From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36845) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3C7r-0003PK-K5 for qemu-devel@nongnu.org; Tue, 14 Jan 2014 17:06:32 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W3C7i-0002Rf-Mc for qemu-devel@nongnu.org; Tue, 14 Jan 2014 17:06:23 -0500 Received: from e9.ny.us.ibm.com ([32.97.182.139]:44912) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3C7i-0002QX-IW for qemu-devel@nongnu.org; Tue, 14 Jan 2014 17:06:14 -0500 Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 14 Jan 2014 17:06:14 -0500 Message-ID: <52D5B4D2.5020801@linux.vnet.ibm.com> Date: Tue, 14 Jan 2014 16:06:10 -0600 From: Thomas Falcon MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] [PATCH] gdbstub: allow byte swapping for reading/writing registers List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-ppc@nongnu.org, agraf@suse.de 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 only if the MSR:LE value is set and if the host machine is big endian. Signed-off-by: Thomas Falcon --- target-ppc/gdbstub.c | 50 ++++++++++++++++++++++++++++++++------------------ 1 file changed, 32 insertions(+), 18 deletions(-) diff --git a/target-ppc/gdbstub.c b/target-ppc/gdbstub.c index 1c91090..eba501a 100644 --- a/target-ppc/gdbstub.c +++ b/target-ppc/gdbstub.c @@ -21,6 +21,19 @@ #include "qemu-common.h" #include "exec/gdbstub.h" +/* The following macros 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 + */ + +#define end_swap64(x) (msr_le && HOST_WORDS_BIGENDIAN) ? bswap64(x) : x +#define end_swap32(x) (msr_le && HOST_WORDS_BIGENDIAN) ? bswap32(x) : x +#if TARGET_LONG_BITS == 64 +#define end_swapl(x) end_swap64(x) +#else +#define end_swapl(x) end_swap32(x) +#endif + /* 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 @@ -35,20 +48,20 @@ int ppc_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n) if (n < 32) { /* gprs */ - return gdb_get_regl(mem_buf, env->gpr[n]); + return gdb_get_regl(mem_buf, end_swapl(env->gpr[n])); } else if (n < 64) { /* fprs */ if (gdb_has_xml) { return 0; } - stfq_p(mem_buf, env->fpr[n-32]); + stfq_p(mem_buf, end_swapl(env->fpr[n-32])); return 8; } else { switch (n) { case 64: - return gdb_get_regl(mem_buf, env->nip); + return gdb_get_regl(mem_buf, end_swapl(env->nip)); case 65: - return gdb_get_regl(mem_buf, env->msr); + return gdb_get_regl(mem_buf, end_swapl(env->msr)); case 66: { uint32_t cr = 0; @@ -56,20 +69,20 @@ int ppc_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n) for (i = 0; i < 8; i++) { cr |= env->crf[i] << (32 - ((i + 1) * 4)); } - return gdb_get_reg32(mem_buf, cr); + return gdb_get_reg32(mem_buf, end_swap32(cr)); } case 67: - return gdb_get_regl(mem_buf, env->lr); + return gdb_get_regl(mem_buf, end_swapl(env->lr)); case 68: - return gdb_get_regl(mem_buf, env->ctr); + return gdb_get_regl(mem_buf, end_swapl(env->ctr)); case 69: - return gdb_get_regl(mem_buf, env->xer); + return gdb_get_regl(mem_buf, end_swapl(env->xer)); case 70: { if (gdb_has_xml) { return 0; } - return gdb_get_reg32(mem_buf, env->fpscr); + return gdb_get_reg32(mem_buf, end_swap32(env->fpscr)); } } } @@ -83,47 +96,48 @@ int ppc_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n) if (n < 32) { /* gprs */ - env->gpr[n] = ldtul_p(mem_buf); + env->gpr[n] = end_swapl(ldtul_p(mem_buf)); return sizeof(target_ulong); } else if (n < 64) { /* fprs */ if (gdb_has_xml) { return 0; } - env->fpr[n-32] = ldfq_p(mem_buf); + env->fpr[n-32] = end_swapl(ldfq_p(mem_buf)); return 8; } else { switch (n) { case 64: - env->nip = ldtul_p(mem_buf); + env->nip = end_swapl(ldtul_p(mem_buf)); return sizeof(target_ulong); case 65: - ppc_store_msr(env, ldtul_p(mem_buf)); + ppc_store_msr(env, end_swapl(ldtul_p(mem_buf))); return sizeof(target_ulong); case 66: { uint32_t cr = ldl_p(mem_buf); int i; for (i = 0; i < 8; i++) { - env->crf[i] = (cr >> (32 - ((i + 1) * 4))) & 0xF; + env->crf[i] = end_swap32((cr >> (32 - + ((i + 1) * 4))) & 0xF); } return 4; } case 67: - env->lr = ldtul_p(mem_buf); + env->lr = end_swapl(ldtul_p(mem_buf)); return sizeof(target_ulong); case 68: - env->ctr = ldtul_p(mem_buf); + env->ctr = end_swapl(ldtul_p(mem_buf)); return sizeof(target_ulong); case 69: - env->xer = ldtul_p(mem_buf); + env->xer = end_swapl(ldtul_p(mem_buf)); return sizeof(target_ulong); case 70: /* fpscr */ if (gdb_has_xml) { return 0; } - store_fpscr(env, ldtul_p(mem_buf), 0xffffffff); + store_fpscr(env, end_swapl(ldtul_p(mem_buf)), 0xffffffff); return sizeof(target_ulong); } } -- 1.8.3.1