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GET /api/1.2/patches/808887/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 808887,
    "url": "http://patchwork.ozlabs.org/api/1.2/patches/808887/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/linux-arc/patch/1504289162-25977-1-git-send-email-vgupta@synopsys.com/",
    "project": {
        "id": 48,
        "url": "http://patchwork.ozlabs.org/api/1.2/projects/48/?format=api",
        "name": "Linux ARC development",
        "link_name": "linux-arc",
        "list_id": "linux-snps-arc.lists.infradead.org",
        "list_email": "linux-snps-arc@lists.infradead.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": "",
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<1504289162-25977-1-git-send-email-vgupta@synopsys.com>",
    "list_archive_url": null,
    "date": "2017-09-01T18:06:02",
    "name": "ARC: Machine Check Exception: enable MMU in single place",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "d4090402fa3e5a7fdd9ccd58ec4f029356f657eb",
    "submitter": {
        "id": 26707,
        "url": "http://patchwork.ozlabs.org/api/1.2/people/26707/?format=api",
        "name": "Vineet Gupta",
        "email": "Vineet.Gupta1@synopsys.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/linux-arc/patch/1504289162-25977-1-git-send-email-vgupta@synopsys.com/mbox/",
    "series": [
        {
            "id": 1091,
            "url": "http://patchwork.ozlabs.org/api/1.2/series/1091/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/linux-arc/list/?series=1091",
            "date": "2017-09-01T18:06:02",
            "name": "ARC: Machine Check Exception: enable MMU in single place",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/1091/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/808887/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/808887/checks/",
    "tags": {},
    "related": [],
    "headers": {
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        ],
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        "From": "Vineet Gupta <Vineet.Gupta1@synopsys.com>",
        "To": "<linux-snps-arc@lists.infradead.org>",
        "Subject": "[PATCH] ARC: Machine Check Exception: enable MMU in single place",
        "Date": "Fri, 1 Sep 2017 11:06:02 -0700",
        "Message-ID": "<1504289162-25977-1-git-send-email-vgupta@synopsys.com>",
        "X-Mailer": "git-send-email 2.7.4",
        "In-Reply-To": "<d0f55ba3b94de5c1bb7c93cbadb9829fa6889fed.1504281896.git.joabreu@synopsys.com>",
        "References": "<d0f55ba3b94de5c1bb7c93cbadb9829fa6889fed.1504281896.git.joabreu@synopsys.com>",
        "MIME-Version": "1.0",
        "X-Originating-IP": "[10.12.196.101]",
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        "X-CRM114-Status": "UNSURE (   7.96  )",
        "X-CRM114-Notice": "Please train this message.",
        "X-Spam-Score": "-1.9 (-)",
        "X-Spam-Report": "SpamAssassin version 3.4.1 on bombadil.infradead.org summary:\n\tContent analysis details:   (-1.9 points)\n\tpts rule name              description\n\t---- ----------------------\n\t--------------------------------------------------\n\t-0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay\n\tdomain\n\t-0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/,\n\tno trust [198.182.47.9 listed in list.dnswl.org]\n\t-1.9 BAYES_00               BODY: Bayes spam probability is 0 to 1%\n\t[score: 0.0000]",
        "X-BeenThere": "linux-snps-arc@lists.infradead.org",
        "X-Mailman-Version": "2.1.21",
        "Precedence": "list",
        "List-Id": "Linux on Synopsys ARC Processors\n\t<linux-snps-arc.lists.infradead.org>",
        "List-Unsubscribe": "<http://lists.infradead.org/mailman/options/linux-snps-arc>, \n\t<mailto:linux-snps-arc-request@lists.infradead.org?subject=unsubscribe>",
        "List-Archive": "<http://lists.infradead.org/pipermail/linux-snps-arc/>",
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        "List-Subscribe": "<http://lists.infradead.org/mailman/listinfo/linux-snps-arc>, \n\t<mailto:linux-snps-arc-request@lists.infradead.org?subject=subscribe>",
        "Cc": "Jose.Abreu@synopsys.com, Vineet Gupta <Vineet.Gupta1@synopsys.com>,\n\tlinux-kernel@vger.kernel.org",
        "Content-Type": "text/plain; charset=\"us-ascii\"",
        "Content-Transfer-Encoding": "7bit",
        "Sender": "\"linux-snps-arc\" <linux-snps-arc-bounces@lists.infradead.org>",
        "Errors-To": "linux-snps-arc-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org"
    },
    "content": "Machine check Exception is handled in distinc ways depending on cause\n - Duplicate TLB Entry (relevent mostly for ARC700)\n - everything else\n\nCurrently we re-enable MMU seperately for each of these cases, which can\nbe consolidated by dign this before we fork off the handling in low\nlevel handler.\n\nSigned-off-by: Vineet Gupta <vgupta@synopsys.com>\n---\n arch/arc/kernel/entry.S | 6 ++++++\n arch/arc/kernel/traps.c | 6 ------\n arch/arc/mm/tlb.c       | 3 ---\n 3 files changed, 6 insertions(+), 9 deletions(-)",
    "diff": "diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S\nindex 1eea99beecc3..85d9ea4a0acc 100644\n--- a/arch/arc/kernel/entry.S\n+++ b/arch/arc/kernel/entry.S\n@@ -92,6 +92,12 @@ ENTRY(EV_MachineCheck)\n \tlr  r0, [efa]\n \tmov r1, sp\n \n+\t; hardware auto-disables MMU, re-enable it to allow kernel vaddr\n+\t; access for say stack unwinding of modules for crash dumps\n+\tlr\tr3, [ARC_REG_PID]\n+\tor\tr3, r3, MMU_ENABLE\n+\tsr\tr3, [ARC_REG_PID]\n+\n \tlsr  \tr3, r2, 8\n \tbmsk \tr3, r3, 7\n \tbrne    r3, ECR_C_MCHK_DUP_TLB, 1f\ndiff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c\nindex b636dfe8ee9e..b03daa7a9a2b 100644\n--- a/arch/arc/kernel/traps.c\n+++ b/arch/arc/kernel/traps.c\n@@ -105,12 +105,6 @@ int do_misaligned_access(unsigned long address, struct pt_regs *regs,\n  */\n void do_machine_check_fault(unsigned long address, struct pt_regs *regs)\n {\n-\t/*\n-\t * Hardware auto-disables MMU upon this exception hence re-enabled\n-\t * for ksym lookup in modules to work (in kernel vaddr space)\n-\t */\n-\twrite_aux_reg(ARC_REG_PID, MMU_ENABLE | read_aux_reg(ARC_REG_PID));\n-\n \tdie(\"Unhandled Machine Check Exception\", regs, address);\n }\n \ndiff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c\nindex edc59a0a9c9b..8ceefbf72fb0 100644\n--- a/arch/arc/mm/tlb.c\n+++ b/arch/arc/mm/tlb.c\n@@ -908,9 +908,6 @@ void do_tlb_overlap_fault(unsigned long cause, unsigned long address,\n \n \tlocal_irq_save(flags);\n \n-\t/* re-enable the MMU */\n-\twrite_aux_reg(ARC_REG_PID, MMU_ENABLE | read_aux_reg(ARC_REG_PID));\n-\n \t/* loop thru all sets of TLB */\n \tfor (set = 0; set < mmu->sets; set++) {\n \n",
    "prefixes": []
}