From nobody Tue Dec 16 08:51:33 2025 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B8987145356 for ; Tue, 27 Feb 2024 15:19:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709047170; cv=none; b=jSGOftHebmwxT8ci03GUvVUkXqPKB593GNMlpfPJpoK/unejq6cQik2Kubb2ghIlp+zpRSlJ3kM0wXJyc9XD9LmH9bAODvSkgq/ilssKb0FFLvkSCYjOGRZNW5n9/clwyRQX/TrvDJ4+nUblXyoi2bIIdkssG/JX3ABBQmHeeng= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709047170; c=relaxed/simple; bh=X6/OzZGiJqFpxqpC0njbNWYz6ODH6zW8Z1ABMSbDTS4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=WUMB0nV7stk+Zi11rW4hAiRijIYxK+Ypwu+o7m+mVjKkS3JHgtbxXghZqOKBrn3XBNZb2YBs0RpWfdW3/0kJnLmWjGHUpmq4PElhfwtRCRrKRe8n2HfJfZamSvLAOgnxZ+KMq2diWHBIdxig7Z4NTejWy+gWkaKVDIGVLw8asw4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=rReYyReM; arc=none smtp.client-ip=209.85.219.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rReYyReM" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-dbf618042daso6691509276.0 for ; Tue, 27 Feb 2024 07:19:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1709047168; x=1709651968; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Y5GeRQDtmrQKN4psfZmd6RkmjsdFQnHB8sOV6dww9xU=; b=rReYyReMccWVAE3OSLOF4pa/aTGkPQB/+kIIUW8bT2A32mF44Lr9B0Nh+ZMfOTYp0z OashlJ/oTPlgiRqm3CwTurtEh/DoFiSzfDUF8IPhboblwkqzhZUeroaN4xtOYQ9O9KtK bRAtnprD3e9fRLE3nmFCG+EmPY9cg5YVzXwpDHPxukI1kAvE35mMOOqeQ32aBr8dB3DI aH51/PPmOynLegTSxagLpEj8yDc33B0xMlWXcbI+n2IcRZO3d/XCNhem1lPsiw3H2DAY uOxVbwrDBExy9VHQCRSjEClAChX6lawqkPprZytm77XcuL3m35K2OvJ0SRkjOKxNf5sA l85A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709047168; x=1709651968; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Y5GeRQDtmrQKN4psfZmd6RkmjsdFQnHB8sOV6dww9xU=; b=qcxQgphbD09koAcBK3YUD8NolTNkJqXdVEbNtUbK6rX13pjN//YJJnlja0xKT0WzxN 0d1XBZ8lHoEJyGg7ArTqKGhhAyX7u1p2gPT5ArgS5pK4T1c6Yt4DIGxTzjsuSCDv1T0X RKQbqccHI/hf+td3O2Clpkfk3uYDRAU7CW9OcAo9sSC0NyjDyckNmQsvaIQP9FlqtxtL glvkvoy2lt0MgoZLXfoIxEZc8WxNm0smST6fpLj5BOtP6lk19T7WtshWtuA7G32KBBCO I342wbEZq8ADnEOBmds+TevycyMZYszgGBOpE+QG5nk5BY8lmNrUOHW1adDK2HxmlqqR ySHw== X-Gm-Message-State: AOJu0YzmJCBUhTi9Xo7Q3+FfluiSfeLON3P92alWy1Z6QCv5QazNlNim p4V4LHqSQftP7jwuqGkQGekbVbhgKMM0Q7u0ugYNikDNTF3OFkYBVxaDT2GDmpIZNrDwGYaKsq/ L2qZnahMRjQ4XVed1gqfpffcMrs0+nJt/HSc5rM8d7Ac0m48u7+gZ4QlyT0kW9VQKdQXypHBg3L LiRmBpzDswnK2o3ArSEvYGWU9GB/XAlg== X-Google-Smtp-Source: AGHT+IEA1JwrjX9NbLPuGgU7IQqerLyenqMpBskU343Gwd36pNaNnPUHHb/tx0w9vjnjOqTrxlsQUZ7C X-Received: from palermo.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:118a]) (user=ardb job=sendgmr) by 2002:a05:6902:1005:b0:dc2:5273:53f9 with SMTP id w5-20020a056902100500b00dc2527353f9mr134018ybt.1.1709047167684; Tue, 27 Feb 2024 07:19:27 -0800 (PST) Date: Tue, 27 Feb 2024 16:19:10 +0100 In-Reply-To: <20240227151907.387873-11-ardb+git@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240227151907.387873-11-ardb+git@google.com> X-Mailer: git-send-email 2.44.0.rc1.240.g4c46232300-goog Message-ID: <20240227151907.387873-13-ardb+git@google.com> Subject: [PATCH v7 2/9] x86/startup_64: Defer assignment of 5-level paging global variables From: Ard Biesheuvel To: linux-kernel@vger.kernel.org Cc: Ard Biesheuvel , Kevin Loughlin , Tom Lendacky , Dionna Glaze , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andy Lutomirski , Brian Gerst Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Ard Biesheuvel Assigning the 5-level paging related global variables from the earliest C code using explicit references that use the 1:1 translation of memory