[PATCH V3 0/7] riscv: Add GENERIC_ENTRY, irq stack support

[Conor.Dooley at microchip.com]

On 07/09/2022 03:52, Guo Ren wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Hi Conor,
> 
> I've found the root cause, you are using llvm:

Yup, probably should have specified - sorry. I didn't realise that
that was something GCC wouldn't complain about. It was an LLVM=1
build with clang-15.

I usually do builds with clang while testing patches as it seems
to be lesser used.

Thanks,
Conor.

> 
> $ grep "bare sym" llvm -rn |grep RISCV
> llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:1296: return
> Error(ErrorLoc, "operand must be a bare symbol name");
> llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp:1304: return
> Error(ErrorLoc, "operand must be a bare symbol name");
> 
> That means we could fix up Binutils with a warning at least.
> 
> Thx for pointing it out.
> 
> On Wed, Sep 7, 2022 at 8:54 AM Guo Ren <guoren at kernel.org> wrote:
>>
>> On Wed, Sep 7, 2022 at 1:42 AM <Conor.Dooley at microchip.com> wrote:
>>>
>>> On 06/09/2022 04:54, guoren at kernel.org wrote:
>>>> From: Guo Ren <guoren at linux.alibaba.com>
>>>>
>>>> The patches convert riscv to use the generic entry infrastructure from
>>>> kernel/entry/*. Add independent irq stacks (IRQ_STACKS) for percpu to
>>>> prevent kernel stack overflows. Add the HAVE_SOFTIRQ_ON_OWN_STACK
>>>> feature for the IRQ_STACKS config. You can try it directly with [1].
>>>
>>> Hey Guo Ren,
>>> I applied this patchset to v6.0-rc4 & ran into a build error:
>>> /stuff/linux/arch/riscv/kernel/entry.S:347:9: error: operand must be a bare symbol name
>>>   la a3, ((1 << (12)) << (2 + 0))
>> Yes, please try:
>> -       la      a3, IRQ_STACK_SIZE
>> +       li      a3, IRQ_STACK_SIZE
>>
>> la is for the symbol, not immediate. But why does my toolchain not
>> report the error?
>>
>> ➜  linux git:(generic_entry_v3) make ARCH=riscv
>> CROSS_COMPILE=riscv64-unknown-linux-gnu- EXTRA_CFLAGS+=-g
>> O=../build-riscv/ -kj62 all -kj
>> ➜  linux git:(generic_entry_v3) riscv64-unknown-linux-gnu-gcc -v
>> Using built-in specs.
>> COLLECT_GCC=riscv64-unknown-linux-gnu-gcc
>> COLLECT_LTO_WRAPPER=/opt/riscv/libexec/gcc/riscv64-unknown-linux-gnu/11.1.0/lto-wrapper
>> Target: riscv64-unknown-linux-gnu
>> Configured with:
>> /home/guoren/source/riscv-gnu-toolchain/riscv-gcc/configure
>> --target=riscv64-unknown-linux-gnu --prefix=/opt/riscv
>> --with-sysroot=/opt/riscv/sysroot --with-pkgversion=g5964b5cd7272
>> --with-system-zlib --enable-shared --enable-tls
>> --enable-languages=c,c++,fortran --disable-libmudflap --disable-libssp
>> --disable-libquadmath --disable-libsanitizer --disable-nls
>> --disable-bootstrap --src=.././riscv-gcc --enable-multilib
>> --with-abi=lp64d --with-arch=rv64imafdc --with-tune=rocket
>> --with-isa-spec=2.2 'CFLAGS_FOR_TARGET=-O2   -mcmodel=medlow'
>> 'CXXFLAGS_FOR_TARGET=-O2   -mcmodel=medlow'
>> Thread model: posix
>> Supported LTO compression algorithms: zlib
>> gcc version 11.1.0 (g5964b5cd7272)
>>
>>
>>
>>>          ^
>>>    CC      arch/riscv/kernel/process.o
>>> make[5]: *** [/stuff/linux/scripts/Makefile.build:322: arch/riscv/kernel/entry.o] Error 1
>>> make[5]: *** Waiting for unfinished jobs....
>>>
>>> Thanks,
>>> Conor.
>>>>
>>>> [1] https://github.com/guoren83/linux/tree/generic_entry_v3
>>>>
>>>> V3:
>>>>   - Fixup CONFIG_COMPAT=n compile error
>>>>   - Add THREAD_SIZE_ORDER config
>>>>   - Optimize elf_kexec.c warning fixup
>>>>   - Add static to irq_stack_ptr definition
>>>>
>>>> V2:
>>>>   Link: https://lore.kernel.org/linux-riscv/20220904072637.8619-1-guoren@kernel.org/
>>>>   - Fixup compile error by include "riscv: ptrace: Remove duplicate
>>>>     operation"
>>>>   - Fixup compile warning
>>>>     Reported-by: kernel test robot <lkp at intel.com>
>>>>   - Add test repo link in cover letter
>>>>
>>>> V1:
>>>>   Link: https://lore.kernel.org/linux-riscv/20220903163808.1954131-1-guoren@kernel.org/
>>>>
>>>> Guo Ren (7):
>>>>    riscv: elf_kexec: Fixup compile warning
>>>>    riscv: compat_syscall_table: Fixup compile warning
>>>>    riscv: ptrace: Remove duplicate operation
>>>>    riscv: convert to generic entry
>>>>    riscv: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
>>>>    riscv: Support HAVE_SOFTIRQ_ON_OWN_STACK
>>>>    riscv: Add config of thread stack size
>>>>
>>>>   arch/riscv/Kconfig                    |  19 ++
>>>>   arch/riscv/include/asm/csr.h          |   1 -
>>>>   arch/riscv/include/asm/entry-common.h |   8 +
>>>>   arch/riscv/include/asm/irq.h          |   3 +
>>>>   arch/riscv/include/asm/ptrace.h       |  10 +-
>>>>   arch/riscv/include/asm/stacktrace.h   |   5 +
>>>>   arch/riscv/include/asm/syscall.h      |   6 +
>>>>   arch/riscv/include/asm/thread_info.h  |  19 +-
>>>>   arch/riscv/include/asm/vmap_stack.h   |  28 +++
>>>>   arch/riscv/kernel/Makefile            |   1 +
>>>>   arch/riscv/kernel/elf_kexec.c         |   2 +-
>>>>   arch/riscv/kernel/entry.S             | 255 +++++---------------------
>>>>   arch/riscv/kernel/irq.c               |  75 ++++++++
>>>>   arch/riscv/kernel/ptrace.c            |  41 -----
>>>>   arch/riscv/kernel/signal.c            |  21 +--
>>>>   arch/riscv/kernel/sys_riscv.c         |  27 +++
>>>>   arch/riscv/kernel/traps.c             |  11 ++
>>>>   arch/riscv/mm/fault.c                 |  12 +-
>>>>   18 files changed, 259 insertions(+), 285 deletions(-)
>>>>   create mode 100644 arch/riscv/include/asm/entry-common.h
>>>>   create mode 100644 arch/riscv/include/asm/vmap_stack.h
>>>>
>>
>>
>>
>> --
>> Best Regards
>>   Guo Ren
> 
> 
> 
> --
> Best Regards
>   Guo Ren