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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2008-02-09 18:24:37 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-02-09 18:24:41 +0100
commit6252d702c5311ce916caf75ed82e5c8245171c92 (patch)
tree3490f27b5f888ff2c1ec915d4e7201000f37a771 /arch/s390/mm/fault.c
parent5a216a20837c5f5fa1ca4b8ae8991ffd96b08e6f (diff)
downloadop-kernel-dev-6252d702c5311ce916caf75ed82e5c8245171c92.zip
op-kernel-dev-6252d702c5311ce916caf75ed82e5c8245171c92.tar.gz
[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>
Diffstat (limited to 'arch/s390/mm/fault.c')
-rw-r--r--arch/s390/mm/fault.c40
1 files changed, 40 insertions, 0 deletions
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 @@ void __kprobes do_dat_exception(struct pt_regs *regs, unsigned long error_code)
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.
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