Commit 7de0446f authored by Alexander Gordeev's avatar Alexander Gordeev
Browse files

s390/boot: Make identity mapping base address explicit 



This is a preparatory rework to allow uncoupling virtual
and physical addresses spaces.

Currently the identity mapping base address is implicit
and is always set to zero. Make it explicit by putting
into __identity_base persistent boot variable and use it
in proper context - which is the value of PAGE_OFFSET.

Acked-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent 3bb11234

arch/s390/include/asm/page.h

+4 −2
Original line number Diff line number Diff line
@@ -181,6 +181,7 @@ int arch_make_page_accessible(struct page *page); 
struct vm_layout {

	unsigned long kaslr_offset;

	unsigned long kaslr_offset_phys;

	unsigned long identity_base;

	unsigned long identity_size;

};
@@ -188,6 +189,7 @@ extern struct vm_layout vm_layout; 


#define __kaslr_offset		vm_layout.kaslr_offset

#define __kaslr_offset_phys	vm_layout.kaslr_offset_phys

#define __identity_base		vm_layout.identity_base

#define ident_map_size		vm_layout.identity_size



static inline unsigned long kaslr_offset(void)
@@ -203,8 +205,8 @@ static inline int kaslr_enabled(void) 
	return 0;

}



#define __PAGE_OFFSET		0x0UL

#define PAGE_OFFSET		0x0UL

#define __PAGE_OFFSET		__identity_base

#define PAGE_OFFSET		__PAGE_OFFSET



#define __pa_nodebug(x)		((unsigned long)(x))

arch/s390/kernel/setup.c

+1 −0
Original line number Diff line number Diff line
@@ -149,6 +149,7 @@ unsigned long __bootdata_preserved(max_mappable); 
struct physmem_info __bootdata(physmem_info);



struct vm_layout __bootdata_preserved(vm_layout);

EXPORT_SYMBOL_GPL(vm_layout);

int __bootdata_preserved(__kaslr_enabled);

unsigned int __bootdata_preserved(zlib_dfltcc_support);

EXPORT_SYMBOL(zlib_dfltcc_support);