riscv: Extending cpufeature.c to detect V-extension

[platform/kernel/linux-starfive.git] / arch / riscv / kernel / cpufeature.c

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index b1d6b7e..7aaf92f 100644 (file)
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -107,6 +107,7 @@ void __init riscv_fill_hwcap(void)
        isa2hwcap['f' - 'a'] = COMPAT_HWCAP_ISA_F;
        isa2hwcap['d' - 'a'] = COMPAT_HWCAP_ISA_D;
        isa2hwcap['c' - 'a'] = COMPAT_HWCAP_ISA_C;
+       isa2hwcap['v' - 'a'] = COMPAT_HWCAP_ISA_V;
 
        elf_hwcap = 0;
 
@@ -267,6 +268,16 @@ void __init riscv_fill_hwcap(void)
                elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
        }
 
+       if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+               /*
+                * ISA string in device tree might have 'v' flag, but
+                * CONFIG_RISCV_ISA_V is disabled in kernel.
+                * Clear V flag in elf_hwcap if CONFIG_RISCV_ISA_V is disabled.
+                */
+               if (!IS_ENABLED(CONFIG_RISCV_ISA_V))
+                       elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
+       }
+
        memset(print_str, 0, sizeof(print_str));
        for (i = 0, j = 0; i < NUM_ALPHA_EXTS; i++)
                if (riscv_isa[0] & BIT_MASK(i))