s390/mm: provide simple ARCH_HAS_DEBUG_VIRTUAL support

Provide a very simple ARCH_HAS_DEBUG_VIRTUAL implementation.
For now errors are only reported for the following cases:

- Trying to translate a vmalloc or module address to a physical address

- Translating a supposed to be ZONE_DMA virtual address into a physical
  address, and the resulting physical address is larger than two GiB

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/Kconfig

@@ -63,6 +63,7 @@ config S390
 	select ARCH_ENABLE_MEMORY_HOTREMOVE
 	select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
 	select ARCH_HAS_CURRENT_STACK_POINTER
+	select ARCH_HAS_DEBUG_VIRTUAL
 	select ARCH_HAS_DEBUG_VM_PGTABLE
 	select ARCH_HAS_DEBUG_WX
 	select ARCH_HAS_DEVMEM_IS_ALLOWED

arch/s390/Makefile

@@ -29,6 +29,7 @@ KBUILD_AFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),$(aflags_dwarf))
 endif
 KBUILD_CFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -O2 -mpacked-stack
 KBUILD_CFLAGS_DECOMPRESSOR += -DDISABLE_BRANCH_PROFILING -D__NO_FORTIFY
+KBUILD_CFLAGS_DECOMPRESSOR += -D__DECOMPRESSOR
 KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float -mbackchain
 KBUILD_CFLAGS_DECOMPRESSOR += -fno-asynchronous-unwind-tables
 KBUILD_CFLAGS_DECOMPRESSOR += -ffreestanding

arch/s390/configs/debug_defconfig

@@ -810,6 +810,7 @@ CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER=y
 CONFIG_DEBUG_STACK_USAGE=y
 CONFIG_DEBUG_VM=y
 CONFIG_DEBUG_VM_PGFLAGS=y
+CONFIG_DEBUG_VIRTUAL=y
 CONFIG_DEBUG_MEMORY_INIT=y
 CONFIG_MEMORY_NOTIFIER_ERROR_INJECT=m
 CONFIG_DEBUG_PER_CPU_MAPS=y

arch/s390/include/asm/dma-types.h

@@ -37,7 +37,7 @@ typedef u64 __bitwise dma64_t;
  */
 static inline dma32_t virt_to_dma32(void *ptr)
 {
-	return (__force dma32_t)__pa(ptr);
+	return (__force dma32_t)__pa32(ptr);
 }
 
 static inline void *dma32_to_virt(dma32_t addr)

arch/s390/include/asm/page.h

@@ -181,9 +181,35 @@ int arch_make_page_accessible(struct page *page);
 #define __PAGE_OFFSET		0x0UL
 #define PAGE_OFFSET		0x0UL
 
-#define __pa(x)			((unsigned long)(x))
+#define __pa_nodebug(x)		((unsigned long)(x))
+
+#ifdef __DECOMPRESSOR
+
+#define __pa(x)			__pa_nodebug(x)
+#define __pa32(x)		__pa(x)
 #define __va(x)			((void *)(unsigned long)(x))
 
+#else /* __DECOMPRESSOR */
+
+#ifdef CONFIG_DEBUG_VIRTUAL
+
+unsigned long __phys_addr(unsigned long x, bool is_31bit);
+
+#else /* CONFIG_DEBUG_VIRTUAL */
+
+static inline unsigned long __phys_addr(unsigned long x, bool is_31bit)
+{
+	return __pa_nodebug(x);
+}
+
+#endif /* CONFIG_DEBUG_VIRTUAL */
+
+#define __pa(x)			__phys_addr((unsigned long)(x), false)
+#define __pa32(x)		__phys_addr((unsigned long)(x), true)
+#define __va(x)			((void *)(unsigned long)(x))
+
+#endif /* __DECOMPRESSOR */
+
 #define phys_to_pfn(phys)	((phys) >> PAGE_SHIFT)
 #define pfn_to_phys(pfn)	((pfn) << PAGE_SHIFT)
 
@@ -205,7 +231,7 @@ static inline unsigned long virt_to_pfn(const void *kaddr)
 #define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))
 #define page_to_virt(page)	pfn_to_virt(page_to_pfn(page))
 
-#define virt_addr_valid(kaddr)	pfn_valid(virt_to_pfn(kaddr))
+#define virt_addr_valid(kaddr)	pfn_valid(phys_to_pfn(__pa_nodebug(kaddr)))
 
 #define VM_DATA_DEFAULT_FLAGS	VM_DATA_FLAGS_NON_EXEC
 

arch/s390/mm/Makefile

@@ -7,6 +7,7 @@ obj-y		:= init.o fault.o extmem.o mmap.o vmem.o maccess.o
 obj-y		+= page-states.o pageattr.o pgtable.o pgalloc.o extable.o
 
 obj-$(CONFIG_CMM)		+= cmm.o
+obj-$(CONFIG_DEBUG_VIRTUAL)	+= physaddr.o
 obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
 obj-$(CONFIG_PTDUMP_CORE)	+= dump_pagetables.o
 obj-$(CONFIG_PGSTE)		+= gmap.o

arch/s390/mm/physaddr.c

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/mmdebug.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <asm/page.h>
+
+unsigned long __phys_addr(unsigned long x, bool is_31bit)
+{
+	VIRTUAL_BUG_ON(is_vmalloc_or_module_addr((void *)(x)));
+	x = __pa_nodebug(x);
+	if (is_31bit)
+		VIRTUAL_BUG_ON(x >> 31);
+	return x;
+}
+EXPORT_SYMBOL(__phys_addr);