[edk2-devel] [PATCH v4] BaseTools GenFw: Add support for RISCV GOT/PLT relocations
Pete Batard
pete at akeo.ie
Mon Jul 12 12:04:44 UTC 2021
Since I was also impacted by this in the RISC-V NTFS driver, and I can
vouch that this patch does produce a functional executable when tested
with QEMU, I'll add my T-b as well.
On 2021.06.24 14:25, Sunil V L wrote:
> 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-846682710
>
> Changes in v4:
> - Fixed the typecast issue found by VS2019.
>
> Changes in v3:
> - Added the comments to address Liming's feedback.
>
> 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 at ventanamicro.com>
>
> Acked-by: Abner Chang <abner.chang at hpe.com>
> Reviewed-by: Daniel Schaefer <daniel.schaefer at hpe.com>
> Tested-by: Daniel Schaefer <daniel.schaefer at hpe.com>
>
> Cc: Bob Feng <bob.c.feng at intel.com>
> Cc: Liming Gao <gaoliming at byosoft.com.cn>
> Cc: Yuwei Chen <yuwei.chen at intel.com>
> Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
> BaseTools/Source/C/GenFw/Elf64Convert.c | 59 ++++++++++++++++++++++---
> 1 file changed, 53 insertions(+), 6 deletions(-)
>
> diff --git a/BaseTools/Source/C/GenFw/Elf64Convert.c b/BaseTools/Source/C/GenFw/Elf64Convert.c
> index d097db8632..f86be95fbb 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
>
> @@ -473,17 +475,18 @@ WriteSectionRiscV64 (
> {
>
> UINT32 Value;
>
> UINT32 Value2;
>
> + Elf64_Addr GOTEntryRva;
>
>
>
> switch (ELF_R_TYPE(Rel->r_info)) {
>
> case R_RISCV_NONE:
>
> 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 +536,18 @@ WriteSectionRiscV64 (
> mRiscVPass1SymSecIndex = 0;
>
> break;
>
>
>
> + case R_RISCV_GOT_HI20:
>
> + GOTEntryRva = (Sym->st_value - Rel->r_offset);
>
> + mRiscVPass1Offset = RV_X(GOTEntryRva, 0, 12);
>
> + Value = (UINT32)RV_X(GOTEntryRva, 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 +560,17 @@ 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 +590,35 @@ 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
>
> + //
>
> + // |31 20|19 15|14 12|11 7|6 0|
>
> + // |-----------------------------------------|
>
> + // |imm[11:0] | rs1 | 011 | rd | 0000011 | LD
>
> + // -----------------------------------------
>
> +
>
> + // |-----------------------------------------|
>
> + // |imm[11:0] | rs1 | 000 | rd | 0010011 | ADDI
>
> + // -----------------------------------------
>
> +
>
> + // To convert, let's first reset bits 12-14 and 0-6 using ~0x707f
>
> + // Then modify the opcode to ADDI (0010011)
>
> + // All other fields will remain same.
>
> +
>
> + *(UINT32 *)Targ = ((*(UINT32 *)Targ & ~0x707f) | 0x13);
>
> + } 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 +630,7 @@ 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 +1573,7 @@ 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 +1583,7 @@ 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;
>
>
>
Tested-by: Pete Batard <pete at akeo.ie>
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