[uml-devel] [patch] host-skas3 for 2.6.9-rc2

[uml-devel] [patch] host-skas3 for 2.6.9-rc2

[Gerd Knorr]

On Thu, Sep 16, 2004 at 01:03:23PM +0200, Gerd Knorr wrote:
> Some change between -rc1 and -rc1-bk1 broke the skas patch, still
> looking ...

Found it: init_new_empty_context needs a arch_pick_mmap_layout call,
otherwise we'll get a NULL ptr dereferences for the function pointers
added recently to mm_struct.

enjoy,

  Gerd

Index: host-2.6.9-rc2/arch/i386/Kconfig
===================================================================
--- host-2.6.9-rc2.orig/arch/i386/Kconfig	2004-09-13 16:29:41.000000000 +0200
+++ host-2.6.9-rc2/arch/i386/Kconfig	2004-09-15 16:40:00.000000000 +0200
@@ -720,6 +720,10 @@ config X86_PAE
 	depends on HIGHMEM64G
 	default y
 
+config PROC_MM
+	bool "/proc/mm support"
+	default y
+
 # Common NUMA Features
 config NUMA
 	bool "Numa Memory Allocation and Scheduler Support"
Index: host-2.6.9-rc2/arch/i386/kernel/entry.S
===================================================================
--- host-2.6.9-rc2.orig/arch/i386/kernel/entry.S	2004-09-13 16:29:54.000000000 +0200
+++ host-2.6.9-rc2/arch/i386/kernel/entry.S	2004-09-15 16:40:00.000000000 +0200
@@ -256,7 +256,7 @@ sysenter_past_esp:
 	SAVE_ALL
 	GET_THREAD_INFO(%ebp)
 
-	testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
+	testb $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
 	jnz syscall_trace_entry
 	cmpl $(nr_syscalls), %eax
 	jae syscall_badsys
@@ -279,7 +279,7 @@ ENTRY(system_call)
 	SAVE_ALL
 	GET_THREAD_INFO(%ebp)
 					# system call tracing in operation
-	testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
+	testb $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
 	jnz syscall_trace_entry
 	cmpl $(nr_syscalls), %eax
 	jae syscall_badsys
@@ -340,6 +340,9 @@ syscall_trace_entry:
 	movl %esp, %eax
 	xorl %edx,%edx
 	call do_syscall_trace
+	cmpl $0, %eax
+	jne syscall_exit		# ret != 0 -> running under PTRACE_SYSEMU,
+					# so must skip actual syscall
 	movl ORIG_EAX(%esp), %eax
 	cmpl $(nr_syscalls), %eax
 	jnae syscall_call
Index: host-2.6.9-rc2/arch/i386/kernel/ldt.c
===================================================================
--- host-2.6.9-rc2.orig/arch/i386/kernel/ldt.c	2004-09-13 16:30:53.000000000 +0200
+++ host-2.6.9-rc2/arch/i386/kernel/ldt.c	2004-09-16 14:32:56.000000000 +0200
@@ -18,6 +18,7 @@
 #include <asm/system.h>
 #include <asm/ldt.h>
 #include <asm/desc.h>
+#include <asm/mmu_context.h>
 
 #ifdef CONFIG_SMP /* avoids "defined but not used" warnig */
 static void flush_ldt(void *null)
@@ -54,7 +55,7 @@ static int alloc_ldt(mm_context_t *pc, i
 	pc->size = mincount;
 	wmb();
 
-	if (reload) {
+	if (reload && (&current->active_mm->context == pc)) {
 #ifdef CONFIG_SMP
 		cpumask_t mask;
 		preempt_disable();
@@ -89,14 +90,10 @@ static inline int copy_ldt(mm_context_t 
  * we do not have to muck with descriptors here, that is
  * done in switch_mm() as needed.
  */
-int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+int copy_context(struct mm_struct *mm, struct mm_struct *old_mm)
 {
-	struct mm_struct * old_mm;
 	int retval = 0;
 
-	init_MUTEX(&mm->context.sem);
-	mm->context.size = 0;
-	old_mm = current->mm;
 	if (old_mm && old_mm->context.size > 0) {
 		down(&old_mm->context.sem);
 		retval = copy_ldt(&mm->context, &old_mm->context);
@@ -105,6 +102,12 @@ int init_new_context(struct task_struct 
 	return retval;
 }
 
