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GET /api/patches/817579/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 817579,
    "url": "http://patchwork.ozlabs.org/api/patches/817579/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/1506092407-26985-19-git-send-email-peter.maydell@linaro.org/",
    "project": {
        "id": 14,
        "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api",
        "name": "QEMU Development",
        "link_name": "qemu-devel",
        "list_id": "qemu-devel.nongnu.org",
        "list_email": "qemu-devel@nongnu.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": "",
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<1506092407-26985-19-git-send-email-peter.maydell@linaro.org>",
    "list_archive_url": null,
    "date": "2017-09-22T15:00:05",
    "name": "[18/20] target/arm: Implement BLXNS",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "1c372215341697596680da8c5c2892e255118d35",
    "submitter": {
        "id": 5111,
        "url": "http://patchwork.ozlabs.org/api/people/5111/?format=api",
        "name": "Peter Maydell",
        "email": "peter.maydell@linaro.org"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/1506092407-26985-19-git-send-email-peter.maydell@linaro.org/mbox/",
    "series": [
        {
            "id": 4650,
            "url": "http://patchwork.ozlabs.org/api/series/4650/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=4650",
            "date": "2017-09-22T14:59:47",
            "name": "ARM v8M: exception entry, exit and security",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/4650/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/817579/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/817579/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>",
        "X-Original-To": "incoming@patchwork.ozlabs.org",
        "Delivered-To": "patchwork-incoming@bilbo.ozlabs.org",
        "Authentication-Results": "ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=<UNKNOWN>)",
        "Received": [
            "from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xzHCc4Pw7z9sNw\n\tfor <incoming@patchwork.ozlabs.org>;\n\tSat, 23 Sep 2017 01:17:32 +1000 (AEST)",
            "from localhost ([::1]:59423 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>)\n\tid 1dvPhq-0006jJ-Kl\n\tfor incoming@patchwork.ozlabs.org; Fri, 22 Sep 2017 11:17:30 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:47329)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <pm215@archaic.org.uk>) id 1dvPQm-00089V-1x\n\tfor qemu-devel@nongnu.org; Fri, 22 Sep 2017 10:59:53 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <pm215@archaic.org.uk>) id 1dvPQk-0004M9-VZ\n\tfor qemu-devel@nongnu.org; Fri, 22 Sep 2017 10:59:52 -0400",
            "from orth.archaic.org.uk ([2001:8b0:1d0::2]:37588)\n\tby eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <pm215@archaic.org.uk>)\n\tid 1dvPQg-0004EW-Ek; Fri, 22 Sep 2017 10:59:46 -0400",
            "from pm215 by orth.archaic.org.uk with local (Exim 4.89)\n\t(envelope-from <pm215@archaic.org.uk>)\n\tid 1dvPQc-0007G2-7Y; Fri, 22 Sep 2017 15:59:42 +0100"
        ],
        "From": "Peter Maydell <peter.maydell@linaro.org>",
        "To": "qemu-arm@nongnu.org,\n\tqemu-devel@nongnu.org",
        "Date": "Fri, 22 Sep 2017 16:00:05 +0100",
        "Message-Id": "<1506092407-26985-19-git-send-email-peter.maydell@linaro.org>",
        "X-Mailer": "git-send-email 2.7.4",
        "In-Reply-To": "<1506092407-26985-1-git-send-email-peter.maydell@linaro.org>",
        "References": "<1506092407-26985-1-git-send-email-peter.maydell@linaro.org>",
        "X-detected-operating-system": "by eggs.gnu.org: Genre and OS details not\n\trecognized.",
        "X-Received-From": "2001:8b0:1d0::2",
        "Subject": "[Qemu-devel] [PATCH 18/20] target/arm: Implement BLXNS",
        "X-BeenThere": "qemu-devel@nongnu.org",
        "X-Mailman-Version": "2.1.21",
        "Precedence": "list",
        "List-Id": "<qemu-devel.nongnu.org>",
        "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>",
        "List-Archive": "<http://lists.nongnu.org/archive/html/qemu-devel/>",
        "List-Post": "<mailto:qemu-devel@nongnu.org>",
        "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>",
        "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=subscribe>",
        "Cc": "patches@linaro.org",
        "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org",
        "Sender": "\"Qemu-devel\"\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>"
    },
    "content": "Implement the BLXNS instruction, which allows secure code to\ncall non-secure code.\n\nSigned-off-by: Peter Maydell <peter.maydell@linaro.org>\n---\n target/arm/helper.h    |  1 +\n target/arm/internals.h |  1 +\n target/arm/helper.c    | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++\n target/arm/translate.c | 17 +++++++++++++--\n 4 files changed, 76 insertions(+), 2 deletions(-)",
