From: Ben Gras <ben@minix3.org>
Date: Fri, 29 May 2009 18:47:31 +0000 (+0000)
Subject: further messing with page fault handling
X-Git-Tag: v3.1.4~16
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/zlib_tech.html?a=commitdiff_plain;h=f16eb59bbf63fb600507cb59a3949353183499b5;p=minix.git

further messing with page fault handling
---

diff --git a/kernel/arch/i386/exception.c b/kernel/arch/i386/exception.c
index 0e137755d..b28d7d03b 100755
--- a/kernel/arch/i386/exception.c
+++ b/kernel/arch/i386/exception.c
@@ -18,32 +18,48 @@ extern u32_t vm_copy_from_p, vm_copy_to_p, vm_copy_cr3;
 extern u32_t catchrange_lo, catchrange_hi;
 
 u32_t pagefault_cr2, pagefault_count = 0;
+vir_bytes *old_eip_ptr = NULL, *old_eax_ptr = NULL;
 
-void pagefault(struct proc *pr, int trap_errno)
+void pagefault(vir_bytes old_eip, struct proc *pr, int trap_errno)
 {
 	int s;
 	vir_bytes ph;
 	u32_t pte;
+	int procok = 0, pcok = 0, rangeok = 0;
+
+	vmassert(old_eip_ptr);
+	vmassert(old_eax_ptr);
+
+	vmassert(*old_eip_ptr == old_eip);
+	vmassert(old_eip_ptr != &old_eip);
 
 	vmassert(pagefault_count == 1);
 
-	if((iskernelp(pr) || k_reenter) && catch_pagefaults
-		&& (pr->p_reg.pc > (vir_bytes) _memcpy_k &&
-		   pr->p_reg.pc < (vir_bytes) _memcpy_k_fault) &&
-		   pagefault_cr2 >= catchrange_lo &&
-		   pagefault_cr2 < catchrange_hi) {
-		kprintf("handling pagefault during copy\n");
-		pr->p_reg.pc = (vir_bytes) _memcpy_k_fault;
-		pr->p_reg.retreg = pagefault_cr2;
-		pagefault_count = 0;
-		return;
+	if(catch_pagefaults &&
+		(rangeok = (pagefault_cr2 >= catchrange_lo &&
+		   pagefault_cr2 < catchrange_hi))) {
+		vir_bytes test_eip;
+		test_eip = k_reenter ? old_eip : pr->p_reg.pc;
+		if((pcok = ((test_eip > (vir_bytes) _memcpy_k) &&
+		   (test_eip < (vir_bytes) _memcpy_k_fault)))) {
+			kprintf("handling pagefault during copy\n");
+			pagefault_count = 0;
+
+			*old_eip_ptr = _memcpy_k_fault;
+			*old_eax_ptr = pagefault_cr2;
+
+			return;
+		}
 	}
 
-	proc_stacktrace(pr);
+	kprintf("kernel stacktrace in pagefault: "); 
+	util_stacktrace();
 
 	if(catch_pagefaults) {
-		printf("k_reenter: %d addr: 0x%lx range: 0x%lx-0x%lx\n",
-			k_reenter, pagefault_cr2, catchrange_lo, catchrange_hi);
+		kprintf("procok: %d pcok: %d rangeok: %d\n",
+			procok, pcok, rangeok);
+		printf("k_reenter: %d addr: 0x%lx range: 0x%lx-0x%lx pc: 0x%lx\n",
+			k_reenter, pagefault_cr2, catchrange_lo, catchrange_hi, pr->p_reg.pc);
 	}
 
 	/* System processes that don't have their own page table can't
@@ -150,7 +166,7 @@ struct proc *t;
   }
 
   if(vec_nr == PAGE_FAULT_VECTOR) {
-		pagefault(saved_proc, trap_errno);
+		pagefault(old_eip, saved_proc, trap_errno);
 		return;
   }
 
@@ -214,7 +230,7 @@ PUBLIC void proc_stacktrace(struct proc *proc)
 	while(v_bp) {
 
 #define PRCOPY(pr, pv, v, n) \
-  (iskernelp(pr) ? (memcpy(v, pv, n), OK) : \
+  (iskernelp(pr) ? (memcpy((char *) v, (char *) pv, n), OK) : \
      data_copy(pr->p_endpoint, pv, SYSTEM, (vir_bytes) (v), n))
 
