回复: [RESEND PATCH v2] BaseTools: Add support for RISCV GOT/PLT relocations

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

Sunil:
  I add my comments below. 

Thanks
Liming
> -----邮件原件-----
> 发件人: Sunil V L <sunilvl@ventanamicro.com>
> 发送时间: 2021年6月11日 22:05
> 收件人: devel@edk2.groups.io
> 抄送: Sunil V L <sunilvl@ventanamicro.com>; Abner Chang
> <abner.chang@hpe.com>; Daniel Schaefer <daniel.schaefer@hpe.com>; Bob
> Feng <bob.c.feng@intel.com>; Liming Gao <gaoliming@byosoft.com.cn>;
> Yuwei Chen <yuwei.chen@intel.com>; Heinrich Schuchardt
> <xypron.glpk@gmx.de>
> 主题: [RESEND PATCH v2] BaseTools: Add support for RISCV GOT/PLT
> relocations
> 
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3096
> 
> This patch adds support for R_RISCV_CALL_PLT and R_RISCV_GOT_HI20
> relocations generated by PIE enabled compiler. This also needed
> changes to R_RISCV_32 and R_RISCV_64 relocations as explained in
> https://github.com/riscv/riscv-gnu-toolchain/issues/905#issuecomment-8466
> 82710
> 
> Changes in v2:
>   - Addressed Daniel's comment on formatting
> 
> Testing:
> 1) Debian GCC 8.3.0 and booted sifive_u and QMEU virt models.
> 2) Debian 10.2.0 and booted QEMU virt model.
> 3) riscv-gnu-tool chain 9.2 and booted QEMU virt model.
> 
> Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> 
> Acked-by: Abner Chang <abner.chang@hpe.com>
> Reviewed-by: Daniel Schaefer <daniel.schaefer@hpe.com>
> Tested-by: <daniel.schaefer@hpe.com>

Tested-By format is invalid. Its format is same Reviewed-by. 

> 
> Cc: Bob Feng <bob.c.feng@intel.com>
> Cc: Liming Gao <gaoliming@byosoft.com.cn>
> Cc: Yuwei Chen <yuwei.chen@intel.com>
> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
> ---
>  BaseTools/Source/C/GenFw/Elf64Convert.c | 44
> +++++++++++++++++++++----
>  1 file changed, 38 insertions(+), 6 deletions(-)
> 
> diff --git a/BaseTools/Source/C/GenFw/Elf64Convert.c
> b/BaseTools/Source/C/GenFw/Elf64Convert.c
> index d097db8632..d684318269 100644
> --- a/BaseTools/Source/C/GenFw/Elf64Convert.c
> +++ b/BaseTools/Source/C/GenFw/Elf64Convert.c
> @@ -129,6 +129,8 @@ STATIC UINT32 mDebugOffset;
>  STATIC UINT8       *mRiscVPass1Targ = NULL;
> 
>  STATIC Elf_Shdr    *mRiscVPass1Sym = NULL;
> 
>  STATIC Elf64_Half  mRiscVPass1SymSecIndex = 0;
> 
> +STATIC INT32       mRiscVPass1Offset;
> 
> +STATIC INT32       mRiscVPass1GotFixup;
> 
> 
> 
>  //
> 
>  // Initialization Function
> 
> @@ -479,11 +481,11 @@ WriteSectionRiscV64 (
>      break;
> 
> 
> 
>    case R_RISCV_32:
> 
> -    *(UINT32 *)Targ = (UINT32)((UINT64)(*(UINT32 *)Targ) -
> SymShdr->sh_addr + mCoffSectionsOffset[Sym->st_shndx]);
> 
> +    *(UINT64 *)Targ = Sym->st_value + Rel->r_addend;
> 
>      break;
> 
> 
> 
>    case R_RISCV_64:
> 
> -    *(UINT64 *)Targ = *(UINT64 *)Targ - SymShdr->sh_addr +
> mCoffSectionsOffset[Sym->st_shndx];
> 
> +    *(UINT64 *)Targ = Sym->st_value + Rel->r_addend;
> 
>      break;
> 
> 
> 
>    case R_RISCV_HI20:
> 
> @@ -533,6 +535,18 @@ WriteSectionRiscV64 (
>      mRiscVPass1SymSecIndex = 0;
> 
>      break;
> 
> 
> 
> +  case R_RISCV_GOT_HI20:
> 
> +    Value = (Sym->st_value - Rel->r_offset);
> 
> +    mRiscVPass1Offset = RV_X(Value, 0, 12);
> 
> +    Value = RV_X(Value, 12, 20);
> 
> +    *(UINT32 *)Targ = (Value << 12) | (RV_X(*(UINT32*)Targ, 0, 12));
> 
> +
> 
> +    mRiscVPass1Targ = Targ;
> 
> +    mRiscVPass1Sym = SymShdr;
> 
> +    mRiscVPass1SymSecIndex = Sym->st_shndx;
> 
> +    mRiscVPass1GotFixup = 1;
> 
> +    break;
> 
> +
> 
>    case R_RISCV_PCREL_HI20:
> 
>      mRiscVPass1Targ = Targ;
> 
>      mRiscVPass1Sym = SymShdr;
> 
> @@ -545,11 +559,17 @@ WriteSectionRiscV64 (
>      if (mRiscVPass1Targ != NULL && mRiscVPass1Sym != NULL &&
> mRiscVPass1SymSecIndex != 0) {
> 
>        int i;
> 
>        Value2 = (UINT32)(RV_X(*(UINT32 *)mRiscVPass1Targ, 12, 20));
> 
> -      Value = (UINT32)(RV_X(*(UINT32 *)Targ, 20, 12));
> 
> -      if(Value & (RISCV_IMM_REACH/2)) {
> 
> -        Value |= ~(RISCV_IMM_REACH-1);
> 
> +
> 
> +      if(mRiscVPass1GotFixup) {
> 
> +        Value = (UINT32)(mRiscVPass1Offset);
> 
> +      } else {
> 
> +        Value = (UINT32)(RV_X(*(UINT32 *)Targ, 20, 12));
> 
> +        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;
> 
> @@ -569,12 +589,21 @@ WriteSectionRiscV64 (
>          }
> 
>        }
> 
> 
> 
> -      *(UINT32 *)Targ = (RV_X(Value, 0, 12) << 20) |
(RV_X(*(UINT32*)Targ,
> 0, 20));
> 
> +      if(mRiscVPass1GotFixup) {
> 
> +        *(UINT32 *)Targ = (RV_X((UINT32)Value, 0, 12) << 20)
> 
> +                            | (RV_X(*(UINT32*)Targ, 0, 20));
> 
> +        /* Convert LD instruction to ADDI */
> 
> +        *(UINT32 *)Targ = ((*(UINT32 *)Targ & ~0x707f) | 0x13);
> 
Can you add the comments for the hard value 0x707f and 0x13? 

