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[S390] dynamic page tables.

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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>
This commit is contained in:
Martin Schwidefsky
2008-02-09 18:24:37 +01:00
parent 5a216a2083
commit 6252d702c5
13 changed files with 258 additions and 48 deletions
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40
arch/s390/mm/fault.c
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@ -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.