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authorMike Frysinger <vapier@gentoo.org>2009-08-24 20:48:04 -0400
committerMike Frysinger <vapier@gentoo.org>2009-09-02 05:58:38 -0400
commit9c46e71af2b03ccd721c56b1dc906ead702d6fb5 (patch)
tree4b97879f42b15dc48b15776d1ff672b090731de3
parent69a25ce3578f34c8accb476f70089f3a44b78ed9 (diff)
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Blackfin: use scratch pad for exception stack
If the memory layout pushes the stack out of the default DCPLB coverage, the exception handler may trigger a double fault by trying to push onto the uncovered stack. So handle the exception stack similar to the kernel by using the top of the scratch pad SRAM. Signed-off-by: Mike Frysinger <vapier@gentoo.org>
-rw-r--r--cpu/blackfin/interrupt.S5
-rw-r--r--include/asm-blackfin/config.h4
2 files changed, 9 insertions, 0 deletions
diff --git a/cpu/blackfin/interrupt.S b/cpu/blackfin/interrupt.S
index dd2cc53..71e0fc6 100644
--- a/cpu/blackfin/interrupt.S
+++ b/cpu/blackfin/interrupt.S
@@ -5,6 +5,7 @@
* Licensed under the GPL-2 or later.
*/
+#include <config.h>
#include <asm/blackfin.h>
#include <asm/entry.h>
@@ -12,12 +13,16 @@
/* default entry point for exceptions */
ENTRY(_trap)
+ CONFIG_BFIN_SCRATCH_REG = sp;
+ sp.l = LO(L1_SRAM_SCRATCH_END - 20);
+ sp.h = HI(L1_SRAM_SCRATCH_END - 20);
SAVE_ALL_SYS
r0 = sp; /* stack frame pt_regs pointer argument ==> r0 */
sp += -12;
call _trap_c;
sp += 12;
RESTORE_ALL_SYS
+ sp = CONFIG_BFIN_SCRATCH_REG;
rtx;
ENDPROC(_trap)
diff --git a/include/asm-blackfin/config.h b/include/asm-blackfin/config.h
index 5739b13..25794dd 100644
--- a/include/asm-blackfin/config.h
+++ b/include/asm-blackfin/config.h
@@ -14,6 +14,10 @@
# error CONFIG_BFIN_CPU: your board config needs to define this
#endif
+#ifndef CONFIG_BFIN_SCRATCH_REG
+# define CONFIG_BFIN_SCRATCH_REG retn
+#endif
+
/* Make sure the structure is properly aligned */
#if ((CONFIG_SYS_GBL_DATA_ADDR & -4) != CONFIG_SYS_GBL_DATA_ADDR)
# error CONFIG_SYS_GBL_DATA_ADDR: must be 4 byte aligned