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arm64: mm: avoid x18 in idmap_kpti_install_ng_mappings

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idmap_kpti_install_ng_mappings uses x18 as a temporary register, which
will result in a conflict when x18 is reserved. Use x16 and x17 instead
where needed.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Sami Tolvanen 2019-12-06 14:13:37 -08:00 committed by Will Deacon
parent c54f90c262
commit e3ec6582d1
1 changed files with 35 additions and 34 deletions
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69
arch/arm64/mm/proc.S
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@ -250,15 +250,15 @@ ENTRY(idmap_kpti_install_ng_mappings)
/* We're the boot CPU. Wait for the others to catch up */
sevl
1: wfe
ldaxr w18, [flag_ptr]
eor w18, w18, num_cpus
cbnz w18, 1b
ldaxr w17, [flag_ptr]
eor w17, w17, num_cpus
cbnz w17, 1b
/* We need to walk swapper, so turn off the MMU. */
pre_disable_mmu_workaround
mrs x18, sctlr_el1
bic x18, x18, #SCTLR_ELx_M
msr sctlr_el1, x18
mrs x17, sctlr_el1
bic x17, x17, #SCTLR_ELx_M
msr sctlr_el1, x17
isb
/* Everybody is enjoying the idmap, so we can rewrite swapper. */
@ -281,9 +281,9 @@ skip_pgd:
isb
/* We're done: fire up the MMU again */
mrs x18, sctlr_el1
orr x18, x18, #SCTLR_ELx_M
msr sctlr_el1, x18
mrs x17, sctlr_el1
orr x17, x17, #SCTLR_ELx_M
msr sctlr_el1, x17
isb
/*
@ -353,34 +353,9 @@ skip_pte:
b.ne do_pte
b next_pmd
/* Secondary CPUs end up here */
__idmap_kpti_secondary:
/* Uninstall swapper before surgery begins */
__idmap_cpu_set_reserved_ttbr1 x18, x17
/* Increment the flag to let the boot CPU we're ready */
1: ldxr w18, [flag_ptr]
add w18, w18, #1
stxr w17, w18, [flag_ptr]
cbnz w17, 1b
/* Wait for the boot CPU to finish messing around with swapper */
sevl
1: wfe
ldxr w18, [flag_ptr]
cbnz w18, 1b
/* All done, act like nothing happened */
offset_ttbr1 swapper_ttb, x18
msr ttbr1_el1, swapper_ttb
isb
ret
.unreq cpu
.unreq num_cpus
.unreq swapper_pa
.unreq swapper_ttb
.unreq flag_ptr
.unreq cur_pgdp
.unreq end_pgdp
.unreq pgd
@ -393,6 +368,32 @@ __idmap_kpti_secondary:
.unreq cur_ptep
.unreq end_ptep
.unreq pte
/* Secondary CPUs end up here */
__idmap_kpti_secondary:
/* Uninstall swapper before surgery begins */
__idmap_cpu_set_reserved_ttbr1 x16, x17
/* Increment the flag to let the boot CPU we're ready */
1: ldxr w16, [flag_ptr]
add w16, w16, #1
stxr w17, w16, [flag_ptr]
cbnz w17, 1b
/* Wait for the boot CPU to finish messing around with swapper */
sevl
1: wfe
ldxr w16, [flag_ptr]
cbnz w16, 1b
/* All done, act like nothing happened */
offset_ttbr1 swapper_ttb, x16
msr ttbr1_el1, swapper_ttb
isb
ret
.unreq swapper_ttb
.unreq flag_ptr
ENDPROC(idmap_kpti_install_ng_mappings)
.popsection
#endif