diff options
Diffstat (limited to 'arch/powerpc/boot/crt0.S')
| -rw-r--r-- | arch/powerpc/boot/crt0.S | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S new file mode 100644 index 0000000000..121cab9d57 --- /dev/null +++ b/arch/powerpc/boot/crt0.S @@ -0,0 +1,308 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) Paul Mackerras 1997. + * + * Adapted for 64 bit LE PowerPC by Andrew Tauferner + */ + +#include "ppc_asm.h" + +RELA = 7 +RELASZ = 8 +RELAENT = 9 + + .data + /* A procedure descriptor used when booting this as a COFF file. + * When making COFF, this comes first in the link and we're + * linked at 0x500000. + */ + .globl _zimage_start_opd +_zimage_start_opd: + .long 0x500000, 0, 0, 0 + .text + b _zimage_start + +#ifdef __powerpc64__ +.balign 8 +p_start: .8byte _start +p_etext: .8byte _etext +p_bss_start: .8byte __bss_start +p_end: .8byte _end + +p_toc: .8byte .TOC. - p_base +p_dyn: .8byte __dynamic_start - p_base +p_rela: .8byte __rela_dyn_start - p_base +p_prom: .8byte 0 + .weak _platform_stack_top +p_pstack: .8byte _platform_stack_top +#else +p_start: .long _start +p_etext: .long _etext +p_bss_start: .long __bss_start +p_end: .long _end + + .weak _platform_stack_top +p_pstack: .long _platform_stack_top +#endif + + .weak _zimage_start +_zimage_start: + .globl _zimage_start_lib +_zimage_start_lib: + /* Work out the offset between the address we were linked at + and the address where we're running. */ + bcl 20,31,.+4 +p_base: mflr r10 /* r10 now points to runtime addr of p_base */ +#ifndef __powerpc64__ + /* grab the link address of the dynamic section in r11 */ + addis r11,r10,(_GLOBAL_OFFSET_TABLE_-p_base)@ha + lwz r11,(_GLOBAL_OFFSET_TABLE_-p_base)@l(r11) + cmpwi r11,0 + beq 3f /* if not linked -pie */ + /* get the runtime address of the dynamic section in r12 */ + .weak __dynamic_start + addis r12,r10,(__dynamic_start-p_base)@ha + addi r12,r12,(__dynamic_start-p_base)@l + subf r11,r11,r12 /* runtime - linktime offset */ + + /* The dynamic section contains a series of tagged entries. + * We need the RELA and RELACOUNT entries. */ + li r9,0 + li r0,0 +9: lwz r8,0(r12) /* get tag */ + cmpwi r8,0 + beq 10f /* end of list */ + cmpwi r8,RELA + bne 11f + lwz r9,4(r12) /* get RELA pointer in r9 */ + b 12f +11: cmpwi r8,RELASZ + bne .Lcheck_for_relaent + lwz r0,4(r12) /* get RELASZ value in r0 */ + b 12f +.Lcheck_for_relaent: + cmpwi r8,RELAENT + bne 12f + lwz r14,4(r12) /* get RELAENT value in r14 */ +12: addi r12,r12,8 + b 9b + + /* The relocation section contains a list of relocations. + * We now do the R_PPC_RELATIVE ones, which point to words + * which need to be initialized with addend + offset */ +10: /* skip relocation if we don't have both */ + cmpwi r0,0 + beq 3f + cmpwi r9,0 + beq 3f + cmpwi r14,0 + beq 3f + + add r9,r9,r11 /* Relocate RELA pointer */ + divwu r0,r0,r14 /* RELASZ / RELAENT */ + mtctr r0 +2: lbz r0,4+3(r9) /* ELF32_R_INFO(reloc->r_info) */ + cmpwi r0,22 /* R_PPC_RELATIVE */ + bne .Lnext + lwz r12,0(r9) /* reloc->r_offset */ + lwz r0,8(r9) /* reloc->r_addend */ + add r0,r0,r11 + stwx r0,r11,r12 +.Lnext: add r9,r9,r14 + bdnz 2b + + /* Do a cache flush for our text, in case the loader didn't */ +3: lwz r9,p_start-p_base(r10) /* note: these are relocated now */ + lwz r8,p_etext-p_base(r10) +4: dcbf r0,r9 + icbi r0,r9 + addi r9,r9,0x20 + cmplw cr0,r9,r8 + blt 4b + sync + isync + + /* Clear the BSS */ + lwz r9,p_bss_start-p_base(r10) + lwz r8,p_end-p_base(r10) + li r0,0 +5: stw r0,0(r9) + addi r9,r9,4 + cmplw cr0,r9,r8 + blt 5b + + /* Possibly set up a custom stack */ + lwz r8,p_pstack-p_base(r10) + cmpwi