riscv: hwcap: Don't alphabetize ISA extension IDs

While the comment above the ISA extension ID definitions says
"Entries are sorted alphabetically.", this stopped being good
advice with commit d8a3d8a75206 ("riscv: hwcap: make ISA extension
ids can be used in asm"), as we now use macros instead of enums.
Reshuffling defines is error-prone, so, since they don't need to be
in any particular order, change the advice to just adding new
extensions at the bottom. Also, take the opportunity to change
spaces to tabs, merge three comments into one, and move the base
and max defines into more logical locations wrt the ID definitions.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230209123636.123537-1-ajones@ventanamicro.com
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 831beba..8f3994a 100644 (file)
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -24,29 +24,27 @@
 #define RISCV_ISA_EXT_u                ('u' - 'a')
 
 /*
- * Increse this to higher value as kernel support more ISA extensions.
- */
-#define RISCV_ISA_EXT_MAX      64
-#define RISCV_ISA_EXT_NAME_LEN_MAX 32
-
-/* The base ID for multi-letter ISA extensions */
-#define RISCV_ISA_EXT_BASE 26
-
-/*
- * These macros represent the logical ID for each multi-letter RISC-V ISA extension.
- * The logical ID should start from RISCV_ISA_EXT_BASE and must not exceed
- * RISCV_ISA_EXT_MAX. 0-25 range is reserved for single letter
- * extensions while all the multi-letter extensions should define the next
- * available logical extension id.
- * Entries are sorted alphabetically.
+ * These macros represent the logical IDs of each multi-letter RISC-V ISA
+ * extension and are used in the ISA bitmap. The logical IDs start from
+ * RISCV_ISA_EXT_BASE, which allows the 0-25 range to be reserved for single
+ * letter extensions. The maximum, RISCV_ISA_EXT_MAX, is defined in order
+ * to allocate the bitmap and may be increased when necessary.
+ *
+ * New extensions should just be added to the bottom, rather than added
+ * alphabetically, in order to avoid unnecessary shuffling.
  */
-#define RISCV_ISA_EXT_SSCOFPMF         26
-#define RISCV_ISA_EXT_SSTC             27
-#define RISCV_ISA_EXT_SVINVAL          28
-#define RISCV_ISA_EXT_SVPBMT           29
-#define RISCV_ISA_EXT_ZBB              30
-#define RISCV_ISA_EXT_ZICBOM           31
-#define RISCV_ISA_EXT_ZIHINTPAUSE      32
+#define RISCV_ISA_EXT_BASE             26
+
+#define RISCV_ISA_EXT_SSCOFPMF         26
+#define RISCV_ISA_EXT_SSTC             27
+#define RISCV_ISA_EXT_SVINVAL          28
+#define RISCV_ISA_EXT_SVPBMT           29
+#define RISCV_ISA_EXT_ZBB              30
+#define RISCV_ISA_EXT_ZICBOM           31
+#define RISCV_ISA_EXT_ZIHINTPAUSE      32
+
+#define RISCV_ISA_EXT_MAX              64
+#define RISCV_ISA_EXT_NAME_LEN_MAX     32
 
 #ifndef __ASSEMBLY__