[PATCH 0/4] RISC-V: Support more rigorous check for CSR, and update them to spec 1.12.

[Nelson Chu]

Ok, I will fix this ASAP :)

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> Palmer Dabbelt <palmerdabbelt@google.com> 於 2019年12月3日 上午7:16 寫道：
> 
> On Sun, 24 Nov 2019 23:40:08 PST (-0800), nelson.chu@sifive.com wrote:
>> 
>> According to the riscv privilege spec, CSR have some restrictions when we use
>> them.  Some of CSR are only valid when the specific extension is set.  Some of
>> CSR are read-only CSR, and we have no write access for them.  These for patches
>> are used to support more rigorous check for CSR, and the currently supported
>> checks are shown as follows:
>> 
>> * The ISA-dependent CSR checking
>>  - The CSR are only valid when the f extension is set.
>>  - The CSR are only valid for the rv32.
>> 
>> * The read-only CSR checking
>>  - CSRRW and CSRRWI always write CSR.  CSRRS, CSRRC, CSRRSI and CSRRCI write
>>    CSR when RS1 isn't zero.  We can not write the read-ony CSR by these CSR
>>    instructions.
>> 
>> For now, consider the CSR checking will cause some backwards incompatibilities,
>> we disable the CSR checking by default, and support two new .options
>> (.option csrcheck/nocsrcheck) and two new GAS options (-mcsrcheck/-mno-csrcheck)
>> to enbale/disable CSR checking if user need.
>> 
>> The previous patches are a lot hard to read, so I re-send them by the
>> git-send-email again.  These four patches are almost same as the previous
>> version.  But there are two places that are different.  One is that I remove
>> the redundant source files of testsuite in the second patch (priv-reg-fail-fext.s
>> and priv-reg-fail-rv32-only.s), and add one new testsuite for the CSR read-only
>> checking in the third patch (priv-reg-fail-readonly-01).  Another is that the
>> previous third patch has an error in the riscv_csr_read_only_check (readonly).
>> I have fixed it in the newest patch.
> 
> Looks like this has a conflict with the recent GDB changes to allow CSRs in
> debug info and the patch set no longer applies.  Do you mind re-spinning it?