Re: [PULL 15/21] linux-user/riscv: Add vdso

[Richard Henderson]

On 1/13/24 10:37, Vineet Gupta wrote:
> On 1/12/24 13:35, Richard Henderson wrote:
> > On 1/12/24 08:49, Vineet Gupta wrote:
> > > Hi Richard, Alistair
> > >
> > > On 10/30/23 14:17, Richard Henderson wrote:
> > > > diff --git a/linux-user/riscv/Makefile.vdso b/linux-user/riscv/Makefile.vdso
> > > > new file mode 100644
> > > > index 0000000000..2c257dbfda
> > > > --- /dev/null
> > > > +++ b/linux-user/riscv/Makefile.vdso
> > > > @@ -0,0 +1,15 @@
> > > > +include $(BUILD_DIR)/tests/tcg/riscv64-linux-user/config-target.mak
> > > > +
> > > > +SUBDIR = $(SRC_PATH)/linux-user/riscv
> > > > +VPATH += $(SUBDIR)
> > > > +
> > > > +all: $(SUBDIR)/vdso-32.so $(SUBDIR)/vdso-64.so
> > > > +
> > > > +LDFLAGS = -nostdlib -shared -fpic -Wl,-h,linux-vdso.so.1 -Wl,--build-id=sha1 \
> > > > +         -Wl,--hash-style=both -Wl,-T,$(SUBDIR)/vdso.ld
> > > > +
> > > > +$(SUBDIR)/vdso-32.so: vdso.S vdso.ld vdso-asmoffset.h
> > > > +       $(CC) -o $@ $(LDFLAGS) -mabi=ilp32d -march=rv32g $<
> > > > +
> > > > +$(SUBDIR)/vdso-64.so: vdso.S vdso.ld vdso-asmoffset.h
> > > > +       $(CC) -o $@ $(LDFLAGS) -mabi=lp64d -march=rv64g $<
> > > So by default qemu ships the vdso binary. How can one rebuild it ?
> > >
> > >   From skimming the build files it seems following ought to do it
> > >       make update-linux-vdso
> > >
> > > with a prior configure cmd like below with PATH pointing to the cross
> > > compiler.
> > > ../configure  --target-list=riscv64-linux-user
> > > --cross-cc-riscv64=riscv64-unknown-linux-gnu-gcc
> > Yes, that should do it.
> >
> > > But it doesn't, I'm sure we are missing something basis here.
> > Do you get an error message?
> > Did $(BUILD_DIR)/tests/tcg/riscv64-linux-user/config-target.mak get created 
> > properly?
>
> It was indeed, but invoking make wasn't doing anything.

Odd.  It Just Works here...

What do you have in the "Cross compilers" section of the configure output?

I would expect '--cross-prefix-riscv64=...' to be a better option that just gcc.  And if 
you have it installed as "riscv64-linux-gnu-", I would not expect you to need to provide 
any configure option at all -- it should be auto-detected.