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authorRusty Russell <rusty@rustcorp.com.au>2006-09-26 08:52:39 (GMT)
committerAndi Kleen <andi@basil.nowhere.org>2006-09-26 08:52:39 (GMT)
commit78be3706b21a232310590fe00258b224177ac05f (patch)
tree57dbe444e57241613067145b04c0e15c98278cd6 /include/asm-i386/ptrace.h
parent0da5db313317e3195482d3e660a1074857374a89 (diff)
downloadlinux-fsl-qoriq-78be3706b21a232310590fe00258b224177ac05f.tar.xz
[PATCH] i386: Allow a kernel not to be in ring 0
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). This is Chris' [RFC PATCH 15/33] move segment checks to subarch, except rather than using #define USER_MODE_MASK which depends on a config option, we use Zach's more flexible approach of assuming ring 3 == userspace. I also used "get_kernel_rpl()" over "get_kernel_cs()" because I think it reads better in the code... 1) Remove the hardcoded 3 and introduce #define SEGMENT_RPL_MASK 3 2) Add a get_kernel_rpl() macro, and don't assume it's zero. And: Clean up of patch for letting kernel run other than ring 0: a. Add some comments about the SEGMENT_IS_*_CODE() macros. b. Add a USER_RPL macro. (Code was comparing a value to a mask in some places and to the magic number 3 in other places.) c. Add macros for table indicator field and use them. d. Change the entry.S tests for LDT stack segment to use the macros Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'include/asm-i386/ptrace.h')
-rw-r--r--include/asm-i386/ptrace.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/include/asm-i386/ptrace.h b/include/asm-i386/ptrace.h
index 30a442e..21bb916 100644
--- a/include/asm-i386/ptrace.h
+++ b/include/asm-i386/ptrace.h
@@ -60,6 +60,7 @@ struct pt_regs {
#ifdef __KERNEL__
#include <asm/vm86.h>
+#include <asm/segment.h>
struct task_struct;
extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code);
@@ -73,11 +74,11 @@ extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int erro
*/
static inline int user_mode(struct pt_regs *regs)
{
- return (regs->xcs & 3) != 0;
+ return (regs->xcs & SEGMENT_RPL_MASK) == USER_RPL;
}
static inline int user_mode_vm(struct pt_regs *regs)
{
- return ((regs->xcs & 3) | (regs->eflags & VM_MASK)) != 0;
+ return ((regs->xcs & SEGMENT_RPL_MASK) | (regs->eflags & VM_MASK)) >= USER_RPL;
}
#define instruction_pointer(regs) ((regs)->eip)
extern unsigned long profile_pc(struct pt_regs *regs);