On Tue, Feb 02, 2016 at 12:06:47PM +0800, Hanjun Guo wrote: > From: Will Deacon <will.deacon@xxxxxxx> > > The arm64 booting document requires that the bootloader has cleaned the > kernel image to the PoC. However, when a CPU re-enters the kernel due to > either a CPU hotplug "on" event or resuming from a low-power state (e.g. > cpuidle), the kernel text may in-fact be dirty at the PoU due to things > like alternative patching or even module loading. > > Thanks to I-cache speculation with the MMU off, stale instructions could > be fetched prior to enabling the MMU, potentially leading to crashes > when executing regions of code that have been modified at runtime. > > This patch addresses the issue by ensuring that the local I-cache is > invalidated immediately after a CPU has enabled its MMU but before > jumping out of the identity mapping. Any stale instructions fetched from > the PoC will then be discarded and refetched correctly from the PoU. > Patching kernel text executed prior to the MMU being enabled is > prohibited, so the early entry code will always be clean. > > Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx> > Tested-by: Mark Rutland <mark.rutland@xxxxxxx> > Signed-off-by: Will Deacon <will.deacon@xxxxxxx> > Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx> > --- > arch/arm64/kernel/head.S | 8 ++++++++ > arch/arm64/kernel/sleep.S | 8 ++++++++ > arch/arm64/mm/proc.S | 1 - > 3 files changed, 16 insertions(+), 1 deletion(-) You forgot to say what the upstream git commit id is for this :( -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html