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Blackfin: use scratch pad for exception stack

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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>
This commit is contained in:
Mike Frysinger 2009-08-24 20:48:04 -04:00
parent 69a25ce357
commit 9c46e71af2
2 changed files with 9 additions and 0 deletions
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5
cpu/blackfin/interrupt.S
View File

@ -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)

4
include/asm-blackfin/config.h
View File

@ -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