From patchwork Thu Oct 31 16:46:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11221631 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 54F0015AB for ; Thu, 31 Oct 2019 16:58:59 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id A90AF2087F for ; Thu, 31 Oct 2019 16:58:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="kscd/Ryy" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A90AF2087F 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-17186-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 25965 invoked by uid 550); 31 Oct 2019 16:58:53 -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 Delivered-To: moderator for kernel-hardening@lists.openwall.com Received: (qmail 12262 invoked from network); 31 Oct 2019 16:46:58 -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=m8czdyKZmnHleycOU1GN1JDqnDhqDwUuQ2BzB2+NnLE=; b=kscd/Ryyvnax6ORha3g+9N2ycFdZdVKcUL7nn52FBqZCdom/ukOvZNiLYcIVHGWjJI RL+cSRsSc0KMkWX7Hpm6WW5mwmzyULTl69SeLKpONSPknn5ZqEZWkbRqognGlyERPXLo SV9nRf3GJ7wBfRyfYIInjM+YQGy1pLtrwhArDoKPFew1LEH2KfjE14WBRpDYQ6T6vBcN bTuA6HnIE/mjRqWbsSXxpwwDhLN9CG23XGon/2Fh6QYLxfPuum6XKBQrb0xQTBoamtRg GqrJFN7dDnqowhR+BaVm165Nc4KqgxxBwyK/OZ+cl3NUbIFIXQthBUWLYI6b8XUFTWxv fUxQ== 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=m8czdyKZmnHleycOU1GN1JDqnDhqDwUuQ2BzB2+NnLE=; b=RQwUqGr/ZEPzktOZt4ig81VVR/beT7UZwNVH+PT0YcCW2BEpyN3NwFI1ppNa5riHnF QYtaSi+V2VsZvPPTCKuQFOzNV4g1ovRHC7pbyFHfV1pAAkTRYCgg4M1qnIkCO4fSvPxT jRphOFRd6dXQF8Jtl5Z3wdHtZSCwu9VMjxOE2HVnxPZV1E1j4eqU2HofIT4D5cbW2AaR 7WpQAsS+Ja/a4Dl9pnCGlMSdJpi8NEZj8oRbu44x1k5pi8B7xeLzRl0ag8SUN2BbvvMu 3MBPlNDQDws/IHBWHyQcqcKUFH8+P21iRwsGZAFD4eQUEDeHAkydP9Lpah0HPyspjZTA UE1g== X-Gm-Message-State: APjAAAW3iGt0KW6kBsNCytkSmhrwPumAixhPbt0UYNpSvDKmVomJ42ke tSkWVUXTQsYgXLnIeoqVFk/ieTy2OsmFkrGx9WA= X-Google-Smtp-Source: APXvYqw9xt1orWeLvt0VfIxUZia5BAPhrbdVX/DF2ex1nZVelw9EIIUv1zSfOLTzEnTa2y67e76C/YQPYBoxghEHbPw= X-Received: by 2002:a63:4b54:: with SMTP id k20mr7973543pgl.70.1572540406049; Thu, 31 Oct 2019 09:46:46 -0700 (PDT) Date: Thu, 31 Oct 2019 09:46:21 -0700 In-Reply-To: <20191031164637.48901-1-samitolvanen@google.com> Message-Id: <20191031164637.48901-2-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191031164637.48901-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.rc0.303.g954a862665-goog Subject: [PATCH v3 01/17] arm64: mm: avoid x18 in idmap_kpti_install_ng_mappings From: samitolvanen@google.com To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel Cc: Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , 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