diff options
Diffstat (limited to 'arch/powerpc/kernel/reloc_64.S')
| -rw-r--r-- | arch/powerpc/kernel/reloc_64.S | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/reloc_64.S b/arch/powerpc/kernel/reloc_64.S new file mode 100644 index 000000000..02d4719bf --- /dev/null +++ b/arch/powerpc/kernel/reloc_64.S @@ -0,0 +1,84 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Code to process dynamic relocations in the kernel. + * + * Copyright 2008 Paul Mackerras, IBM Corp. + */ + +#include <asm/ppc_asm.h> + +RELA = 7 +RELACOUNT = 0x6ffffff9 +R_PPC64_RELATIVE = 22 + +/* + * r3 = desired final address of kernel + */ +_GLOBAL(relocate) + mflr r0 + bcl 20,31,$+4 +0: mflr r12 /* r12 has runtime addr of label 0 */ + mtlr r0 + ld r11,(p_dyn - 0b)(r12) + add r11,r11,r12 /* r11 has runtime addr of .dynamic section */ + ld r9,(p_rela - 0b)(r12) + add r9,r9,r12 /* r9 has runtime addr of .rela.dyn section */ + ld r10,(p_st - 0b)(r12) + add r10,r10,r12 /* r10 has runtime addr of _stext */ + + /* + * Scan the dynamic section for the RELA and RELACOUNT entries. + */ + li r7,0 + li r8,0 +1: ld r6,0(r11) /* get tag */ + cmpdi r6,0 + beq 4f /* end of list */ + cmpdi r6,RELA + bne 2f + ld r7,8(r11) /* get RELA pointer in r7 */ + b 3f +2: addis r6,r6,(-RELACOUNT)@ha + cmpdi r6,RELACOUNT@l + bne 3f + ld r8,8(r11) /* get RELACOUNT value in r8 */ +3: addi r11,r11,16 + b 1b +4: cmpdi r7,0 /* check we have both RELA and RELACOUNT */ + cmpdi cr1,r8,0 + beq 6f + beq cr1,6f + + /* + * Work out linktime address of _stext and hence the + * relocation offset to be applied. + * cur_offset [r7] = rela.run [r9] - rela.link [r7] + * _stext.link [r10] = _stext.run [r10] - cur_offset [r7] + * final_offset [r3] = _stext.final [r3] - _stext.link [r10] + */ + subf r7,r7,r9 /* cur_offset */ + subf r10,r7,r10 + subf r3,r10,r3 /* final_offset */ + + /* + * Run through the list of relocations and process the + * R_PPC64_RELATIVE ones. + */ + mtctr r8 +5: ld r0,8(9) /* ELF64_R_TYPE(reloc->r_info) */ + cmpdi r0,R_PPC64_RELATIVE + bne 6f + ld r6,0(r9) /* reloc->r_offset */ + ld r0,16(r9) /* reloc->r_addend */ + add r0,r0,r3 + stdx r0,r7,r6 + addi r9,r9,24 + bdnz 5b + +6: blr + +.balign 8 +p_dyn: .8byte __dynamic_start - 0b +p_rela: .8byte __rela_dyn_start - 0b +p_st: .8byte _stext - 0b + |