With dynamic PACAs, the kexecing CPU's PACA won't lie within the kernel
static data and there is a chance that something may stomp it when preparing
to kexec. This patch switches this final CPU to a static PACA just before
we pull the switch.
Signed-off-by: Matt Evans <m...@ozlabs.org>
---
arch/powerpc/kernel/machine_kexec_64.c | 19 +++++++++++++++++++
1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/kernel/machine_kexec_64.c
b/arch/powerpc/kernel/machine_kexec_64.c
index 040bd1d..1348e84 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -253,6 +253,12 @@ static void kexec_prepare_cpus(void)
static union thread_union kexec_stack __init_task_data =
{ };
+/*
+ * For similar reasons to the stack above, the kexecing CPU needs to be on a
+ * static PACA; we switch to kexec_paca.
+ */
+struct paca_struct kexec_paca;
+
/* Our assembly helper, in kexec_stub.S */
extern NORET_TYPE void kexec_sequence(void *newstack, unsigned long start,
void *image, void *control,
@@ -280,6 +286,19 @@ void default_machine_kexec(struct kimage *image)
kexec_stack.thread_info.task = current_thread_info()->task;
kexec_stack.thread_info.flags = 0;
+ /* We need a static PACA, too; copy this CPU's PACA over and switch to
+ * it. Also make the SLB cache look invalid as it may have been touched
+ * by an IRQ before we switch to it.
+ */
+ memcpy(&kexec_paca, get_paca(), sizeof(struct paca_struct));
+ kexec_paca.slb_cache_ptr = SLB_CACHE_ENTRIES+1;
+ /* 'local_paca' boils down to GPR13 */
+ local_paca = &kexec_paca;
+
+ /* XXX: If anyone does 'dynamic lppacas' this will also need to be
+ * switched to a static version!
+ */
+
/* Some things are best done in assembly. Finding globals with
* a toc is easier in C, so pass in what we can.
*/
--
1.6.3.3
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