git: 51adf913e881 - main - arm64: disable the EL2 MMU before dropping to EL1
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Date: Fri, 13 May 2022 03:07:27 UTC
The branch main has been updated by kevans: URL: https://cgit.FreeBSD.org/src/commit/?id=51adf913e8815bdc928cb72dd378c596b8b15336 commit 51adf913e8815bdc928cb72dd378c596b8b15336 Author: Kyle Evans <kevans@FreeBSD.org> AuthorDate: 2022-05-13 03:03:32 +0000 Commit: Kyle Evans <kevans@FreeBSD.org> CommitDate: 2022-05-13 03:04:24 +0000 arm64: disable the EL2 MMU before dropping to EL1 An earlier stage may have set HCR_EL2.E2H, the clearing of which may break address translation. We don't need the EL2 MMU at this point, so we can avoid re-enabling it for now and just drop to EL1 as usual. Suggested by: andrew Reviewed by: andrew Differential Revision: https://reviews.freebsd.org/D34644 --- sys/arm64/arm64/locore.S | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/sys/arm64/arm64/locore.S b/sys/arm64/arm64/locore.S index e1b0530006cb..ba85bb4e46b2 100644 --- a/sys/arm64/arm64/locore.S +++ b/sys/arm64/arm64/locore.S @@ -247,6 +247,16 @@ LENTRY(drop_to_el1) b.eq 1f ret 1: + /* + * Disable the MMU. If the HCR_EL2.E2H field is set we will clear it + * which may break address translation. + */ + dsb sy + mrs x2, sctlr_el2 + bic x2, x2, SCTLR_M + msr sctlr_el2, x2 + isb + /* Configure the Hypervisor */ ldr x2, =(HCR_RW | HCR_APK | HCR_API) msr hcr_el2, x2