Revert "s390/smp: rework absolute lowcore access"

This reverts commit 7d06fed77b7d8fc9f6cc41b4e3f2823d32532ad8.

This introduced vmem_mutex locking from vmem_map_4k_page()
function called from smp_reinit_ipl_cpu() with interrupts
disabled. While it is a pre-SMP early initcall no other CPUs
running in parallel nor other code taking vmem_mutex on this
boot stage - it still needs to be fixed.

Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

3 files changed, 15 insertions, 19 deletions

diff --git a/arch/s390/include/asm/abs_lowcore.h b/arch/s390/include/asm/abs_lowcore.h
deleted file mode 100644
index bdef8d24d237..000000000000
--- a/arch/s390/include/asm/abs_lowcore.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_S390_ABS_LOWCORE_H
-#define _ASM_S390_ABS_LOWCORE_H
-
-#include <asm/lowcore.h>
-
-#define ABS_LOWCORE_MAP_SIZE	(NR_CPUS * sizeof(struct lowcore))
-
-extern unsigned long __abs_lowcore;
-extern bool abs_lowcore_mapped;
-
-struct lowcore *get_abs_lowcore(unsigned long *flags);
-void put_abs_lowcore(struct lowcore *lc, unsigned long flags);
-int abs_lowcore_map(int cpu, struct lowcore *lc);
-void abs_lowcore_unmap(int cpu);
-
-#endif /* _ASM_ABS_S390_LOWCORE_H */
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 82506ebd544b..a397b072a580 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1781,8 +1781,6 @@ static inline swp_entry_t __swp_entry(unsigned long type, unsigned long offset)
 
 extern int vmem_add_mapping(unsigned long start, unsigned long size);
 extern void vmem_remove_mapping(unsigned long start, unsigned long size);
-extern int vmem_map_4k_page(unsigned long addr, unsigned long phys, pgprot_t prot);
-extern void vmem_unmap_4k_page(unsigned long addr);
 extern int s390_enable_sie(void);
 extern int s390_enable_skey(void);
 extern void s390_reset_cmma(struct mm_struct *mm);
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 93677ae89e7e..bd66f8e34949 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -307,6 +307,21 @@ static __always_inline void __noreturn disabled_wait(void)
 #define ARCH_LOW_ADDRESS_LIMIT	0x7fffffffUL
 
 extern int memcpy_real(void *, unsigned long, size_t);
+extern void memcpy_absolute(void *, void *, size_t);
+
+#define put_abs_lowcore(member, x) do {					\
+	unsigned long __abs_address = offsetof(struct lowcore, member);	\
+	__typeof__(((struct lowcore *)0)->member) __tmp = (x);		\
+									\
+	memcpy_absolute(__va(__abs_address), &__tmp, sizeof(__tmp));	\
+} while (0)
+
+#define get_abs_lowcore(x, member) do {					\
+	unsigned long __abs_address = offsetof(struct lowcore, member);	\
+	__typeof__(((struct lowcore *)0)->member) *__ptr = &(x);	\
+									\
+	memcpy_absolute(__ptr, __va(__abs_address), sizeof(*__ptr));	\
+} while (0)
 
 extern int s390_isolate_bp(void);
 extern int s390_isolate_bp_guest(void);