x86: pass in pt_regs pointer for syscalls that need it

Some syscalls need to access the pt_regs structure, either to copy
user register state or to modifiy it.  This patch adds stubs to load
the address of the pt_regs struct into the %eax register, and changes
the syscalls to regparm(1) to receive the pt_regs pointer as the
first argument.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 8 deletions

diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 55ea30d2a3d6..8fa6ba7c9233 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -197,9 +197,8 @@ out:
 static int do_vm86_irq_handling(int subfunction, int irqnumber);
 static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk);
 
-asmlinkage int sys_vm86old(struct pt_regs regs)
+ptregscall int sys_vm86old(struct pt_regs *regs, struct vm86_struct __user *v86)
 {
-        struct vm86_struct __user *v86 = (struct vm86_struct __user *)regs.bx;
         struct kernel_vm86_struct info; /* declare this _on top_,
                                          * this avoids wasting of stack space.
                                          * This remains on the stack until we
@@ -218,7 +217,7 @@ asmlinkage int sys_vm86old(struct pt_regs regs)
         if (tmp)
                 goto out;
         memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus);
-        info.regs32 = &regs;
+        info.regs32 = regs;
         tsk->thread.vm86_info = v86;
         do_sys_vm86(&info, tsk);
         ret = 0;        /* we never return here */
@@ -227,7 +226,7 @@ out:
 }
 
 
-asmlinkage int sys_vm86(struct pt_regs regs)
+ptregscall int sys_vm86(struct pt_regs *regs, unsigned long cmd, unsigned long arg)
 {
         struct kernel_vm86_struct info; /* declare this _on top_,
                                          * this avoids wasting of stack space.
@@ -239,12 +238,12 @@ asmlinkage int sys_vm86(struct pt_regs regs)
         struct vm86plus_struct __user *v86;
 
         tsk = current;
-        switch (regs.bx) {
+        switch (cmd) {
         case VM86_REQUEST_IRQ:
         case VM86_FREE_IRQ:
         case VM86_GET_IRQ_BITS:
         case VM86_GET_AND_RESET_IRQ:
-                ret = do_vm86_irq_handling(regs.bx, (int)regs.cx);
+                ret = do_vm86_irq_handling(cmd, (int)arg);
                 goto out;
         case VM86_PLUS_INSTALL_CHECK:
                 /*
@@ -261,14 +260,14 @@ asmlinkage int sys_vm86(struct pt_regs regs)
         ret = -EPERM;
         if (tsk->thread.saved_sp0)
                 goto out;
-        v86 = (struct vm86plus_struct __user *)regs.cx;
+        v86 = (struct vm86plus_struct __user *)arg;
         tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs,
                                        offsetof(struct kernel_vm86_struct, regs32) -
                                        sizeof(info.regs));
         ret = -EFAULT;
         if (tmp)
                 goto out;
-        info.regs32 = &regs;
+        info.regs32 = regs;
         info.vm86plus.is_vm86pus = 1;
         tsk->thread.vm86_info = (struct vm86_struct __user *)v86;
         do_sys_vm86(&info, tsk);