[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, 11 insertions, 0 deletions

diff --git a/arch/arm/mm/proc-sa110.S b/arch/arm/mm/proc-sa110.S
index a2dd5ae1077d..5a760a2c629c 100644
--- a/arch/arm/mm/proc-sa110.S
+++ b/arch/arm/mm/proc-sa110.S
@@ -2,6 +2,7 @@
  *  linux/arch/arm/mm/proc-sa110.S
  *
  *  Copyright (C) 1997-2002 Russell King
+ *  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 version 2 as
@@ -67,7 +68,9 @@ ENTRY(cpu_sa110_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........
@@ -130,11 +133,15 @@ ENTRY(cpu_sa110_dcache_clean_area)
  */
         .align  5
 ENTRY(cpu_sa110_switch_mm)
+#ifdef CONFIG_MMU
         str     lr, [sp, #-4]!
         bl      v4wb_flush_kern_cache_all       @ clears IP
         mcr     p15, 0, r0, c2, c0, 0           @ load page table pointer
         mcr     p15, 0, ip, c8, c7, 0           @ invalidate I & D TLBs
         ldr     pc, [sp], #4
+#else
+        mov     pc, lr
+#endif
 
 /*
  * cpu_sa110_set_pte(ptep, pte)
@@ -143,6 +150,7 @@ ENTRY(cpu_sa110_switch_mm)
  */
         .align  5
 ENTRY(cpu_sa110_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
@@ -164,6 +172,7 @@ ENTRY(cpu_sa110_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
         mov     pc, lr
 
         __INIT
@@ -173,7 +182,9 @@ __sa110_setup:
         mov     r10, #0
         mcr     p15, 0, r10, c7, c7             @ invalidate I,D caches on v4
         mcr     p15, 0, r10, c7, c10, 4         @ drain write buffer on v4
+#ifdef CONFIG_MMU
         mcr     p15, 0, r10, c8, c7             @ invalidate I,D TLBs on v4
+#endif
         mrc     p15, 0, r0, c1, c0              @ get control register v4
         ldr     r5, sa110_cr1_clear
         bic     r0, r0, r5