回复: [PATCH] BaseTools GenFw: Add support for R_RISCV_PCREL_LO12_S relocation

["gaoliming" <gaoliming@byosoft.com.cn>]

Acked-by: Liming Gao <gaoliming@byosoft.com.cn>

> -----邮件原件-----
> 发件人: Sunil V L <sunilvl@ventanamicro.com>
> 发送时间: 2021年7月13日 18:14
> 收件人: Daniel Schaefer <daniel.schaefer@hpe.com>
> 抄送: devel@edk2.groups.io; sunil.vl@gmail.com; Liming Gao
> <gaoliming@byosoft.com.cn>; Bob Feng <bob.c.feng@intel.com>; Yuwei Chen
> <yuwei.chen@intel.com>; Pete Batard <pete@akeo.ie>; Abner Chang
> <abner.chang@hpe.com>
> 主题: Re: [PATCH] BaseTools GenFw: Add support for
> R_RISCV_PCREL_LO12_S relocation
> 
> On Tue, Jul 13, 2021 at 05:27:30PM +0800, Daniel Schaefer wrote:
> > Looks good. I compared it with existing R_RISCV_PCREL_LO12_I and looked
> at
> > the differences.
> >
> Thanks Daniel.
> 
> > This one doesn't do use mRiscVPass1GotFixup.
> > I assume this is an optimization that's not possible here?
> 
> GOT fixup is required only for load to avoid the indirection for symbol
> resolution.
> 
> Thanks
> Sunil
> >
> > Haven't tested that it works but since it works for Pete:
> >
> > Reviewed-by: Daniel Schaefer <daniel.schaefer@hpe.com>
> >
> > Thanks!
> >
> > On 7/10/21 2:31 PM, Sunil V L wrote:
> > > Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3459
> > >
> > > This patch adds support for R_RISCV_PCREL_LO12_S relocation type.
> > > The logic is same as existing R_RISCV_PCREL_LO12_I relocation
> > > except the difference between load vs store instruction formats.
> > >
> > > Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> > >
> > > Cc: Liming Gao <gaoliming@byosoft.com.cn>
> > > Cc: Bob Feng <bob.c.feng@intel.com>
> > > Cc: Yuwei Chen <yuwei.chen@intel.com>
> > > Cc: Pete Batard <pete@akeo.ie>
> > > Cc: Abner Chang <abner.chang@hpe.com>
> > > Cc: Daniel Schaefer <daniel.schaefer@hpe.com>
> > > ---
> > >   BaseTools/Source/C/GenFw/Elf64Convert.c | 55
> +++++++++++++++++++++++++
> > >   1 file changed, 55 insertions(+)
> > >
> > > diff --git a/BaseTools/Source/C/GenFw/Elf64Convert.c
> b/BaseTools/Source/C/GenFw/Elf64Convert.c
> > > index 3d7e20aaff..0bb3ead228 100644
> > > --- a/BaseTools/Source/C/GenFw/Elf64Convert.c
> > > +++ b/BaseTools/Source/C/GenFw/Elf64Convert.c
> > > @@ -557,6 +557,60 @@ WriteSectionRiscV64 (
> > >       Value = (UINT32)(RV_X(*(UINT32 *)mRiscVPass1Targ, 12, 20));
> > >       break;
> > > +  case R_RISCV_PCREL_LO12_S:
> > > +    if (mRiscVPass1Targ != NULL && mRiscVPass1Sym != NULL &&
> mRiscVPass1SymSecIndex != 0) {
> > > +      int i;
> > > +      Value2 = (UINT32)(RV_X(*(UINT32 *)mRiscVPass1Targ, 12, 20));
> > > +
> > > +      Value = ((UINT32)(RV_X(*(UINT32 *)Targ, 25, 7)) << 5);
> > > +      Value = (Value | (UINT32)(RV_X(*(UINT32 *)Targ, 7, 5)));
> > > +
> > > +      if(Value & (RISCV_IMM_REACH/2)) {
> > > +        Value |= ~(RISCV_IMM_REACH-1);
> > > +      }
> > > +      Value = Value - (UINT32)mRiscVPass1Sym->sh_addr +
> mCoffSectionsOffset[mRiscVPass1SymSecIndex];
> > > +
> > > +      if(-2048 > (INT32)Value) {
> > > +        i = (((INT32)Value * -1) / 4096);
> > > +        Value2 -= i;
> > > +        Value += 4096 * i;
> > > +        if(-2048 > (INT32)Value) {
> > > +          Value2 -= 1;
> > > +          Value += 4096;
> > > +        }
> > > +      }
> > > +      else if( 2047 < (INT32)Value) {
> > > +        i = (Value / 4096);
> > > +        Value2 += i;
> > > +        Value -= 4096 * i;
> > > +        if(2047 < (INT32)Value) {
> > > +          Value2 += 1;
> > > +          Value -= 4096;
> > > +        }
> > > +      }
> > > +
> > > +      // Update the IMM of SD instruction
> > > +      //
> > > +      // |31      25|24  20|19  15|14   12 |11      7|6
> 0|
> > > +      // |-------------------------------------------|-------|
> > > +      // |imm[11:5] | rs2  | rs1  | funct3 |imm[4:0] | opcode|
> > > +      //  ---------------------------------------------------
> > > +
> > > +      // First Zero out current IMM
> > > +      *(UINT32 *)Targ &= ~0xfe000f80;
> > > +
> > > +      // Update with new IMM
> > > +      *(UINT32 *)Targ |= (RV_X(Value, 5, 7) << 25);
> > > +      *(UINT32 *)Targ |= (RV_X(Value, 0, 5) << 7);
> > > +
> > > +      // Update previous instruction
> > > +      *(UINT32 *)mRiscVPass1Targ = (RV_X(Value2, 0, 20)<<12) |
> (RV_X(*(UINT32 *)mRiscVPass1Targ, 0, 12));
> > > +    }
> > > +    mRiscVPass1Sym = NULL;
> > > +    mRiscVPass1Targ = NULL;
> > > +    mRiscVPass1SymSecIndex = 0;
> > > +    break;
> > > +
> > >     case R_RISCV_PCREL_LO12_I:
> > >       if (mRiscVPass1Targ != NULL && mRiscVPass1Sym != NULL &&
> mRiscVPass1SymSecIndex != 0) {
> > >         int i;
> > > @@ -1587,6 +1641,7 @@ WriteRelocations64 (
> > >               case R_RISCV_PCREL_HI20:
> > >               case R_RISCV_GOT_HI20:
> > >               case R_RISCV_PCREL_LO12_I:
> > > +            case R_RISCV_PCREL_LO12_S:
> > >                 break;
> > >               default:
> > >