RISC-V: properly determine hardware caps

On the Hifive-U platform, cpu 0 is a masked cpu with less capabilities
than the other cpus.  Ignore it for the purpose of determining the
hardware capabilities of the system.

Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 5493f3228704..0339087aa652 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -28,7 +28,7 @@ bool has_fpu __read_mostly;
 
 void riscv_fill_hwcap(void)
 {
-        struct device_node *node;
+        struct device_node *node = NULL;
         const char *isa;
         size_t i;
         static unsigned long isa2hwcap[256] = {0};
@@ -44,9 +44,11 @@ void riscv_fill_hwcap(void)
 
         /*
          * We don't support running Linux on hertergenous ISA systems.  For
-         * now, we just check the ISA of the first processor.
+         * now, we just check the ISA of the first "okay" processor.
          */
-        node = of_find_node_by_type(NULL, "cpu");
+        while ((node = of_find_node_by_type(node, "cpu")))
+                if (riscv_of_processor_hartid(node) >= 0)
+                        break;
         if (!node) {
                 pr_warning("Unable to find \"cpu\" devicetree entry");
                 return;