1 /* 2 * ARM KGDB support 3 * 4 * Author: Deepak Saxena <dsaxena@mvista.com> 5 * 6 * Copyright (C) 2002 MontaVista Software Inc. 7 * 8 */ 9 10 #ifndef __ARM_KGDB_H__ 11 #define __ARM_KGDB_H__ 12 13 #include <linux/ptrace.h> 14 #include <asm/opcodes.h> 15 16 /* 17 * GDB assumes that we're a user process being debugged, so 18 * it will send us an SWI command to write into memory as the 19 * debug trap. When an SWI occurs, the next instruction addr is 20 * placed into R14_svc before jumping to the vector trap. 21 * This doesn't work for kernel debugging as we are already in SVC 22 * we would loose the kernel's LR, which is a bad thing. This 23 * is bad thing. 24 * 25 * By doing this as an undefined instruction trap, we force a mode 26 * switch from SVC to UND mode, allowing us to save full kernel state. 27 * 28 * We also define a KGDB_COMPILED_BREAK which can be used to compile 29 * in breakpoints. This is important for things like sysrq-G and for 30 * the initial breakpoint from trap_init(). 31 * 32 * Note to ARM HW designers: Add real trap support like SH && PPC to 33 * make our lives much much simpler. :) 34 */ 35 #define BREAK_INSTR_SIZE 4 36 #define GDB_BREAKINST 0xef9f0001 37 #define KGDB_BREAKINST 0xe7ffdefe 38 #define KGDB_COMPILED_BREAK 0xe7ffdeff 39 #define CACHE_FLUSH_IS_SAFE 1 40 41 #ifndef __ASSEMBLY__ 42 43 static inline void arch_kgdb_breakpoint(void) 44 { 45 asm(__inst_arm(0xe7ffdeff)); 46 } 47 48 extern void kgdb_handle_bus_error(void); 49 extern int kgdb_fault_expected; 50 51 #endif /* !__ASSEMBLY__ */ 52 53 /* 54 * From Kevin Hilman: 55 * 56 * gdb is expecting the following registers layout. 57 * 58 * r0-r15: 1 long word each 59 * f0-f7: unused, 3 long words each !! 60 * fps: unused, 1 long word 61 * cpsr: 1 long word 62 * 63 * Even though f0-f7 and fps are not used, they need to be 64 * present in the registers sent for correct processing in 65 * the host-side gdb. 66 * 67 * In particular, it is crucial that CPSR is in the right place, 68 * otherwise gdb will not be able to correctly interpret stepping over 69 * conditional branches. 70 */ 71 #define _GP_REGS 16 72 #define _FP_REGS 8 73 #define _EXTRA_REGS 2 74 #define GDB_MAX_REGS (_GP_REGS + (_FP_REGS * 3) + _EXTRA_REGS) 75 #define DBG_MAX_REG_NUM (_GP_REGS + _FP_REGS + _EXTRA_REGS) 76 77 #define KGDB_MAX_NO_CPUS 1 78 #define BUFMAX 400 79 #define NUMREGBYTES (DBG_MAX_REG_NUM << 2) 80 #define NUMCRITREGBYTES (32 << 2) 81 82 #define _R0 0 83 #define _R1 1 84 #define _R2 2 85 #define _R3 3 86 #define _R4 4 87 #define _R5 5 88 #define _R6 6 89 #define _R7 7 90 #define _R8 8 91 #define _R9 9 92 #define _R10 10 93 #define _FP 11 94 #define _IP 12 95 #define _SPT 13 96 #define _LR 14 97 #define _PC 15 98 #define _CPSR (GDB_MAX_REGS - 1) 99 100 /* 101 * So that we can denote the end of a frame for tracing, 102 * in the simple case: 103 */ 104 #define CFI_END_FRAME(func) __CFI_END_FRAME(_PC, _SPT, func) 105 106 #endif /* __ASM_KGDB_H__ */ 107