@@ -17,6 +17,7 @@
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/cpu.h>
+#include <linux/hardirq.h>
#include <asm/page.h>
#include <asm/current.h>
@@ -335,10 +336,13 @@ void default_machine_kexec(struct kimage *image)
pr_debug("kexec: Starting switchover sequence.\n");
/* switch to a staticly allocated stack. Based on irq stack code.
+ * We setup preempt_count to avoid using VMX in memcpy.
* XXX: the task struct will likely be invalid once we do the copy!
*/
kexec_stack.thread_info.task = current_thread_info()->task;
kexec_stack.thread_info.flags = 0;
+ kexec_stack.thread_info.preempt_count = HARDIRQ_OFFSET;
+ kexec_stack.thread_info.cpu = current_thread_info()->cpu;
/* We need a static PACA, too; copy this CPU's PACA over and switch to
* it. Also poison per_cpu_offset to catch anyone using non-static
This is a note to let you know that I have just added a patch titled powerpc/kexec: Fix kexec when using VMX optimised memcpy to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 6711c99aa4ace9fa45fd0fba2bae031146924532 Mon Sep 17 00:00:00 2001 From: Anton Blanchard <anton@au1.ibm.com> Date: Sun, 12 May 2013 15:04:53 +0000 Subject: powerpc/kexec: Fix kexec when using VMX optimised memcpy commit 79c66ce8f6448a3295a32efeac88c9debd7f7094 upstream. commit b3f271e86e5a (powerpc: POWER7 optimised memcpy using VMX and enhanced prefetch) uses VMX when it is safe to do so (ie not in interrupt). It also looks at the task struct to decide if we have to save the current tasks' VMX state. kexec calls memcpy() at a point where the task struct may have been overwritten by the new kexec segments. If it has been overwritten then when memcpy -> enable_altivec looks up current->thread.regs->msr we get a cryptic oops or lockup. I also notice we aren't initialising thread_info->cpu, which means smp_processor_id is broken. Fix that too. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/powerpc/kernel/machine_kexec_64.c | 4 ++++ 1 file changed, 4 insertions(+) -- 1.8.1.2