Thanks
Liming

> +      } else {
> 
> +        *(UINT32 *)Targ = (RV_X(Value, 0, 12) << 20) |
> (RV_X(*(UINT32*)Targ, 0, 20));
> 
> +      }
> 
>        *(UINT32 *)mRiscVPass1Targ = (RV_X(Value2, 0, 20)<<12) |
> (RV_X(*(UINT32 *)mRiscVPass1Targ, 0, 12));
> 
>      }
> 
>      mRiscVPass1Sym = NULL;
> 
>      mRiscVPass1Targ = NULL;
> 
>      mRiscVPass1SymSecIndex = 0;
> 
> +    mRiscVPass1Offset = 0;
> 
> +    mRiscVPass1GotFixup = 0;
> 
>      break;
> 
> 
> 
>    case R_RISCV_ADD64:
> 
> @@ -586,6 +615,7 @@ WriteSectionRiscV64 (
>    case R_RISCV_GPREL_I:
> 
>    case R_RISCV_GPREL_S:
> 
>    case R_RISCV_CALL:
> 
> +  case R_RISCV_CALL_PLT:
> 
>    case R_RISCV_RVC_BRANCH:
> 
>    case R_RISCV_RVC_JUMP:
> 
>    case R_RISCV_RELAX:
> 
> @@ -1528,6 +1558,7 @@ WriteRelocations64 (
>              case R_RISCV_GPREL_I:
> 
>              case R_RISCV_GPREL_S:
> 
>              case R_RISCV_CALL:
> 
> +            case R_RISCV_CALL_PLT:
> 
>              case R_RISCV_RVC_BRANCH:
> 
>              case R_RISCV_RVC_JUMP:
> 
>              case R_RISCV_RELAX:
> 
> @@ -1537,6 +1568,7 @@ WriteRelocations64 (
>              case R_RISCV_SET16:
> 
>              case R_RISCV_SET32:
> 
>              case R_RISCV_PCREL_HI20:
> 
> +            case R_RISCV_GOT_HI20:
> 
>              case R_RISCV_PCREL_LO12_I:
> 
>                break;
> 
> 
> 
> --
> 2.25.1