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2015-12-18arm: remote GDB: rationalize structure of register offsetsBoris Shingarov
Currently, the wire format of register values in g- and G-packets is modelled using a union of uint8/16/32/64 arrays. The offset positions of each register are expressed as a "register count" scaled according to the width of the register in question. This results in counter- intuitive and error-prone "register count arithmetic", and some formats would even be altogether unrepresentable in such model, e.g. a 64-bit register following a 32-bit one would have a fractional index in the regs64 array. Another difficulty is that the array is allocated before the actual architecture of the workload is known (and therefore before the correct size for the array can be calculated). With this patch I propose a simpler mechanism for expressing the register set structure. In the new code, GdbRegCache is an abstract class; its subclasses contain straightforward structs reflecting the register representation. The determination whether to use e.g. the AArch32 vs. AArch64 register set (or SPARCv8 vs SPARCv9, etc.) is made by polymorphically dispatching getregs() to the concrete subclass. The subclass is not instantiated until it is needed for actual g-/G-packet processing, when the mode is already known. This patch is not meant to be merged in on its own, because it changes the contract between src/base/remote_gdb.* and src/arch/*/remote_gdb.*, so as it stands right now, it would break the other architectures. In this patch only the base and the ARM code are provided for review; once we agree on the structure, I will provide src/arch/*/remote_gdb.* for the other architectures; those patches could then be merged in together. Review Request: http://reviews.gem5.org/r/3207/ Pushed by Joel Hestness <jthestness@gmail.com>
2015-10-25power: Implement Remote GDBBoris Shingarov