[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>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/arm/mm/proc-arm925.S b/arch/arm/mm/proc-arm925.S
index 224ce226a01..8d47c9f3f93 100644
--- a/arch/arm/mm/proc-arm925.S
+++ b/arch/arm/mm/proc-arm925.S
@@ -9,6 +9,8 @@
  *  Update for Linux-2.6 and cache flush improvements
  *  Copyright (C) 2004 Nokia Corporation by Tony Lindgren <tony@atomide.com>
  *
+ *  hacked for non-paged-MM by Hyok S. Choi, 2004.
+ *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
@@ -122,7 +124,9 @@ ENTRY(cpu_arm925_reset)
         mov     ip, #0
         mcr     p15, 0, ip, c7, c7, 0           @ invalidate I,D caches
         mcr     p15, 0, ip, c7, c10, 4          @ drain WB
+#ifdef CONFIG_MMU
         mcr     p15, 0, ip, c8, c7, 0           @ invalidate I & D TLBs
+#endif
         mrc     p15, 0, ip, c1, c0, 0           @ ctrl register
         bic     ip, ip, #0x000f                 @ ............wcam
         bic     ip, ip, #0x1100                 @ ...i...s........
@@ -369,6 +373,7 @@ ENTRY(cpu_arm925_dcache_clean_area)
  */
         .align  5
 ENTRY(cpu_arm925_switch_mm)
+#ifdef CONFIG_MMU
         mov     ip, #0
 #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
         mcr     p15, 0, ip, c7, c6, 0           @ invalidate D cache
@@ -383,6 +388,7 @@ ENTRY(cpu_arm925_switch_mm)
         mcr     p15, 0, ip, c7, c10, 4          @ drain WB
         mcr     p15, 0, r0, c2, c0, 0           @ load page table pointer
         mcr     p15, 0, ip, c8, c7, 0           @ invalidate I & D TLBs
+#endif
         mov     pc, lr
 
 /*
@@ -392,6 +398,7 @@ ENTRY(cpu_arm925_switch_mm)
  */
         .align  5
 ENTRY(cpu_arm925_set_pte)
+#ifdef CONFIG_MMU
         str     r1, [r0], #-2048                @ linux version
 
         eor     r1, r1, #L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_WRITE | L_PTE_DIRTY
@@ -420,6 +427,7 @@ ENTRY(cpu_arm925_set_pte)
         mcr     p15, 0, r0, c7, c10, 1          @ clean D entry
 #endif
         mcr     p15, 0, r0, c7, c10, 4          @ drain WB
+#endif /* CONFIG_MMU */
         mov     pc, lr
 
         __INIT
@@ -438,7 +446,9 @@ __arm925_setup:
         mov     r0, #0
         mcr     p15, 0, r0, c7, c7              @ invalidate I,D caches on v4
         mcr     p15, 0, r0, c7, c10, 4          @ drain write buffer on v4
+#ifdef CONFIG_MMU
         mcr     p15, 0, r0, c8, c7              @ invalidate I,D TLBs on v4
+#endif
 
 #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
         mov     r0, #4                          @ disable write-back on caches explicitly