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	init_new_empty_context(mm);
+	return copy_context(mm, current->mm);
+}
+
 /*
  * No need to lock the MM as we are the last user
  */
@@ -121,11 +124,11 @@ void destroy_context(struct mm_struct *m
 	}
 }
 
-static int read_ldt(void __user * ptr, unsigned long bytecount)
+static int read_ldt(struct mm_struct * mm, void __user * ptr,
+		    unsigned long bytecount)
 {
 	int err;
 	unsigned long size;
-	struct mm_struct * mm = current->mm;
 
 	if (!mm->context.size)
 		return 0;
@@ -174,9 +177,8 @@ static int read_default_ldt(void __user 
 	return err;
 }
 
-static int write_ldt(void __user * ptr, unsigned long bytecount, int oldmode)
+static int write_ldt(struct mm_struct * mm, void __user * ptr, unsigned long bytecount, int oldmode)
 {
-	struct mm_struct * mm = current->mm;
 	__u32 entry_1, entry_2, *lp;
 	int error;
 	struct user_desc ldt_info;
@@ -200,7 +202,7 @@ static int write_ldt(void __user * ptr, 
 
 	down(&mm->context.sem);
 	if (ldt_info.entry_number >= mm->context.size) {
-		error = alloc_ldt(&current->mm->context, ldt_info.entry_number+1, 1);
+		error = alloc_ldt(&mm->context, ldt_info.entry_number+1, 1);
 		if (error < 0)
 			goto out_unlock;
 	}
@@ -233,23 +235,29 @@ out:
 	return error;
 }
 
-asmlinkage int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
+int modify_ldt(struct mm_struct * mm, int func, void __user *ptr,
+	       unsigned long bytecount)
 {
 	int ret = -ENOSYS;
 
 	switch (func) {
 	case 0:
-		ret = read_ldt(ptr, bytecount);
+		ret = read_ldt(mm, ptr, bytecount);
 		break;
 	case 1:
-		ret = write_ldt(ptr, bytecount, 1);
+		ret = write_ldt(mm, ptr, bytecount, 1);
 		break;
 	case 2:
 		ret = read_default_ldt(ptr, bytecount);
 		break;
 	case 0x11:
-		ret = write_ldt(ptr, bytecount, 0);
+		ret = write_ldt(mm, ptr, bytecount, 0);
 		break;
 	}
 	return ret;
 }
+
+asmlinkage int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
+{
+	return modify_ldt(current->mm, func, ptr, bytecount);
+}
Index: host-2.6.9-rc2/arch/i386/kernel/ptrace.c
===================================================================
--- host-2.6.9-rc2.orig/arch/i386/kernel/ptrace.c	2004-09-13 16:29:56.000000000 +0200
+++ host-2.6.9-rc2/arch/i386/kernel/ptrace.c	2004-09-15 16:40:13.000000000 +0200
@@ -15,6 +15,7 @@
 #include <linux/user.h>
 #include <linux/security.h>
 #include <linux/audit.h>
+#include <linux/proc_mm.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -358,6 +359,7 @@ asmlinkage int sys_ptrace(long request, 
 		  }
 		  break;
 
+	case PTRACE_SYSEMU: /* continue and replace next syscall */
 	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 	case PTRACE_CONT: { /* restart after signal. */
 		long tmp;
@@ -365,6 +367,12 @@ asmlinkage int sys_ptrace(long request, 
 		ret = -EIO;
 		if ((unsigned long) data > _NSIG)
 			break;
+		if (request == PTRACE_SYSEMU) {
+			set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+		}
+		else {
+			clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+		}
 		if (request == PTRACE_SYSCALL) {
 			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 		}
@@ -407,6 +415,7 @@ asmlinkage int sys_ptrace(long request, 
 		ret = -EIO;
 		if ((unsigned long) data > _NSIG)
 			break;
+		clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
 		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 		if ((child->ptrace & PT_DTRACE) == 0) {
 			/* Spurious delayed TF traps may occur */
@@ -513,6 +522,56 @@ asmlinkage int sys_ptrace(long request, 
 					(struct user_desc __user *) data);
 		break;
 
