[PATCH v5 07/17] riscv: Add B to hwcap and hwprobe

From: Andrew Jones <[email protected]>

Add B to hwcap and ensure when B is present that Zba, Zbb, and Zbs
are all set. Also expose B via hwprobe (RISCV_HWPROBE_EXT_B in
RISCV_HWPROBE_KEY_IMA_EXT_1) so that userspace can probe B directly,
mirroring the F/D/C/V pattern where each is reported via both hwcap
and hwprobe.

Reviewed-by: Conor Dooley <[email protected]>
Signed-off-by: Andrew Jones <[email protected]>
[Add B to hwprobe]
Signed-off-by: Guodong Xu <[email protected]>
---
v5: Collected Reviewed-by from Conor Dooley.
v4: No change.
v3:
- Indent the added hwprobe.rst entry to match the normalized style.
- Rebased onto v7.1-rc6: index isa2hwcap[] via RISCV_ISA_EXT_B to match the
  macro-ization in commit 41337097f2823.
v2:
- Rebased to v7.1-rc2
- Add B to hwprobe (RISCV_HWPROBE_EXT_B at IMA_EXT_1 bit 6) and
  document it in hwprobe.rst, so userspace can probe B directly.
---
 Documentation/arch/riscv/hwprobe.rst  | 4 ++++
 arch/riscv/include/asm/hwcap.h        | 1 +
 arch/riscv/include/uapi/asm/hwcap.h   | 1 +
 arch/riscv/include/uapi/asm/hwprobe.h | 1 +
 arch/riscv/kernel/cpufeature.c        | 8 ++++++++
 arch/riscv/kernel/sys_hwprobe.c       | 1 +
 6 files changed, 16 insertions(+)

diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
index 893e1a1215d23..fc68dea397aae 100644
--- a/Documentation/arch/riscv/hwprobe.rst
+++ b/Documentation/arch/riscv/hwprobe.rst
@@ -421,3 +421,7 @@ The following keys are defined:
   * :c:macro:`RISCV_HWPROBE_EXT_ZA64RS`: The Za64rs extension is supported,
     as defined in the RISC-V Profiles specification starting from commit
     b1d80660 ("Updated to ratified state.")
+
+  * :c:macro:`RISCV_HWPROBE_EXT_B`: The B extension is supported, as defined
+    in version 1.0 of the Bit-Manipulation ISA extensions, and implies the
+    presence of the Zba, Zbb, and Zbs sub-extensions.
diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 0acb7a01ecc0f..58523b3a1998a 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -11,6 +11,7 @@
 #include <uapi/asm/hwcap.h>
 
 #define RISCV_ISA_EXT_A		('a' - 'a')
+#define RISCV_ISA_EXT_B		('b' - 'a')
 #define RISCV_ISA_EXT_C		('c' - 'a')
 #define RISCV_ISA_EXT_D		('d' - 'a')
 #define RISCV_ISA_EXT_F		('f' - 'a')
diff --git a/arch/riscv/include/uapi/asm/hwcap.h b/arch/riscv/include/uapi/asm/hwcap.h
index c52bb7bbbabe9..96b7cf854e090 100644
--- a/arch/riscv/include/uapi/asm/hwcap.h
+++ b/arch/riscv/include/uapi/asm/hwcap.h
@@ -21,6 +21,7 @@
 #define COMPAT_HWCAP_ISA_F	(1 << ('F' - 'A'))
 #define COMPAT_HWCAP_ISA_D	(1 << ('D' - 'A'))
 #define COMPAT_HWCAP_ISA_C	(1 << ('C' - 'A'))
+#define COMPAT_HWCAP_ISA_B	(1 << ('B' - 'A'))
 #define COMPAT_HWCAP_ISA_V	(1 << ('V' - 'A'))
 
 #endif /* _UAPI_ASM_RISCV_HWCAP_H */
diff --git a/arch/riscv/include/uapi/asm/hwprobe.h b/arch/riscv/include/uapi/asm/hwprobe.h
index 58d1e86e47ae7..430dc49a82863 100644
--- a/arch/riscv/include/uapi/asm/hwprobe.h
+++ b/arch/riscv/include/uapi/asm/hwprobe.h
@@ -121,6 +121,7 @@ struct riscv_hwprobe {
 #define		RISCV_HWPROBE_EXT_ZICCIF	(1ULL << 3)
 #define		RISCV_HWPROBE_EXT_ZICCRSE	(1ULL << 4)
 #define		RISCV_HWPROBE_EXT_ZA64RS	(1ULL << 5)
+#define		RISCV_HWPROBE_EXT_B		(1ULL << 6)
 
 /* Increase RISCV_HWPROBE_MAX_KEY when adding items. */
 
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index d76ce21d4a18a..9eee53b264de1 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -450,6 +450,12 @@ static const unsigned int riscv_c_exts[] = {
 	RISCV_ISA_EXT_ZCD,
 };
 
+static const unsigned int riscv_b_exts[] = {
+	RISCV_ISA_EXT_ZBA,
+	RISCV_ISA_EXT_ZBB,
+	RISCV_ISA_EXT_ZBS,
+};
+
 /*
  * The canonical order of ISA extension names in the ISA string is defined in
  * chapter 27 of the unprivileged specification.
@@ -497,6 +503,7 @@ const struct riscv_isa_ext_data riscv_isa_ext[] = {
 	__RISCV_ISA_EXT_DATA_VALIDATE(d, RISCV_ISA_EXT_D, riscv_ext_d_validate),
 	__RISCV_ISA_EXT_DATA(q, RISCV_ISA_EXT_Q),
 	__RISCV_ISA_EXT_SUPERSET(c, RISCV_ISA_EXT_C, riscv_c_exts),
+	__RISCV_ISA_EXT_SUPERSET(b, RISCV_ISA_EXT_B, riscv_b_exts),
 	__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),
@@ -1115,6 +1122,7 @@ void __init riscv_fill_hwcap(void)
 	isa2hwcap[RISCV_ISA_EXT_F] = COMPAT_HWCAP_ISA_F;
 	isa2hwcap[RISCV_ISA_EXT_D] = COMPAT_HWCAP_ISA_D;
 	isa2hwcap[RISCV_ISA_EXT_C] = COMPAT_HWCAP_ISA_C;
+	isa2hwcap[RISCV_ISA_EXT_B] = COMPAT_HWCAP_ISA_B;
 	isa2hwcap[RISCV_ISA_EXT_V] = COMPAT_HWCAP_ISA_V;
 
 	if (!acpi_disabled) {
diff --git a/arch/riscv/kernel/sys_hwprobe.c b/arch/riscv/kernel/sys_hwprobe.c
index b15ac9adf7920..dcc102bf8f183 100644
--- a/arch/riscv/kernel/sys_hwprobe.c
+++ b/arch/riscv/kernel/sys_hwprobe.c
@@ -210,6 +210,7 @@ static void hwprobe_isa_ext1(struct riscv_hwprobe *pair,
 		EXT_KEY(isainfo->isa, ZICCIF, pair->value, missing);
 		EXT_KEY(isainfo->isa, ZICCRSE, pair->value, missing);
 		EXT_KEY(isainfo->isa, ZA64RS, pair->value, missing);
+		EXT_KEY(isainfo->isa, B, pair->value, missing);
 	}
 
 	/* Now turn off reporting features if any CPU is missing it. */

-- 
2.43.0


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