diff options
| author | Matt Evans <matt@ozlabs.org> | 2010-07-07 21:55:37 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-07-31 14:56:30 +1000 |
| commit | fc53b4202e61c7e9008c241933ae282aab8a6082 (patch) | |
| tree | c279a5256ba18a27ca0b785ecf6819f592a23509 /arch/powerpc/kernel/machine_kexec_64.c | |
| parent | 7e3f36c3e107bd76b6709e358b1e7c703fb6f81a (diff) | |
powerpc/kexec: Switch to a static PACA on the way out
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 <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/machine_kexec_64.c')
| -rw-r--r-- | arch/powerpc/kernel/machine_kexec_64.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c index de6b70eac51d..022d2f613b7b 100644 --- a/arch/powerpc/kernel/machine_kexec_64.c +++ b/arch/powerpc/kernel/machine_kexec_64.c @@ -260,6 +260,12 @@ 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, @@ -287,6 +293,20 @@ 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 poison per_cpu_offset to catch anyone using non-static + * data. + */ + memcpy(&kexec_paca, get_paca(), sizeof(struct paca_struct)); + kexec_paca.data_offset = 0xedeaddeadeeeeeeeUL; + paca = (struct paca_struct *)RELOC_HIDE(&kexec_paca, 0) - + kexec_paca.paca_index; + setup_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. */ |