+#ifdef CONFIG_PROC_MM
+	case PTRACE_FAULTINFO: {
+		struct ptrace_faultinfo fault;
+
+		fault = ((struct ptrace_faultinfo)
+			{ .is_write	= child->thread.error_code,
+			  .addr		= child->thread.cr2 });
+		ret = copy_to_user((unsigned long *) data, &fault,
+				   sizeof(fault));
+		if(ret)
+			break;
+		break;
+	}
+
+	case PTRACE_SIGPENDING:
+		ret = copy_to_user((unsigned long *) data,
+				   &child->pending.signal,
+				   sizeof(child->pending.signal));
+		break;
+
+	case PTRACE_LDT: {
+		struct ptrace_ldt ldt;
+
+		if(copy_from_user(&ldt, (unsigned long *) data,
+				  sizeof(ldt))){
+			ret = -EIO;
+			break;
+		}
+		ret = modify_ldt(child->mm, ldt.func, ldt.ptr, ldt.bytecount);
+		break;
+	}
+
+	case PTRACE_SWITCH_MM: {
+		struct mm_struct *old = child->mm;
+		struct mm_struct *new = proc_mm_get_mm(data);
+
+		if(IS_ERR(new)){
+			ret = PTR_ERR(new);
+			break;
+		}
+
+		atomic_inc(&new->mm_users);
+		child->mm = new;
+		child->active_mm = new;
+		mmput(old);
+		ret = 0;
+		break;
+	}
+#endif
+
 	default:
 		ret = ptrace_request(child, request, addr, data);
 		break;
@@ -528,7 +587,7 @@ out:
  * - triggered by current->work.syscall_trace
  */
 __attribute__((regparm(3)))
-void do_syscall_trace(struct pt_regs *regs, int entryexit)
+int do_syscall_trace(struct pt_regs *regs, int entryexit)
 {
 	if (unlikely(current->audit_context)) {
 		if (!entryexit)
@@ -540,10 +599,11 @@ void do_syscall_trace(struct pt_regs *re
 	}
 
 	if (!test_thread_flag(TIF_SYSCALL_TRACE) &&
+	    !test_thread_flag(TIF_SYSCALL_EMU)   &&
 	    !test_thread_flag(TIF_SINGLESTEP))
-		return;
+		return 0;
 	if (!(current->ptrace & PT_PTRACED))
-		return;
+		return 0;
 	/* the 0x80 provides a way for the tracing parent to distinguish
 	   between a syscall stop and SIGTRAP delivery */
 	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) &&
@@ -558,4 +618,6 @@ void do_syscall_trace(struct pt_regs *re
 		send_sig(current->exit_code, current, 1);
 		current->exit_code = 0;
 	}
+	/* != 0 if nullifying the syscall, 0 if running it normally */
+	return test_thread_flag(TIF_SYSCALL_EMU);
 }
Index: host-2.6.9-rc2/arch/i386/kernel/sys_i386.c
===================================================================
--- host-2.6.9-rc2.orig/arch/i386/kernel/sys_i386.c	2004-09-13 16:31:28.000000000 +0200
+++ host-2.6.9-rc2/arch/i386/kernel/sys_i386.c	2004-09-15 16:40:00.000000000 +0200
@@ -41,7 +41,7 @@ asmlinkage int sys_pipe(unsigned long __
 }
 
 /* common code for old and new mmaps */
-static inline long do_mmap2(
+long do_mmap2(struct mm_struct *mm,
 	unsigned long addr, unsigned long len,
 	unsigned long prot, unsigned long flags,
 	unsigned long fd, unsigned long pgoff)
@@ -56,9 +56,9 @@ static inline long do_mmap2(
 			goto out;
 	}
 
-	down_write(&current->mm->mmap_sem);
-	error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
-	up_write(&current->mm->mmap_sem);
+	down_write(&mm->mmap_sem);
+	error = __do_mmap_pgoff(mm, file, addr, len, prot, flags, pgoff);
+	up_write(&mm->mmap_sem);
 
 	if (file)
 		fput(file);
@@ -70,7 +70,7 @@ asmlinkage long sys_mmap2(unsigned long 
 	unsigned long prot, unsigned long flags,
 	unsigned long fd, unsigned long pgoff)
 {
-	return do_mmap2(addr, len, prot, flags, fd, pgoff);
+	return do_mmap2(current->mm, addr, len, prot, flags, fd, pgoff);
 }
 
 /*
@@ -101,7 +101,7 @@ asmlinkage int old_mmap(struct mmap_arg_
 	if (a.offset & ~PAGE_MASK)
 		goto out;
 
