Author: jchandra
Date: Thu Aug 12 10:09:28 2010
New Revision: 211217
URL: http://svn.freebsd.org/changeset/base/211217
Log:
Implement pmap changes suggested by alc@:
1. Move dirty bit emulation code that is duplicted for kernel and user
in trap.c to a function pmap_emulate_modified() in pmap.c.
2. While doing dirty bit emulation, it is not necessary to update the
TLB entry on all CPUs using smp_rendezvous(), we can just update the
TLB entry on the current CPU, and let the other CPUs update their TLB
entry lazily if they get an exception.
Reviewed by: alc, neel
Modified:
head/sys/mips/include/pmap.h
head/sys/mips/mips/pmap.c
head/sys/mips/mips/trap.c
Modified: head/sys/mips/include/pmap.h
==============================================================================
--- head/sys/mips/include/pmap.h Thu Aug 12 09:15:27 2010
(r211216)
+++ head/sys/mips/include/pmap.h Thu Aug 12 10:09:28 2010
(r211217)
@@ -157,16 +157,14 @@ void pmap_bootstrap(void);
void *pmap_mapdev(vm_offset_t, vm_size_t);
void pmap_unmapdev(vm_offset_t, vm_size_t);
vm_offset_t pmap_steal_memory(vm_size_t size);
-void pmap_set_modified(vm_offset_t pa);
int page_is_managed(vm_offset_t pa);
void pmap_kenter(vm_offset_t va, vm_paddr_t pa);
void pmap_kremove(vm_offset_t va);
void *pmap_kenter_temporary(vm_paddr_t pa, int i);
void pmap_kenter_temporary_free(vm_paddr_t pa);
int pmap_compute_pages_to_dump(void);
-void pmap_update_page(pmap_t pmap, vm_offset_t va, pt_entry_t pte);
void pmap_flush_pvcache(vm_page_t m);
-
+int pmap_emulate_modified(pmap_t pmap, vm_offset_t va);
#endif /* _KERNEL */
#endif /* !LOCORE */
Modified: head/sys/mips/mips/pmap.c
==============================================================================
--- head/sys/mips/mips/pmap.c Thu Aug 12 09:15:27 2010 (r211216)
+++ head/sys/mips/mips/pmap.c Thu Aug 12 10:09:28 2010 (r211217)
@@ -180,6 +180,7 @@ static void pmap_remove_page(struct pmap
static void pmap_remove_entry(struct pmap *pmap, vm_page_t m, vm_offset_t va);
static boolean_t pmap_try_insert_pv_entry(pmap_t pmap, vm_page_t mpte,
vm_offset_t va, vm_page_t m);
+static void pmap_update_page(pmap_t pmap, vm_offset_t va, pt_entry_t pte);
static void pmap_invalidate_all(pmap_t pmap);
static void pmap_invalidate_page(pmap_t pmap, vm_offset_t va);
static int _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m);
@@ -704,7 +705,7 @@ struct pmap_update_page_arg {
pt_entry_t pte;
};
-void
+static void
pmap_update_page(pmap_t pmap, vm_offset_t va, pt_entry_t pte)
{
struct pmap_update_page_arg arg;
@@ -723,7 +724,7 @@ pmap_update_page_action(void *arg)
pmap_update_page_local(p->pmap, p->va, p->pte);
}
#else
-void
+static void
pmap_update_page(pmap_t pmap, vm_offset_t va, pt_entry_t pte)
{
@@ -3265,15 +3266,49 @@ init_pte_prot(vm_offset_t va, vm_page_t
}
/*
- * pmap_set_modified:
+ * pmap_emulate_modified : do dirty bit emulation
*
- * Sets the page modified and reference bits for the specified page.
+ * On SMP, update just the local TLB, other CPUs will update their
+ * TLBs from PTE lazily, if they get the exception.
+ * Returns 0 in case of sucess, 1 if the page is read only and we
+ * need to fault.
