On 2016/2/15 5:00, Greg KH wrote: > 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 :( > Sorry, it's 8ec41987436d566f7c4559c6871738b869f7ef07. Thanks Hanjun -- 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