/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * Code to process dynamic relocations for PPC32. * * Copyrights (C) IBM Corporation, 2011. * Author: Suzuki Poulose <suzuki@in.ibm.com> * * - Based on ppc64 code - reloc_64.S */ #include <asm/ppc_asm.h> /* Dynamic section table entry tags */ DT_RELA = 7 /* Tag for Elf32_Rela section */ DT_RELASZ = 8 /* Size of the Rela relocs */ DT_RELAENT = 9 /* Size of one Rela reloc entry */ STN_UNDEF = 0 /* Undefined symbol index */ STB_LOCAL = 0 /* Local binding for the symbol */ R_PPC_ADDR16_LO = 4 /* Lower half of (S+A) */ R_PPC_ADDR16_HI = 5 /* Upper half of (S+A) */ R_PPC_ADDR16_HA = 6 /* High Adjusted (S+A) */ R_PPC_RELATIVE = 22 /* * r3 = desired final address */ _GLOBAL(relocate) mflr r0 /* Save our LR */ bcl 20,31,$+4 /* Find our current runtime address */ 0: mflr r12 /* Make it accessible */ mtlr r0 lwz r11, (p_dyn - 0b)(r12) add r11, r11, r12 /* runtime address of .dynamic section */ lwz r9, (p_rela - 0b)(r12) add r9, r9, r12 /* runtime address of .rela.dyn section */ lwz r10, (p_st - 0b)(r12) add r10, r10, r12 /* runtime address of _stext section */ lwz r13, (p_sym - 0b)(r12) add r13, r13, r12 /* runtime address of .dynsym section */ /* * Scan the dynamic section for RELA, RELASZ entries */ li r6, 0 li r7, 0 li r8, 0 1: lwz r5, 0(r11) /* ELF_Dyn.d_tag */ cmpwi r5, 0 /* End of ELF_Dyn[] */ beq eodyn cmpwi r5, DT_RELA bne relasz lwz r7, 4(r11) /* r7 = rela.link */ b skip relasz: cmpwi r5, DT_RELASZ bne relaent lwz r8, 4(r11) /* r8 = Total Rela relocs size */ b skip relaent: cmpwi r5, DT_RELAENT bne skip lwz r6, 4(r11) /* r6 = Size of one Rela reloc */ skip: addi r11, r11, 8 b 1b eodyn: /* End of Dyn Table scan */ /* Check if we have found all the entries */ cmpwi r7, 0 beq done cmpwi r8, 0 beq done cmpwi r6, 0 beq done /* * Work out the current offset from the link time address of .rela * section. * cur_offset[r7] = rela.run[r9] - rela.link [r7] * _stext.link[r12] = _stext.run[r10] - cur_offset[r7] * final_offset[r3] = _stext.final[r3] - _stext.link[r12] */ subf r7, r7, r9 /* cur_offset */ subf r12, r7, r10 subf r3, r12, r3 /* final_offset */ subf r8, r6, r8 /* relaz -= relaent */ /* * Scan through the .rela table and process each entry * r9 - points to the current .rela table entry * r13 - points to the symbol table */ /* * Check if we have a relocation based on symbol * r5 will hold the value of the symbol. */ applyrela: lwz r4, 4(r9) /* r4 = rela.r_info */ srwi r5, r4, 8 /* ELF32_R_SYM(r_info) */ cmpwi r5, STN_UNDEF /* sym == STN_UNDEF ? */ beq get_type /* value = 0 */ /* Find the value of the symbol at index(r5) */ slwi r5, r5, 4 /* r5 = r5 * sizeof(Elf32_Sym) */ add r12, r13, r5 /* r12 = &__dyn_sym[Index] */ /* * GNU ld has a bug, where dynamic relocs based on * STB_LOCAL symbols, the value should be assumed * to be zero. - Alan Modra */ /* XXX: Do we need to check if we are using GNU ld ? */ lbz r5, 12(r12) /* r5 = dyn_sym[Index].st_info */ extrwi r5, r5, 4, 24 /* r5 = ELF32_ST_BIND(r5) */ cmpwi r5, STB_LOCAL /* st_value = 0, ld bug */ beq get_type /* We have r5 = 0 */ lwz r5, 4(r12) /* r5 = __dyn_sym[Index].st_value */ get_type: /* Load the relocation type to r4 */ extrwi r4, r4, 8, 24 /* r4 = ELF32_R_TYPE(r_info) = ((char*)r4)[3] */ /* R_PPC_RELATIVE */ cmpwi r4, R_PPC_RELATIVE bne hi16 lwz r4, 0(r9) /* r_offset */ lwz r0, 8(r9) /* r_addend */ add r0, r0, r3 /* final addend */ stwx r0, r4, r7 /* memory[r4+r7]) = (u32)r0 */ b nxtrela /* continue */ /* R_PPC_ADDR16_HI */ hi16: cmpwi r4, R_PPC_ADDR16_HI bne ha16 lwz r4, 0(r9) /* r_offset */ lwz r0, 8(r9) /* r_addend */ add r0, r0, r3 add r0, r0, r5 /* r0 = (S+A+Offset) */ extrwi r0, r0, 16, 0 /* r0 = (r0 >> 16) */ b store_half /* R_PPC_ADDR16_HA */ ha16: cmpwi r4, R_PPC_ADDR16_HA bne lo16 lwz r4, 0(r9) /* r_offset */ lwz r0, 8(r9) /* r_addend */ add r0, r0, r3 add r0, r0, r5 /* r0 = (S+A+Offset) */ extrwi r5, r0, 1, 16 /* Extract bit 16 */ extrwi r0, r0, 16, 0 /* r0 = (r0 >> 16) */ add r0, r0, r5 /* Add it to r0 */ b store_half /* R_PPC_ADDR16_LO */ lo16: cmpwi r4, R_PPC_ADDR16_LO bne unknown_type lwz r4, 0(r9) /* r_offset */ lwz r0, 8(r9) /* r_addend */ add r0, r0, r3 add r0, r0, r5 /* r0 = (S+A+Offset) */ extrwi r0, r0, 16, 16 /* r0 &= 0xffff */ /* Fall through to */ /* Store half word */ store_half: sthx r0, r4, r7 /* memory[r4+r7] = (u16)r0 */ nxtrela: /* * We have to flush the modified instructions to the * main storage from the d-cache. And also, invalidate the * cached instructions in i-cache which has been modified. * * We delay the sync / isync operation till the end, since * we won't be executing the modified instructions until * we return from here. */ dcbst r4,r7 sync /* Ensure the data is flushed before icbi */ icbi r4,r7 unknown_type: cmpwi r8, 0 /* relasz = 0 ? */ ble done add r9, r9, r6 /* move to next entry in the .rela table */ subf r8, r6, r8 /* relasz -= relaent */ b applyrela done: sync /* Wait for the flush to finish */ isync /* Discard prefetched instructions */ blr p_dyn: .long __dynamic_start - 0b p_rela: .long __rela_dyn_start - 0b p_sym: .long __dynamic_symtab - 0b p_st: .long _stext - 0b
