linux-vax-kern-commit

[Andy P. <at...@us...>]

Update of /cvsroot/linux-vax/kernel-2.4/arch/vax/mm
In directory usw-pr-cvs1:/tmp/cvs-serv23775

Modified Files:
	init.c fault.c pgalloc.c 
Log Message:
fix vmalloc handling pte_alloc_kernel and kernel pmd


Index: init.c
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.4/arch/vax/mm/init.c,v
retrieving revision 1.15
retrieving revision 1.16
diff -u -r1.15 -r1.16
--- init.c	2001/07/31 17:28:26	1.15
+++ init.c	2001/08/20 21:29:07	1.16
@@ -36,6 +36,7 @@
    context in task 0. */
 
 pgd_t swapper_pg_dir[PTRS_PER_PGD];
+pmd_t swapper_pm_dir[2048]; 		/* two pages for the kernel pmd */
 
 /*
  * In other architectures, paging_init sets up the kernel's page tables.
@@ -50,7 +51,13 @@
    
     /* sort out page table. */
     pg0 = (pte_t *)SPT_BASE;
-     
+    
+    /* set up pmd */
+    swapper_pg_dir[2].pmd  = swapper_pm_dir;
+    swapper_pg_dir[2].pmd2 = &swapper_pm_dir[1024];
+    /* FIXME: I _really_ dont like this flag. */
+    pmd_val(swapper_pm_dir[PGD_SPECIAL]) = (unsigned long)swapper_pg_dir | 0x1;
+   
     /* FIXME: This is where the VMALLOC stuff from head.S should go */
     
     printk("VAXMM: Initialising mm layer for %d tasks of size %dMB\n",TASK_MAXUPRC,(TASK_WSMAX>>20));

Index: fault.c
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.4/arch/vax/mm/fault.c,v
retrieving revision 1.8
retrieving revision 1.9
diff -u -r1.8 -r1.9
--- fault.c	2001/08/17 20:20:41	1.8
+++ fault.c	2001/08/20 21:29:07	1.9
@@ -121,10 +121,6 @@
  */
 bad_area:
 	up(&mm->mmap_sem);
-        printk("\nStack dump\n");
-        hex_dump((void *)(regs->r1), 256);
-        show_regs(regs); 
-        show_cpu_regs(); 
 
         if (user_mode(regs)) {
 		printk("do_page_fault: sending SIGSEGV\n");

Index: pgalloc.c
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.4/arch/vax/mm/pgalloc.c,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- pgalloc.c	2001/07/31 17:28:26	1.2
+++ pgalloc.c	2001/08/20 21:29:07	1.3
@@ -3,8 +3,9 @@
  * pgalloc.c  Routines from include/asm-vax/mm/pgalloc.h 
  *            Allocation of page table entries and so forth. 
  * 
- * Copyright atp Jun 2001 - complete rewrite.
- *   
+ *  Copyright atp Jun 2001 - complete rewrite.
+ *  atp aug 2001 - add in stuff for vmalloc to work (pmd_alloc_kernel) 
+ *   		   fix mistake in pte_alloc_kernel.
  * GNU GPL
 */
 
@@ -15,6 +16,8 @@
 #include <asm/pgalloc.h>
 #include <asm/mmu_context.h>
 
+extern void vaxpanic(char *reason); 
+
 #undef VAX_MM_PGALLOC_DEBUG
 
 /* 
@@ -69,8 +72,8 @@
 	  ret[0].lr = 0x0;
 	  /* this comes in handy later */
 	  ret[0].slot = taskslot;
-	  /* p1br points at what would be page mapping 0x40000000 */
-	  ret[1].br = taskslot+ (P1PTE_OFFSET) - 0x800000 ;
+	  /* p1br points at what would be page mapping 0x40000000 (i.e. the _end_ of the slot)*/
+	  ret[1].br = taskslot+ (P1PTE_OFFSET) /*+ (N_HWPTE_TASK_P1<<2)*/ - 0x800000 ;
 	  /* This is the unmapped number of PTEs */
 	  ret[1].lr = 0x40000;
 	  ret[1].slot = taskslot;
@@ -122,7 +125,10 @@
         unsigned long adjaddr;
    
