diff options
Diffstat (limited to 'gdb/doc')
| -rw-r--r-- | gdb/doc/ChangeLog | 10 | ||||
| -rw-r--r-- | gdb/doc/gdb.texinfo | 53 |
2 files changed, 61 insertions, 2 deletions
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index 2124414..d5b7f1c 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,13 @@ +2010-05-26 Pedro Alves <pedro@codesourcery.com> + + * gdb.texinfo (General Query Packets) <qSupported>: Describe the + `qRelocInsn' feature. + (Relocate instruction reply packet): New subsection + of `Tracepoint Packets'. + (Tracepoint Packets): Mention that packets QTDP and QTStart + support the qRelocInsn request, and add cross reference to new + subsection. + 2010-05-25 Doug Evans <dje@google.com> * gdb.texinfo (Exception Handling): Document gdb.GdbError. diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 9466745..72c86e9 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -31446,6 +31446,11 @@ This feature indicates that @value{GDBN} supports the XML target description. If the stub sees @samp{xmlRegisters=} with target specific strings separated by a comma, it will report register description. + +@item qRelocInsn +This feature indicates whether @value{GDBN} supports the +@samp{qRelocInsn} packet (@pxref{Tracepoint Packets,,Relocate +instruction reply packet}). @end table Stubs should ignore any unknown values for @@ -32054,6 +32059,8 @@ Replies: @table @samp @item OK The packet was understood and carried out. +@item qRelocInsn +@xref{Tracepoint Packets,,Relocate instruction reply packet}. @item The packet was not recognized. @end table @@ -32118,6 +32125,8 @@ Replies: @table @samp @item OK The packet was understood and carried out. +@item qRelocInsn +@xref{Tracepoint Packets,,Relocate instruction reply packet}. @item The packet was not recognized. @end table @@ -32209,8 +32218,10 @@ Like @samp{QTFrame:range:@var{start}:@var{end}}, but select the first frame @emph{outside} the given range of addresses (exclusive). @item QTStart -Begin the tracepoint experiment. Begin collecting data from tracepoint -hits in the trace frame buffer. +Begin the tracepoint experiment. Begin collecting data from +tracepoint hits in the trace frame buffer. This packet supports the +@samp{qRelocInsn} reply (@pxref{Tracepoint Packets,,Relocate +instruction reply packet}). @item QTStop End the tracepoint experiment. Stop collecting trace frames. @@ -32371,6 +32382,44 @@ This packet directs the target to use a circular trace buffer if @end table +@subsection Relocate instruction reply packet +When installing fast tracepoints in memory, the target may need to +relocate the instruction currently at the tracepoint address to a +different address in memory. For most instructions, a simple copy is +enough, but, for example, call instructions that implicitly push the +return address on the stack, and relative branches or other +PC-relative instructions require offset adjustment, so that the effect +of executing the instruction at a different address is the same as if +it had executed in the original location. + +In response to several of the tracepoint packets, the target may also +respond with a number of intermediate @samp{qRelocInsn} request +packets before the final result packet, to have @value{GDBN} handle +this relocation operation. If a packet supports this mechanism, its +documentation will explicitly say so. See for example the above +descriptions for the @samp{QTStart} and @samp{QTDP} packets. The +format of the request is: + +@table @samp +@item qRelocInsn:@var{from};@var{to} + +This requests @value{GDBN} to copy instruction at address @var{from} +to address @var{to}, possibly adjusted so that executing the +instruction at @var{to} has the same effect as executing it at +@var{from}. @value{GDBN} writes the adjusted instruction to target +memory starting at @var{to}. +@end table + +Replies: +@table @samp +@item qRelocInsn:@var{adjusted_size} +Informs the stub the relocation is complete. @var{adjusted_size} is +the length in bytes of resulting relocated instruction sequence. +@item E @var{NN} +A badly formed request was detected, or an error was encountered while +relocating the instruction. +@end table + @node Host I/O Packets @section Host I/O Packets @cindex Host I/O, remote protocol |