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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, May 11, 2020 at 08:51:15AM +0100, Will Deacon wrote: > On Sun, May 10, 2020 at 09:54:41AM +0200, Christoph Hellwig wrote: > > The second argument is the end "pointer", not the length. > > > > Signed-off-by: Christoph Hellwig > > --- > > arch/arm64/kernel/machine_kexec.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c > > index 8e9c924423b4e..a0b144cfaea71 100644 > > --- a/arch/arm64/kernel/machine_kexec.c > > +++ b/arch/arm64/kernel/machine_kexec.c > > @@ -177,6 +177,7 @@ void machine_kexec(struct kimage *kimage) > > * the offline CPUs. Therefore, we must use the __* variant here. > > */ > > __flush_icache_range((uintptr_t)reboot_code_buffer, > > + (uintptr_t)reboot_code_buffer + > > arm64_relocate_new_kernel_size); > > Urgh, well spotted. It's annoyingly different from __flush_dcache_area(). > > But now I'm wondering what this code actually does... the loop condition > in invalidate_icache_by_line works with 64-bit arithmetic, so we could > spend a /very/ long time here afaict. I think it goes through the loop only once. The 'b.lo' saves us here. OTOH, there is no I-cache maintenance done. > It's also a bit annoying that we do a bunch of redundant D-cache > maintenance too. Should we use invalidate_icache_range() here instead? Since we have the __flush_dcache_area() above it for cleaning to PoC, we could use invalidate_icache_range() here. We probably didn't have this function at the time, it was added for KVM (commit 4fee94736603cd6). > (and why does that thing need to toggle uaccess)? invalidate_icache_range() doesn't need to, it works on the kernel linear map. __flush_icache_range() doesn't need to either, that's a side-effect of the fall-through implementation. Anyway, I think Christoph's patch needs to go in with a fixes tag: Fixes: d28f6df1305a ("arm64/kexec: Add core kexec support") Cc: # 4.8.x- and we'll change these functions/helpers going forward for arm64. Happy to pick this up via the arm64 for-next/fixes branch. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel