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b830c8754e
relocate() uses r13 in early boot before it is used for the paca. Use a different register for this so r13 is kept unchanged until it is set to the paca pointer. Avoid r14 as well while we're here, there's no reason not to use the volatile registers which is a bit less surprising, and r14 could be used as another fixed reg one day. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220926055620.2676869-4-npiggin@gmail.com
111 lines
2.4 KiB
ArmAsm
111 lines
2.4 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Code to process dynamic relocations in the kernel.
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*
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* Copyright 2008 Paul Mackerras, IBM Corp.
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*/
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#include <asm/ppc_asm.h>
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RELA = 7
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RELASZ = 8
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RELAENT = 9
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R_PPC64_RELATIVE = 22
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R_PPC64_UADDR64 = 43
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/*
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* r3 = desired final address of kernel
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*/
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_GLOBAL(relocate)
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mflr r0
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bcl 20,31,$+4
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0: mflr r12 /* r12 has runtime addr of label 0 */
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mtlr r0
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ld r11,(p_dyn - 0b)(r12)
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add r11,r11,r12 /* r11 has runtime addr of .dynamic section */
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ld r9,(p_rela - 0b)(r12)
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add r9,r9,r12 /* r9 has runtime addr of .rela.dyn section */
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ld r10,(p_st - 0b)(r12)
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add r10,r10,r12 /* r10 has runtime addr of _stext */
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ld r4,(p_sym - 0b)(r12)
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add r4,r4,r12 /* r4 has runtime addr of .dynsym */
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/*
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* Scan the dynamic section for the RELA, RELASZ and RELAENT entries.
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*/
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li r7,0
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li r8,0
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.Ltags:
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ld r6,0(r11) /* get tag */
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cmpdi r6,0
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beq .Lend_of_list /* end of list */
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cmpdi r6,RELA
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bne 2f
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ld r7,8(r11) /* get RELA pointer in r7 */
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b 4f
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2: cmpdi r6,RELASZ
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bne 3f
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ld r8,8(r11) /* get RELASZ value in r8 */
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b 4f
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3: cmpdi r6,RELAENT
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bne 4f
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ld r12,8(r11) /* get RELAENT value in r12 */
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4: addi r11,r11,16
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b .Ltags
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.Lend_of_list:
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cmpdi r7,0 /* check we have RELA, RELASZ, RELAENT */
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cmpdi cr1,r8,0
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beq .Lout
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beq cr1,.Lout
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cmpdi r12,0
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beq .Lout
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/*
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* Work out linktime address of _stext and hence the
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* relocation offset to be applied.
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* cur_offset [r7] = rela.run [r9] - rela.link [r7]
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* _stext.link [r10] = _stext.run [r10] - cur_offset [r7]
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* final_offset [r3] = _stext.final [r3] - _stext.link [r10]
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*/
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subf r7,r7,r9 /* cur_offset */
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subf r10,r7,r10
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subf r3,r10,r3 /* final_offset */
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/*
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* Run through the list of relocations and process the
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* R_PPC64_RELATIVE and R_PPC64_UADDR64 ones.
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*/
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divd r8,r8,r12 /* RELASZ / RELAENT */
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mtctr r8
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.Lrels: ld r0,8(r9) /* ELF64_R_TYPE(reloc->r_info) */
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cmpdi r0,R_PPC64_RELATIVE
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bne .Luaddr64
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ld r6,0(r9) /* reloc->r_offset */
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ld r0,16(r9) /* reloc->r_addend */
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b .Lstore
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.Luaddr64:
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srdi r5,r0,32 /* ELF64_R_SYM(reloc->r_info) */
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clrldi r0,r0,32
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cmpdi r0,R_PPC64_UADDR64
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bne .Lnext
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ld r6,0(r9)
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ld r0,16(r9)
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mulli r5,r5,24 /* 24 == sizeof(elf64_sym) */
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add r5,r5,r4 /* elf64_sym[ELF64_R_SYM] */
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ld r5,8(r5)
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add r0,r0,r5
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.Lstore:
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add r0,r0,r3
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stdx r0,r7,r6
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.Lnext:
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add r9,r9,r12
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bdnz .Lrels
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.Lout:
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blr
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.balign 8
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p_dyn: .8byte __dynamic_start - 0b
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p_rela: .8byte __rela_dyn_start - 0b
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p_sym: .8byte __dynamic_symtab - 0b
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p_st: .8byte _stext - 0b
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