-	err = do_mmap2(a.addr, a.len, a.prot, a.flags, a.fd, a.offset >> PAGE_SHIFT);
+	err = do_mmap2(current->mm, a.addr, a.len, a.prot, a.flags, a.fd, a.offset >> PAGE_SHIFT);
 out:
 	return err;
 }
Index: host-2.6.9-rc2/include/asm-i386/desc.h
===================================================================
--- host-2.6.9-rc2.orig/include/asm-i386/desc.h	2004-09-13 16:29:15.000000000 +0200
+++ host-2.6.9-rc2/include/asm-i386/desc.h	2004-09-15 16:40:00.000000000 +0200
@@ -126,6 +126,9 @@ static inline void load_LDT(mm_context_t
 	put_cpu();
 }
 
+extern int modify_ldt(struct mm_struct * mm, int func, void __user *ptr,
+		      unsigned long bytecount);
+
 #endif /* !__ASSEMBLY__ */
 
 #endif
Index: host-2.6.9-rc2/include/asm-i386/mmu_context.h
===================================================================
--- host-2.6.9-rc2.orig/include/asm-i386/mmu_context.h	2004-09-13 16:29:16.000000000 +0200
+++ host-2.6.9-rc2/include/asm-i386/mmu_context.h	2004-09-16 14:33:56.000000000 +0200
@@ -6,13 +6,26 @@
 #include <asm/atomic.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
+#include <asm/semaphore.h>
 
 /*
- * Used for LDT copy/destruction.
+ * Used for LDT initialization/destruction. You cannot copy an LDT with
+ * init_new_context, since it thinks you are passing it a new LDT and won't
+ * deallocate its old content.
  */
 int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
 void destroy_context(struct mm_struct *mm);
 
+/* LDT initialization for a clean environment - needed for SKAS.*/
+static inline void init_new_empty_context(struct mm_struct *mm)
+{
+	init_MUTEX(&mm->context.sem);
+	mm->context.size = 0;
+	arch_pick_mmap_layout(mm);
+}
+
+/* LDT copy for SKAS - for the above problem.*/
+int copy_context(struct mm_struct *mm, struct mm_struct *old_mm);
 
 static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 {
@@ -29,6 +42,10 @@ static inline void switch_mm(struct mm_s
 {
 	int cpu = smp_processor_id();
 
+#ifdef CONFIG_SMP
+	prev = cpu_tlbstate[cpu].active_mm;
+#endif
+
 	if (likely(prev != next)) {
 		/* stop flush ipis for the previous mm */
 		cpu_clear(cpu, prev->cpu_vm_mask);
@@ -50,7 +67,6 @@ static inline void switch_mm(struct mm_s
 #ifdef CONFIG_SMP
 	else {
 		per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_OK;
-		BUG_ON(per_cpu(cpu_tlbstate, cpu).active_mm != next);
 
 		if (!cpu_test_and_set(cpu, next->cpu_vm_mask)) {
 			/* We were in lazy tlb mode and leave_mm disabled 
Index: host-2.6.9-rc2/include/asm-i386/ptrace.h
===================================================================
--- host-2.6.9-rc2.orig/include/asm-i386/ptrace.h	2004-09-13 16:29:29.000000000 +0200
+++ host-2.6.9-rc2/include/asm-i386/ptrace.h	2004-09-15 16:40:00.000000000 +0200
@@ -64,4 +64,26 @@ extern unsigned long profile_pc(struct p
 #endif
 #endif
 
+/*For SKAS3 support.*/
+#ifndef _LINUX_PTRACE_STRUCT_DEF
+#define _LINUX_PTRACE_STRUCT_DEF
+
+#define PTRACE_FAULTINFO	  52
+#define PTRACE_SIGPENDING	  53
+#define PTRACE_LDT		  54
+#define PTRACE_SWITCH_MM 	  55
+
+struct ptrace_faultinfo {
+	int is_write;
+	unsigned long addr;
+};
+
+struct ptrace_ldt {
+	int func;
+  	void *ptr;
+	unsigned long bytecount;
+};
+
+#endif /*ifndef _LINUX_PTRACE_STRUCT_DEF*/
+
 #endif
Index: host-2.6.9-rc2/include/asm-i386/thread_info.h
===================================================================
--- host-2.6.9-rc2.orig/include/asm-i386/thread_info.h	2004-09-13 16:29:39.000000000 +0200
+++ host-2.6.9-rc2/include/asm-i386/thread_info.h	2004-09-15 16:40:00.000000000 +0200
@@ -143,6 +143,7 @@ static inline unsigned long current_stac
 #define TIF_NEED_RESCHED	3	/* rescheduling necessary */
 #define TIF_SINGLESTEP		4	/* restore singlestep on return to user mode */
 #define TIF_IRET		5	/* return with iret */
+#define TIF_SYSCALL_EMU		6	/* syscall emulation active */
 #define TIF_SYSCALL_AUDIT	7	/* syscall auditing active */
 #define TIF_POLLING_NRFLAG	16	/* true if poll_idle() is polling TIF_NEED_RESCHED */
 