*/
-void
-pmap_set_modified(vm_offset_t pa)
+int
+pmap_emulate_modified(pmap_t pmap, vm_offset_t va)
{
+ vm_page_t m;
+ pt_entry_t *pte;
+ vm_offset_t pa;
- PHYS_TO_VM_PAGE(pa)->md.pv_flags |= (PV_TABLE_REF | PV_TABLE_MOD);
+ PMAP_LOCK(pmap);
+ pte = pmap_pte(pmap, va);
+ if (pte == NULL)
+ panic("pmap_emulate_modified: can't find PTE");
+#ifdef SMP
+ /* It is possible that some other CPU changed m-bit */
+ if (!pte_test(pte, PTE_V) || pte_test(pte, PTE_D)) {
+ pmap_update_page_local(pmap, va, *pte);
+ PMAP_UNLOCK(pmap);
+ return (0);
+ }
+#else
+ if (!pte_test(pte, PTE_V) || pte_test(pte, PTE_D))
+ panic("pmap_emulate_modified: invalid pte");
+#endif
+ if (pte_test(pte, PTE_RO)) {
+ /* write to read only page in the kernel */
+ PMAP_UNLOCK(pmap);
+ return (1);
+ }
+ pte_set(pte, PTE_D);
+ pmap_update_page_local(pmap, va, *pte);
+ pa = TLBLO_PTE_TO_PA(*pte);
+ if (!page_is_managed(pa))
+ panic("pmap_emulate_modified: unmanaged page");
+ m = PHYS_TO_VM_PAGE(pa);
+ m->md.pv_flags |= (PV_TABLE_REF | PV_TABLE_MOD);
+ PMAP_UNLOCK(pmap);
+ return (0);
}
/*
Modified: head/sys/mips/mips/trap.c
==============================================================================
--- head/sys/mips/mips/trap.c Thu Aug 12 09:15:27 2010 (r211216)
+++ head/sys/mips/mips/trap.c Thu Aug 12 10:09:28 2010 (r211217)
@@ -281,7 +281,6 @@ trap(struct trapframe *trapframe)
struct thread *td = curthread;
struct proc *p = curproc;
vm_prot_t ftype;
- pt_entry_t *pte;
pmap_t pmap;
int access_type;
ksiginfo_t ksi;
@@ -372,82 +371,24 @@ trap(struct trapframe *trapframe)
case T_TLB_MOD:
/* check for kernel address */
if (KERNLAND(trapframe->badvaddr)) {
- vm_offset_t pa;
-
- PMAP_LOCK(kernel_pmap);
- pte = pmap_pte(kernel_pmap, trapframe->badvaddr);
- if (pte == NULL)
- panic("trap: ktlbmod: can't find PTE");
-#ifdef SMP
- /* It is possible that some other CPU changed m-bit */
- if (!pte_test(pte, PTE_V) || pte_test(pte, PTE_D)) {
- pmap_update_page(kernel_pmap,
- trapframe->badvaddr, *pte);
- PMAP_UNLOCK(kernel_pmap);
- return (trapframe->pc);
- }
-#else
- if (!pte_test(pte, PTE_V) || pte_test(pte, PTE_D))
- panic("trap: ktlbmod: invalid pte");
-#endif
- if (pte_test(pte, PTE_RO)) {
- /* write to read only page in the kernel */
+ if (pmap_emulate_modified(kernel_pmap,
+ trapframe->badvaddr) != 0) {
ftype = VM_PROT_WRITE;
- PMAP_UNLOCK(kernel_pmap);
goto kernel_fault;
}
- pte_set(pte, PTE_D);
- pmap_update_page(kernel_pmap, trapframe->badvaddr,
*pte);
- pa = TLBLO_PTE_TO_PA(*pte);
- if (!page_is_managed(pa))
- panic("trap: ktlbmod: unmanaged page");
- pmap_set_modified(pa);
- PMAP_UNLOCK(kernel_pmap);
return (trapframe->pc);
}
/* FALLTHROUGH */
case T_TLB_MOD + T_USER:
- {
- vm_offset_t pa;
-
- pmap = &p->p_vmspace->vm_pmap;
-
- PMAP_LOCK(pmap);
- pte = pmap_pte(pmap, trapframe->badvaddr);
- if (pte == NULL)
- panic("trap: utlbmod: can't find PTE");
-#ifdef SMP
- /* It is possible that some other CPU changed m-bit */
- if (!pte_test(pte, PTE_V) || pte_test(pte, PTE_D)) {
- pmap_update_page(pmap, trapframe->badvaddr,
*pte);
- PMAP_UNLOCK(pmap);
- goto out;
- }
-#else
- if (!pte_test(pte, PTE_V) || pte_test(pte, PTE_D))
- panic("trap: utlbmod: invalid pte");
-#endif
-
- if (pte_test(pte, PTE_RO)) {
- /* write to read only page */
- ftype = VM_PROT_WRITE;
- PMAP_UNLOCK(pmap);
- goto dofault;
- }
- pte_set(pte, PTE_D);
- pmap_update_page(pmap, trapframe->badvaddr, *pte);
- pa = TLBLO_PTE_TO_PA(*pte);
- if (!page_is_managed(pa))
- panic("trap: utlbmod: unmanaged page");
- pmap_set_modified(pa);
-
- PMAP_UNLOCK(pmap);
- if (!usermode) {
- return (trapframe->pc);
- }
- goto out;
+ pmap = &p->p_vmspace->vm_pmap;
+ if (pmap_emulate_modified(pmap, trapframe->badvaddr) != 0) {
+ ftype = VM_PROT_WRITE;
+ goto dofault;
}
+ if (!usermode)
+ return (trapframe->pc);
+ goto out;
case T_TLB_LD_MISS:
case T_TLB_ST_MISS:
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