RISC-V: simplify register width check in ISA string parsing

Saving off the `isa` pointer to a temp variable, followed by checking if
it has been incremented is a bit of an odd pattern. Perhaps it was done
to avoid a funky looking if statement mixed with the ifdeffery.

Now that we use IS_ENABLED() here just return from the parser as soon as
we detect a mismatch between the string and the currently running
kernel.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20230607-splatter-bacterium-a75bb9f0d0b7@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index e3324d6..c863521 100644 (file)
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -126,7 +126,6 @@ void __init riscv_fill_hwcap(void)
        for_each_possible_cpu(cpu) {
                unsigned long this_hwcap = 0;
                DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX);
-               const char *temp;
 
                if (acpi_disabled) {
                        node = of_cpu_device_node_get(cpu);
@@ -149,14 +148,14 @@ void __init riscv_fill_hwcap(void)
                        }
                }
 
-               temp = isa;
-               if (IS_ENABLED(CONFIG_32BIT) && !strncasecmp(isa, "rv32", 4))
-                       isa += 4;
-               else if (IS_ENABLED(CONFIG_64BIT) && !strncasecmp(isa, "rv64", 4))
-                       isa += 4;
-               /* The riscv,isa DT property must start with rv64 or rv32 */
-               if (temp == isa)
+               if (IS_ENABLED(CONFIG_32BIT) && strncasecmp(isa, "rv32", 4))
                        continue;
+
+               if (IS_ENABLED(CONFIG_64BIT) && strncasecmp(isa, "rv64", 4))
+                       continue;
+
+               isa += 4;
+
                bitmap_zero(this_isa, RISCV_ISA_EXT_MAX);
                for (; *isa; ++isa) {
                        const char *ext = isa++;