diff options
Diffstat (limited to 'gdbstub/internals.h')
| -rw-r--r-- | gdbstub/internals.h | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/gdbstub/internals.h b/gdbstub/internals.h index bf5a5c6..92466b2 100644 --- a/gdbstub/internals.h +++ b/gdbstub/internals.h @@ -11,7 +11,27 @@ #include "exec/cpu-common.h" -#define MAX_PACKET_LENGTH 4096 +/* + * Most "large" transfers (e.g. memory reads, feature XML + * transfer) have mechanisms in the gdb protocol for splitting + * them. However, register values in particular cannot currently + * be split. This packet size must therefore be at least big enough + * for the worst-case register size. Currently that is Arm SME + * ZA storage with a 256x256 byte value. We also must account + * for the conversion from raw data to hex in gdb_memtohex(), + * which writes 2 * size bytes, and for other protocol overhead + * including command, register number and checksum which add + * another 4 bytes of overhead. However, to be consistent with + * the changes made in gdbserver to address this same requirement, + * we add a total of 32 bytes to account for protocol overhead + * (unclear why specifically 32 bytes), bringing the value of + * MAX_PACKET_LENGTH to 2 * 256 * 256 + 32 = 131104. + * + * The commit making this change for gdbserver can be found here: + * https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h= + * b816042e88583f280ad186ff124ab84d31fb592b + */ +#define MAX_PACKET_LENGTH 131104 /* * Shared structures and definitions |