[PATCH] riscv: compat: Using seperated vdso_maps for compat_vdso_info

[Guo Ren]

On Thu, May 26, 2022 at 8:39 AM Palmer Dabbelt <palmer at dabbelt.com> wrote:
>
> On Wed, 25 May 2022 15:56:07 PDT (-0700), linux at roeck-us.net wrote:
> > On 5/25/22 14:34, Palmer Dabbelt wrote:
> >> On Wed, 25 May 2022 14:15:03 PDT (-0700), linux at roeck-us.net wrote:
> >>> On 5/25/22 09:04, guoren at kernel.org wrote:
> >>>> From: Guo Ren <guoren at linux.alibaba.com>
> >>>>
> >>>> This is a fixup for vdso implementation which caused musl to
> >>>> fail.
> >>>>
> >>>> [   11.600082] Run /sbin/init as init process
> >>>> [   11.628561] init[1]: unhandled signal 11 code 0x1 at
> >>>> 0x0000000000000000 in libc.so[ffffff8ad39000+a4000]
> >>>> [   11.629398] CPU: 0 PID: 1 Comm: init Not tainted
> >>>> 5.18.0-rc7-next-20220520 #1
> >>>> [   11.629462] Hardware name: riscv-virtio,qemu (DT)
> >>>> [   11.629546] epc : 00ffffff8ada1100 ra : 00ffffff8ada13c8 sp :
> >>>> 00ffffffc58199f0
> >>>> [   11.629586]  gp : 00ffffff8ad39000 tp : 00ffffff8ade0998 t0 :
> >>>> ffffffffffffffff
> >>>> [   11.629598]  t1 : 00ffffffc5819fd0 t2 : 0000000000000000 s0 :
> >>>> 00ffffff8ade0cc0
> >>>> [   11.629610]  s1 : 00ffffff8ade0cc0 a0 : 0000000000000000 a1 :
> >>>> 00ffffffc5819a00
> >>>> [   11.629622]  a2 : 0000000000000001 a3 : 000000000000001e a4 :
> >>>> 00ffffffc5819b00
> >>>> [   11.629634]  a5 : 00ffffffc5819b00 a6 : 0000000000000000 a7 :
> >>>> 0000000000000000
> >>>> [   11.629645]  s2 : 00ffffff8ade0ac8 s3 : 00ffffff8ade0ec8 s4 :
> >>>> 00ffffff8ade0728
> >>>> [   11.629656]  s5 : 00ffffff8ade0a90 s6 : 0000000000000000 s7 :
> >>>> 00ffffffc5819e40
> >>>> [   11.629667]  s8 : 00ffffff8ade0ca0 s9 : 00ffffff8addba50 s10:
> >>>> 0000000000000000
> >>>> [   11.629678]  s11: 0000000000000000 t3 : 0000000000000002 t4 :
> >>>> 0000000000000001
> >>>> [   11.629688]  t5 : 0000000000020000 t6 : ffffffffffffffff
> >>>> [   11.629699] status: 0000000000004020 badaddr: 0000000000000000
> >>>> cause: 000000000000000d
> >>>>
> >>>> The last __vdso_init(&compat_vdso_info) replaces the data in normal
> >>>> vdso_info. This is an obvious bug.
> >>>>
> >>>> Reported-by: Guenter Roeck <linux at roeck-us.net>
> >>>> Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> >>>> Signed-off-by: Guo Ren <guoren at kernel.org>
> >>>> Cc: Palmer Dabbelt <palmer at dabbelt.com>
> >>>> Cc: Heiko Stübner <heiko at sntech.de>
> >>>
> >>> Tested-by: Guenter Roeck <linux at roeck-us.net>
> >>
> >> Sorry I'm a bit buried right now, this is fixing the issue you pointed out earlier?
> >>
> > Yes.
>
> Awosome, I think that was the only big blocker so far.
>
> I added a musl-based userspace to my test setup, which is rv64-only
> (buildroot doesn't have rv32 musl, I thought upstream had it but maybe
Here is rv32 musl information, I think it could be ready.
https://www.openwall.com/lists/musl/2020/03/12/1

> i'm misremembering).  This patch fixes the bug, so I've added it to
> for-next with
>
> Fixes: 3092eb456375 ("riscv: compat: vdso: Add setup additional pages implementation")
If for-next has merged into the Linus tree, please help add the above.

>
> which I think is correct, but LMK if there's an issue.
>
> Thanks!
>
> (and also sorry I poked Geert instead of you about this one, oops ;))
>
> >
> > Thanks,
> > Guenter
> >
> >>>
> >>>> ---
> >>>>   arch/riscv/kernel/vdso.c | 15 +++++++++++++--
> >>>>   1 file changed, 13 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
> >>>> index 50fe4c877603..69b05b6c181b 100644
> >>>> --- a/arch/riscv/kernel/vdso.c
> >>>> +++ b/arch/riscv/kernel/vdso.c
> >>>> @@ -206,12 +206,23 @@ static struct __vdso_info vdso_info __ro_after_init = {
> >>>>   };
> >>>>
> >>>>   #ifdef CONFIG_COMPAT
> >>>> +static struct vm_special_mapping rv_compat_vdso_maps[] __ro_after_init = {
> >>>> +    [RV_VDSO_MAP_VVAR] = {
> >>>> +        .name   = "[vvar]",
> >>>> +        .fault = vvar_fault,
> >>>> +    },
> >>>> +    [RV_VDSO_MAP_VDSO] = {
> >>>> +        .name   = "[vdso]",
> >>>> +        .mremap = vdso_mremap,
> >>>> +    },
> >>>> +};
> >>>> +
> >>>>   static struct __vdso_info compat_vdso_info __ro_after_init = {
> >>>>       .name = "compat_vdso",
> >>>>       .vdso_code_start = compat_vdso_start,
> >>>>       .vdso_code_end = compat_vdso_end,
> >>>> -    .dm = &rv_vdso_maps[RV_VDSO_MAP_VVAR],
> >>>> -    .cm = &rv_vdso_maps[RV_VDSO_MAP_VDSO],
> >>>> +    .dm = &rv_compat_vdso_maps[RV_VDSO_MAP_VVAR],
> >>>> +    .cm = &rv_compat_vdso_maps[RV_VDSO_MAP_VDSO],
> >>>>   };
> >>>>   #endif
> >>>>



-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/