is unnecessary, as the startup code itself does not rely on them to create the initial page tables, and this is all it should be doing. So defer these assignments to the primary C entry code that executes via the ordinary kernel virtual mapping. Signed-off-by: Ard Biesheuvel Reviewed-by: Borislav Petkov (AMD) --- arch/x86/include/asm/pgtable_64_types.h | 2 +- arch/x86/kernel/head64.c | 44 +++++++------------- 2 files changed, 15 insertions(+), 31 deletions(-) diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm= /pgtable_64_types.h index 38b54b992f32..9053dfe9fa03 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -21,9 +21,9 @@ typedef unsigned long pgprotval_t; typedef struct { pteval_t pte; } pte_t; typedef struct { pmdval_t pmd; } pmd_t; =20 -#ifdef CONFIG_X86_5LEVEL extern unsigned int __pgtable_l5_enabled; =20 +#ifdef CONFIG_X86_5LEVEL #ifdef USE_EARLY_PGTABLE_L5 /* * cpu_feature_enabled() is not available in early boot code. diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 72351c3121a6..deaaea3280d9 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -23,6 +23,7 @@ #include =20 #include +#include #include #include #include @@ -77,24 +78,11 @@ static struct desc_struct startup_gdt[GDT_ENTRIES] __in= itdata =3D { [GDT_ENTRY_KERNEL_DS] =3D GDT_ENTRY_INIT(DESC_DATA64, 0, 0xffff= f), }; =20 -#ifdef CONFIG_X86_5LEVEL -static void __head *fixup_pointer(void *ptr, unsigned long physaddr) -{ - return ptr - (void *)_text + (void *)physaddr; -} - -static unsigned long __head *fixup_long(void *ptr, unsigned long physaddr) +static inline bool check_la57_support(void) { - return fixup_pointer(ptr, physaddr); -} - -static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr) -{ - return fixup_pointer(ptr, physaddr); -} + if (!IS_ENABLED(CONFIG_X86_5LEVEL)) + return false; =20 -static bool __head check_la57_support(unsigned long physaddr) -{ /* * 5-level paging is detected and enabled at kernel decompression * stage. Only check if it has been enabled there. @@ -102,21 +90,8 @@ static bool __head check_la57_support(unsigned long phy= saddr) if (!(native_read_cr4() & X86_CR4_LA57)) return false; =20 - *fixup_int(&__pgtable_l5_enabled, physaddr) =3D 1; - *fixup_int(&pgdir_shift, physaddr) =3D 48; - *fixup_int(&ptrs_per_p4d, physaddr) =3D 512; - *fixup_long(&page_offset_base, physaddr) =3D __PAGE_OFFSET_BASE_L5; - *fixup_long(&vmalloc_base, physaddr) =3D __VMALLOC_BASE_L5; - *fixup_long(&vmemmap_base, physaddr) =3D __VMEMMAP_BASE_L5; - return true; } -#else -static bool __head check_la57_support(unsigned long physaddr) -{ - return false; -} -#endif =20 static unsigned long __head sme_postprocess_startup(struct boot_params *bp= , pmdval_t *pmd) { @@ -180,7 +155,7 @@ unsigned long __head __startup_64(unsigned long physadd= r, bool la57; int i; =20 - la57 =3D check_la57_support(physaddr); + la57 =3D check_la57_support(); =20 /* Is the address too large? */ if (physaddr >> MAX_PHYSMEM_BITS) @@ -465,6 +440,15 @@ asmlinkage __visible void __init __noreturn x86_64_sta= rt_kernel(char * real_mode (__START_KERNEL & PGDIR_MASK))); BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <=3D MODULES_END); =20 + if (check_la57_support()) { + __pgtable_l5_enabled =3D 1; + pgdir_shift =3D 48; + ptrs_per_p4d =3D 512; + page_offset_base =3D __PAGE_OFFSET_BASE_L5; + vmalloc_base =3D __VMALLOC_BASE_L5; + vmemmap_base =3D __VMEMMAP_BASE_L5; + } + cr4_init_shadow(); =20 /* Kill off the identity-map trampoline */ --=20 2.44.0.rc1.240.g4c46232300-goog