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