This patch allows registers to be properly read from and written to when using the gdbstub to debug a ppc guest running in little endian mode. It accomplishes this goal by byte swapping the values of any registers if the MSR:LE value is set.
Signed-off-by: Thomas Falcon <tlfal...@linux.vnet.ibm.com> --- Differences from v2: Fixed formatting issues Added logic to ensure only FP registers have a guaranteed size of 8 bytes --- target-ppc/cpu-qom.h | 2 ++ target-ppc/gdbstub.c | 46 +++++++++++++++++++++++++++++++++++++++++++++ target-ppc/translate_init.c | 4 ++-- 3 files changed, 50 insertions(+), 2 deletions(-) diff --git a/target-ppc/cpu-qom.h b/target-ppc/cpu-qom.h index 72b2232..992963f 100644 --- a/target-ppc/cpu-qom.h +++ b/target-ppc/cpu-qom.h @@ -109,7 +109,9 @@ void ppc_cpu_dump_statistics(CPUState *cpu, FILE *f, fprintf_function cpu_fprintf, int flags); hwaddr ppc_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr); int ppc_cpu_gdb_read_register(CPUState *cpu, uint8_t *buf, int reg); +int ppc_cpu_gdb_read_register_wrap(CPUState *cpu, uint8_t *buf, int reg); int ppc_cpu_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg); +int ppc_cpu_gdb_write_register_wrap(CPUState *cpu, uint8_t *buf, int reg); int ppc64_cpu_write_elf64_qemunote(WriteCoreDumpFunction f, CPUState *cpu, void *opaque); int ppc64_cpu_write_elf64_note(WriteCoreDumpFunction f, CPUState *cs, diff --git a/target-ppc/gdbstub.c b/target-ppc/gdbstub.c index 1c91090..18db8a2 100644 --- a/target-ppc/gdbstub.c +++ b/target-ppc/gdbstub.c @@ -21,6 +21,52 @@ #include "qemu-common.h" #include "exec/gdbstub.h" +/* The following functions are used to ensure the correct + * transfer of registers between a little endian ppc target + * and a big endian host by checking the LE bit in the Machine State Register + */ + +int ppc_cpu_gdb_read_register_wrap(CPUState *cs, uint8_t *mem_buf, int n) +{ + PowerPCCPU *cpu = POWERPC_CPU(cs); + CPUPPCState *env = &cpu->env; + + int len = ppc_cpu_gdb_read_register(cs, mem_buf, n), i; + if (msr_le) { + uint8_t tmp; + for (i = 0; i < len/2 ; i++) { + tmp = *(mem_buf + i); + *(mem_buf + i) = *(mem_buf + len - 1 - i); + *(mem_buf + len - 1 - i) = tmp; + } + } + return len; +} + +int ppc_cpu_gdb_write_register_wrap(CPUState *cs, uint8_t *mem_buf, int n) +{ + PowerPCCPU *cpu = POWERPC_CPU(cs); + CPUPPCState *env = &cpu->env; + + if (msr_le) { + int len = 0, i = 0; + if (n > 31 && n < 64) { + len = 8; + } else if (n == 66) { + len = 4; + } else { + len = sizeof(target_ulong); + } + uint8_t tmp; + for (i = 0; i < len/2; i++) { + tmp = *(mem_buf + i); + *(mem_buf+i) = *(mem_buf + len - 1 - i); + *(mem_buf + len - 1 - i) = tmp; + } + } + return ppc_cpu_gdb_write_register(cs, mem_buf, n); +} + /* Old gdb always expects FP registers. Newer (xml-aware) gdb only * expects whatever the target description contains. Due to a * historical mishap the FP registers appear in between core integer diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c index c030a20..41ea4b7 100644 --- a/target-ppc/translate_init.c +++ b/target-ppc/translate_init.c @@ -8655,8 +8655,8 @@ static void ppc_cpu_class_init(ObjectClass *oc, void *data) cc->dump_state = ppc_cpu_dump_state; cc->dump_statistics = ppc_cpu_dump_statistics; cc->set_pc = ppc_cpu_set_pc; - cc->gdb_read_register = ppc_cpu_gdb_read_register; - cc->gdb_write_register = ppc_cpu_gdb_write_register; + cc->gdb_read_register = ppc_cpu_gdb_read_register_wrap; + cc->gdb_write_register = ppc_cpu_gdb_write_register_wrap; #ifndef CONFIG_USER_ONLY cc->get_phys_page_debug = ppc_cpu_get_phys_page_debug; cc->vmsd = &vmstate_ppc_cpu; -- 1.8.3.1