On Thu, Jul 14, 2022 at 05:22:25PM +0100, James Morse wrote: > 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@xxxxxxxxxx> > Tested-by: Sumit Gupta <sumitg@xxxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> > Signed-off-by: James Morse <james.morse@xxxxxxx> > --- > This only applies to the v4.9 backport, as v4.14 has the QCOM_FALKOR_E1003 > workaround. > > arch/arm64/kernel/entry.S | 1 + > 1 file changed, 1 insertion(+) Now queued up, thanks. greg k-h