 	        if(PRCOPY(proc, v_bp, &v_hbp, sizeof(v_hbp)) != OK) {
diff --git a/kernel/arch/i386/memory.c b/kernel/arch/i386/memory.c
index c747932d6..ea725e3a7 100644
--- a/kernel/arch/i386/memory.c
+++ b/kernel/arch/i386/memory.c
@@ -723,7 +723,6 @@ u32_t read_cr3(void)
 				kprintf("kernel: pde %d 0x%lx for proc %d\n", \
 					pde_index, pdeval, PROC->p_endpoint); \
 			}						\
-			if(copyverbose) { kprintf("installing pde val 0x%lx from pde index %d of proc %d into my pde\n", pdeval, pde_index, PROC->p_endpoint); }	\
 		} else {						\
 			pdeval = (LINADDR & I386_VM_ADDR_MASK_4MB) | 	\
 				I386_VM_BIGPAGE | I386_VM_PRESENT | 	\
@@ -745,7 +744,7 @@ int lin_lin_copy(struct proc *srcproc, vir_bytes srclinaddr, u8_t *vsrc,
 	int srcseg,
 	struct proc *dstproc, vir_bytes dstlinaddr, u8_t *vdst,
 	int dstseg,
-	vir_bytes bytes, int copyverbose)
+	vir_bytes bytes)
 {
 	u32_t addr;
 	int procslot;
@@ -780,8 +779,6 @@ int lin_lin_copy(struct proc *srcproc, vir_bytes srclinaddr, u8_t *vsrc,
 		vir_bytes srcoffset, dstoffset;
 		vir_bytes chunk = bytes;
 
-		FIXME("copyverbose");
-
 		/* Set up 4MB ranges. */
 		CREATEPDE(srcproc, srcptr, srclinaddr, srcoffset,
 			freepdes[FREEPDE_SRC], vsrc, srcseg, chunk, bytes);
@@ -850,7 +847,6 @@ int vm_phys_memset(phys_bytes ph, u8_t c, phys_bytes bytes)
 		vir_bytes chunk = bytes;
 		u8_t *ptr;
 		u32_t offset;
-		int copyverbose = 0;
 		CREATEPDE(((struct proc *) NULL), ptr, ph,
 			offset, freepdes[FREEPDE_MEMSET], 0, 0, chunk, bytes);
 		/* We can memset as many bytes as we have remaining,
@@ -957,20 +953,11 @@ int vmcheck;			/* if nonzero, can return VMSUSPEND */
   if(vm_running) {
 	int r;
 	struct proc *target, *caller;
-	int verbose = 0;
-
-		if(procs[_SRC_] && procs[_DST_] && 
-		  procs[_SRC_]->p_endpoint == PM_PROC_NR &&
-		  (procs[_DST_]->p_endpoint == INIT_PROC_NR ||
-		  procs[_DST_]->p_endpoint == 35549) &&
-		  bytes == sizeof(message)) {
-			verbose = 1;
-		}
 
 	if((r=lin_lin_copy(procs[_SRC_], phys_addr[_SRC_],
 		 (u8_t *) src_addr->offset, src_addr->segment,
 		procs[_DST_], phys_addr[_DST_], (u8_t *) dst_addr->offset,
-		dst_addr->segment, bytes, verbose)) != OK) {
+		dst_addr->segment, bytes)) != OK) {
 		if(r != EFAULT_SRC && r != EFAULT_DST)
 			minix_panic("lin_lin_copy failed", r);
 		if(!vmcheck) {
@@ -1002,17 +989,6 @@ int vmcheck;			/* if nonzero, can return VMSUSPEND */
 	  	NOREC_RETURN(virtualcopy, VMSUSPEND);
 	}
 
-	if(verbose) {
-		static int count = 0;
-		message *m;
-		kprintf("lin_lin_copy: PM to %d: %d bytes copy OK\n",
-			procs[_DST_]->p_endpoint, bytes);
-		if(count++ < 10) {
-			vm_print(procs[_SRC_]->p_seg.p_cr3);
-			vm_print(procs[_DST_]->p_seg.p_cr3);
-		}
-	}
-
   	NOREC_RETURN(virtualcopy, OK);
   }
 
diff --git a/kernel/arch/i386/mpx386.s b/kernel/arch/i386/mpx386.s
index 844d93d87..61b849c8d 100755
--- a/kernel/arch/i386/mpx386.s
+++ b/kernel/arch/i386/mpx386.s
@@ -76,6 +76,8 @@ begbss:
 .define	save
 .define	_pagefault_cr2
 .define _pagefault_count
+.define _old_eip_ptr
+.define _old_eax_ptr
 