@@ -152,12 +153,13 @@ static inline unsigned long current_stac
 #define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
 #define _TIF_SINGLESTEP		(1<<TIF_SINGLESTEP)
 #define _TIF_IRET		(1<<TIF_IRET)
+#define _TIF_SYSCALL_EMU	(1<<TIF_SYSCALL_EMU)
 #define _TIF_SYSCALL_AUDIT	(1<<TIF_SYSCALL_AUDIT)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
 
 /* work to do on interrupt/exception return */
 #define _TIF_WORK_MASK \
-  (0x0000FFFF & ~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP))
+  (0x0000FFFF & ~(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP))
 #define _TIF_ALLWORK_MASK	0x0000FFFF	/* work to do on any return to u-space */
 
 /*
Index: host-2.6.9-rc2/include/linux/mm.h
===================================================================
--- host-2.6.9-rc2.orig/include/linux/mm.h	2004-09-13 16:29:26.000000000 +0200
+++ host-2.6.9-rc2/include/linux/mm.h	2004-09-15 16:40:00.000000000 +0200
@@ -623,6 +623,9 @@ struct shrinker;
 extern struct shrinker *set_shrinker(int, shrinker_t);
 extern void remove_shrinker(struct shrinker *shrinker);
 
+extern long do_mprotect(struct mm_struct *mm, unsigned long start,
+			size_t len, unsigned long prot);
+
 /*
  * On a two-level page table, this ends up being trivial. Thus the
  * inlining and the symmetry break with pte_alloc_map() that does all
@@ -682,9 +685,15 @@ extern void exit_mmap(struct mm_struct *
 
 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
 
-extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
+extern unsigned long __do_mmap_pgoff(struct mm_struct *mm, struct file *file,
+				   unsigned long addr, unsigned long len,
+				   unsigned long prot, unsigned long flag,
+				   unsigned long pgoff);
+static inline unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 	unsigned long len, unsigned long prot,
-	unsigned long flag, unsigned long pgoff);
+	unsigned long flag, unsigned long pgoff) {
+	return __do_mmap_pgoff(current->mm, file, addr, len, prot, flag, pgoff);
+}
 
 static inline unsigned long do_mmap(struct file *file, unsigned long addr,
 	unsigned long len, unsigned long prot,
Index: host-2.6.9-rc2/include/linux/proc_mm.h
===================================================================
--- host-2.6.9-rc2.orig/include/linux/proc_mm.h	2004-04-06 15:27:52.000000000 +0200
+++ host-2.6.9-rc2/include/linux/proc_mm.h	2004-09-15 16:40:00.000000000 +0200
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef __PROC_MM_H
+#define __PROC_MM_H
+
+#include "linux/sched.h"
+
+#define MM_MMAP 54
+#define MM_MUNMAP 55
+#define MM_MPROTECT 56
+#define MM_COPY_SEGMENTS 57
+
+struct mm_mmap {
+	unsigned long addr;
+	unsigned long len;
+	unsigned long prot;
+	unsigned long flags;
+	unsigned long fd;
+	unsigned long offset;
+};
+
+struct mm_munmap {
+	unsigned long addr;
+	unsigned long len;
+};
+
+struct mm_mprotect {
+	unsigned long addr;
+	unsigned long len;
+        unsigned int prot;
+};
+
+struct proc_mm_op {
+	int op;
+	union {
+		struct mm_mmap mmap;
+		struct mm_munmap munmap;
+	        struct mm_mprotect mprotect;
+		int copy_segments;
+	} u;
+};
+
+extern struct mm_struct *proc_mm_get_mm(int fd);
+
+#endif
Index: host-2.6.9-rc2/include/linux/ptrace.h
===================================================================
--- host-2.6.9-rc2.orig/include/linux/ptrace.h	2004-09-13 16:29:32.000000000 +0200
+++ host-2.6.9-rc2/include/linux/ptrace.h	2004-09-15 16:40:00.000000000 +0200
@@ -20,6 +20,7 @@
 #define PTRACE_DETACH		0x11
 
