We allow for the fact that the guest kernel may not run in ring 0.
This requires some abstraction in a few places when setting %cs or
checking privilege level (user vs kernel).
Signed-off-by: Ian Pratt <[email protected]>
Signed-off-by: Christian Limpach <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
---
arch/i386/kernel/process.c | 2 +-
arch/i386/mm/fault.c | 8 +++++---
include/asm-i386/mach-default/mach_segment.h | 8 ++++++++
include/asm-i386/mach-xen/mach_segment.h | 9 +++++++++
include/asm-i386/mach-xen/mach_system.h | 1 +
include/asm-i386/ptrace.h | 6 ++++--
include/asm-i386/segment.h | 2 ++
include/asm-i386/system.h | 1 +
8 files changed, 31 insertions(+), 6 deletions(-)
diff -r 0bc9790d1ce3 arch/i386/kernel/process.c
--- a/arch/i386/kernel/process.c Tue Jul 18 04:04:39 2006 -0400
+++ b/arch/i386/kernel/process.c Tue Jul 18 04:33:57 2006 -0400
@@ -346,7 +346,7 @@ int kernel_thread(int (*fn)(void *), voi
regs.xes = __USER_DS;
regs.orig_eax = -1;
regs.eip = (unsigned long) kernel_thread_helper;
- regs.xcs = __KERNEL_CS;
+ regs.xcs = get_kernel_cs();
regs.eflags = X86_EFLAGS_IF | X86_EFLAGS_SF | X86_EFLAGS_PF | 0x2;
/* Ok, create the new process.. */
diff -r 0bc9790d1ce3 arch/i386/mm/fault.c
--- a/arch/i386/mm/fault.c Tue Jul 18 04:04:39 2006 -0400
+++ b/arch/i386/mm/fault.c Tue Jul 18 04:33:57 2006 -0400
@@ -28,6 +28,8 @@
#include <asm/desc.h>
#include <asm/kdebug.h>
+#include <mach_segment.h>
+
extern void die(const char *,struct pt_regs *,long);
#ifdef CONFIG_KPROBES
@@ -119,10 +121,10 @@ static inline unsigned long get_segment_
}
/* The standard kernel/user address space limit. */
- *eip_limit = (seg & 3) ? USER_DS.seg : KERNEL_DS.seg;
+ *eip_limit = (seg & USER_MODE_MASK) ? USER_DS.seg : KERNEL_DS.seg;
/* By far the most common cases. */
- if (likely(seg == __USER_CS || seg == __KERNEL_CS))
+ if (likely(seg == __USER_CS || seg == get_kernel_cs()))
return eip;
/* Check the segment exists, is within the current LDT/GDT size,
@@ -437,7 +439,7 @@ good_area:
switch (error_code & 3) {
default: /* 3: write, present */
#ifdef TEST_VERIFY_AREA
- if (regs->cs == KERNEL_CS)
+ if (regs->cs == get_kernel_cs())
printk("WP fault at %08lx\n", regs->eip);
#endif
/* fall through */
diff -r 0bc9790d1ce3 include/asm-i386/ptrace.h
--- a/include/asm-i386/ptrace.h Tue Jul 18 04:04:39 2006 -0400
+++ b/include/asm-i386/ptrace.h Tue Jul 18 04:33:57 2006 -0400
@@ -1,5 +1,7 @@
#ifndef _I386_PTRACE_H
#define _I386_PTRACE_H
+
+#include <mach_segment.h>
#define EBX 0
#define ECX 1
@@ -73,11 +75,11 @@ extern void send_sigtrap(struct task_str
*/
static inline int user_mode(struct pt_regs *regs)
{
- return (regs->xcs & 3) != 0;
+ return (regs->xcs & USER_MODE_MASK) != 0;
}
static inline int user_mode_vm(struct pt_regs *regs)
{
- return ((regs->xcs & 3) | (regs->eflags & VM_MASK)) != 0;
+ return ((regs->xcs & USER_MODE_MASK) | (regs->eflags & VM_MASK)) != 0;
}
#define instruction_pointer(regs) ((regs)->eip)
#if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER)
diff -r 0bc9790d1ce3 include/asm-i386/segment.h
--- a/include/asm-i386/segment.h Tue Jul 18 04:04:39 2006 -0400
+++ b/include/asm-i386/segment.h Tue Jul 18 04:33:57 2006 -0400
@@ -1,5 +1,7 @@
#ifndef _ASM_SEGMENT_H
#define _ASM_SEGMENT_H
+
+#include <mach_segment.h>
/*
* The layout of the per-CPU GDT under Linux:
diff -r 0bc9790d1ce3 include/asm-i386/system.h
--- a/include/asm-i386/system.h Tue Jul 18 04:04:39 2006 -0400
+++ b/include/asm-i386/system.h Tue Jul 18 04:33:57 2006 -0400
@@ -487,6 +487,7 @@ static inline unsigned long long __cmpxc
#endif
#include <linux/irqflags.h>
+#include <mach_system.h>
/*
* disable hlt during certain critical i/o operations
diff -r 0bc9790d1ce3 include/asm-i386/mach-xen/mach_system.h
--- a/include/asm-i386/mach-xen/mach_system.h Tue Jul 18 04:04:39 2006 -0400
+++ b/include/asm-i386/mach-xen/mach_system.h Tue Jul 18 04:33:57 2006 -0400
@@ -1,5 +1,6 @@
#ifndef __ASM_MACH_SYSTEM_H
#define __ASM_MACH_SYSTEM_H
+#include <asm/hypervisor.h>
#endif /* __ASM_MACH_SYSTEM_H */
diff -r 0bc9790d1ce3 include/asm-i386/mach-default/mach_segment.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/include/asm-i386/mach-default/mach_segment.h Tue Jul 18 04:33:57 2006 -0400
@@ -0,0 +1,8 @@
+#ifndef __ASM_MACH_SEGMENT_H
+#define __ASM_MACH_SEGMENT_H
+
+#define USER_MODE_MASK 3
+
+#define get_kernel_cs() __KERNEL_CS
+
+#endif /* __ASM_MACH_SEGMENT_H */
diff -r 0bc9790d1ce3 include/asm-i386/mach-xen/mach_segment.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/include/asm-i386/mach-xen/mach_segment.h Tue Jul 18 04:33:57 2006 -0400
@@ -0,0 +1,9 @@
+#ifndef __ASM_MACH_SEGMENT_H
+#define __ASM_MACH_SEGMENT_H
+
+#define USER_MODE_MASK 2
+
+#define get_kernel_cs() \
+ (__KERNEL_CS + (xen_feature(XENFEAT_supervisor_mode_kernel) ? 0 : 1))
+
+#endif /* __ASM_MACH_SEGMENT_H */
--
-
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