linux-kernel - [PATCH v9 15/36] x86/fred: No ESPFIX needed when FRED is enabled

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230731063317.3720-16-xin3.li@intel.com>
Date:   Sun, 30 Jul 2023 23:32:56 -0700
From:   Xin Li <xin3.li@...el.com>
To:     linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-edac@...r.kernel.org, linux-hyperv@...r.kernel.org,
        kvm@...r.kernel.org, xen-devel@...ts.xenproject.org
Cc:     Jonathan Corbet <corbet@....net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H . Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>,
        Oleg Nesterov <oleg@...hat.com>,
        Tony Luck <tony.luck@...el.com>,
        "K . Y . Srinivasan" <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juergen Gross <jgross@...e.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
        Josh Poimboeuf <jpoimboe@...nel.org>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Kim Phillips <kim.phillips@....com>,
        Xin Li <xin3.li@...el.com>,
        Hyeonggon Yoo <42.hyeyoo@...il.com>,
        "Liam R . Howlett" <Liam.Howlett@...cle.com>,
        Sebastian Reichel <sebastian.reichel@...labora.com>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Jiaxi Chen <jiaxi.chen@...ux.intel.com>,
        Babu Moger <babu.moger@....com>,
        Jim Mattson <jmattson@...gle.com>,
        Sandipan Das <sandipan.das@....com>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Reinette Chatre <reinette.chatre@...el.com>,
        Daniel Sneddon <daniel.sneddon@...ux.intel.com>,
        Breno Leitao <leitao@...ian.org>,
        Nikunj A Dadhania <nikunj@....com>,
        Brian Gerst <brgerst@...il.com>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        Alexander Potapenko <glider@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        "Eric W . Biederman" <ebiederm@...ssion.com>,
        Kees Cook <keescook@...omium.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Ze Gao <zegao2021@...il.com>, Fei Li <fei1.li@...el.com>,
        Conghui <conghui.chen@...el.com>,
        Ashok Raj <ashok.raj@...el.com>,
        "Jason A . Donenfeld" <Jason@...c4.com>,
        Mark Rutland <mark.rutland@....com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>,
        Jane Malalane <jane.malalane@...rix.com>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Yantengsi <siyanteng@...ngson.cn>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Sathvika Vasireddy <sv@...ux.ibm.com>
Subject: [PATCH v9 15/36] x86/fred: No ESPFIX needed when FRED is enabled

From: "H. Peter Anvin (Intel)" <hpa@...or.com>

Because FRED always restores the full value of %rsp, ESPFIX is
no longer needed when it's enabled.

Signed-off-by: H. Peter Anvin (Intel) <hpa@...or.com>
Tested-by: Shan Kang <shan.kang@...el.com>
Signed-off-by: Xin Li <xin3.li@...el.com>
---
 arch/x86/kernel/espfix_64.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c
index 16f9814c9be0..48d133a54f45 100644
--- a/arch/x86/kernel/espfix_64.c
+++ b/arch/x86/kernel/espfix_64.c
@@ -106,6 +106,10 @@ void __init init_espfix_bsp(void)
 	pgd_t *pgd;
 	p4d_t *p4d;
 
+	/* FRED systems don't need ESPFIX */
+	if (cpu_feature_enabled(X86_FEATURE_FRED))
+		return;
+
 	/* Install the espfix pud into the kernel page directory */
 	pgd = &init_top_pgt[pgd_index(ESPFIX_BASE_ADDR)];
 	p4d = p4d_alloc(&init_mm, pgd, ESPFIX_BASE_ADDR);
@@ -129,6 +133,10 @@ void init_espfix_ap(int cpu)
 	void *stack_page;
 	pteval_t ptemask;
 
+	/* FRED systems don't need ESPFIX */
+	if (cpu_feature_enabled(X86_FEATURE_FRED))
+		return;
+
 	/* We only have to do this once... */
 	if (likely(per_cpu(espfix_stack, cpu)))
 		return;		/* Already initialized */
-- 
2.34.1