^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) /* SPDX-License-Identifier: GPL-2.0-only */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * AArch64 KGDB support
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Based on arch/arm/include/kgdb.h
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Copyright (C) 2013 Cavium Inc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #ifndef __ARM_KGDB_H
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #define __ARM_KGDB_H
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/ptrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <asm/debug-monitors.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #ifndef __ASSEMBLY__
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) static inline void arch_kgdb_breakpoint(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) asm ("brk %0" : : "I" (KGDB_COMPILED_DBG_BRK_IMM));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) extern void kgdb_handle_bus_error(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) extern int kgdb_fault_expected;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) #endif /* !__ASSEMBLY__ */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) * gdb remote procotol (well most versions of it) expects the following
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) * register layout.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) * General purpose regs:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * r0-r30: 64 bit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) * sp,pc : 64 bit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * pstate : 32 bit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) * Total: 33 + 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) * FPU regs:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * f0-f31: 128 bit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * fpsr & fpcr: 32 bit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * Total: 32 + 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) * To expand a little on the "most versions of it"... when the gdb remote
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) * protocol for AArch64 was developed it depended on a statement in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) * Architecture Reference Manual that claimed "SPSR_ELx is a 32-bit register".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) * and, as a result, allocated only 32-bits for the PSTATE in the remote
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) * protocol. In fact this statement is still present in ARM DDI 0487A.i.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * Unfortunately "is a 32-bit register" has a very special meaning for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) * system registers. It means that "the upper bits, bits[63:32], are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) * RES0.". RES0 is heavily used in the ARM architecture documents as a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) * way to leave space for future architecture changes. So to translate a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) * little for people who don't spend their spare time reading ARM architecture
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) * manuals, what "is a 32-bit register" actually means in this context is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) * "is a 64-bit register but one with no meaning allocated to any of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) * upper 32-bits... *yet*".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * Perhaps then we should not be surprised that this has led to some
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) * confusion. Specifically a patch, influenced by the above translation,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) * that extended PSTATE to 64-bit was accepted into gdb-7.7 but the patch
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) * was reverted in gdb-7.8.1 and all later releases, when this was
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) * discovered to be an undocumented protocol change.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) * So... it is *not* wrong for us to only allocate 32-bits to PSTATE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) * here even though the kernel itself allocates 64-bits for the same
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) * state. That is because this bit of code tells the kernel how the gdb
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) * remote protocol (well most versions of it) describes the register state.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) * Note that if you are using one of the versions of gdb that supports
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) * the gdb-7.7 version of the protocol you cannot use kgdb directly
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) * without providing a custom register description (gdb can load new
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) * protocol descriptions at runtime).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) #define _GP_REGS 33
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) #define _FP_REGS 32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) #define _EXTRA_REGS 3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) * general purpose registers size in bytes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) * pstate is only 4 bytes. subtract 4 bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) #define GP_REG_BYTES (_GP_REGS * 8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) #define DBG_MAX_REG_NUM (_GP_REGS + _FP_REGS + _EXTRA_REGS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) * Size of I/O buffer for gdb packet.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) * considering to hold all register contents, size is set
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) #define BUFMAX 2048
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) * Number of bytes required for gdb_regs buffer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) * _GP_REGS: 8 bytes, _FP_REGS: 16 bytes and _EXTRA_REGS: 4 bytes each
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) * GDB fails to connect for size beyond this with error
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) * "'g' packet reply is too long"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) #define NUMREGBYTES ((_GP_REGS * 8) + (_FP_REGS * 16) + \
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) (_EXTRA_REGS * 4))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) #endif /* __ASM_KGDB_H */
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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