Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 01/28] arm64: entry: Restore tramp_map_kernel ISB | Date | Tue, 19 Jul 2022 13:53:39 +0200 |
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From: James Morse <james.morse@arm.com>
Summit reports that the BHB backports for v4.9 prevent vulnerable platforms from booting when CONFIG_RANDOMIZE_BASE is enabled.
This is because the trampoline code takes a translation fault when accessing the data page, because the TTBR write hasn't been completed by an ISB before the access is made.
Upstream has a complex erratum workaround for QCOM_FALKOR_E1003 in this area, which removes the ISB when the workaround has been applied. v4.9 lacks this workaround, but should still have the ISB.
Restore the barrier.
Fixes: aee10c2dd013 ("arm64: entry: Add macro for reading symbol addresses from the trampoline") Reported-by: Sumit Gupta <sumitg@nvidia.com> Tested-by: Sumit Gupta <sumitg@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/arm64/kernel/entry.S | 1 + 1 file changed, 1 insertion(+)
--- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -964,6 +964,7 @@ __ni_sys_trace: b . 2: tramp_map_kernel x30 + isb tramp_data_read_var x30, vectors prfm plil1strm, [x30, #(1b - \vector_start)] msr vbar_el1, x30
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