 .define errexception
 .define exception1
@@ -524,10 +526,16 @@ errexception:
  sseg	pop	(ex_number)
  sseg	pop	(trap_errno)
 exception1:				! Common for all exceptions.
+ sseg	mov	(_old_eax_ptr), esp	! where will eax be saved?
+ sseg	sub	(_old_eax_ptr), PCREG-AXREG	! here
+
 	push	eax			! eax is scratch register
 
 	mov	eax, 0+4(esp)		! old eip
  sseg	mov	(old_eip), eax
+	mov	eax, esp
+	add	eax, 4
+ sseg	mov	(_old_eip_ptr), eax
 	movzx	eax, 4+4(esp)		! old cs
  sseg	mov	(old_cs), eax
 	mov	eax, 8+4(esp)		! old eflags
diff --git a/kernel/arch/i386/proto.h b/kernel/arch/i386/proto.h
index ccb90ff86..3c9a0f36a 100644
--- a/kernel/arch/i386/proto.h
+++ b/kernel/arch/i386/proto.h
@@ -76,6 +76,7 @@ _PROTOTYPE( void phys_outsw, (U16_t port, phys_bytes buf, size_t count) );
 _PROTOTYPE( void i386_invlpg_level0, (void) );
 _PROTOTYPE( int _memcpy_k, (void *dst, void *src, size_t n) );
 _PROTOTYPE( int _memcpy_k_fault, (void) );
+_PROTOTYPE( u32_t read_cr3, (void) );
 
 /* protect.c */
 _PROTOTYPE( void prot_init, (void)                     			);
diff --git a/kernel/proc.c b/kernel/proc.c
index 02b1ade1d..2fee24eac 100755
--- a/kernel/proc.c
+++ b/kernel/proc.c
@@ -87,17 +87,17 @@ FORWARD _PROTOTYPE( void pick_proc, (void));
 			kprintf("error %d\n", r);	\
 		  minix_panic("CopyMess: copy error", __LINE__); \
 		 } \
-		vm_suspend(dp, dp);				\
+		minix_panic("parameters unknown", NO_NUM);	\
 		(dp)->p_vmrequest.saved.msgcopy.dst = (dp);	\
 		(dp)->p_vmrequest.saved.msgcopy.dst_v = (vir_bytes) dm;	\
+		(dp)->p_vmrequest.saved.msgcopy.msgbuf.m_source = e; \
+		(dp)->p_vmrequest.type = VMSTYPE_MSGCOPY; \
   		if(data_copy((sp)->p_endpoint,	\
 			(vir_bytes) (sm), SYSTEM,	\
 			(vir_bytes) &(dp)->p_vmrequest.saved.msgcopy.msgbuf, \
 			sizeof(message)) != OK) {		\
 				minix_panic("CopyMess: data_copy failed", __LINE__);\
 			}				\
-			(dp)->p_vmrequest.saved.msgcopy.msgbuf.m_source = e; \
-			(dp)->p_vmrequest.type = VMSTYPE_MSGCOPY; \
 	}
 
 #define CopyMess(s,sp,sm,dp,dm) do { 			\
diff --git a/kernel/system/do_vmctl.c b/kernel/system/do_vmctl.c
index 9fa261827..fa2a30dfc 100644
--- a/kernel/system/do_vmctl.c
+++ b/kernel/system/do_vmctl.c
@@ -43,8 +43,11 @@ register message *m_ptr;	/* pointer to request message */
 		if(!RTS_ISSET(rp, VMREQUEST))
 			minix_panic("do_vmctl: no VMREQUEST set", NO_NUM);
 
-		printf("kernel: vm request sent by: %s / %d about %d\n",
-			rp->p_name, rp->p_endpoint, rp->p_vmrequest.who);
+		printf("kernel: vm request sent by: %s / %d about %d; 0x%lx-0x%lx, wr %d\n",
+			rp->p_name, rp->p_endpoint, rp->p_vmrequest.who,
+			rp->p_vmrequest.start,
+			rp->p_vmrequest.start + rp->p_vmrequest.length,
+			rp->p_vmrequest.writeflag);
 
 		/* Reply with request fields. */
 		m_ptr->SVMCTL_MRG_ADDR = (char *) rp->p_vmrequest.start;
diff --git a/servers/vm/i386/vm.c b/servers/vm/i386/vm.c
index 43d6db1c3..6ff14ddb3 100644
--- a/servers/vm/i386/vm.c
+++ b/servers/vm/i386/vm.c
@@ -30,11 +30,13 @@
  *===========================================================================*/
 PUBLIC vir_bytes arch_map2vir(struct vmproc *vmp, vir_bytes addr)
 {
-	vir_bytes bottom = CLICK2ABS(vmp->vm_arch.vm_seg[D].mem_phys);
+	vir_bytes textstart = CLICK2ABS(vmp->vm_arch.vm_seg[T].mem_phys);
+	vir_bytes datastart = CLICK2ABS(vmp->vm_arch.vm_seg[D].mem_phys);
 
-	vm_assert(bottom <= addr);
+	/* Could be a text address. */
+	vm_assert(datastart <= addr || textstart <= addr);
 
-	return addr - bottom;
+	return addr - datastart;
 }
 
 /*===========================================================================*