From 37d669427f8b90f3c9d17a6e04d72c731d3abdbc Mon Sep 17 00:00:00 2001 From: Pierre Langlois Date: Mon, 29 Jun 2015 10:34:42 +0100 Subject: [PATCH] [GDBServer][AArch64] Use the same break instruction as GDB GDB uses a "brk #0" instruction to perform a software breakpoint while GDBServer uses an illegal instruction. Both instructions should match. When enabling support for the 'Z0' packet, we let GDBServer insert the breakpoint instruction instead of GDB. And in case of permanent breakpoints for example, GDB will check if a breakpoint is inserted in the inferior with `program_breakpoint_here_p (gdbarch, address)', and compare the instruction read from the inferior with the breakpoint instruction. On AArch64, instructions are always little endian so we need to represent it as an array of bytes, as done in aarch64-tdep.c. gdb/gdbserver/ChangeLog: * linux-aarch64-low.c: Remove comment about endianness. (aarch64_breakpoint): Change type to gdb_byte[]. Set to "brk #0". (aarch64_breakpoint_at): Change type of insn to gdb_byte[]. Use memcmp. --- gdb/gdbserver/ChangeLog | 7 +++++++ gdb/gdbserver/linux-aarch64-low.c | 14 ++++++++------ 2 files changed, 15 insertions(+), 6 deletions(-) diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog index 2528f0f5d1..8dad98ef3c 100644 --- a/gdb/gdbserver/ChangeLog +++ b/gdb/gdbserver/ChangeLog @@ -1,3 +1,10 @@ +2015-06-29 Pierre Langlois + + * linux-aarch64-low.c: Remove comment about endianness. + (aarch64_breakpoint): Change type to gdb_byte[]. Set to "brk #0". + (aarch64_breakpoint_at): Change type of insn to gdb_byte[]. Use + memcmp. + 2015-06-24 Gary Benson * linux-i386-ipa.c (stdint.h): Do not include. diff --git a/gdb/gdbserver/linux-aarch64-low.c b/gdb/gdbserver/linux-aarch64-low.c index 043458d68e..b0a277528d 100644 --- a/gdb/gdbserver/linux-aarch64-low.c +++ b/gdb/gdbserver/linux-aarch64-low.c @@ -295,19 +295,21 @@ aarch64_set_pc (struct regcache *regcache, CORE_ADDR pc) supply_register_by_name (regcache, "pc", &newpc); } -/* Correct in either endianness. */ - #define aarch64_breakpoint_len 4 -static const unsigned long aarch64_breakpoint = 0x00800011; +/* AArch64 BRK software debug mode instruction. + This instruction needs to match gdb/aarch64-tdep.c + (aarch64_default_breakpoint). */ +static const gdb_byte aarch64_breakpoint[] = {0x00, 0x00, 0x20, 0xd4}; static int aarch64_breakpoint_at (CORE_ADDR where) { - unsigned long insn; + gdb_byte insn[aarch64_breakpoint_len]; - (*the_target->read_memory) (where, (unsigned char *) &insn, 4); - if (insn == aarch64_breakpoint) + (*the_target->read_memory) (where, (unsigned char *) &insn, + aarch64_breakpoint_len); + if (memcmp (insn, aarch64_breakpoint, aarch64_breakpoint_len) == 0) return 1; return 0; -- 2.34.1