[PATCH 1/8] lib: sbi: add 64 bit csr macros

[Anup Patel]

On Tue, Apr 15, 2025 at 8:13 PM Radim Krčmář <rkrcmar at ventanamicro.com> wrote:
>
> Most CSRs are XLEN bits wide, but some are 64 bit, so rv32 needs two
> accesses, plaguing the code with ifdefs.
>
> Add new helpers that split 64 bit operation into two operations on rv32.
>
> The helpers don't use "csr + 0x10", but append "H" at the end of the csr
> name to get a compile-time error when accessing a non 64 bit register.
> This has the downside that you have to use the name when accessing them.
> e.g. csr_read64(0x1234) or csr_read64(CSR_SATP) won't compile and the
> error messages you get for these bugs are not straightforward.
>
> Signed-off-by: Radim Krčmář <rkrcmar at ventanamicro.com>
> ---
>  include/sbi/riscv_asm.h | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/include/sbi/riscv_asm.h b/include/sbi/riscv_asm.h
> index 4605db20bd7a..d19281ac1961 100644
> --- a/include/sbi/riscv_asm.h
> +++ b/include/sbi/riscv_asm.h
> @@ -156,6 +156,27 @@
>                                      : "memory");                  \
>         })
>
> +

Redundant newline.

> +#if __riscv_xlen == 64
> +#define __csrrw64(op, csr, csrh, val) (true ? op(csr, val) : (uint64_t)csrh)
> +#define __csrr64( op, csr, csrh)      (true ? op(csr)      : (uint64_t)csrh)
> +#define __csrw64( op, csr, csrh, val) (true ? op(csr, val) : (uint64_t)csrh)
> +#elif __riscv_xlen == 32
> +#define __csrrw64(op, csr, csrh, val) (  op(csr, val) | (uint64_t)op(csrh, val >> 32) << 32)
> +#define __csrr64( op, csr, csrh)      (  op(csr)      | (uint64_t)op(csrh)            << 32)
> +#define __csrw64( op, csr, csrh, val) ({ op(csr, val);            op(csrh, val >> 32);    })
> +#endif
> +
> +#define csr_swap64(        csr, val) __csrrw64(csr_swap,         csr, csr ## H, val)
> +#define csr_read64(        csr)      __csrr64 (csr_read,         csr, csr ## H)
> +#define csr_read_relaxed64(csr)      __csrr64 (csr_read_relaxed, csr, csr ## H)
> +#define csr_write64(       csr, val) __csrw64 (csr_write,        csr, csr ## H, val)
> +#define csr_read_set64(    csr, val) __csrrw64(csr_read_set,     csr, csr ## H, val)
> +#define csr_set64(         csr, val) __csrw64 (csr_set,          csr, csr ## H, val)
> +#define csr_clear64(       csr, val) __csrw64 (csr_clear,        csr, csr ## H, val)
> +#define csr_read_clear64(  csr, val) __csrrw64(csr_read_clear,   csr, csr ## H, val)
> +#define csr_clear64(       csr, val) __csrw64 (csr_clear,        csr, csr ## H, val)
> +
>  unsigned long csr_read_num(int csr_num);
>
>  void csr_write_num(int csr_num, unsigned long val);
> --
> 2.48.1
>
>
> --
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Otherwise, LGTM.

Reviewed-by: Anup Patel <anup at brainfault.org>

Regards,
Anup