s390/dump: rework CPU register dump code

To collect the CPU registers of the crashed system allocated a single
page with memblock_alloc_base and use it as a copy buffer. Replace the
stop-and-store-status sigp with a store-status-at-address sigp in
smp_save_dump_cpus() and smp_store_status(). In both cases the target
CPU is already stopped and store-status-at-address avoids the detour
via the absolute zero page.

For kexec simplify s390_reset_system and call store_status() before
the prefix register of the boot CPU has been set to zero. Use STPX
to store the prefix register and remove dump_prefix_page.

Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

4 files changed, 4 insertions, 14 deletions

diff --git a/arch/s390/include/asm/fpu/internal.h b/arch/s390/include/asm/fpu/internal.h
index 2559b16da525..ea91ddfe54eb 100644
--- a/arch/s390/include/asm/fpu/internal.h
+++ b/arch/s390/include/asm/fpu/internal.h
@@ -12,21 +12,13 @@
 #include <asm/ctl_reg.h>
 #include <asm/fpu/types.h>
 
-static inline void save_vx_regs_safe(__vector128 *vxrs)
+static inline void save_vx_regs(__vector128 *vxrs)
 {
-	unsigned long cr0, flags;
-
-	flags = arch_local_irq_save();
-	__ctl_store(cr0, 0, 0);
-	__ctl_set_bit(0, 17);
-	__ctl_set_bit(0, 18);
 	asm volatile(
 		"	la	1,%0\n"
 		"	.word	0xe70f,0x1000,0x003e\n"	/* vstm 0,15,0(1) */
 		"	.word	0xe70f,0x1100,0x0c3e\n"	/* vstm 16,31,256(1) */
 		: "=Q" (*(struct vx_array *) vxrs) : : "1");
-	__ctl_load(cr0, 0, 0);
-	arch_local_irq_restore(flags);
 }
 
 static inline void convert_vx_to_fp(freg_t *fprs, __vector128 *vxrs)
diff --git a/arch/s390/include/asm/ipl.h b/arch/s390/include/asm/ipl.h
index 86634e71b69f..1dc55db8cd81 100644
--- a/arch/s390/include/asm/ipl.h
+++ b/arch/s390/include/asm/ipl.h
@@ -87,7 +87,6 @@ struct ipl_parameter_block {
  * IPL validity flags
  */
 extern u32 ipl_flags;
-extern u32 dump_prefix_page;
 
 struct dump_save_areas {
 	struct save_area_ext **areas;
@@ -176,7 +175,7 @@ enum diag308_rc {
 
 extern int diag308(unsigned long subcode, void *addr);
 extern void diag308_reset(void);
-extern void store_status(void);
+extern void store_status(void (*fn)(void *), void *data);
 extern void lgr_info_log(void);
 
 #endif /* _ASM_S390_IPL_H */
diff --git a/arch/s390/include/asm/reset.h b/arch/s390/include/asm/reset.h
index 72786067b300..fe11fa88a0e0 100644
--- a/arch/s390/include/asm/reset.h
+++ b/arch/s390/include/asm/reset.h
@@ -15,6 +15,5 @@ struct reset_call {
 
 extern void register_reset_call(struct reset_call *reset);
 extern void unregister_reset_call(struct reset_call *reset);
-extern void s390_reset_system(void (*fn_pre)(void),
-			      void (*fn_post)(void *), void *data);
+extern void s390_reset_system(void);
 #endif /* _ASM_S390_RESET_H */
diff --git a/arch/s390/include/asm/smp.h b/arch/s390/include/asm/smp.h
index 5df26b11cf47..0cc383b9be7f 100644
--- a/arch/s390/include/asm/smp.h
+++ b/arch/s390/include/asm/smp.h
@@ -18,6 +18,7 @@
 extern struct mutex smp_cpu_state_mutex;
 extern unsigned int smp_cpu_mt_shift;
 extern unsigned int smp_cpu_mtid;
+extern __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
 
 extern int __cpu_up(unsigned int cpu, struct task_struct *tidle);
 
@@ -55,7 +56,6 @@ static inline int smp_store_status(int cpu) { return 0; }
 static inline int smp_vcpu_scheduled(int cpu) { return 1; }
 static inline void smp_yield_cpu(int cpu) { }
 static inline void smp_fill_possible_mask(void) { }
-static inline void smp_save_dump_cpus(void) { }
 
 #endif /* CONFIG_SMP */