Re: [PATCH v2 2/2] RISC-V: Don't use a global include guard for uapi/asm/syscalls.h

[Guenter Roeck]

On 08/09/2018 08:59 PM, Palmer Dabbelt wrote:
> On Thu, 09 Aug 2018 19:40:55 PDT (-0700), linux@xxxxxxxxxxxx wrote:
> > On 08/09/2018 06:03 PM, Palmer Dabbelt wrote:
> > > On Thu, 09 Aug 2018 14:24:22 PDT (-0700), linux@xxxxxxxxxxxx wrote:
> > > > On Thu, Aug 09, 2018 at 01:25:24PM -0700, Palmer Dabbelt wrote:
> > > > > This file is expected to be included multiple times in the same file in
> > > > > order to allow the __SYSCALL macro to generate system call tables. With
> > > > > a global include guard we end up missing __NR_riscv_flush_icache in the
> > > > > syscall table, which results in icache flushes that escape the vDSO call
> > > > > to not actually do anything.
> > > > >
> > > > > The fix is to move to per-#define include guards, which allows the
> > > > > system call tables to actually be populated. Thanks to Macrus Comstedt
> > > > > for finding and fixing the bug!
> > > > >
> > > > > I also went ahead and fixed the SPDX header to use a //-style comment,
> > > > > which I've been told is the canonical way to do it.
> > > > >
> > > > > Cc: Marcus Comstedt <marcus@xxxxxxxx>
> > > > > Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxx>
> > > >
> > > > [Compile-]Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > > >
> > > > on top of linux-next after reverting the version of the patch there.
> > > >
> > > > I also tried to run the resulting image (defconfig) with qemu (built
> > > > from https://github.com/riscv/riscv-qemu.git), but that still doesn't
> > > > work. I assume there are still some patches missing ?
> > >
> > > Do you have the PLIC patches? They'll be necessary to make this all work, and there's a v4 out now that when combined with for-next should get you to userspace.
> > >
> > > ÂÂÂ https://lore.kernel.org/lkml/20180809075602.989-1-hch@xxxxxx/T/#u
> > Yes, after merging that branch on top of linux-next I can boot into Linux.
> > If I add my "riscv: Drop setup_initrd" patch as well, I can boot using
> > initrd, otherwise I have to use virtio-blk-device.
>
> Awesome! If you patch isn't on for-next then I must have missed it, do you mind sending me a pointer? I can't find any references in my email.
Hmm ... weird. I don't find it either. Maybe I sent it only in my dreams.
I'll send it out for review.

Guenter

> > > Also, what is your methodology? I follow
> > >
> > > ÂÂÂ https://wiki.qemu.org/Documentation/Platforms/RISCV
> > >
> > > and could could natively compile and run hello world with an earlier version of Christoph's patch set, which is really only cosmetically different than the v4. I use qemu's master branch as well, which when I tried was exactly 3.0.0-rc3.
> >
> > That doesn't work for me, possibly because I don't specify a bbl
> > image with -kernel but vmlinux (using -bios for the bbl image).
> > I use branch qemu-for-upstream of https://github.com/riscv/riscv-qemu.git.
> >
> > Guenter