[PATCH] powerpc: Merge thread_info.h

Merge ppc32 and ppc64 versions of thread_info.h.  They were pretty
similar already, the chief changes are:

	- Instead of inline asm to implement current_thread_info(),
which needs to be different for ppc32 and ppc64, we use C with an
asm("r1") register variable.  gcc turns it into the same asm as we
used to have for both platforms.
	- We replace ppc32's 'local_flags' with the ppc64
'syscall_noerror' field.  The noerror flag was in fact the only thing
in the local_flags field anyway, so the ppc64 approach is simpler, and
means we only need a load-immediate/store instead of load/mask/store
when clearing the flag.
	- In readiness for 64k pages, when THREAD_SIZE will be less
than a page, ppc64 used kmalloc() rather than get_free_pages() to
allocate the kernel stack.  With this patch we do the same for ppc32,
since there's no strong reason not to.
	- For ppc64, we no longer export THREAD_SHIFT and THREAD_SIZE
via asm-offsets, thread_info.h can now be safely included in asm, as
on ppc32.

Built and booted on G4 Powerbook (ARCH=ppc and ARCH=powerpc) and
Power5 (ARCH=ppc64 and ARCH=powerpc).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/ppc/kernel/entry.S

@@ -200,9 +200,8 @@ _GLOBAL(DoSyscall)
 	bl	do_show_syscall
 #endif /* SHOW_SYSCALLS */
 	rlwinm	r10,r1,0,0,18	/* current_thread_info() */
-	lwz	r11,TI_LOCAL_FLAGS(r10)
-	rlwinm	r11,r11,0,~_TIFL_FORCE_NOERROR
-	stw	r11,TI_LOCAL_FLAGS(r10)
+	li	r11,0
+	stb	r11,TI_SC_NOERR(r10)
 	lwz	r11,TI_FLAGS(r10)
 	andi.	r11,r11,_TIF_SYSCALL_T_OR_A
 	bne-	syscall_dotrace
@@ -227,8 +226,8 @@ ret_from_syscall:
 	cmplw	0,r3,r11
 	rlwinm	r12,r1,0,0,18	/* current_thread_info() */
 	blt+	30f
-	lwz	r11,TI_LOCAL_FLAGS(r12)
-	andi.	r11,r11,_TIFL_FORCE_NOERROR
+	lbz	r11,TI_SC_NOERR(r12)
+	cmpwi	r11,0
 	bne	30f
 	neg	r3,r3
 	lwz	r10,_CCR(r1)	/* Set SO bit in CR */