RE: [uml-devel] SKAS on AMD 64-Bit

["Anthony Brock" <brocka@sterlingcgi.com>]

[-- Attachment #1: Type: text/plain, Size: 2148 bytes --]

It would probably help if I included the patch! :)

Tony


> -----Original Message-----
> From: user-mode-linux-devel-admin@lists.sourceforge.net
> [mailto:user-mode-linux-devel-admin@lists.sourceforge.net]On Behalf Of
> Anthony Brock
> Sent: Sunday, August 15, 2004 2:44 PM
> To: user-mode-linux-devel@lists.sourceforge.net
> Subject: RE: [uml-devel] SKAS on AMD 64-Bit
>
>
> Given a lack of responses to my inquiry, I've attempted to migrate the
> existing patches to the "arch/i386" and "include/asm-i386" directories to
> the corresponding "arch/x86_64" and "include/asm-x86_64" directories.
>
> However, I am experiencing the following issue during boot of a previously
> functional guest UML when I use the new Host Kernel:
>
> Checking for the skas3 patch in the host...found
> Checking for /proc/mm...found
> Linux version 2.6.7-1um (root@vs1) (gcc version 3.3.3 (SuSE Linux)) #2 Thu
> Jul 29 08:57:53 PDT 2004
> On node 0 totalpages: 122880
>   DMA zone: 122880 pages, LIFO batch:16
>   Normal zone: 0 pages, LIFO batch:1
>   HighMem zone: 0 pages, LIFO batch:1
> Built 1 zonelists
>
> *** OUTPUT TRIMMED ***
>
> kjournald starting.  Commit interval 5 seconds
> EXT3-fs: mounted filesystem with ordered data mode.
> VFS: Mounted root (ext3 filesystem) readonly.
> Kernel panic: kernel BUG at mm/mmap.c:700!
>
>
> Any ideas? How would I generate a backtrace for this issue?
>
> I am attaching a copy of the non-functional patch. This patch applies
> against a vanilla 2.6.7 kernel with host-skas3-2.6.7-v1.patch pre-applied
> (in other words, it's a patch to the SKAS3 patch). Thanks in advance!
>
> Tony
>
>
>
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[-- Attachment #2: x86_64-host-skas3-2.6.7-v1.patch --]
[-- Type: application/octet-stream, Size: 7878 bytes --]

diff -ur arch/x86_64/Kconfig.skas arch/x86_64/Kconfig
--- arch/x86_64/Kconfig.skas	2004-06-15 22:19:44.000000000 -0700
+++ arch/x86_64/Kconfig	2004-08-06 14:29:12.447093965 -0700
@@ -249,6 +249,10 @@
 	  cost of slightly increased overhead in some places. If unsure say
 	  N here.
 
+config PROC_MM
+       bool "/proc/mm support"
+       default y
+
 config K8_NUMA
        bool "K8 NUMA support"
        depends on SMP
diff -ur arch/x86_64/kernel/ldt.c.skas arch/x86_64/kernel/ldt.c
--- arch/x86_64/kernel/ldt.c.skas	2004-06-15 22:20:03.000000000 -0700
+++ arch/x86_64/kernel/ldt.c	2004-08-06 14:25:55.828722076 -0700
@@ -58,7 +58,7 @@
 	wmb();
 	pc->size = mincount;
 	wmb();
-	if (reload) {
+	if (reload && (&current->active_mm->context == pc)) {
 #ifdef CONFIG_SMP
 		cpumask_t mask;
 
@@ -94,14 +94,12 @@
  * 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 __init_new_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);
@@ -110,6 +108,11 @@
 	return retval;
 }
 
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	return __init_new_context(mm, current->mm);
+}
+
 /*
  * 
  * Don't touch the LDT register - we're already in the next thread.
@@ -125,11 +128,11 @@
 	}
 }
 
-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;
@@ -164,10 +167,9 @@
 	return bytecount; 
 }
 
