[ARM] nommu: Initial uCLinux support for MMU-based CPUs
In noMMU mode, various of functions which are defined in mm/proc-*.S
is not valid or needed to be avoided. i.g. switch_mm is not needed,
just returns and this makes the I & D caches are valid which shows
great improvement of performance including task switching and IPC.
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index 09b1a41..ca13d4d 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S
@@ -2,6 +2,7 @@
* linux/arch/arm/mm/proc-v6.S
*
* Copyright (C) 2001 Deep Blue Solutions Ltd.
+ * Modified by Catalin Marinas for noMMU support
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -88,6 +89,7 @@
* - we are not using split page tables
*/
ENTRY(cpu_v6_switch_mm)
+#ifdef CONFIG_MMU
mov r2, #0
ldr r1, [r1, #MM_CONTEXT_ID] @ get mm->context.id
#ifdef CONFIG_SMP
@@ -97,6 +99,7 @@
mcr p15, 0, r2, c7, c10, 4 @ drain write buffer
mcr p15, 0, r0, c2, c0, 0 @ set TTB 0
mcr p15, 0, r1, c13, c0, 1 @ set context ID
+#endif
mov pc, lr
/*
@@ -119,6 +122,7 @@
* 1111 0 1 1 r/w r/w
*/
ENTRY(cpu_v6_set_pte)
+#ifdef CONFIG_MMU
str r1, [r0], #-2048 @ linux version
bic r2, r1, #0x000003f0
@@ -145,6 +149,7 @@
str r2, [r0]
mcr p15, 0, r0, c7, c10, 1 @ flush_pte
+#endif
mov pc, lr
@@ -194,12 +199,14 @@
mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
mcr p15, 0, r0, c7, c15, 0 @ clean+invalidate cache
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer
+#ifdef CONFIG_MMU
mcr p15, 0, r0, c8, c7, 0 @ invalidate I + D TLBs
mcr p15, 0, r0, c2, c0, 2 @ TTB control register
#ifdef CONFIG_SMP
orr r4, r4, #TTB_RGN_WBWA|TTB_S @ mark PTWs shared, outer cacheable
#endif
mcr p15, 0, r4, c2, c0, 1 @ load TTB1
+#endif /* CONFIG_MMU */
#ifdef CONFIG_VFP
mrc p15, 0, r0, c1, c0, 2
orr r0, r0, #(0xf << 20)