[PATCH v2] lib: sbi: Fix sign-extension in sbi_misaligned_load_handler()

[Anup Patel]

> -----Original Message-----
> From: Atish Patra <atishp at atishpatra.org>
> Sent: 22 December 2020 05:28
> To: Anup Patel <Anup.Patel at wdc.com>
> Cc: Atish Patra <Atish.Patra at wdc.com>; Alistair Francis
> <Alistair.Francis at wdc.com>; Anup Patel <anup at brainfault.org>; OpenSBI
> <opensbi at lists.infradead.org>
> Subject: Re: [PATCH v2] lib: sbi: Fix sign-extension in
> sbi_misaligned_load_handler()
> 
> On Sun, Dec 20, 2020 at 8:26 PM Anup Patel <anup.patel at wdc.com> wrote:
> >
> > The misaligned load emulation does not sign-extend values correctly
> > due to missing sign typecast in value passed to the SET_RD() macro.
> >
> > A very easy way to reproduce this issue is to load 16-bit value 0xff1e
> > from a byte aligned address using LH instruction on hardware lacking
> > misaligned load/store.
> >
> > This patch fixes sbi_misaligned_load_handler() for above issue.
> >
> > Signed-off-by: Anup Patel <anup.patel at wdc.com>
> > ---
> > Changes since v1:
> >  - Cast after left-shift and use braces.
> > ---
> >  lib/sbi/sbi_misaligned_ldst.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/lib/sbi/sbi_misaligned_ldst.c
> > b/lib/sbi/sbi_misaligned_ldst.c index 964a372..5057cb5 100644
> > --- a/lib/sbi/sbi_misaligned_ldst.c
> > +++ b/lib/sbi/sbi_misaligned_ldst.c
> > @@ -128,7 +128,7 @@ int sbi_misaligned_load_handler(ulong addr, ulong
> tval2, ulong tinst,
> >         }
> >
> >         if (!fp)
> > -               SET_RD(insn, regs, val.data_ulong << shift >> shift);
> > +               SET_RD(insn, regs, ((long)(val.data_ulong << shift))
> > + >> shift);
> >  #ifdef __riscv_flen
> >         else if (len == 8)
> >                 SET_F64_RD(insn, regs, val.data_u64);
> > --
> > 2.25.1
> >
> >
> > --
> > opensbi mailing list
> > opensbi at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/opensbi
> 
> 
> Reviewed-by: Atish Patra <atish.patra at wdc.com>

Applied this patch on riscv/opensbi repo

Regards,
Anup