         is_p1 = pgd->segment;
-   	adjaddr = (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
+   	adjaddr = pmd_index(address);
+#ifdef VAX_MM_PGALLOC_DEBUG
+        printk(KERN_DEBUG "VAXMM: Calling pmd_alloc with (pgd=%8p,pmd=%8lx,address %8lx, adjaddr %8lx)\n",pgd,pgd->pmd,address,adjaddr);
+#endif	   
         
         /* sanity check */
           /* FIXME: is this pgd_none? */
@@ -190,6 +196,22 @@
    	return (pmd_t *) pgd->pmd+adjaddr;
 }
 
+/* the kernel pmd is in mm/init.c */
+extern pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)
+{
+   /* we rely on init.c to set up the pmd pointers in the pgd for us. 
+    * This leaves us just a pmd_offset sort of job */
+#ifdef VAX_MM_PGALLOC_DEBUG   
+   printk(KERN_DEBUG "VAXMM: pmd_alloc_kernel: pgd %8p, pgd->pmd %8lx, address %8lx\n",pgd,pgd->pmd,address);
+#endif 
+   return pmd_offset(pgd, address);
+}
+
+extern void pmd_free_kernel(pmd_t *pmd)
+{
+   return;
+}
+
 /* This inverts the remapping done in remap_and_clear */ 
 unsigned long get_pageaddr_from_pte(pte_t *ptep)
 {
@@ -232,11 +254,11 @@
    
    /* sanity checks */
    if (!s0addr) {
-      printk(KERN_ERR "VAXMM: null S0 address in remap_and_clear_pte_page!\n");
+      vaxpanic("VAXMM: null S0 address in remap_and_clear_pte_page!\n");
       return;
    }
    if (!pte_page) {
-      printk(KERN_ERR "VAXMM: null pte_page in remap_and_clear_pte_page!\n");
+      vaxpanic("VAXMM: null pte_page in remap_and_clear_pte_page!\n");
       return;
    }
    
@@ -332,18 +354,38 @@
  *  
  *  - Indeed, however, the implementation is still not obvious to me.
  *    atp July 2001.
+ *  - let me qualify that. pte_alloc_kernel is called infrequently. 
+ *    Mostly by the VMALLOC stuff, which already has a VMALLOC_END check.
+ *    so the only reason for calling this is if we are in the middle of 
+ *    some operation, outside of the vmalloc family, mapping system space.
+ *    Hence the current implementation suffices, and I cant see a reason
+ *    to implement an expandable s0 page table. 
  */
 
 
 pte_t * pte_alloc_kernel(pmd_t * pmd, unsigned long address)
 {
-  pgd_t *pgdptr = (pgd_t *)pmd;
-
-  /* note the lr in the system pgd is in PAGELETS.... shift it down to 
-     give page view */
-//printk("pte_allock: pmd, %p, address %8lx\n",pmd,address);  
-  if ((address >> PAGE_SHIFT) < (pgdptr->lr>>3)) 
-    return pte_offset(pmd, address);
+  pgd_t *pgdptr = (pgd_t *)&swapper_pg_dir[2];
+  unsigned long int adjusted_address;
+  unsigned long int spt_entry;
+  pte_t *spte;
+   
+  adjusted_address = ((pmd - (pmd_t *)(pgdptr->pmd))<<(PAGE_SHIFT+7)) + (address&~PMD_MASK);
+#ifdef VAX_MM_PGALLOC_DEBUG   
+  printk(KERN_DEBUG "VAXMM:pte_alloc_kernel: pmd, %p, address %8lx, adjaddr %8lx\n",pmd,address,adjusted_address);  
+#endif
+   
+   /* note the lr in the system pgd is in PAGELETS */
+  if (((adjusted_address) >> PAGELET_SHIFT) < (pgdptr->lr)) {
+    /* fill in any bits missing. Perhaps we should do this when we set up the
+     * SPT in init.c just to be consistent */
+    if (pmd_val(*pmd)==NULL) { 
+     spt_entry = (pmd - (pmd_t *)(pgdptr->pmd))<< (PAGE_SHIFT+7) | PAGE_OFFSET;   
+     spte = GET_SPTE_VIRT(spt_entry);
+     pmd_val(*pmd) = spte;
+    }
+    return pte_offset(pmd, adjusted_address);
+  }
   else
     return NULL;
 }
@@ -390,11 +432,11 @@
    /* FIXME: should test pgdp. this is pointless otherwise */
    if ((!pgdp)||(pgd_none(*pgdp))) {
       printk(KERN_ERR "VAXMM: Bad PGD (%8p, from pmd %8p) in pte_alloc\n",pgdp,pmd_basep);
-      return NULL;
+      goto give_segv;
    }
    if (pgdp->pmd != (unsigned long)pmd_basep) {
       printk(KERN_ERR "VAXMM: Mismatched PGD (%8p, has pmd %8lx from pmd %8p) in pte_alloc\n",pgdp,pgdp->pmd,pmd_basep);
-      return NULL;
+      goto give_segv;
    }
    