    "diff": "diff --git a/target/arm/helper.h b/target/arm/helper.h\nindex 64afbac..2cf6f74 100644\n--- a/target/arm/helper.h\n+++ b/target/arm/helper.h\n@@ -64,6 +64,7 @@ DEF_HELPER_3(v7m_msr, void, env, i32, i32)\n DEF_HELPER_2(v7m_mrs, i32, env, i32)\n \n DEF_HELPER_2(v7m_bxns, void, env, i32)\n+DEF_HELPER_2(v7m_blxns, void, env, i32)\n \n DEF_HELPER_4(access_check_cp_reg, void, env, ptr, i32, i32)\n DEF_HELPER_3(set_cp_reg, void, env, ptr, i32)\ndiff --git a/target/arm/internals.h b/target/arm/internals.h\nindex fd9a7e8..1746737 100644\n--- a/target/arm/internals.h\n+++ b/target/arm/internals.h\n@@ -60,6 +60,7 @@ static inline bool excp_is_internal(int excp)\n FIELD(V7M_CONTROL, NPRIV, 0, 1)\n FIELD(V7M_CONTROL, SPSEL, 1, 1)\n FIELD(V7M_CONTROL, FPCA, 2, 1)\n+FIELD(V7M_CONTROL, SFPA, 3, 1)\n \n /* Bit definitions for v7M exception return payload */\n FIELD(V7M_EXCRET, ES, 0, 1)\ndiff --git a/target/arm/helper.c b/target/arm/helper.c\nindex 8df819d..30dc2a9 100644\n--- a/target/arm/helper.c\n+++ b/target/arm/helper.c\n@@ -5890,6 +5890,12 @@ void HELPER(v7m_bxns)(CPUARMState *env, uint32_t dest)\n     g_assert_not_reached();\n }\n \n+void HELPER(v7m_blxns)(CPUARMState *env, uint32_t dest)\n+{\n+    /* translate.c should never generate calls here in user-only mode */\n+    g_assert_not_reached();\n+}\n+\n void switch_mode(CPUARMState *env, int mode)\n {\n     ARMCPU *cpu = arm_env_get_cpu(env);\n@@ -6182,6 +6188,59 @@ void HELPER(v7m_bxns)(CPUARMState *env, uint32_t dest)\n     env->regs[15] = dest & ~1;\n }\n \n+void HELPER(v7m_blxns)(CPUARMState *env, uint32_t dest)\n+{\n+    /* Handle v7M BLXNS:\n+     *  - bit 0 of the destination address is the target security state\n+     */\n+\n+    /* At this point regs[15] is the address just after the BLXNS */\n+    uint32_t nextinst = env->regs[15] | 1;\n+    uint32_t sp = env->regs[13] - 8;\n+    uint32_t saved_psr;\n+\n+    /* translate.c will have made BLXNS UNDEF unless we're secure */\n+    assert(env->v7m.secure);\n+\n+    if (dest & 1) {\n+        /* target is Secure, so this is just a normal BLX,\n+         * except that the low bit doesn't indicate Thumb/not.\n+         */\n+        env->regs[14] = nextinst;\n+        env->thumb = 1;\n+        env->regs[15] = dest & ~1;\n+        return;\n+    }\n+\n+    /* Target is non-secure: first push a stack frame */\n+    if (!QEMU_IS_ALIGNED(sp, 8)) {\n+        qemu_log_mask(LOG_GUEST_ERROR,\n+                      \"BLXNS with misaligned SP is UNPREDICTABLE\\n\");\n+    }\n+\n+    saved_psr = env->v7m.exception;\n+    if (env->v7m.control[M_REG_S] & R_V7M_CONTROL_SFPA_MASK) {\n+        saved_psr |= XPSR_SFPA;\n+    }\n+\n+    /* Note that these stores can throw exceptions on MPU faults */\n+    cpu_stl_data(env, sp, nextinst);\n+    cpu_stl_data(env, sp + 4, saved_psr);\n+\n+    env->regs[13] = sp;\n+    env->regs[14] = 0xfeffffff;\n+    if (arm_v7m_is_handler_mode(env)) {\n+        /* Write a dummy value to IPSR, to avoid leaking the current secure\n+         * exception number to non-secure code. This is guaranteed not\n+         * to cause write_v7m_exception() to actually change stacks.\n+         */\n+        write_v7m_exception(env, 1);\n+    }\n+    switch_v7m_security_state(env, dest & 1);\n+    env->thumb = 1;\n+    env->regs[15] = dest & ~1;\n+}\n+\n static uint32_t *get_v7m_sp_ptr(CPUARMState *env, bool secure, bool threadmode,\n                                 bool spsel)\n {\ndiff --git a/target/arm/translate.c b/target/arm/translate.c\nindex ab1a12a..53694bb 100644\n--- a/target/arm/translate.c\n+++ b/target/arm/translate.c\n@@ -1013,6 +1013,20 @@ static inline void gen_bxns(DisasContext *s, int rm)\n     s->base.is_jmp = DISAS_EXIT;\n }\n \n+static inline void gen_blxns(DisasContext *s, int rm)\n+{\n+    TCGv_i32 var = load_reg(s, rm);\n+\n+    /* We don't need to sync condexec state, for the same reason as blxns.\n+     * We do however need to set the PC, because the blxns helper reads it.\n+     * The blxns helper may throw an exception.\n+     */\n+    gen_set_pc_im(s, s->pc);\n+    gen_helper_v7m_blxns(cpu_env, var);\n+    tcg_temp_free_i32(var);\n+    s->base.is_jmp = DISAS_EXIT;\n+}\n+\n /* Variant of store_reg which uses branch&exchange logic when storing\n    to r15 in ARM architecture v7 and above. The source must be a temporary\n    and will be marked as dead. */\n@@ -11221,8 +11235,7 @@ static void disas_thumb_insn(CPUARMState *env, DisasContext *s)\n                         goto undef;\n                     }\n                     if (link) {\n-                        /* BLXNS: not yet implemented */\n-                        goto undef;\n+                        gen_blxns(s, rm);\n                     } else {\n                         gen_bxns(s, rm);\n                     }\n",
    "prefixes": [
        "18/20"
    ]
}