_HWPROBE_EXT_ZALRSC`: The Zalrsc extension is supported as
>         defined in the in the RISC-V ISA manual starting from commit e87412e621f1
>         ("integrate Zaamo and Zalrsc text (#1304)").
> @@ -360,4 +363,4 @@ The following keys are defined:
>
>      * :c:macro:`RISCV_HWPROBE_VENDOR_EXT_XSFVFWMACCQQQ`: The Xsfvfwmaccqqq
>          vendor extension is supported in version 1.0 of Matrix Multiply Accumulate
> -       Instruction Extensions Specification.
> \ No newline at end of file
> +       Instruction Extensions Specification.
> diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
> index aaf6ad9704993..d3a65f8ff7da4 100644
> --- a/arch/riscv/include/uapi/asm/hwprobe.h
> +++ b/arch/riscv/include/uapi/asm/hwprobe.h
> @@ -82,6 +82,7 @@ struct riscv_hwprobe {
>  #define                RISCV_HWPROBE_EXT_ZAAMO         (1ULL << 56)
>  #define                RISCV_HWPROBE_EXT_ZALRSC        (1ULL << 57)
>  #define                RISCV_HWPROBE_EXT_ZABHA         (1ULL << 58)
> +#define                RISCV_HWPROBE_EXT_ZALASR        (1ULL << 59)
>  #define RISCV_HWPROBE_KEY_CPUPERF_0    5
>  #define                RISCV_HWPROBE_MISALIGNED_UNKNOWN        (0 << 0)
>  #define                RISCV_HWPROBE_MISALIGNED_EMULATED       (1 << 0)
> diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
> index 0b170e18a2beb..0529e692b1173 100644
> --- a/arch/riscv/kernel/sys_hwprobe.c
> +++ b/arch/riscv/kernel/sys_hwprobe.c
> @@ -99,6 +99,7 @@ static void hwprobe_isa_ext0(struct riscv_hwprobe *pair,
>                 EXT_KEY(ZAAMO);
>                 EXT_KEY(ZABHA);
>                 EXT_KEY(ZACAS);
> +               EXT_KEY(ZALASR);
>                 EXT_KEY(ZALRSC);
>                 EXT_KEY(ZAWRS);
>                 EXT_KEY(ZBA);
> --
> 2.20.1
>


-- 
Best Regards
 Guo Ren

Re: [PATCH v4 02/10] dt-bindings: riscv: Add Zalasr ISA extension description

[Conor Dooley]

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Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

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Re: [PATCH v4 00/10] riscv: Add Zalasr ISA extension support

[Andrea Parri]

On Mon, Oct 20, 2025 at 12:20:46PM +0800, Xu Lu wrote:
> This patch adds support for the Zalasr ISA extension, which supplies the
> real load acquire/store release instructions.
> 
> The specification can be found here:
> https://github.com/riscv/riscv-zalasr/blob/main/chapter2.adoc
> 
> This patch seires has been tested with ltp on Qemu with Brensan's zalasr
> support patch[1].
> 
> Some false positive spacing error happens during patch checking. Thus I
> CCed maintainers of checkpatch.pl as well.
> 
> [1] https://lore.kernel.org/all/CAGPSXwJEdtqW=nx71oufZp64nK6tK=0rytVEcz4F-gfvCOXk2w@mail.gmail.com/
> 
> v4:
>  - Apply acquire/release semantics to arch_atomic operations. Thanks
>  to Andrea.

Perhaps I wasn't clear enough, sorry, but I did mean my suggestion
(specifically, the use of .aq/.rl annotations) to be conditional on
zalasr.  Same observation for xchg/cmpxchg below.  IOW, I really
expected this series to introduce _no changes_ to our lowerings when
!zalasr.  If any !zalasr-changes are needed, I'd suggest isolating
/submitting them in dedicated patches.

But other than that, this looks pretty good to me.  Perhaps something
else to consider for zalasr is our lowering of smp_cond_load_acquire()
(can't spot an actual bug now, but recall the principle "zalasr -> use
.aq/.rl annotations ..."): riscv currently uses the "generic", fence-
based implementation from include/asm-generic/barrier.h; compare that
with e.g. the implementation from arch/arm64/include/asm/barrier.h .

  Andrea


> v3:
>  - Apply acquire/release semantics to arch_xchg/arch_cmpxchg operations
>  so as to ensure FENCE.TSO ordering between operations which precede the
>  UNLOCK+LOCK sequence and operations which follow the sequence. Thanks
>  to Andrea.
>  - Support hwprobe of Zalasr.
>  - Allow Zalasr extensions for Guest/VM.
> 
> v2:
>  - Adjust the order of Zalasr and Zalrsc in dt-bindings. Thanks to
>  Conor.
> 
> Xu Lu (10):
>   riscv: Add ISA extension parsing for Zalasr
>   dt-bindings: riscv: Add Zalasr ISA extension description
>   riscv: hwprobe: Export Zalasr extension
>   riscv: Introduce Zalasr instructions
>   riscv: Apply Zalasr to smp_load_acquire/smp_store_release
>   riscv: Apply acquire/release semantics to arch_xchg/arch_cmpxchg
>     operations
>   riscv: Apply acquire/release semantics to arch_atomic operations
>   riscv: Remove arch specific __atomic_acquire/release_fence
>   RISC-V: KVM: Allow Zalasr extensions for Guest/VM
>   RISC-V: KVM: selftests: Add Zalasr extensions to get-reg-list test
> 
>  Documentation/arch/riscv/hwprobe.rst          |   5 +-
>  .../devicetree/bindings/riscv/extensions.yaml |   5 +
>  arch/riscv/include/asm/atomic.h               |  70 ++++++++-
>  arch/riscv/include/asm/barrier.h              |  91 +++++++++--
>  arch/riscv/include/asm/cmpxchg.h              | 144 +++++++++---------
>  arch/riscv/include/asm/fence.h                |   4 -
>  arch/riscv/include/asm/hwcap.h                |   1 +
>  arch/riscv/include/asm/insn-def.h             |  79 ++++++++++
>  arch/riscv/include/uapi/asm/hwprobe.h         |   1 +
>  arch/riscv/include/uapi/asm/kvm.h             |   1 +
>  arch/riscv/kernel/cpufeature.c                |   1 +
>  arch/riscv/kernel/sys_hwprobe.c               |   1 +
>  arch/riscv/kvm/vcpu_onereg.c                  |   2 +
>  .../selftests/kvm/riscv/get-reg-list.c        |   4 +
>  14 files changed, 314 insertions(+), 95 deletions(-)
> 
> -- 
> 2.20.1
>