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powerpc/64: avoid using r13 in relocate

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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
This commit is contained in:
Nicholas Piggin 2022-09-26 15:56:18 +10:00 committed by Michael Ellerman
parent 2f5182cffa
commit b830c8754e
1 changed files with 7 additions and 7 deletions
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14
arch/powerpc/kernel/reloc_64.S
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@ -27,8 +27,8 @@ _GLOBAL(relocate)
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 */
ld r13,(p_sym - 0b)(r12)
add r13,r13,r12 /* r13 has runtime addr of .dynsym */
ld r4,(p_sym - 0b)(r12)
add r4,r4,r12 /* r4 has runtime addr of .dynsym */
/*
* Scan the dynamic section for the RELA, RELASZ and RELAENT entries.
@ -84,16 +84,16 @@ _GLOBAL(relocate)
ld r0,16(r9) /* reloc->r_addend */
b .Lstore
.Luaddr64:
srdi r14,r0,32 /* ELF64_R_SYM(reloc->r_info) */
srdi r5,r0,32 /* ELF64_R_SYM(reloc->r_info) */
clrldi r0,r0,32
cmpdi r0,R_PPC64_UADDR64
bne .Lnext
ld r6,0(r9)
ld r0,16(r9)
mulli r14,r14,24 /* 24 == sizeof(elf64_sym) */
add r14,r14,r13 /* elf64_sym[ELF64_R_SYM] */
ld r14,8(r14)
add r0,r0,r14
mulli r5,r5,24 /* 24 == sizeof(elf64_sym) */
add r5,r5,r4 /* elf64_sym[ELF64_R_SYM] */
ld r5,8(r5)
add r0,r0,r5
.Lstore:
add r0,r0,r3
stdx r0,r7,r6