summaryrefslogtreecommitdiffstats
path: root/arch/arm/include/asm/kgdb.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/include/asm/kgdb.h')
-rw-r--r--arch/arm/include/asm/kgdb.h104
1 files changed, 104 insertions, 0 deletions
diff --git a/arch/arm/include/asm/kgdb.h b/arch/arm/include/asm/kgdb.h
new file mode 100644
index 0000000..67af4b8
--- /dev/null
+++ b/arch/arm/include/asm/kgdb.h
@@ -0,0 +1,104 @@
+/*
+ * ARM KGDB support
+ *
+ * Author: Deepak Saxena <dsaxena@mvista.com>
+ *
+ * Copyright (C) 2002 MontaVista Software Inc.
+ *
+ */
+
+#ifndef __ARM_KGDB_H__
+#define __ARM_KGDB_H__
+
+#include <linux/ptrace.h>
+
+/*
+ * GDB assumes that we're a user process being debugged, so
+ * it will send us an SWI command to write into memory as the
+ * debug trap. When an SWI occurs, the next instruction addr is
+ * placed into R14_svc before jumping to the vector trap.
+ * This doesn't work for kernel debugging as we are already in SVC
+ * we would loose the kernel's LR, which is a bad thing. This
+ * is bad thing.
+ *
+ * By doing this as an undefined instruction trap, we force a mode
+ * switch from SVC to UND mode, allowing us to save full kernel state.
+ *
+ * We also define a KGDB_COMPILED_BREAK which can be used to compile
+ * in breakpoints. This is important for things like sysrq-G and for
+ * the initial breakpoint from trap_init().
+ *
+ * Note to ARM HW designers: Add real trap support like SH && PPC to
+ * make our lives much much simpler. :)
+ */
+#define BREAK_INSTR_SIZE 4
+#define GDB_BREAKINST 0xef9f0001
+#define KGDB_BREAKINST 0xe7ffdefe
+#define KGDB_COMPILED_BREAK 0xe7ffdeff
+#define CACHE_FLUSH_IS_SAFE 1
+
+#ifndef __ASSEMBLY__
+
+static inline void arch_kgdb_breakpoint(void)
+{
+ asm(".word 0xe7ffdeff");
+}
+
+extern void kgdb_handle_bus_error(void);
+extern int kgdb_fault_expected;
+
+#endif /* !__ASSEMBLY__ */
+
+/*
+ * From Kevin Hilman:
+ *
+ * gdb is expecting the following registers layout.
+ *
+ * r0-r15: 1 long word each
+ * f0-f7: unused, 3 long words each !!
+ * fps: unused, 1 long word
+ * cpsr: 1 long word
+ *
+ * Even though f0-f7 and fps are not used, they need to be
+ * present in the registers sent for correct processing in
+ * the host-side gdb.
+ *
+ * In particular, it is crucial that CPSR is in the right place,
+ * otherwise gdb will not be able to correctly interpret stepping over
+ * conditional branches.
+ */
+#define _GP_REGS 16
+#define _FP_REGS 8
+#define _EXTRA_REGS 2
+#define GDB_MAX_REGS (_GP_REGS + (_FP_REGS * 3) + _EXTRA_REGS)
+
+#define KGDB_MAX_NO_CPUS 1
+#define BUFMAX 400
+#define NUMREGBYTES (GDB_MAX_REGS << 2)
+#define NUMCRITREGBYTES (32 << 2)
+
+#define _R0 0
+#define _R1 1
+#define _R2 2
+#define _R3 3
+#define _R4 4
+#define _R5 5
+#define _R6 6
+#define _R7 7
+#define _R8 8
+#define _R9 9
+#define _R10 10
+#define _FP 11
+#define _IP 12
+#define _SPT 13
+#define _LR 14
+#define _PC 15
+#define _CPSR (GDB_MAX_REGS - 1)
+
+/*
+ * So that we can denote the end of a frame for tracing,
+ * in the simple case:
+ */
+#define CFI_END_FRAME(func) __CFI_END_FRAME(_PC, _SPT, func)
+
+#endif /* __ASM_KGDB_H__ */
OpenPOWER on IntegriCloud