 #define PTRACE_SYSCALL		  24
+#define PTRACE_SYSEMU		  31
 
 /* 0x4200-0x4300 are reserved for architecture-independent additions.  */
 #define PTRACE_SETOPTIONS	0x4200
Index: host-2.6.9-rc2/kernel/fork.c
===================================================================
--- host-2.6.9-rc2.orig/kernel/fork.c	2004-09-13 16:29:32.000000000 +0200
+++ host-2.6.9-rc2/kernel/fork.c	2004-09-15 16:40:00.000000000 +0200
@@ -1038,6 +1038,7 @@ static task_t *copy_process(unsigned lon
 	 * of CLONE_PTRACE.
 	 */
 	clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
+	clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
 
 	/* Our parent execution domain becomes current domain
 	   These must match for thread signalling to apply */
Index: host-2.6.9-rc2/mm/Makefile
===================================================================
--- host-2.6.9-rc2.orig/mm/Makefile	2004-09-13 16:30:46.000000000 +0200
+++ host-2.6.9-rc2/mm/Makefile	2004-09-15 16:40:00.000000000 +0200
@@ -17,4 +17,4 @@ obj-$(CONFIG_HUGETLBFS)	+= hugetlb.o
 obj-$(CONFIG_NUMA) 	+= mempolicy.o
 obj-$(CONFIG_SHMEM) += shmem.o
 obj-$(CONFIG_TINY_SHMEM) += tiny-shmem.o
-
+obj-$(CONFIG_PROC_MM)	+= proc_mm.o
Index: host-2.6.9-rc2/mm/mmap.c
===================================================================
--- host-2.6.9-rc2.orig/mm/mmap.c	2004-09-13 16:30:44.000000000 +0200
+++ host-2.6.9-rc2/mm/mmap.c	2004-09-15 16:40:00.000000000 +0200
@@ -759,11 +759,11 @@ void __vm_stat_account(struct mm_struct 
  * The caller must hold down_write(current->mm->mmap_sem).
  */
 
-unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
-			unsigned long len, unsigned long prot,
-			unsigned long flags, unsigned long pgoff)
+unsigned long __do_mmap_pgoff(struct mm_struct *mm, struct file * file,
+			    unsigned long addr, unsigned long len,
+			    unsigned long prot, unsigned long flags,
+			    unsigned long pgoff)
 {
-	struct mm_struct * mm = current->mm;
 	struct vm_area_struct * vma, * prev;
 	struct inode *inode;
 	unsigned int vm_flags;
@@ -1032,7 +1032,7 @@ unacct_error:
 	return error;
 }
 
-EXPORT_SYMBOL(do_mmap_pgoff);
+EXPORT_SYMBOL(__do_mmap_pgoff);
 
 /* Get an address range which is currently unmapped.
  * For shmat() with addr=0.
Index: host-2.6.9-rc2/mm/mprotect.c
===================================================================
--- host-2.6.9-rc2.orig/mm/mprotect.c	2004-09-13 16:31:39.000000000 +0200
+++ host-2.6.9-rc2/mm/mprotect.c	2004-09-15 16:40:00.000000000 +0200
@@ -92,19 +92,20 @@ change_protection(struct vm_area_struct 
 {
 	pgd_t *dir;
 	unsigned long beg = start;
+	struct mm_struct * mm = vma->vm_mm;
 
-	dir = pgd_offset(current->mm, start);
+	dir = pgd_offset(mm, start);
 	flush_cache_range(vma, beg, end);
 	if (start >= end)
 		BUG();
-	spin_lock(&current->mm->page_table_lock);
+	spin_lock(&mm->page_table_lock);
 	do {
 		change_pmd_range(dir, start, end - start, newprot);
 		start = (start + PGDIR_SIZE) & PGDIR_MASK;
 		dir++;
 	} while (start && (start < end));
 	flush_tlb_range(vma, beg, end);
-	spin_unlock(&current->mm->page_table_lock);
+	spin_unlock(&mm->page_table_lock);
 	return;
 }
 
