Sunil:
I add my comments below.

Thanks
Liming

-----邮件原件-----
发件人: Sunil V L <sunilvl@...>
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@...>; Abner Chang
<abner.chang@...>; Daniel Schaefer <daniel.schaefer@...>; Bob
Feng <bob.c.feng@...>; Liming Gao <gaoliming@...>;
Yuwei Chen <yuwei.chen@...>; Heinrich Schuchardt
<xypron.glpk@...>
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@...>

Acked-by: Abner Chang <abner.chang@...>
Reviewed-by: Daniel Schaefer <daniel.schaefer@...>
Tested-by: <daniel.schaefer@...>

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

Cc: Bob Feng <bob.c.feng@...>
Cc: Liming Gao <gaoliming@...>
Cc: Yuwei Chen <yuwei.chen@...>
Cc: Heinrich Schuchardt <xypron.glpk@...>
---
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