From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57340) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1csX8L-0001OX-1K for qemu-devel@nongnu.org; Mon, 27 Mar 2017 12:04:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1csX8K-0003h9-1e for qemu-devel@nongnu.org; Mon, 27 Mar 2017 12:04:41 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:48932) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1csX8J-0003YE-Ry for qemu-devel@nongnu.org; Mon, 27 Mar 2017 12:04:40 -0400 From: Peter Maydell Date: Mon, 27 Mar 2017 17:04:29 +0100 Message-Id: <1490630670-15818-2-git-send-email-peter.maydell@linaro.org> In-Reply-To: <1490630670-15818-1-git-send-email-peter.maydell@linaro.org> References: <1490630670-15818-1-git-send-email-peter.maydell@linaro.org> Subject: [Qemu-devel] [PATCH for-2.9 1/2] tcg/sparc: Zero extend data argument to store helpers List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: patches@linaro.org, Richard Henderson 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(+) 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. */ -- 2.7.4