@@ -187,8 +188,9 @@ fail:
 	return error;
 }
 
-asmlinkage long
-sys_mprotect(unsigned long start, size_t len, unsigned long prot)
+long
+do_mprotect(struct mm_struct *mm, unsigned long start, size_t len,
+	     unsigned long prot)
 {
 	unsigned long vm_flags, nstart, end, tmp;
 	struct vm_area_struct *vma, *prev;
@@ -217,9 +219,9 @@ sys_mprotect(unsigned long start, size_t
 
 	vm_flags = calc_vm_prot_bits(prot);
 
-	down_write(&current->mm->mmap_sem);
+	down_write(&mm->mmap_sem);
 
-	vma = find_vma_prev(current->mm, start, &prev);
+	vma = find_vma_prev(mm, start, &prev);
 	error = -ENOMEM;
 	if (!vma)
 		goto out;
@@ -285,6 +287,11 @@ sys_mprotect(unsigned long start, size_t
 		}
 	}
 out:
-	up_write(&current->mm->mmap_sem);
+	up_write(&mm->mmap_sem);
 	return error;
 }
+
+asmlinkage long sys_mprotect(unsigned long start, size_t len, unsigned long prot)
+{
+        return(do_mprotect(current->mm, start, len, prot));
+}
Index: host-2.6.9-rc2/mm/proc_mm.c
===================================================================
--- host-2.6.9-rc2.orig/mm/proc_mm.c	2004-04-06 15:27:52.000000000 +0200
+++ host-2.6.9-rc2/mm/proc_mm.c	2004-09-15 16:40:00.000000000 +0200
@@ -0,0 +1,181 @@
+/*
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#include "linux/mm.h"
+#include "linux/init.h"
+#include "linux/proc_fs.h"
+#include "linux/proc_mm.h"
+#include "linux/file.h"
+#include "linux/mman.h"
+#include "asm/uaccess.h"
+#include "asm/mmu_context.h"
+
+static struct file_operations proc_mm_fops;
+
+struct mm_struct *proc_mm_get_mm(int fd)
+{
+	struct mm_struct *ret = ERR_PTR(-EBADF);
+	struct file *file;
+
+	file = fget(fd);
+	if (!file)
+		goto out;
+
+	ret = ERR_PTR(-EINVAL);
+	if(file->f_op != &proc_mm_fops)
+		goto out_fput;
+
+	ret = file->private_data;
+ out_fput:
+	fput(file);
+ out:
+	return(ret);
+}
+
+extern long do_mmap2(struct mm_struct *mm, unsigned long addr,
+		     unsigned long len, unsigned long prot,
+		     unsigned long flags, unsigned long fd,
+		     unsigned long pgoff);
+
+static ssize_t write_proc_mm(struct file *file, const char *buffer,
+			     size_t count, loff_t *ppos)
+{
+	struct mm_struct *mm = file->private_data;
+	struct proc_mm_op req;
+	int n, ret;
+
+	if(count > sizeof(req))
+		return(-EINVAL);
+
+	n = copy_from_user(&req, buffer, count);
+	if(n != 0)
+		return(-EFAULT);
+
+	ret = count;
+	switch(req.op){
+	case MM_MMAP: {
+		struct mm_mmap *map = &req.u.mmap;
+
+		/* Nobody ever noticed it, but do_mmap_pgoff() calls
+		 * get_unmapped_area() which checks current->mm, if
+		 * MAP_FIXED is not set, so mmap() could replace
+		 * an old mapping.
+		 */
+		if (! (map->flags & MAP_FIXED))
+			return(-EINVAL);
+
+		ret = do_mmap2(mm, map->addr, map->len, map->prot,
+			       map->flags, map->fd, map->offset >> PAGE_SHIFT);
+		if((ret & ~PAGE_MASK) == 0)
+			ret = count;
+
+		break;
+	}
+	case MM_MUNMAP: {
+		struct mm_munmap *unmap = &req.u.munmap;
+
+		down_write(&mm->mmap_sem);
+		ret = do_munmap(mm, unmap->addr, unmap->len);
+		up_write(&mm->mmap_sem);
+
+		if(ret == 0)
+			ret = count;
+		break;
+	}
+	case MM_MPROTECT: {
+		struct mm_mprotect *protect = &req.u.mprotect;
+
+		ret = do_mprotect(mm, protect->addr, protect->len,
+				  protect->prot);
+		if(ret == 0)
+			ret = count;
+		break;
+	}
+
+	case MM_COPY_SEGMENTS: {
+		struct mm_struct *from = proc_mm_get_mm(req.u.copy_segments);
+
+		if(IS_ERR(from)){
+			ret = PTR_ERR(from);
+			break;
+		}
+
+		ret = copy_context(mm, from);
+		if(ret == 0)
+			ret = count;
+		break;
+	}
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return(ret);
+}
+
+static int open_proc_mm(struct inode *inode, struct file *file)
+{
+	struct mm_struct *mm = mm_alloc();
+	int ret;
+
+	ret = -ENOMEM;
+	if(mm == NULL)
+		goto out_mem;
+
+	init_new_empty_context(mm);
+
+	spin_lock(&mmlist_lock);
+	list_add(&mm->mmlist, &current->mm->mmlist);
+	mmlist_nr++;
+	spin_unlock(&mmlist_lock);
+
+	file->private_data = mm;
+
+	return(0);
+
+ out_mem:
+	return(ret);
+}
+
+static int release_proc_mm(struct inode *inode, struct file *file)
+{
+	struct mm_struct *mm = file->private_data;
+
+	mmput(mm);
+	return(0);
+}
+
+static struct file_operations proc_mm_fops = {
+	.open		= open_proc_mm,
+	.release	= release_proc_mm,
+	.write		= write_proc_mm,
+};
+
+static int make_proc_mm(void)
+{
+	struct proc_dir_entry *ent;
+
+	ent = create_proc_entry("mm", 0222, &proc_root);
+	if(ent == NULL){
+		printk("make_proc_mm : Failed to register /proc/mm\n");
+		return(0);
+	}
+	ent->proc_fops = &proc_mm_fops;
+
+	return(0);
+}
+
+__initcall(make_proc_mm);
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */


