1bcf5763bSVijaya Kumar K /* 2bcf5763bSVijaya Kumar K * AArch64 KGDB support 3bcf5763bSVijaya Kumar K * 4bcf5763bSVijaya Kumar K * Based on arch/arm/include/kgdb.h 5bcf5763bSVijaya Kumar K * 6bcf5763bSVijaya Kumar K * Copyright (C) 2013 Cavium Inc. 7bcf5763bSVijaya Kumar K * Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com> 8bcf5763bSVijaya Kumar K * 9bcf5763bSVijaya Kumar K * This program is free software; you can redistribute it and/or modify 10bcf5763bSVijaya Kumar K * it under the terms of the GNU General Public License version 2 as 11bcf5763bSVijaya Kumar K * published by the Free Software Foundation. 12bcf5763bSVijaya Kumar K * 13bcf5763bSVijaya Kumar K * This program is distributed in the hope that it will be useful, 14bcf5763bSVijaya Kumar K * but WITHOUT ANY WARRANTY; without even the implied warranty of 15bcf5763bSVijaya Kumar K * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16bcf5763bSVijaya Kumar K * GNU General Public License for more details. 17bcf5763bSVijaya Kumar K * 18bcf5763bSVijaya Kumar K * You should have received a copy of the GNU General Public License 19bcf5763bSVijaya Kumar K * along with this program. If not, see <http://www.gnu.org/licenses/>. 20bcf5763bSVijaya Kumar K */ 21bcf5763bSVijaya Kumar K 22bcf5763bSVijaya Kumar K #ifndef __ARM_KGDB_H 23bcf5763bSVijaya Kumar K #define __ARM_KGDB_H 24bcf5763bSVijaya Kumar K 25bcf5763bSVijaya Kumar K #include <linux/ptrace.h> 26bcf5763bSVijaya Kumar K #include <asm/debug-monitors.h> 27bcf5763bSVijaya Kumar K 28bcf5763bSVijaya Kumar K #ifndef __ASSEMBLY__ 29bcf5763bSVijaya Kumar K 30bcf5763bSVijaya Kumar K static inline void arch_kgdb_breakpoint(void) 31bcf5763bSVijaya Kumar K { 327acf71d1SCatalin Marinas asm ("brk %0" : : "I" (KGDB_COMPILED_DBG_BRK_IMM)); 33bcf5763bSVijaya Kumar K } 34bcf5763bSVijaya Kumar K 35bcf5763bSVijaya Kumar K extern void kgdb_handle_bus_error(void); 36bcf5763bSVijaya Kumar K extern int kgdb_fault_expected; 37bcf5763bSVijaya Kumar K 38bcf5763bSVijaya Kumar K #endif /* !__ASSEMBLY__ */ 39bcf5763bSVijaya Kumar K 40bcf5763bSVijaya Kumar K /* 41*0d15ef67SDaniel Thompson * gdb remote procotol (well most versions of it) expects the following 42*0d15ef67SDaniel Thompson * register layout. 43bcf5763bSVijaya Kumar K * 44bcf5763bSVijaya Kumar K * General purpose regs: 45bcf5763bSVijaya Kumar K * r0-r30: 64 bit 46bcf5763bSVijaya Kumar K * sp,pc : 64 bit 47*0d15ef67SDaniel Thompson * pstate : 32 bit 48*0d15ef67SDaniel Thompson * Total: 33 + 1 49bcf5763bSVijaya Kumar K * FPU regs: 50bcf5763bSVijaya Kumar K * f0-f31: 128 bit 51bcf5763bSVijaya Kumar K * fpsr & fpcr: 32 bit 52*0d15ef67SDaniel Thompson * Total: 32 + 2 53bcf5763bSVijaya Kumar K * 54*0d15ef67SDaniel Thompson * To expand a little on the "most versions of it"... when the gdb remote 55*0d15ef67SDaniel Thompson * protocol for AArch64 was developed it depended on a statement in the 56*0d15ef67SDaniel Thompson * Architecture Reference Manual that claimed "SPSR_ELx is a 32-bit register". 