From: Dave Hansen <dave.hansen@linux.intel.com> To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, dave.hansen@linux.intel.com, moritz.lipp@iaik.tugraz.at, daniel.gruss@iaik.tugraz.at, michael.schwarz@iaik.tugraz.at, richard.fellner@student.tugraz.at, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, x86@kernel.org Subject: [PATCH 06/23] x86, kaiser: allow NX poison to be set in p4d/pgd Date: Wed, 22 Nov 2017 16:34:48 -0800 [thread overview] Message-ID: <20171123003448.C6AB3575@viggo.jf.intel.com> (raw) In-Reply-To: <20171123003438.48A0EEDE@viggo.jf.intel.com> From: Dave Hansen <dave.hansen@linux.intel.com> The user portion of the kernel page tables use the NX bit to poison them for userspace. But, that trips the p4d/pgd_bad() checks. Make sure it does not do that. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Moritz Lipp <moritz.lipp@iaik.tugraz.at> Cc: Daniel Gruss <daniel.gruss@iaik.tugraz.at> Cc: Michael Schwarz <michael.schwarz@iaik.tugraz.at> Cc: Richard Fellner <richard.fellner@student.tugraz.at> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Kees Cook <keescook@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: x86@kernel.org --- b/arch/x86/include/asm/pgtable.h | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff -puN arch/x86/include/asm/pgtable.h~kaiser-p4d-allow-nx arch/x86/include/asm/pgtable.h --- a/arch/x86/include/asm/pgtable.h~kaiser-p4d-allow-nx 2017-11-22 15:45:47.382619743 -0800 +++ b/arch/x86/include/asm/pgtable.h 2017-11-22 15:45:47.386619743 -0800 @@ -846,7 +846,12 @@ static inline pud_t *pud_offset(p4d_t *p static inline int p4d_bad(p4d_t p4d) { - return (p4d_flags(p4d) & ~(_KERNPG_TABLE | _PAGE_USER)) != 0; + unsigned long ignore_flags = _KERNPG_TABLE | _PAGE_USER; + + if (IS_ENABLED(CONFIG_KAISER)) + ignore_flags |= _PAGE_NX; + + return (p4d_flags(p4d) & ~ignore_flags) != 0; } #endif /* CONFIG_PGTABLE_LEVELS > 3 */ @@ -880,7 +885,12 @@ static inline p4d_t *p4d_offset(pgd_t *p static inline int pgd_bad(pgd_t pgd) { - return (pgd_flags(pgd) & ~_PAGE_USER) != _KERNPG_TABLE; + unsigned long ignore_flags = _PAGE_USER; + + if (IS_ENABLED(CONFIG_KAISER)) + ignore_flags |= _PAGE_NX; + + return (pgd_flags(pgd) & ~ignore_flags) != _KERNPG_TABLE; } static inline int pgd_none(pgd_t pgd) _
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@linux.intel.com> To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, dave.hansen@linux.intel.com, moritz.lipp@iaik.tugraz.at, daniel.gruss@iaik.tugraz.at, michael.schwarz@iaik.tugraz.at, richard.fellner@student.tugraz.at, luto@kernel.org, torvalds@linux-foundation.org, keescook@google.com, hughd@google.com, x86@kernel.org Subject: [PATCH 06/23] x86, kaiser: allow NX poison to be set in p4d/pgd Date: Wed, 22 Nov 2017 16:34:48 -0800 [thread overview] Message-ID: <20171123003448.C6AB3575@viggo.jf.intel.com> (raw) In-Reply-To: <20171123003438.48A0EEDE@viggo.jf.intel.com> From: Dave Hansen <dave.hansen@linux.intel.com> The user portion of the kernel page tables use the NX bit to poison them for userspace. But, that trips the p4d/pgd_bad() checks. Make sure it does not do that. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Moritz Lipp <moritz.lipp@iaik.tugraz.at> Cc: Daniel Gruss <daniel.gruss@iaik.tugraz.at> Cc: Michael Schwarz <michael.schwarz@iaik.tugraz.at> Cc: Richard Fellner <richard.fellner@student.tugraz.at> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Kees Cook <keescook@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: x86@kernel.org --- b/arch/x86/include/asm/pgtable.h | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff -puN arch/x86/include/asm/pgtable.h~kaiser-p4d-allow-nx arch/x86/include/asm/pgtable.h --- a/arch/x86/include/asm/pgtable.h~kaiser-p4d-allow-nx 2017-11-22 15:45:47.382619743 -0800 +++ b/arch/x86/include/asm/pgtable.h 2017-11-22 15:45:47.386619743 -0800 @@ -846,7 +846,12 @@ static inline pud_t *pud_offset(p4d_t *p static inline int p4d_bad(p4d_t p4d) { - return (p4d_flags(p4d) & ~(_KERNPG_TABLE | _PAGE_USER)) != 