Sometimes it's useful to test if a memory operation works or
aborts. This adds data_abort_mask() to ignore data aborts and
data_abort_unmask() to enable them again. This is used in the
next step for the 'md' command so that illegal addresses just
show '' instead of crashing the system.
Signed-off-by: Sascha Hauer s.ha...@pengutronix.de
---
arch/arm/cpu/exceptions.S | 22 ++
arch/arm/cpu/interrupts.c | 17 +
arch/arm/include/asm/barebox.h | 4
include/abort.h| 37 +
4 files changed, 80 insertions(+)
create mode 100644 include/abort.h
diff --git a/arch/arm/cpu/exceptions.S b/arch/arm/cpu/exceptions.S
index 167c8d1..51c3903 100644
--- a/arch/arm/cpu/exceptions.S
+++ b/arch/arm/cpu/exceptions.S
@@ -88,6 +88,21 @@
movspc, lr
.endm
+ .macro try_data_abort
+ ldr r13, =arm_ignore_data_abort @ check try mode
+ ldr r13, [r13]
+ cmp r13, #0
+ beq do_abort_\@
+ ldr r13, =arm_data_abort_occured
+ str r13, [r13]
+ mrs r13, spsr @ read saved CPSR
+ tst r13, #15 @ check Thumb mode
+ subeq lr, #4 @ next ARM instr
+ subne lr, #6 @ next Thumb instr
+ movspc, lr
+do_abort_\@:
+ .endm
+
.macro get_irq_stack@ setup IRQ stack
ldr sp, IRQ_STACK_START
.endm
@@ -122,6 +137,7 @@ prefetch_abort:
.align 5
data_abort:
+ try_data_abort
get_bad_stack
bad_save_user_regs
bl do_data_abort
@@ -202,5 +218,11 @@ _fiq: .word fiq
.section .data
.align 4
+.global arm_ignore_data_abort
+arm_ignore_data_abort:
+.word arm_ignore_data_abort /* When != 0 data aborts are ignored */
+.global arm_data_abort_occured
+arm_data_abort_occured:
+.word arm_data_abort_occured /* set != 0 by the data abort handler */
abort_stack:
.space 8
diff --git a/arch/arm/cpu/interrupts.c b/arch/arm/cpu/interrupts.c
index 6e60adc..8064776 100644
--- a/arch/arm/cpu/interrupts.c
+++ b/arch/arm/cpu/interrupts.c
@@ -23,6 +23,7 @@
*/
#include common.h
+#include abort.h
#include asm/ptrace.h
#include asm/unwind.h
@@ -161,3 +162,19 @@ void do_irq (struct pt_regs *pt_regs)
printf (interrupt request\n);
do_exception(pt_regs);
}
+
+extern volatile int arm_ignore_data_abort;
+extern volatile int arm_data_abort_occured;
+
+void data_abort_mask(void)
+{
+ arm_data_abort_occured = 0;
+ arm_ignore_data_abort = 1;
+}
+
+int data_abort_unmask(void)
+{
+ arm_ignore_data_abort = 0;
+
+ return arm_data_abort_occured;
+}
diff --git a/arch/arm/include/asm/barebox.h b/arch/arm/include/asm/barebox.h
index 2b08d68..31a8e15 100644
--- a/arch/arm/include/asm/barebox.h
+++ b/arch/arm/include/asm/barebox.h
@@ -5,4 +5,8 @@
#define ARCH_HAS_STACK_DUMP
#endif
+#ifdef CONFIG_ARM_EXCEPTIONS
+#define ARCH_HAS_DATA_ABORT_MASK
+#endif
+
#endif /* _BAREBOX_H_ */
diff --git a/include/abort.h b/include/abort.h
new file mode 100644
index 000..7f14cb0
--- /dev/null
+++ b/include/abort.h
@@ -0,0 +1,37 @@
+#ifndef __ABORT_H
+#define __ABORT_H
+
+#include asm/barebox.h
+
+#ifdef ARCH_HAS_DATA_ABORT_MASK
+
+/*
+ * data_abort_mask - ignore data aborts
+ *
+ * If data aborts are ignored the data abort handler
+ * will just return.
+ */
+void data_abort_mask(void);
+
+/*
+ * data_abort_unmask - Enable data aborts
+ *
+ * returns true if a data abort has happened between calling data_abort_mask()
+ * and data_abort_unmask()
+ */
+int data_abort_unmask(void);
+
+#else
+
+static inline void data_abort_mask(void)
+{
+}
+
+static inline int data_abort_unmask(void)
+{
+ return 0;
+}
+
+#endif
+
+#endif /* __ABORT_H */
--
2.1.4
___
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox
