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-gfvCOX...
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(-)
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),
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
Acked-by: Conor Dooley conor.dooley@microchip.com pw-bot: not-applicable
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);
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
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))
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
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-gfvCOX...
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
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-gfvCOX...
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
linux-kselftest-mirror@lists.linaro.org
-
Andrea Parri -
Conor Dooley -
Guo Ren -
Xu Lu