[S390] dynamic page tables.
Add support for different number of page table levels dependent
on the highest address used for a process. This will cause a 31 bit
process to use a two level page table instead of the four level page
table that is the default after the pud has been introduced. Likewise
a normal 64 bit process will use three levels instead of four. Only
if a process runs out of the 4 tera bytes which can be addressed with
a three level page table the fourth level is dynamically added. Then
the process can use up to 8 peta byte.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 2456b52..ed13d429 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -32,6 +32,7 @@
#include <asm/system.h>
#include <asm/pgtable.h>
#include <asm/s390_ext.h>
+#include <asm/mmu_context.h>
#ifndef CONFIG_64BIT
#define __FAIL_ADDR_MASK 0x7ffff000
@@ -444,6 +445,45 @@
do_exception(regs, error_code & 0xff, 0);
}
+#ifdef CONFIG_64BIT
+void __kprobes do_asce_exception(struct pt_regs *regs, unsigned long error_code)
+{
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ unsigned long address;
+ int space;
+
+ mm = current->mm;
+ address = S390_lowcore.trans_exc_code & __FAIL_ADDR_MASK;
+ space = check_space(current);
+
+ if (unlikely(space == 0 || in_atomic() || !mm))
+ goto no_context;
+
+ local_irq_enable();
+
+ down_read(&mm->mmap_sem);
+ vma = find_vma(mm, address);
+ up_read(&mm->mmap_sem);
+
+ if (vma) {
+ update_mm(mm, current);
+ return;
+ }
+
+ /* User mode accesses just cause a SIGSEGV */
+ if (regs->psw.mask & PSW_MASK_PSTATE) {
+ current->thread.prot_addr = address;
+ current->thread.trap_no = error_code;
+ do_sigsegv(regs, error_code, SEGV_MAPERR, address);
+ return;
+ }
+
+no_context:
+ do_no_context(regs, error_code, address);
+}
+#endif
+
#ifdef CONFIG_PFAULT
/*
* 'pfault' pseudo page faults routines.