    is_p1=pgdp->segment;
@@ -404,14 +446,18 @@
    /* make an adjusted address + calculate linear page table entry */
    
    adjusted_address = (((pmd-pmd_basep))<<(PAGE_SHIFT+7))+ (address&~PMD_MASK);
+   
+       
+   /* enforce wsmax memory limits */
    if (is_p1){  
       adjusted_address |= 0x40000000;
+      if (adjusted_address <= (PAGE_OFFSET-TASK_STKMAX)) goto give_segv;
       pte_number = (adjusted_address - 0x40000000) >> PAGE_SHIFT;
    } else {
+      if (adjusted_address >= (TASK_WSMAX+TASK_MMAPMAX)) goto give_segv; 
       pte_number = (adjusted_address>>PAGE_SHIFT);
    }
 
-   /* FIXME: check against WSMAX */
    
    /* check that the pte we want isnt already allocated */
    if (is_p1) {
@@ -451,7 +497,7 @@
    for (ii=0; ii<npages; ii++) {	
       if (!(pte_page=pte_alloc_one(pmdi))) {
 	 printk(KERN_ERR "VAXMM: Unable to expand process page table (pgd=%8p)\n",pgdp);
-	 return NULL;
+	 goto give_segv;
       }
       
         /* remap and clear this page */
@@ -483,6 +529,11 @@
    /* we flush tlb anways as we have touched S0 page tables */
    flush_tlb_all();
    return pte_offset(pmd, adjusted_address);
+
+give_segv:
+   printk(KERN_ERR "pte_alloc: sending SIGSEGV to process %p\n",current);
+   force_sig(SIGSEGV,current);
+   return NULL;
    
 } /* pte_alloc */
 
@@ -507,11 +558,20 @@
 }
 
 /* Find an entry in the third-level page table.. */
+#ifdef VAX_MM_PGALLOC_DEBUG   
+pte_t * pte_offset(pmd_t * dir, unsigned long address)
+{
+  unsigned long int offset;
+  offset = (pmd_val(*dir)+(((address>>PAGE_SHIFT)&(PTRS_PER_PTE-1))<<SIZEOF_PTE_LOG2)); 
+  printk(KERN_DEBUG "VAXMM:pte_offset: pmd %8p, address %8lx, pte_offset %8lx\n",dir, address, offset);
+  return offset;
+}
+#else
 pte_t * pte_offset(pmd_t * dir, unsigned long address)
 {
   return (pmd_val(*dir)+(((address>>PAGE_SHIFT)&(PTRS_PER_PTE-1))<<SIZEOF_PTE_LOG2));
 }
-
+#endif
 /* get_pte_kernel_slow. allocate a page of PTEs for the S0 pagetable.
  * See comments in include/asm/mm/pgalloc.h for get_pte_kernel.
  */