x86/entry: Convert Bounds exception to IDTENTRY

Convert #BR to IDTENTRY:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes
  - Remove the RCU warning as the new entry macro ensures correctness

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134904.863001309@linutronix.de





diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 54c41b3..d7c160b 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -79,5 +79,6 @@ static __always_inline void __##func(struct pt_regs *regs)
 /* Simple exception entry points. No hardware error code */
 DECLARE_IDTENTRY(X86_TRAP_DE,		exc_divide_error);
 DECLARE_IDTENTRY(X86_TRAP_OF,		exc_overflow);
+DECLARE_IDTENTRY(X86_TRAP_BR,		exc_bounds);
 
 #endif