This patch can be dropped. I noticed Kito finally fixed that before committing
to master after I submitted this patch.
> On Oct 14, 2024, at 18:18, Yangyu Chen <chenyan...@isrc.iscas.ac.cn> wrote:
>
> The feature_bits.c file failed to compile on non-Linux targets because
> we forgot to remove the __riscv_vendor_feature_bits.vendorID set
> when target is not Linux.
>
> This commit fixed this and also has several improvements including:
> - Initialize all data to zero when syscall is not supported.
> - Add detailed comments on processing implied extensions.
>
> Fixes: ca44eb7f6a33 ("RISC-V: Implement __init_riscv_feature_bits,
> __riscv_feature_bits, and
> __riscv_vendor_feature_bits")
>
> libgcc/ChangeLog:
>
> * config/riscv/feature_bits.c (__init_riscv_features_bits_linux):
> Remove __riscv_vendor_feature_bits.vendorID set when target is
> not Linux, and initialize all data to zero when syscall is not
> supported.
>
> Signed-off-by: Yangyu Chen <chenyan...@isrc.iscas.ac.cn>
> ---
> libgcc/config/riscv/feature_bits.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/libgcc/config/riscv/feature_bits.c
> b/libgcc/config/riscv/feature_bits.c
> index 9bdbc466fee..44f8eeee4e7 100644
> --- a/libgcc/config/riscv/feature_bits.c
> +++ b/libgcc/config/riscv/feature_bits.c
> @@ -262,7 +262,15 @@ static void __init_riscv_features_bits_linux ()
> 0, 0);
>
> if (res)
> - return;
> + {
> + /* When syscall is not supported, just initialize that into all zeros.
> */
> + __riscv_feature_bits.length = 0;
> + __riscv_vendor_feature_bits.length = 0;
> + __riscv_cpu_model.mvendorid = 0;
> + __riscv_cpu_model.marchid = 0;
> + __riscv_cpu_model.mimpid = 0;
> + return;
> + }
>
> const struct riscv_hwprobe hwprobe_mvendorid = hwprobes[0];
>
> @@ -290,9 +298,12 @@ static void __init_riscv_features_bits_linux ()
> }
>
> const struct riscv_hwprobe hwprobe_ima_ext = hwprobes[4];
> -
> /* Every time we add new extensions, we should check if previous extensions
> - imply the new extension and set the corresponding bit. */
> + imply the new extension and set the corresponding bit.
> + We don't need to handle cases where:
> + 1. The new extension implies a previous extension (e.g., Zve32f -> F).
> + 2. The extensions imply some other extensions appear in the same
> release
> + version of Linux Kernel (e.g., Zbc - > Zbkc). */
>
> if (hwprobe_ima_ext.value & RISCV_HWPROBE_IMA_FD)
> {
> @@ -397,7 +408,7 @@ __init_riscv_feature_bits ()
> #ifdef __linux
> __init_riscv_features_bits_linux ();
> #else
> - /* Unsupported, just initlizaed that into all zeros. */
> + /* Unsupported, just initialize that into all zeros. */
> __riscv_feature_bits.length = 0;
> __riscv_vendor_feature_bits.length = 0;
> __riscv_cpu_model.mvendorid = 0;
> --
> 2.45.2
