From patchwork Tue Nov 5 23:55:55 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11228959 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D1B081599 for ; Tue, 5 Nov 2019 23:56:36 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 1914C21D7C for ; Tue, 5 Nov 2019 23:56:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="LjxE0fDU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1914C21D7C Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17301-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 21748 invoked by uid 550); 5 Nov 2019 23:56:31 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 21632 invoked from network); 5 Nov 2019 23:56:30 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=g+FZBFl4/jtEHUrecvJjSJDyfo/JMaY/R05FvQww7Ew=; b=LjxE0fDUxx+3kVeg7vE5j0MDU6Zrcc+p5G7NQHNr0s5wHIkvFvwli6ZXOWnme85ije jBJFUcvifEowqIp9Q6kPG5XRfqnPWYKqq4lT3u/yEAAZ5inT/AF+WQUIdE+FH5coJnOx 45x+2YFn2EYwM9VkqAdU3t2ESgAwh/7S4v2oNrjoZrg07nQ2hDPts2xOAKtZcY1tbEs6 3BRjCQrnrIFpGViCfkicQ6TBibwhSYlPM7ALdbEMaEB9hM3UBZtHRO6ILY/gCNjMJwRI YnbDHHQcPorEK5ZZXqtDFbBOJQNgPXXh+FRps8QgyWzlYJKUT+fzyLMVa7bzsM74FsHD faAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=g+FZBFl4/jtEHUrecvJjSJDyfo/JMaY/R05FvQww7Ew=; b=dDCmFLCoKptwpB4lu/XVyIhDeSZ6iHyaBRmPWo7PicTpNzp7Ic3bC5hM/FsUBrMIr9 LPTpg/UCVkePwgJns1q6wESlR2OvGdNVQ8AbnGzUNGjRye7tNjm9Ra3DEqQmPgbcy4/9 ezGNA2eqVj6bazAV+o/a81zpuf/kdsj4cOEJVlYv56qFCg6hC5UwHSWtl5jHcS9JVY9Z StfOFVIHbdC0ns3V6Y2QgUDC0tR3ytECKg18Enm46JqEdX+xWwkIFq/BGJZaeCgGxx1x K27Aegr0R1r5KQlR+diJq0KIZkHb0PEZuCkpzkn0NgMVLmhmqHEvX5BkO8HjhLRlkrmH bv5A== X-Gm-Message-State: APjAAAUgP2epFXruzbxJk5ZBM2J/iNLNAX4fbsX5rYe/DRpAuyKCv759 xQvRthA0gbK7GVVt3RsQGwCOAQla0HLvm6VneQg= X-Google-Smtp-Source: APXvYqzW2J087dvbO8FxXmHSAb+jdYJ+R4A3JyspfZmNdbBUl+tfRqF1Deu+G73dGWQ5VPZ8TBLnfQxrufA2nMsUivc= X-Received: by 2002:a63:6cf:: with SMTP id 198mr39116524pgg.259.1572998178011; Tue, 05 Nov 2019 15:56:18 -0800 (PST) Date: Tue, 5 Nov 2019 15:55:55 -0800 In-Reply-To: <20191105235608.107702-1-samitolvanen@google.com> Message-Id: <20191105235608.107702-2-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191105235608.107702-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v5 01/14] arm64: mm: avoid x18 in idmap_kpti_install_ng_mappings From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel Cc: Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , Marc Zyngier , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sami Tolvanen idmap_kpti_install_ng_mappings uses x18 as a temporary register, which will result in a conflict when x18 is reserved. Use x16 and x17 instead where needed. Signed-off-by: Sami Tolvanen Reviewed-by: Nick Desaulniers Reviewed-by: Mark Rutland --- arch/arm64/mm/proc.S | 63 ++++++++++++++++++++++---------------------- 1 file changed, 32 insertions(+), 31 deletions(-) diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index a1e0592d1fbc..fdabf40a83c8 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -250,15 +250,15 @@ ENTRY(idmap_kpti_install_ng_mappings) /* We're the boot CPU. Wait for the others to catch up */ sevl 1: wfe - ldaxr w18, [flag_ptr] - eor w18, w18, num_cpus - cbnz w18, 1b + ldaxr w17, [flag_ptr] + eor w17, w17, num_cpus + cbnz w17, 1b /* We need to walk swapper, so turn off the MMU. */ pre_disable_mmu_workaround - mrs x18, sctlr_el1 - bic x18, x18, #SCTLR_ELx_M - msr sctlr_el1, x18 + mrs x17, sctlr_el1 + bic x17, x17, #SCTLR_ELx_M + msr sctlr_el1, x17 isb /* Everybody is enjoying the idmap, so we can rewrite swapper. */ @@ -281,9 +281,9 @@ skip_pgd: isb /* We're done: fire up the MMU again */ - mrs x18, sctlr_el1 - orr x18, x18, #SCTLR_ELx_M - msr sctlr_el1, x18 + mrs x17, sctlr_el1 + orr x17, x17, #SCTLR_ELx_M + msr sctlr_el1, x17 isb /* @@ -353,46 +353,47 @@ skip_pte: b.ne do_pte b next_pmd + .unreq cpu + .unreq num_cpus + .unreq swapper_pa + .unreq cur_pgdp + .unreq end_pgdp + .unreq pgd + .unreq cur_pudp + .unreq end_pudp + .unreq pud + .unreq cur_pmdp + .unreq end_pmdp + .unreq pmd + .unreq cur_ptep + .unreq end_ptep + .unreq pte + /* Secondary CPUs end up here */ __idmap_kpti_secondary: /* Uninstall swapper before surgery begins */ - __idmap_cpu_set_reserved_ttbr1 x18, x17 + __idmap_cpu_set_reserved_ttbr1 x16, x17 /* Increment the flag to let the boot CPU we're ready */ -1: ldxr w18, [flag_ptr] - add w18, w18, #1 - stxr w17, w18, [flag_ptr] +1: ldxr w16, [flag_ptr] + add w16, w16, #1 + stxr w17, w16, [flag_ptr] cbnz w17, 1b /* Wait for the boot CPU to finish messing around with swapper */ sevl 1: wfe - ldxr w18, [flag_ptr] - cbnz w18, 1b + ldxr w16, [flag_ptr] + cbnz w16, 1b /* All done, act like nothing happened */ - offset_ttbr1 swapper_ttb, x18 + offset_ttbr1 swapper_ttb, x16 msr ttbr1_el1, swapper_ttb isb ret - .unreq cpu - .unreq num_cpus - .unreq swapper_pa .unreq swapper_ttb .unreq flag_ptr - .unreq cur_pgdp - .unreq end_pgdp - .unreq pgd - .unreq cur_pudp - .unreq end_pudp - .unreq pud - .unreq cur_pmdp - .unreq end_pmdp - .unreq pmd - .unreq cur_ptep - .unreq end_ptep - .unreq pte ENDPROC(idmap_kpti_install_ng_mappings) .popsection #endif