[U-Boot] [PATCH v5 4/4] riscv: Remove redundant a2 store on DRAM base in start.S

Auer, Lukas lukas.auer at aisec.fraunhofer.de
Mon Nov 26 22:10:46 UTC 2018


On Mon, 2018-11-26 at 23:10 +0800, Bin Meng wrote:
> On Mon, Nov 26, 2018 at 6:43 PM Anup Patel <anup at brainfault.org>
> wrote:
> > 
> > Currently, the RISC-V U-Boot is saving a2 register at
> > CONFIG_SYS_DRAM_BASE in start.S which does not make sense
> > because there is no information passed by previous booting
> > stage in a2 register.
> > 
> > This patch removes redundant a2 store on DRAM base.
> > 
> > Signed-off-by: Anup Patel <anup at brainfault.org>
> > ---
> >  arch/riscv/cpu/start.S | 2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S
> > index 704190f946..e4276e8e19 100644
> > --- a/arch/riscv/cpu/start.S
> > +++ b/arch/riscv/cpu/start.S
> > @@ -38,8 +38,6 @@ _start:
> >         mv      s0, a0
> >         mv      s1, a1
> > 
> > -       li      t0, CONFIG_SYS_SDRAM_BASE
> > -       SREG    a2, 0(t0)
> >         la      t0, trap_entry
> >  #ifdef CONFIG_RISCV_SMODE
> >         csrw    stvec, t0
> > --
> 
> This is weird. I remember these two lines were already removed by
> Lukas's patch series before? Did not have time to dig out the history
> though.
> 
> Regards,
> Bin

You are correct, however I removed it again, because I did not want to
break Rick's board. He did add a commit to the last pull request that
removes these two lines and adjusts his board accordingly, but it is
not in the current one.

Thanks,
Lukas


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