[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, 9 insertions, 0 deletions

diff --git a/arch/arm/mm/proc-arm920.S b/arch/arm/mm/proc-arm920.S
index a17f79e0199c..31dc839ba07c 100644
--- a/arch/arm/mm/proc-arm920.S
+++ b/arch/arm/mm/proc-arm920.S
@@ -3,6 +3,7 @@
  *
  *  Copyright (C) 1999,2000 ARM Limited
  *  Copyright (C) 2000 Deep Blue Solutions Ltd.
+ *  hacked for non-paged-MM by Hyok S. Choi, 2003.
  *
  * 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
@@ -97,7 +98,9 @@ ENTRY(cpu_arm920_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........
@@ -317,6 +320,7 @@ ENTRY(cpu_arm920_dcache_clean_area)
  */
         .align  5
 ENTRY(cpu_arm920_switch_mm)
+#ifdef CONFIG_MMU
         mov     ip, #0
 #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
         mcr     p15, 0, ip, c7, c6, 0           @ invalidate D cache
@@ -337,6 +341,7 @@ ENTRY(cpu_arm920_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
 
 /*
@@ -346,6 +351,7 @@ ENTRY(cpu_arm920_switch_mm)
  */
         .align  5
 ENTRY(cpu_arm920_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
@@ -372,6 +378,7 @@ ENTRY(cpu_arm920_set_pte)
         mov     r0, r0
         mcr     p15, 0, r0, c7, c10, 1          @ clean D entry
         mcr     p15, 0, r0, c7, c10, 4          @ drain WB
+#endif /* CONFIG_MMU */
         mov     pc, lr
 
         __INIT
@@ -381,7 +388,9 @@ __arm920_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
         mrc     p15, 0, r0, c1, c0              @ get control register v4
         ldr     r5, arm920_cr1_clear
         bic     r0, r0, r5