[PATCH v2 04/10] 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 <guodong at riscstar.com>

---
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 c3bb26d70c748..05f746061f679 100644
--- a/Documentation/arch/riscv/hwprobe.rst
+++ b/Documentation/arch/riscv/hwprobe.rst
@@ -289,6 +289,10 @@ The following keys are defined:
        defined in the RISC-V ISA manual starting from commit f88abf1 ("Integrating
        load/store pair for RV32 with the main manual") of the riscv-isa-manual.
 
+  * :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.")
+
 * :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: Deprecated.  Returns similar values to
      :c:macro:`RISCV_HWPROBE_KEY_MISALIGNED_SCALAR_PERF`, but the key was
      mistakenly classified as a bitmask rather than a value.
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 5cf463570229d..4b4a8157277a3 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