r8,0 + beq 6f + lwz r1,0(r8) + li r0,0 + stwu r0,-16(r1) /* establish a stack frame */ +6: +#else /* __powerpc64__ */ + /* Save the prom pointer at p_prom. */ + std r5,(p_prom-p_base)(r10) + + /* Set r2 to the TOC. */ + ld r2,(p_toc-p_base)(r10) + add r2,r2,r10 + + /* Grab the link address of the dynamic section in r11. */ + ld r11,-32768(r2) + cmpwi r11,0 + beq 3f /* if not linked -pie then no dynamic section */ + + ld r11,(p_dyn-p_base)(r10) + add r11,r11,r10 + ld r9,(p_rela-p_base)(r10) + add r9,r9,r10 + + li r13,0 + li r8,0 +9: ld r12,0(r11) /* get tag */ + cmpdi r12,0 + beq 12f /* end of list */ + cmpdi r12,RELA + bne 10f + ld r13,8(r11) /* get RELA pointer in r13 */ + b 11f +10: cmpwi r12,RELASZ + bne .Lcheck_for_relaent + lwz r8,8(r11) /* get RELASZ pointer in r8 */ + b 11f +.Lcheck_for_relaent: + cmpwi r12,RELAENT + bne 11f + lwz r14,8(r11) /* get RELAENT pointer in r14 */ +11: addi r11,r11,16 + b 9b +12: + cmpdi r13,0 /* check we have both RELA, RELASZ, RELAENT*/ + cmpdi cr1,r8,0 + beq 3f + beq cr1,3f + cmpdi r14,0 + beq 3f + + /* Calcuate the runtime offset. */ + subf r13,r13,r9 + + /* Run through the list of relocations and process the + * R_PPC64_RELATIVE ones. */ + divdu r8,r8,r14 /* RELASZ / RELAENT */ + mtctr r8 +13: ld r0,8(r9) /* ELF64_R_TYPE(reloc->r_info) */ + cmpdi r0,22 /* R_PPC64_RELATIVE */ + bne .Lnext + ld r12,0(r9) /* reloc->r_offset */ + ld r0,16(r9) /* reloc->r_addend */ + add r0,r0,r13 + stdx r0,r13,r12 +.Lnext: add r9,r9,r14 + bdnz 13b + + /* Do a cache flush for our text, in case the loader didn't */ +3: ld r9,p_start-p_base(r10) /* note: these are relocated now */ + ld r8,p_etext-p_base(r10) +4: dcbf r0,r9 + icbi r0,r9 + addi r9,r9,0x20 + cmpld cr0,r9,r8 + blt 4b + sync + isync + + /* Clear the BSS */ + ld r9,p_bss_start-p_base(r10) + ld r8,p_end-p_base(r10) + li r0,0 +5: std r0,0(r9) + addi r9,r9,8 + cmpld cr0,r9,r8 + blt 5b + + /* Possibly set up a custom stack */ + ld r8,p_pstack-p_base(r10) + cmpdi r8,0 + beq 6f + ld r1,0(r8) + li r0,0 + stdu r0,-112(r1) /* establish a stack frame */ +6: +#endif /* __powerpc64__ */ + /* Call platform_init() */ + bl platform_init + + /* Call start */ + b start + +#ifdef __powerpc64__ + +#define PROM_FRAME_SIZE 512 + +.macro OP_REGS op, width, start, end, base, offset + .Lreg=\start + .rept (\end - \start + 1) + \op .Lreg,\offset+\width*.Lreg(\base) + .Lreg=.Lreg+1 + .endr +.endm + +#define SAVE_GPRS(start, end, base) OP_REGS std, 8, start, end, base, 0 +#define REST_GPRS(start, end, base) OP_REGS ld, 8, start, end, base, 0 +#define SAVE_GPR(n, base) SAVE_GPRS(n, n, base) +#define REST_GPR(n, base) REST_GPRS(n, n, base) + +/* prom handles the jump into and return from firmware. The prom args pointer + is loaded in r3. */ +.globl prom +prom: + mflr r0 + std r0,16(r1) + stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */ + + SAVE_GPR(2, r1) + SAVE_GPRS(13, 31, r1) + mfcr r10 + std r10,8*32(r1) + mfmsr r10 + std r10,8*33(r1) + + /* remove MSR_LE from msr but keep MSR_SF */ + mfmsr r10 + rldicr r10,r10,0,62 + mtsrr1 r10 + + /* Load FW address, set LR to label 1, and jump to FW */ + bcl 20,31,0f +0: mflr r10 + addi r11,r10,(1f-0b) + mtlr r11 + + ld r10,(p_prom-0b)(r10) + mtsrr0 r10 + + rfid + +1: /* Return from OF */ + FIXUP_ENDIAN + + /* Restore registers and return. */ + rldicl r1,r1,0,32 + + /* Restore the MSR (back to 64 bits) */ + ld r10,8*(33)(r1) + mtmsr r10 + isync + + /* Restore other registers */ + REST_GPR(2, r1) + REST_GPRS(13, 31, r1) + ld r10,8*32(r1) + mtcr r10 + + addi r1,r1,PROM_FRAME_SIZE + ld r0,16(r1) + mtlr r0 + blr +#endif |