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[174.21.6.47]) by smtp.gmail.com with ESMTPSA id z19sm9760028pfh.185.2018.01.24.15.26.49 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 24 Jan 2018 15:26:49 -0800 (PST) From: Richard Henderson Date: Wed, 24 Jan 2018 15:25:55 -0800 Message-Id: <20180124232625.30105-16-richard.henderson@linaro.org> In-Reply-To: <20180124232625.30105-1-richard.henderson@linaro.org> References: <20180124232625.30105-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH v3 15/45] target/hppa: Avoid privilege level decrease during branches List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org These instructions force the destination privilege level of the branch destination to be no higher than current. Signed-off-by: Richard Henderson --- target/hppa/translate.c | 52 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 47 insertions(+), 5 deletions(-) diff --git a/target/hppa/translate.c b/target/hppa/translate.c index 6be9e0c3ff..4a69f05a91 100644 --- a/target/hppa/translate.c +++ b/target/hppa/translate.c @@ -1862,6 +1862,40 @@ static DisasJumpType do_ibranch(DisasContext *ctx, TCGv_reg dest, return DISAS_NEXT; } +/* Implement + * if (IAOQ_Front{30..31} < GR[b]{30..31}) + * IAOQ_Next{30..31} ← GR[b]{30..31}; + * else + * IAOQ_Next{30..31} ← IAOQ_Front{30..31}; + * which keeps the privilege level from being increased. + */ +static TCGv_reg do_ibranch_priv(DisasContext *ctx, TCGv_reg offset) +{ +#ifdef CONFIG_USER_ONLY + return offset; +#else + TCGv_reg dest; + switch (ctx->privilege) { + case 0: + /* Privilege 0 is maximum and is allowed to decrease. */ + return offset; + case 3: + /* Privilege 3 is minimum and is never allowed increase. */ + dest = get_temp(ctx); + tcg_gen_ori_reg(dest, offset, 3); + break; + default: + dest = tcg_temp_new(); + tcg_gen_andi_reg(dest, offset, -4); + tcg_gen_ori_reg(dest, dest, ctx->privilege); + tcg_gen_movcond_reg(TCG_COND_GTU, dest, dest, offset, dest, offset); + tcg_temp_free(dest); + break; + } + return dest; +#endif +} + #ifdef CONFIG_USER_ONLY /* On Linux, page zero is normally marked execute only + gateway. Therefore normal read or write is supposed to fail, but specific @@ -3441,6 +3475,7 @@ static DisasJumpType trans_be(DisasContext *ctx, uint32_t insn, bool is_l) unsigned n = extract32(insn, 1, 1); unsigned b = extract32(insn, 21, 5); target_sreg disp = assemble_17(insn); + TCGv_reg tmp; /* unsigned s = low_uextract(insn, 13, 3); */ /* ??? It seems like there should be a good way of using @@ -3449,16 +3484,19 @@ static DisasJumpType trans_be(DisasContext *ctx, uint32_t insn, bool is_l) manage along side branch delay slots. Therefore we handle entry into the gateway page via absolute address. */ +#ifdef CONFIG_USER_ONLY /* Since we don't implement spaces, just branch. Do notice the special case of "be disp(*,r0)" using a direct branch to disp, so that we can goto_tb to the TB containing the syscall. */ if (b == 0) { return do_dbranch(ctx, disp, is_l ? 31 : 0, n); - } else { - TCGv_reg tmp = get_temp(ctx); - tcg_gen_addi_reg(tmp, load_gpr(ctx, b), disp); - return do_ibranch(ctx, tmp, is_l ? 31 : 0, n); } +#endif + + tmp = get_temp(ctx); + tcg_gen_addi_reg(tmp, load_gpr(ctx, b), disp); + tmp = do_ibranch_priv(ctx, tmp); + return do_ibranch(ctx, tmp, is_l ? 31 : 0, n); } static DisasJumpType trans_bl(DisasContext *ctx, uint32_t insn, @@ -3490,6 +3528,7 @@ static DisasJumpType trans_blr(DisasContext *ctx, uint32_t insn, tcg_gen_shli_reg(tmp, load_gpr(ctx, rx), 3); tcg_gen_addi_reg(tmp, tmp, ctx->iaoq_f + 8); + /* The computation here never changes privilege level. */ return do_ibranch(ctx, tmp, link, n); } @@ -3508,6 +3547,7 @@ static DisasJumpType trans_bv(DisasContext *ctx, uint32_t insn, tcg_gen_shli_reg(dest, load_gpr(ctx, rx), 3); tcg_gen_add_reg(dest, dest, load_gpr(ctx, rb)); } + dest = do_ibranch_priv(ctx, dest); return do_ibranch(ctx, dest, 0, n); } @@ -3517,8 +3557,10 @@ static DisasJumpType trans_bve(DisasContext *ctx, uint32_t insn, unsigned n = extract32(insn, 1, 1); unsigned rb = extract32(insn, 21, 5); unsigned link = extract32(insn, 13, 1) ? 2 : 0; + TCGv_reg dest; - return do_ibranch(ctx, load_gpr(ctx, rb), link, n); + dest = do_ibranch_priv(ctx, load_gpr(ctx, rb)); + return do_ibranch(ctx, dest, link, n); } static const DisasInsn table_branch[] = { -- 2.14.3