From patchwork Tue Jan 14 21:47:53 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Falcon X-Patchwork-Id: 310887 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 693C22C007E for ; Wed, 15 Jan 2014 09:26:34 +1100 (EST) Received: from localhost ([::1]:50997 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3CRM-0004A7-82 for incoming@patchwork.ozlabs.org; Tue, 14 Jan 2014 17:26:32 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41256) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3CQw-00049j-1d for qemu-devel@nongnu.org; Tue, 14 Jan 2014 17:26:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W3CQq-00087W-15 for qemu-devel@nongnu.org; Tue, 14 Jan 2014 17:26:05 -0500 Received: from [32.97.110.51] (port=33073 helo=oc8738282158.ibm.com) by eggs.gnu.org with smtp (Exim 4.71) (envelope-from ) id 1W3CQf-00085t-Q7; Tue, 14 Jan 2014 17:25:59 -0500 Received: by oc8738282158.ibm.com (Postfix, from userid 500) id D3E42300730; Tue, 14 Jan 2014 15:47:57 -0600 (CST) From: Thomas Falcon To: qemu-devel@nongnu.org Date: Tue, 14 Jan 2014 15:47:53 -0600 Message-Id: <1389736073-20582-1-git-send-email-tlfalcon@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.1 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 32.97.110.51 Cc: Thomas Falcon , qemu-ppc@nongnu.org, agraf@suse.de Subject: [Qemu-devel] [PATCH] gdbstub: allow byte swapping for reading/writing registers X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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); } }