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ARC: stop using pt_regs->orig_r8

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Historically, pt_regs have had orig_r8, an overloaded container for
  (1) backup copy of r8 (syscall number Trap Exceptions)
  (2) additional system state: (syscall/Exception/Interrupt)

There is no point in keeping (1) since syscall number is never clobbered
in-place, in pt_regs, unlike r0 which duals as first syscall arg as well
as syscall return value and in case of syscall restart, the orig arg0
needs restoring (from orig_r0)  after having been updated in-place with
syscall ret value.

This further paves way to convert (2) to contain ECR itself (rather than
current madeup values)

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta
2013-06-22 12:38:59 +05:30
parent 359105bdb0
commit 352c1d95e3
3 changed files with 4 additions and 16 deletions
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5
arch/arc/include/asm/syscall.h
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@@ -18,7 +18,7 @@ static inline long
syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
{
if (user_mode(regs) && in_syscall(regs))
return regs->orig_r8;
return regs->r8;
else
return -1;
}
@@ -26,8 +26,7 @@ syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
static inline void
syscall_rollback(struct task_struct *task, struct pt_regs *regs)
{
/* XXX: I can't fathom how pt_regs->r8 will be clobbered ? */
regs->r8 = regs->orig_r8;
regs->r0 = regs->orig_r0;
}
static inline long