[PATCH v3 04/15] riscv: Add Zicclsm to cpufeature and hwprobe

[Guodong Xu]

From: Jesse Taube <jesse at rivosinc.com>

Zicclsm requires misaligned support for all regular load and store
instructions, both scalar and vector, but not AMOs or other
specialized forms of memory access, to main memory regions with both
the cacheability and coherence PMAs, as defined in the profiles spec.
Even though mandated, misaligned loads and stores might execute
extremely slowly. Standard software distributions should assume their
existence only for correctness, not for performance.

Reviewed-by: Conor Dooley <conor.dooley at microchip.com>
Reviewed-by: Andy Chiu <andy.chiu at sifive.com>
Reviewed-by: Charlie Jenkins <charlie at rivosinc.com>
Tested-by: Charlie Jenkins <charlie at rivosinc.com>
Signed-off-by: Jesse Taube <jesse at rivosinc.com>
[Rebased, rewrote doc text, minor commit message revisions]
Signed-off-by: Andrew Jones <andrew.jones at oss.qualcomm.com>
Signed-off-by: Guodong Xu <docular.xu at gmail.com>

---
v3:
- Move the hwprobe.rst entry to the IMA_EXT_1 section so its
  documentation matches the IMA_EXT_1 bit it was allocated in v2
  (Sashiko, agreed by Andrew).
v2:
- Rebased onto v7.1-rc2; moved ZICCLSM to IMA_EXT_1 and
  allocated a new bit for it
---
 Documentation/arch/riscv/hwprobe.rst  | 4 ++++
 arch/riscv/include/asm/hwcap.h        | 1 +
 arch/riscv/include/uapi/asm/hwprobe.h | 1 +
 arch/riscv/kernel/cpufeature.c        | 1 +
 arch/riscv/kernel/sys_hwprobe.c       | 1 +
 5 files changed, 8 insertions(+)

diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
index 3cedaaa53f331..fa2810bfc1477 100644
--- a/Documentation/arch/riscv/hwprobe.rst
+++ b/Documentation/arch/riscv/hwprobe.rst
@@ -401,3 +401,7 @@ The following keys are defined:
     as defined in version 1.0 of the RISC-V Control-flow Integrity (CFI)
     extensions specification, ratified in commit ff03d8485a04 ("Update to
     ratified state") of riscv-cfi.
+
+  * :c:macro:`RISCV_HWPROBE_EXT_ZICCLSM`: The Zicclsm extension is supported,
+    as defined in the RISC-V Profiles specification starting from commit
+    b1d80660 ("Updated to ratified state.")
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 44bf8c7d8acc5..e8f4a7dd96a93 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -112,6 +112,7 @@
 #define RISCV_ISA_EXT_ZCLSD		103
 #define RISCV_ISA_EXT_ZICFILP		104
 #define RISCV_ISA_EXT_ZICFISS		105
+#define RISCV_ISA_EXT_ZICCLSM		106
 
 #define RISCV_ISA_EXT_XLINUXENVCFG	127
 
diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
index 9139edba0aecb..6819df159c51e 100644
--- a/arch/riscv/include/uapi/asm/hwprobe.h
+++ b/arch/riscv/include/uapi/asm/hwprobe.h
@@ -116,6 +116,7 @@ struct riscv_hwprobe {
 #define RISCV_HWPROBE_KEY_ZICBOP_BLOCK_SIZE	15
 #define RISCV_HWPROBE_KEY_IMA_EXT_1		16
 #define		RISCV_HWPROBE_EXT_ZICFISS	(1ULL << 0)
+#define		RISCV_HWPROBE_EXT_ZICCLSM	(1ULL << 1)
 
 /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
 
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 686dde3ce3b98..1fb595581adcf 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -502,6 +502,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__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(zicclsm, RISCV_ISA_EXT_ZICCLSM),
 	__RISCV_ISA_EXT_DATA(ziccrse, RISCV_ISA_EXT_ZICCRSE),
 	__RISCV_ISA_EXT_SUPERSET_VALIDATE(zicfilp, RISCV_ISA_EXT_ZICFILP, riscv_xlinuxenvcfg_exts,
 					  riscv_cfilp_validate),
diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index f8f68ba781b45..9cf62266f1890 100644
--- a/arch/riscv/kernel/sys_hwprobe.c
+++ b/arch/riscv/kernel/sys_hwprobe.c
@@ -205,6 +205,7 @@ static void hwprobe_isa_ext1(struct riscv_hwprobe *pair,
 		 * in the hart_isa bitmap, are made.
 		 */
 		EXT_KEY(isainfo->isa, ZICFISS, pair->value, missing);
+		EXT_KEY(isainfo->isa, ZICCLSM, pair->value, missing);
 	}
 
 	/* Now turn off reporting features if any CPU is missing it. */

-- 
2.43.0