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 --- cpu/blackfin/interrupt.S | 5 +++++ include/asm-blackfin/config.h | 4 ++++ 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