riscv: cpufeature: Do not drop Linux-internal extensions

The Linux-internal Xlinuxenvcfg ISA extension is omitted from the
riscv_isa_ext array because it has no DT binding and should not appear
in /proc/cpuinfo. The logic added in commit 625034abd52a ("riscv: add
ISA extensions validation callback") assumes all extensions are included
in riscv_isa_ext, and so riscv_resolve_isa() wrongly drops Xlinuxenvcfg
from the final ISA string. Instead, accept such Linux-internal ISA
extensions as if they have no validation callback.

Fixes: 625034abd52a ("riscv: add ISA extensions validation callback")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240718213011.2600150-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 8f20607adb406d2fd94ae2628de1872c75defd11..b427188b28fc16defce7c05ae178b8b9de346d8f 100644 (file)
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -432,28 +432,26 @@ static void __init riscv_resolve_isa(unsigned long *source_isa,
                bitmap_copy(prev_resolved_isa, resolved_isa, RISCV_ISA_EXT_MAX);
                for_each_set_bit(bit, source_isa, RISCV_ISA_EXT_MAX) {
                        ext = riscv_get_isa_ext_data(bit);
-                       if (!ext)
-                               continue;
 
-                       if (ext->validate) {
+                       if (ext && ext->validate) {
                                ret = ext->validate(ext, resolved_isa);
                                if (ret == -EPROBE_DEFER) {
                                        loop = true;
                                        continue;
                                } else if (ret) {
                                        /* Disable the extension entirely */
-                                       clear_bit(ext->id, source_isa);
+                                       clear_bit(bit, source_isa);
                                        continue;
                                }
                        }
 
-                       set_bit(ext->id, resolved_isa);
+                       set_bit(bit, resolved_isa);
                        /* No need to keep it in source isa now that it is enabled */
-                       clear_bit(ext->id, source_isa);
+                       clear_bit(bit, source_isa);
 
                        /* Single letter extensions get set in hwcap */
-                       if (ext->id < RISCV_ISA_EXT_BASE)
-                               *this_hwcap |= isa2hwcap[ext->id];
+                       if (bit < RISCV_ISA_EXT_BASE)
+                               *this_hwcap |= isa2hwcap[bit];
                }
        } while (loop && memcmp(prev_resolved_isa, resolved_isa, sizeof(prev_resolved_isa)));
 }