From 3744b5280e67f54579abe92576deec0079242323 Mon Sep 17 00:00:00 2001 From: Pasha Tatashin Date: Thu, 30 Sep 2021 14:31:09 +0000 Subject: arm64: kexec: install a copy of the linear-map To perform the kexec relocation with the MMU enabled, we need a copy of the linear map. Create one, and install it from the relocation code. This has to be done from the assembly code as it will be idmapped with TTBR0. The kernel runs in TTRB1, so can't use the break-before-make sequence on the mapping it is executing from. The makes no difference yet as the relocation code runs with the MMU disabled. Suggested-by: James Morse Signed-off-by: Pasha Tatashin Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20210930143113.1502553-12-pasha.tatashin@soleen.com Signed-off-by: Will Deacon --- arch/arm64/include/asm/assembler.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'arch/arm64/include/asm/assembler.h') diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index d5281f75a58d..5da176dd37a9 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -483,6 +483,25 @@ alternative_endif _cond_extable .Licache_op\@, \fixup .endm +/* + * To prevent the possibility of old and new partial table walks being visible + * in the tlb, switch the ttbr to a zero page when we invalidate the old + * records. D4.7.1 'General TLB maintenance requirements' in ARM DDI 0487A.i + * Even switching to our copied tables will cause a changed output address at + * each stage of the walk. + */ + .macro break_before_make_ttbr_switch zero_page, page_table, tmp, tmp2 + phys_to_ttbr \tmp, \zero_page + msr ttbr1_el1, \tmp + isb + tlbi vmalle1 + dsb nsh + phys_to_ttbr \tmp, \page_table + offset_ttbr1 \tmp, \tmp2 + msr ttbr1_el1, \tmp + isb + .endm + /* * reset_pmuserenr_el0 - reset PMUSERENR_EL0 if PMUv3 present */ -- cgit v1.2.3