[PATCH 10/35] m68k: set register a2 to current if MMU enabled on ColdFire

gerg
2011-11-25T03:39:29Z

Virtual memory m68k systems build with register a2 dedicated to being the
current proc pointer (non-MMU don't do this). Add code to the ColdFire
interrupt and exception processing to set this on entry, and at context
switch time. We use the same GET_CURRENT() macro that MMU enabled code
uses - modifying it so that the assembler is ColdFire clean.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
---
arch/m68k/include/asm/entry.h | 10 +++++++++-
arch/m68k/kernel/entry_no.S | 3 +++
arch/m68k/platform/coldfire/entry.S | 6 +++++-
3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/arch/m68k/include/asm/entry.h b/arch/m68k/include/asm/entry.h
index c3c5a86..c717f57 100644
--- a/arch/m68k/include/asm/entry.h
+++ b/arch/m68k/include/asm/entry.h
@@ -222,16 +222,24 @@
* Non-MMU systems do not reserve %a2 in this way, and this definition is
* not used for them.
*/
+#ifdef CONFIG_MMU
+
#define curptr a2

#define GET_CURRENT(tmp) get_current tmp
.macro get_current reg=%d0
movel %sp,\reg
- andw #-THREAD_SIZE,\reg
+ andl #-THREAD_SIZE,\reg
movel \reg,%curptr
movel %curptr@,%curptr
.endm

+#else
+
+#define GET_CURRENT(tmp)
+
+#endif /* CONFIG_MMU */
+
#else /* C source */

#define STR(X) STR1(X)
diff --git a/arch/m68k/kernel/entry_no.S b/arch/m68k/kernel/entry_no.S
index ac86a9f..d80cba4 100644
--- a/arch/m68k/kernel/entry_no.S
+++ b/arch/m68k/kernel/entry_no.S
@@ -44,6 +44,7 @@

ENTRY(buserr)
SAVE_ALL_INT
+ GET_CURRENT(%d0)
movel %sp,%sp@- /* stack frame pointer argument */
jsr buserr_c
addql #4,%sp
@@ -51,6 +52,7 @@ ENTRY(buserr)

ENTRY(trap)
SAVE_ALL_INT
+ GET_CURRENT(%d0)
movel %sp,%sp@- /* stack frame pointer argument */
jsr trap_c
addql #4,%sp
@@ -61,6 +63,7 @@ ENTRY(trap)
.globl dbginterrupt
ENTRY(dbginterrupt)
SAVE_ALL_INT
+ GET_CURRENT(%d0)
movel %sp,%sp@- /* stack frame pointer argument */
jsr dbginterrupt_c
addql #4,%sp
diff --git a/arch/m68k/platform/coldfire/entry.S b/arch/m68k/platform/coldfire/entry.S
index f567a16..863889f 100644
--- a/arch/m68k/platform/coldfire/entry.S
+++ b/arch/m68k/platform/coldfire/entry.S
@@ -62,6 +62,7 @@ enosys:
ENTRY(system_call)
SAVE_ALL_SYS
move #0x2000,%sr /* enable intrs again */
+ GET_CURRENT(%d2)

cmpl #NR_syscalls,%d0
jcc enosys
@@ -165,6 +166,7 @@ Lsignal_return:
*/
ENTRY(inthandler)
SAVE_ALL_INT
+ GET_CURRENT(%d2)

movew %sp@(PT_OFF_FORMATVEC),%d0 /* put exception # in d0 */
andl #0x03fc,%d0 /* mask out vector only */
@@ -190,7 +192,9 @@ ENTRY(resume)
movel %sp,%a0@(TASK_THREAD+THREAD_KSP) /* save kernel stack pointer */
RDUSP /* movel %usp,%a3 */
movel %a3,%a0@(TASK_THREAD+THREAD_USP) /* save thread user stack */
-
+#ifdef CONFIG_MMU
+ movel %a1,%a2 /* set new current */
+#endif
movel %a1@(TASK_THREAD+THREAD_USP),%a3 /* restore thread user stack */
WRUSP /* movel %a3,%usp */
movel %a1@(TASK_THREAD+THREAD_KSP),%sp /* restore new kernel stack */
--
1.7.0.4