57*0d15ef67SDaniel Thompson * and, as a result, allocated only 32-bits for the PSTATE in the remote 58*0d15ef67SDaniel Thompson * protocol. In fact this statement is still present in ARM DDI 0487A.i. 59*0d15ef67SDaniel Thompson * 60*0d15ef67SDaniel Thompson * Unfortunately "is a 32-bit register" has a very special meaning for 61*0d15ef67SDaniel Thompson * system registers. It means that "the upper bits, bits[63:32], are 62*0d15ef67SDaniel Thompson * RES0.". RES0 is heavily used in the ARM architecture documents as a 63*0d15ef67SDaniel Thompson * way to leave space for future architecture changes. So to translate a 64*0d15ef67SDaniel Thompson * little for people who don't spend their spare time reading ARM architecture 65*0d15ef67SDaniel Thompson * manuals, what "is a 32-bit register" actually means in this context is 66*0d15ef67SDaniel Thompson * "is a 64-bit register but one with no meaning allocated to any of the 67*0d15ef67SDaniel Thompson * upper 32-bits... *yet*". 68*0d15ef67SDaniel Thompson * 69*0d15ef67SDaniel Thompson * Perhaps then we should not be surprised that this has led to some 70*0d15ef67SDaniel Thompson * confusion. Specifically a patch, influenced by the above translation, 71*0d15ef67SDaniel Thompson * that extended PSTATE to 64-bit was accepted into gdb-7.7 but the patch 72*0d15ef67SDaniel Thompson * was reverted in gdb-7.8.1 and all later releases, when this was 73*0d15ef67SDaniel Thompson * discovered to be an undocumented protocol change. 74*0d15ef67SDaniel Thompson * 75*0d15ef67SDaniel Thompson * So... it is *not* wrong for us to only allocate 32-bits to PSTATE 76*0d15ef67SDaniel Thompson * here even though the kernel itself allocates 64-bits for the same 77*0d15ef67SDaniel Thompson * state. That is because this bit of code tells the kernel how the gdb 78*0d15ef67SDaniel Thompson * remote protocol (well most versions of it) describes the register state. 79*0d15ef67SDaniel Thompson * 80*0d15ef67SDaniel Thompson * Note that if you are using one of the versions of gdb that supports 81*0d15ef67SDaniel Thompson * the gdb-7.7 version of the protocol you cannot use kgdb directly 82*0d15ef67SDaniel Thompson * without providing a custom register description (gdb can load new 83*0d15ef67SDaniel Thompson * protocol descriptions at runtime). 84bcf5763bSVijaya Kumar K */ 85bcf5763bSVijaya Kumar K 86*0d15ef67SDaniel Thompson #define _GP_REGS 33 87bcf5763bSVijaya Kumar K #define _FP_REGS 32 88*0d15ef67SDaniel Thompson #define _EXTRA_REGS 3 89bcf5763bSVijaya Kumar K /* 90bcf5763bSVijaya Kumar K * general purpose registers size in bytes. 91bcf5763bSVijaya Kumar K * pstate is only 4 bytes. subtract 4 bytes 92bcf5763bSVijaya Kumar K */ 93bcf5763bSVijaya Kumar K #define GP_REG_BYTES (_GP_REGS * 8) 94bcf5763bSVijaya Kumar K #define DBG_MAX_REG_NUM (_GP_REGS + _FP_REGS + _EXTRA_REGS) 95bcf5763bSVijaya Kumar K 96bcf5763bSVijaya Kumar K /* 97bcf5763bSVijaya Kumar K * Size of I/O buffer for gdb packet. 98bcf5763bSVijaya Kumar K * considering to hold all register contents, size is set 99bcf5763bSVijaya Kumar K */ 100bcf5763bSVijaya Kumar K 101bcf5763bSVijaya Kumar K #define BUFMAX 2048 102bcf5763bSVijaya Kumar K 103bcf5763bSVijaya Kumar K /* 104bcf5763bSVijaya Kumar K * Number of bytes required for gdb_regs buffer. 105bcf5763bSVijaya Kumar K * _GP_REGS: 8 bytes, _FP_REGS: 16 bytes and _EXTRA_REGS: 4 bytes each 106bcf5763bSVijaya Kumar K * GDB fails to connect for size beyond this with error 107bcf5763bSVijaya Kumar K * "'g' packet reply is too long" 108bcf5763bSVijaya Kumar K */ 109bcf5763bSVijaya Kumar K 110bcf5763bSVijaya Kumar K #define NUMREGBYTES ((_GP_REGS * 8) + (_FP_REGS * 16) + \ 111bcf5763bSVijaya Kumar K (_EXTRA_REGS * 4)) 112bcf5763bSVijaya Kumar K 113bcf5763bSVijaya Kumar K #endif /* __ASM_KGDB_H */ 114