From fc53b4202e61c7e9008c241933ae282aab8a6082 Mon Sep 17 00:00:00 2001 From: Matt Evans Date: Wed, 7 Jul 2010 21:55:37 +0000 Subject: [PATCH] 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 Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/paca.h | 2 +- arch/powerpc/kernel/machine_kexec_64.c | 20 ++++++++++++++++++++ arch/powerpc/kernel/paca.c | 10 ++++++++++ arch/powerpc/kernel/setup_64.c | 10 ---------- 4 files changed, 31 insertions(+), 11 deletions(-) diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index 8ce7963ad41d..1ff6662f7faf 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -146,7 +146,7 @@ struct paca_struct { extern struct paca_struct *paca; extern __initdata struct paca_struct boot_paca; extern void initialise_paca(struct paca_struct *new_paca, int cpu); - +extern void setup_paca(struct paca_struct *new_paca); extern void allocate_pacas(void); extern void free_unused_pacas(void); 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. */ diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c index f88acf0218db..3db8d64f40e1 100644 --- a/arch/powerpc/kernel/paca.c +++ b/arch/powerpc/kernel/paca.c @@ -105,6 +105,16 @@ void __init initialise_paca(struct paca_struct *new_paca, int cpu) #endif /* CONFIG_PPC_STD_MMU_64 */ } +/* Put the paca pointer into r13 and SPRG_PACA */ +void setup_paca(struct paca_struct *new_paca) +{ + local_paca = new_paca; + mtspr(SPRN_SPRG_PACA, local_paca); +#ifdef CONFIG_PPC_BOOK3E + mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb); +#endif +} + static int __initdata paca_size; void __init allocate_pacas(void) diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index c352f322dbdd..96e662c1d46b 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -142,16 +142,6 @@ early_param("smt-enabled", early_smt_enabled); #define check_smt_enabled() #endif /* CONFIG_SMP */ -/* Put the paca pointer into r13 and SPRG_PACA */ -static void __init setup_paca(struct paca_struct *new_paca) -{ - local_paca = new_paca; - mtspr(SPRN_SPRG_PACA, local_paca); -#ifdef CONFIG_PPC_BOOK3E - mtspr(SPRN_SPRG_TLB_EXFRAME, local_paca->extlb); -#endif -} - /* * Early initialization entry point. This is called by head.S * with MMU translation disabled. We rely on the "feature" of -- 2.11.0