Re: [PATCH v3 07/12] riscv: Add option to support RISC-V privileged spec 1.9.1

[Sean Anderson]

On 2/4/20 9:38 AM, Bin Meng wrote:
> Hi Sean,
> 
> On Tue, Feb 4, 2020 at 10:19 PM Sean Anderson <sean...@gmail.com> wrote:
>> I believe the macro compiles to "csrs CSR_FOO". At least with my
>> gcc/binutils (9.2.0/2.33.1) this style is not available for these older
>> CSRs. Perhaps it would work if we switched to letting it compile with
>> the numeric CSR as defined earlier in asm/csr.h
> 
> It's already using the numeric CSR for csr_write(). Could you double check?

Well, the current definition is

#define csr_write(csr, val)                                     \
({                                                              \
        unsigned long __v = (unsigned long)(val);               \
        __asm__ __volatile__ ("csrw " __ASM_STR(csr) ", %0"     \
                              : : "rK" (__v)                    \
                              : "memory");                      \
})

and _ASM_STR(csr) evaluates to #csr. I think that results in something
like

__asm__("csrw " "CSR_FOO" ", %0"

In any case, the errors I get are

arch/riscv/cpu/cpu.c: Assembler messages:
arch/riscv/cpu/cpu.c:94: Error: unknown CSR `CSR_MSCOUNTEREN'
arch/riscv/cpu/cpu.c:94: Error: unknown CSR `CSR_MSCOUNTEREN'

which doesn't seem like a numeric CSR to me.

--Sean