-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 task_struct *me = current;
-	struct mm_struct * mm = me->mm;
 	__u32 entry_1, entry_2, *lp;
 	int error;
 	struct user_desc ldt_info;
@@ -192,7 +194,7 @@
 
 	down(&mm->context.sem);
 	if (ldt_info.entry_number >= (unsigned)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;
 	}
@@ -225,23 +227,29 @@
 	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);
+}
diff -ur arch/x86_64/kernel/ptrace.c.skas arch/x86_64/kernel/ptrace.c
--- arch/x86_64/kernel/ptrace.c.skas	2004-06-15 22:19:09.000000000 -0700
+++ arch/x86_64/kernel/ptrace.c	2004-08-06 14:13:50.589224916 -0700
@@ -17,6 +17,7 @@
 #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>
@@ -477,6 +478,56 @@
 		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;
diff -ur arch/x86_64/kernel/sys_x86_64.c.skas arch/x86_64/kernel/sys_x86_64.c
--- arch/x86_64/kernel/sys_x86_64.c.skas	2004-06-15 22:19:37.000000000 -0700
+++ arch/x86_64/kernel/sys_x86_64.c	2004-08-06 13:51:08.308766765 -0700
@@ -38,7 +38,9 @@
 	return error;
 }
 
-long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags,
+long do_mmap2(struct mm_struct *mm,
+	unsigned long addr, unsigned long len,
+	unsigned long prot, unsigned long flags,
 	unsigned long fd, unsigned long off)
 {
 	long error;
@@ -56,9 +58,9 @@
 		if (!file)
 			goto out;
 	}
-	down_write(&current->mm->mmap_sem);
-	error = do_mmap_pgoff(file, addr, len, prot, flags, off >> PAGE_SHIFT);
-	up_write(&current->mm->mmap_sem);
+	down_write(&mm->mmap_sem);
+	error = __do_mmap_pgoff(mm, file, addr, len, prot, flags, off >> PAGE_SHIFT);
+	up_write(&mm->mmap_sem);
 
 	if (file)
 		fput(file);
@@ -66,6 +68,12 @@
 	return error;
 }
 
+long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags,
+	unsigned long fd, unsigned long off)
+{
+	return do_mmap2(current->mm, addr, len, prot, flags, fd, off);
+}
+
 static void find_start_end(unsigned long flags, unsigned long *begin,
 			   unsigned long *end)
 {
diff -ur include/asm-x86_64/desc.h.skas include/asm-x86_64/desc.h
--- include/asm-x86_64/desc.h.skas	2004-06-15 22:20:26.000000000 -0700
+++ include/asm-x86_64/desc.h	2004-08-06 14:32:39.968349277 -0700
@@ -210,6 +210,9 @@
 	put_cpu();
 }
 
+extern int modify_ldt(struct mm_struct * mm, int func, void __user *ptr,
+		      unsigned long bytecount);
+
 #endif /* !__ASSEMBLY__ */
 
 #endif
diff -ur include/asm-x86_64/processor.h.skas include/asm-x86_64/processor.h
--- include/asm-x86_64/processor.h.skas	2004-06-15 22:20:18.000000000 -0700
+++ include/asm-x86_64/processor.h	2004-08-06 14:34:56.998875865 -0700
@@ -454,6 +454,8 @@
 	ti->task;					\
 })
 
+extern int __init_new_context(struct mm_struct *mm, struct mm_struct *old_mm);
+
 #define cache_line_size() (boot_cpu_data.x86_cache_alignment)
 
 #ifdef CONFIG_SCHED_SMT
diff -ur include/asm-x86_64/ptrace.h.skas include/asm-x86_64/ptrace.h
--- include/asm-x86_64/ptrace.h.skas	2004-06-15 22:19:03.000000000 -0700
+++ include/asm-x86_64/ptrace.h	2004-08-06 14:38:35.353933414 -0700
@@ -110,4 +110,26 @@
 
 #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