From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id 4A25D6B0009 for ; Wed, 14 Feb 2018 13:25:51 -0500 (EST) Received: by mail-pl0-f70.google.com with SMTP id f4so11319175plr.14 for ; Wed, 14 Feb 2018 10:25:51 -0800 (PST) Received: from mga17.intel.com (mga17.intel.com. [192.55.52.151]) by mx.google.com with ESMTPS id l1si140806pgc.548.2018.02.14.10.25.49 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 14 Feb 2018 10:25:50 -0800 (PST) From: "Kirill A. Shutemov" Subject: [PATCH 1/9] x86/mm: Initialize pgtable_l5_enabled at boot-time Date: Wed, 14 Feb 2018 21:25:34 +0300 Message-Id: <20180214182542.69302-2-kirill.shutemov@linux.intel.com> In-Reply-To: <20180214182542.69302-1-kirill.shutemov@linux.intel.com> References: <20180214182542.69302-1-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Ingo Molnar , x86@kernel.org, Thomas Gleixner , "H. Peter Anvin" Cc: Linus Torvalds , Andy Lutomirski , Borislav Petkov , Andi Kleen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" pgtable_l5_enabled indicates which paging mode we are using. We need to initialize it at boot-time according to machine capability. Signed-off-by: Kirill A. Shutemov --- arch/x86/boot/compressed/kaslr.c | 8 +++++++- arch/x86/kernel/head64.c | 24 +++++++++++++++++++++++- 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index b18e8f9512de..d02a838c0ce4 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -47,7 +47,7 @@ #include #ifdef CONFIG_X86_5LEVEL -unsigned int pgtable_l5_enabled __ro_after_init = 1; +unsigned int pgtable_l5_enabled __ro_after_init; unsigned int pgdir_shift __ro_after_init = 48; unsigned int ptrs_per_p4d __ro_after_init = 512; #endif @@ -729,6 +729,12 @@ void choose_random_location(unsigned long input, return; } +#ifdef CONFIG_X86_5LEVEL + if (__read_cr4() & X86_CR4_LA57) { + pgtable_l5_enabled = 1; + } +#endif + boot_params->hdr.loadflags |= KASLR_FLAG; /* Prepare to add new identity pagetables on demand. */ diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 98b0ff49b220..ffb31c50d515 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -40,7 +40,7 @@ static unsigned int __initdata next_early_pgt; pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); #ifdef CONFIG_X86_5LEVEL -unsigned int pgtable_l5_enabled __ro_after_init = 1; +unsigned int pgtable_l5_enabled __ro_after_init; EXPORT_SYMBOL(pgtable_l5_enabled); unsigned int pgdir_shift __ro_after_init = 48; EXPORT_SYMBOL(pgdir_shift); @@ -64,6 +64,26 @@ static void __head *fixup_pointer(void *ptr, unsigned long physaddr) return ptr - (void *)_text + (void *)physaddr; } +#ifdef CONFIG_X86_5LEVEL +static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr) +{ + return fixup_pointer(ptr, physaddr); +} + +static void __head check_la57_support(unsigned long physaddr) +{ + if (native_cpuid_eax(0) < 7) + return; + + if (!(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31)))) + return; + + *fixup_int(&pgtable_l5_enabled, physaddr) = 1; +} +#else +static void __head check_la57_support(unsigned long physaddr) {} +#endif + unsigned long __head __startup_64(unsigned long physaddr, struct boot_params *bp) { @@ -76,6 +96,8 @@ unsigned long __head __startup_64(unsigned long physaddr, int i; unsigned int *next_pgt_ptr; + check_la57_support(physaddr); + /* Is the address too large? */ if (physaddr >> MAX_PHYSMEM_BITS) for (;;); -- 2.15.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org