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Shutemov" To: Dave Hansen , Andy Lutomirski , Peter Zijlstra Cc: x86@kernel.org, Kostya Serebryany , Andrey Ryabinin , Andrey Konovalov , Alexander Potapenko , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv3 OPTIONAL 8/8] x86/mm: Extend LAM to support to LAM_U48 Date: Fri, 10 Jun 2022 17:35:27 +0300 Message-Id: <20220610143527.22974-9-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220610143527.22974-1-kirill.shutemov@linux.intel.com> References: <20220610143527.22974-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1654871735; a=rsa-sha256; cv=none; b=7Sj20/3YR4Si1gZggkJSuj3Scw6O4ObzWKdaehm19EnLOCRf7mIkoVoY/F7tCfchzrluqA dMOLnzgfufbeQgO+De+bB/GwQhsKvHZpv6hjtIBhHiEvSdE6hmDFVz7SxWeDhKTGgf7yU3 pGmrWh2DmWHJOTe3zvNjgVgw6BxVve4= ARC-Authentication-Results: i=1; imf31.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=I2nNPAJR; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf31.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.126) smtp.mailfrom=kirill.shutemov@linux.intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1654871735; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=qV0kLPs13YmrtFANibVvJ3E/jNgyTQwLCoDPRXykKHE=; b=YDMwqyTjN0SIL9wX22HgHVahGwKetz399B36o6FlRWWc9MIBohfz90OISN8xbByuALpbhX 6oA8vmfLxLFhVAvADaHUTIo1Ymskp9ktJs6YmyuYqM/4XEnJsQs3bu3CydPUG5/sAGOu45 tYZVo1D5nL4cLnQ5Is5FiOmRA3854nU= X-Rspamd-Queue-Id: 587D120089 X-Rspam-User: Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=I2nNPAJR; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf31.hostedemail.com: domain of kirill.shutemov@linux.intel.com has no SPF policy when checking 134.134.136.126) smtp.mailfrom=kirill.shutemov@linux.intel.com X-Stat-Signature: 637s534ezomgyqds499yxyniscof7a9o X-Rspamd-Server: rspam02 X-HE-Tag: 1654871735-572207 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: LAM_U48 allows to encode 15 bits of tags into address. LAM_U48 steals bits above 47-bit for tags and makes it impossible for userspace to use full address space on 5-level paging machine. Make these features mutually exclusive: whichever gets enabled first blocks the other one. Signed-off-by: Kirill A. Shutemov --- arch/x86/include/asm/elf.h | 3 ++- arch/x86/include/asm/mmu_context.h | 13 +++++++++++++ arch/x86/kernel/process_64.c | 22 ++++++++++++++++++++++ arch/x86/kernel/sys_x86_64.c | 5 +++-- arch/x86/mm/hugetlbpage.c | 6 ++++-- arch/x86/mm/mmap.c | 9 ++++++++- 6 files changed, 52 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index cb0ff1055ab1..4df13497a770 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -317,7 +317,8 @@ static inline int mmap_is_ia32(void) extern unsigned long task_size_32bit(void); extern unsigned long task_size_64bit(int full_addr_space); extern unsigned long get_mmap_base(int is_legacy); -extern bool mmap_address_hint_valid(unsigned long addr, unsigned long len); +extern bool mmap_address_hint_valid(struct mm_struct *mm, + unsigned long addr, unsigned long len); extern unsigned long get_sigframe_size(void); #ifdef CONFIG_X86_32 diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index a6cded0f5e64..17d31988edd6 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -263,6 +263,19 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, unsigned long __get_current_cr3_fast(void); +#ifdef CONFIG_X86_5LEVEL +static inline bool full_va_allowed(struct mm_struct *mm) +{ + /* LAM_U48 steals VA bits above 47-bit for tags */ + return mm->context.lam_cr3_mask != X86_CR3_LAM_U48; +} +#else +static inline bool full_va_allowed(struct mm_struct *mm) +{ + return false; +} +#endif + #include #endif /* _ASM_X86_MMU_CONTEXT_H */ diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 93c8eba1a66d..56822d313b96 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -742,6 +742,16 @@ static long prctl_map_vdso(const struct vdso_image *image, unsigned long