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SubjectRe: [GIT PULL] x86/paravirt for v2.6.33
On 12/08/09 23:36, Ingo Molnar wrote:
> Jeremy, mind sending a patch that updates this code to use the less
> obfuscated 32-bit version, not the 64-bit version? (a delta patch
> against tip:master would be nice, as there's a fair amount of testing in
> the unification change itself already, which we dont want to discard.)
>

How does this look?

git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git fix-iopl

From: Jeremy Fitzhardinge<jeremy.fitzhardinge@citrix.com>
Date: Wed, 9 Dec 2009 10:26:59 -0800
Subject: [PATCH] x86: Make sys_iopl use passed-in pt_regs

Rather than using task_pt_regs, use the pt_regs * passed into the syscall.
The ABI differences are handled in small 32/64-bit specific functions,
and everything else is handled in the common do_iopl().

Signed-off-by: Jeremy Fitzhardinge<jeremy.fitzhardinge@citrix.com>

diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h
index 5336ce2..70497f0 100644
--- a/arch/x86/include/asm/syscalls.h
+++ b/arch/x86/include/asm/syscalls.h
@@ -33,11 +33,11 @@ long sys_rt_sigreturn(struct pt_regs *);
asmlinkage int sys_set_thread_area(struct user_desc __user *);
asmlinkage int sys_get_thread_area(struct user_desc __user *);

-/* kernel/ioport.c */
-asmlinkage long sys_iopl(unsigned int);
-
/* X86_32 only */
#ifdef CONFIG_X86_32
+/* kernel/ioport.c */
+asmlinkage long sys_iopl(struct pt_regs *);
+
/* kernel/process_32.c */
int sys_clone(struct pt_regs *);
int sys_execve(struct pt_regs *);
@@ -71,6 +71,9 @@ int sys_vm86(struct pt_regs *);

/* X86_64 only */

+/* kernel/ioport.c */
+asmlinkage long sys_iopl(unsigned int, struct pt_regs *);
+
/* kernel/process_64.c */
asmlinkage long sys_clone(unsigned long, unsigned long,
void __user *, void __user *,
diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index bad4f22..ac3cf88 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -105,6 +105,7 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
*/
static int do_iopl(unsigned int level, struct pt_regs *regs)
{
+ struct thread_struct *t =&current->thread;
unsigned int old = (regs->flags>> 12)& 3;

if (level> 3)
@@ -116,21 +117,20 @@ static int do_iopl(unsigned int level, struct pt_regs *regs)
}
regs->flags = (regs->flags& ~X86_EFLAGS_IOPL) | (level<< 12);

+ t->iopl = level<< 12;
+ set_iopl_mask(t->iopl);
+
return 0;
}

-asmlinkage long sys_iopl(unsigned int level)
+#ifdef CONFIG_X86_64
+asmlinkage long sys_iopl(unsigned int level, struct pt_regs *regs)
{
- struct thread_struct *t =&current->thread;
- struct pt_regs *regs = task_pt_regs(current);
- int rc;
-
- rc = do_iopl(level, regs);
- if (rc< 0)
- goto out;
-
- t->iopl = level<< 12;
- set_iopl_mask(t->iopl);
-out:
- return rc;
+ return do_iopl(level, regs);
+}
+#else
+asmlinkage long sys_iopl(struct pt_regs *regs)
+{
+ return do_iopl(regs->bx, regs);
}
+#endif



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