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Re: [uml-devel] [patch] host-skas3 for 2.6.9-rc2

[BlaisorBlade]

On Thursday 16 September 2004 15:39, Gerd Knorr wrote:
> On Thu, Sep 16, 2004 at 01:03:23PM +0200, Gerd Knorr wrote:
> > Some change between -rc1 and -rc1-bk1 broke the skas patch, still
> > looking ...
>
> Found it: init_new_empty_context needs a arch_pick_mmap_layout call,
> otherwise we'll get a NULL ptr dereferences for the function pointers
> added recently to mm_struct.
Well, please cleanup it, because you are affecting the behaviour on fork() 
(the change should be harmless, however, just repeating 
arch_pick_mmap_layout()).

Without the SKAS patch, init_new_context does not call 
arch_pick_mmap_layout(), so it should not after ( and init_new_context calls, 
actually, init_new_empty_context()). I think that the proper place to add the 
call is open_proc_mm(). Do you agree on this?

Bye
-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729


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Re: [uml-devel] [patch] host-skas3 for 2.6.9-rc2

[BlaisorBlade]

On Monday 20 September 2004 17:37, Gerd Knorr wrote:
> > Without the SKAS patch, init_new_context does not call
> > arch_pick_mmap_layout(), so it should not after ( and init_new_context
> > calls, actually, init_new_empty_context()). I think that the proper place
> > to add the call is open_proc_mm(). Do you agree on this?
>
> Sounds ok, changed that, tested, works, new version below.
Yes, agreed.
> There is 
> also another fix in enter_lazy_tlb()
In switch_mm, actually.
> : use the per_cpu() macro (also 
> new in 2.6.9-rc I think).
Ah, yes, that is the only change which I had made when porting the SKAS patch 
to 2.6.9, while fixing the reject below. Basically, what we do is to make 
sure that the BUG_ON check that we remove cannot be triggered; that check is 
done if prev == next, so we must make sure to give to "prev" the value that 
"next" is supposed to have.

The reason is that with PTRACE_SWITCH_MM a thread can be scheduled away while 
having one MM and rescheduled while having a new MM; and if when it's 
scheduled away, a kernel thread goes executing, the kernel thread (using a 
lazy TLB) will keep using the old MM, the one switched away with 
PTRACE_SWITCH_MM, and the one you get with per_cpu(...). The "prev" and 
"next" args, instead, come from current->mm, so prev is wrong (the kernel 
code didn't notice that current->mm has changed). However, this can only be 
triggered on SMP, when the ptracing thread (the UML kernel thread) executes 
on a different CPU than the userspace thread.

Bye
-- 
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729


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