From patchwork Mon Mar 27 16:04:29 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Maydell X-Patchwork-Id: 96083 Delivered-To: patches@linaro.org Received: by 10.140.89.233 with SMTP id v96csp1294608qgd; Mon, 27 Mar 2017 09:04:33 -0700 (PDT) X-Received: by 10.25.157.77 with SMTP id g74mr1611621lfe.29.1490630672952; Mon, 27 Mar 2017 09:04:32 -0700 (PDT) Return-Path: Received: from orth.archaic.org.uk (orth.archaic.org.uk. [2001:8b0:1d0::2]) by mx.google.com with ESMTPS id s128si510831lja.20.2017.03.27.09.04.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 27 Mar 2017 09:04:32 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of pm215@archaic.org.uk designates 2001:8b0:1d0::2 as permitted sender) client-ip=2001:8b0:1d0::2; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of pm215@archaic.org.uk designates 2001:8b0:1d0::2 as permitted sender) smtp.mailfrom=pm215@archaic.org.uk; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: from pm215 by orth.archaic.org.uk with local (Exim 4.84_2) (envelope-from ) id 1csX8B-0000VB-6u; Mon, 27 Mar 2017 17:04:31 +0100 From: Peter Maydell To: qemu-devel@nongnu.org Cc: patches@linaro.org, Richard Henderson Subject: [PATCH for-2.9 1/2] tcg/sparc: Zero extend data argument to store helpers Date: Mon, 27 Mar 2017 17:04:29 +0100 Message-Id: <1490630670-15818-2-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1490630670-15818-1-git-send-email-peter.maydell@linaro.org> References: <1490630670-15818-1-git-send-email-peter.maydell@linaro.org> The C store helper functions take the data argument as a uint8_t, uint16_t, etc depending on the store size. The SPARC calling convention requires that data types smaller than the register size must be extended by the caller. We weren't doing this, which meant that if QEMU was compiled with optimizations enabled we could end up storing incorrect values to guest memory. (In particular the i386 guest BIOS would crash on startup.) Add code to the trampolines that call the store helpers to do the zero extension as required. Signed-off-by: Peter Maydell --- tcg/sparc/tcg-target.inc.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) -- 2.7.4 diff --git a/tcg/sparc/tcg-target.inc.c b/tcg/sparc/tcg-target.inc.c index d1f4c0d..548bea2 100644 --- a/tcg/sparc/tcg-target.inc.c +++ b/tcg/sparc/tcg-target.inc.c @@ -843,6 +843,31 @@ static void tcg_out_mb(TCGContext *s, TCGArg a0) static tcg_insn_unit *qemu_ld_trampoline[16]; static tcg_insn_unit *qemu_st_trampoline[16]; +static void emit_extend(TCGContext *s, TCGReg r, int op) +{ + /* Emit zero extend of 8, 16 or 32 bit data as + * required by the MO_* value op; do nothing for 64 bit. + */ + switch (op) { + case MO_UB: + tcg_out_arithi(s, r, r, 0xff, ARITH_AND); + break; + case MO_LEUW: + case MO_BEUW: + tcg_out_arithi(s, r, r, 16, SHIFT_SLL); + tcg_out_arithi(s, r, r, 16, SHIFT_SRL); + break; + case MO_LEUL: + case MO_BEUL: + if (SPARC64) { + tcg_out_arith(s, r, r, 0, SHIFT_SRL); + } + break; + default: + break; + } +} + static void build_trampolines(TCGContext *s) { static void * const qemu_ld_helpers[16] = { @@ -910,6 +935,7 @@ static void build_trampolines(TCGContext *s) qemu_st_trampoline[i] = s->code_ptr; if (SPARC64) { + emit_extend(s, TCG_REG_O2, i); ra = TCG_REG_O4; } else { ra = TCG_REG_O1; @@ -925,6 +951,7 @@ static void build_trampolines(TCGContext *s) tcg_out_arithi(s, ra, ra + 1, 32, SHIFT_SRLX); ra += 2; } else { + emit_extend(s, i, ra); ra += 1; } /* Skip the oi argument. */