addr) } #endif +static bool lam_u48_allowed(void) +{ + struct mm_struct *mm = current->mm; + + if (!full_va_allowed(mm)) + return true; + + return find_vma(mm, DEFAULT_MAP_WINDOW) == NULL; +} + static int prctl_enable_tagged_addr(unsigned long nr_bits) { struct mm_struct *mm = current->mm; @@ -759,6 +769,18 @@ static int prctl_enable_tagged_addr(unsigned long nr_bits) } else if (nr_bits <= 6) { mm->context.lam_cr3_mask = X86_CR3_LAM_U57; mm->context.untag_mask = ~GENMASK(62, 57); + } else if (nr_bits <= 15) { + if (mmap_write_lock_killable(mm)) + return -EINTR; + + if (!lam_u48_allowed()) { + mmap_write_unlock(mm); + return -EBUSY; + } + + mm->context.lam_cr3_mask = X86_CR3_LAM_U48; + mm->context.untag_mask = ~GENMASK(62, 48); + mmap_write_unlock(mm); } else { return -EINVAL; } diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index 8cc653ffdccd..5ea6aaed89ba 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -21,6 +21,7 @@ #include #include +#include /* * Align a virtual address to avoid aliasing in the I$ on AMD F15h. @@ -182,7 +183,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, /* requesting a specific address */ if (addr) { addr &= PAGE_MASK; - if (!mmap_address_hint_valid(addr, len)) + if (!mmap_address_hint_valid(mm, addr, len)) goto get_unmapped_area; vma = find_vma(mm, addr); @@ -203,7 +204,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, * !in_32bit_syscall() check to avoid high addresses for x32 * (and make it no op on native i386). */ - if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall()) + if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall() && full_va_allowed(mm)) info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW; info.align_mask = 0; diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c index a0d023cb4292..9fdc8db42365 100644 --- a/arch/x86/mm/hugetlbpage.c +++ b/arch/x86/mm/hugetlbpage.c @@ -18,6 +18,7 @@ #include #include #include +#include #if 0 /* This is just for testing */ struct page * @@ -103,6 +104,7 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long pgoff, unsigned long flags) { struct hstate *h = hstate_file(file); + struct mm_struct *mm = current->mm; struct vm_unmapped_area_info info; info.flags = VM_UNMAPPED_AREA_TOPDOWN; @@ -114,7 +116,7 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file, * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area * in the full address space. */ - if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall()) + if (addr > DEFAULT_MAP_WINDOW && !in_32bit_syscall() && full_va_allowed(mm)) info.high_limit += TASK_SIZE_MAX - DEFAULT_MAP_WINDOW; info.align_mask = PAGE_MASK & ~huge_page_mask(h); @@ -161,7 +163,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr, if (addr) { addr &= huge_page_mask(h); - if (!mmap_address_hint_valid(addr, len)) + if (!mmap_address_hint_valid(mm, addr, len)) goto get_unmapped_area; vma = find_vma(mm, addr); diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index c90c20904a60..f9ca824729de 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -21,6 +21,7 @@ #include #include #include +#include #include "physaddr.h" @@ -35,6 +36,8 @@ unsigned long task_size_32bit(void) unsigned long task_size_64bit(int full_addr_space) { + if (!full_va_allowed(current->mm)) + return DEFAULT_MAP_WINDOW; return full_addr_space ? TASK_SIZE_MAX : DEFAULT_MAP_WINDOW; } @@ -206,11 +209,15 @@ const char *arch_vma_name(struct vm_area_struct *vma) * the failure of such a fixed mapping request, so the restriction is not * applied. */ -bool mmap_address_hint_valid(unsigned long addr, unsigned long len) +bool mmap_address_hint_valid(struct mm_struct *mm, + unsigned long addr, unsigned long len) { if (TASK_SIZE - len < addr) return false; + if (addr + len > DEFAULT_MAP_WINDOW && !full_va_allowed(mm)) + return false; + return (addr > DEFAULT_MAP_WINDOW) == (addr + len > DEFAULT_MAP_WINDOW); } -- 2.35.1