0; + unsigned long ignore_flags = _KERNPG_TABLE | _PAGE_USER; + + if (IS_ENABLED(CONFIG_KAISER)) + ignore_flags |= _PAGE_NX; + + return (p4d_flags(p4d) & ~ignore_flags) != 0; } #endif /* CONFIG_PGTABLE_LEVELS > 3 */ @@ -880,7 +885,12 @@ static inline p4d_t *p4d_offset(pgd_t *p static inline int pgd_bad(pgd_t pgd) { - return (pgd_flags(pgd) & ~_PAGE_USER) != _KERNPG_TABLE; + unsigned long ignore_flags = _PAGE_USER; + + if (IS_ENABLED(CONFIG_KAISER)) + ignore_flags |= _PAGE_NX; + + return (pgd_flags(pgd) & ~ignore_flags) != _KERNPG_TABLE; } static inline int pgd_none(pgd_t pgd) _ -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-11-23 0:40 UTC|newest] Thread overview: 131+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-11-23 0:34 [PATCH 00/23] [v4] KAISER: unmap most of the kernel from userspace page tables Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 0:34 ` [PATCH 01/23] x86, kaiser: disable global pages by default with KAISER Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 0:34 ` [PATCH 02/23] x86, kaiser: prepare assembly for entry/exit CR3 switching Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 0:34 ` [PATCH 03/23] x86, kaiser: introduce user-mapped per-cpu areas Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 0:34 ` [PATCH 04/23] x86, kaiser: mark per-cpu data structures required for entry/exit Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 0:34 ` [PATCH 05/23] x86, kaiser: unmap kernel from userspace page tables (core patch) Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 4:07 ` Andy Lutomirski 2017-11-23 4:07 ` Andy Lutomirski 2017-11-26 16:10 ` Andy Lutomirski 2017-11-26 16:10 ` Andy Lutomirski 2017-11-26 16:24 ` Dave Hansen 2017-11-26 16:24 ` Dave Hansen 2017-11-26 16:29 ` Andy Lutomirski 2017-11-26 16:29 ` Andy Lutomirski 2018-01-05 4:16 ` Yisheng Xie 2018-01-05 4:16 ` Yisheng Xie 2018-01-05 5:18 ` Dave Hansen 2018-01-05 5:18 ` Dave Hansen 2018-01-05 6:16 ` Yisheng Xie 2018-01-05 6:16 ` Yisheng Xie 2018-01-05 6:29 ` Dave Hansen 2018-01-05 6:29 ` Dave Hansen 2018-01-05 11:49 ` Andrea Arcangeli 2018-01-05 11:49 ` Andrea Arcangeli 2018-01-05 18:19 ` Jiri Kosina 2018-01-05 18:19 ` Jiri Kosina 2018-01-05 19:00 ` Jiri Kosina 2018-01-05 19:00 ` Jiri Kosina 2018-01-05 19:03 ` Dave Hansen 2018-01-05 19:03 ` Dave Hansen 2018-01-05 19:17 ` Jiri Kosina 2018-01-05 19:17 ` Jiri Kosina 2018-01-05 19:18 ` Jiri Kosina 2018-01-05 19:18 ` Jiri Kosina 2018-01-05 19:55 ` Andrea Arcangeli 2018-01-05 19:55 ` Andrea Arcangeli 2018-01-05 21:07 ` Dave Hansen 2018-01-05 21:07 ` Dave Hansen 2018-01-05 21:14 ` Jiri Kosina 2018-01-05 21:14 ` Jiri Kosina 2018-01-05 21:29 ` Andy Lutomirski 2018-01-05 21:29 ` Andy Lutomirski 2018-01-05 22:48 ` Hugh Dickins 2018-01-05 22:48 ` Hugh Dickins 2018-01-06 4:54 ` Hanjun Guo 2018-01-06 4:54 ` Hanjun Guo 2018-01-06 6:06 ` Dave Hansen 2018-01-06 6:28 ` Hanjun Guo 2018-01-06 6:28 ` Hanjun Guo 2018-01-06 6:53 ` Hanjun Guo 2018-01-06 6:53 ` Hanjun Guo 2018-01-06 7:55 ` Dave Hansen 2018-01-06 7:55 ` Dave Hansen 2018-01-06 8:42 ` Hanjun Guo 2018-01-06 8:42 ` Hanjun Guo 2018-01-06 7:51 ` Dave Hansen 2018-01-06 7:51 ` Dave Hansen 2018-01-06 17:22 ` Andrea Arcangeli 2018-01-06 17:22 ` Andrea Arcangeli 2017-11-23 0:34 ` Dave Hansen [this message] 2017-11-23 0:34 ` [PATCH 06/23] x86, kaiser: allow NX poison to be set in p4d/pgd Dave Hansen 2017-11-23 0:34 ` [PATCH 07/23] x86, kaiser: make sure static PGDs are 8k in size Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 0:34 ` [PATCH 08/23] x86, kaiser: map cpu entry area Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 0:34 ` [PATCH 09/23] x86, kaiser: map dynamically-allocated LDTs Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 19:42 ` Eric Biggers 2017-11-23 19:42 ` Eric Biggers 2017-11-23 20:12 ` Andy Lutomirski 2017-11-23 20:12 ` Andy Lutomirski 2017-11-23 0:34 ` [PATCH 10/23] x86, kaiser: map espfix structures Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 0:34 ` [PATCH 11/23] x86, kaiser: map entry stack variables Dave Hansen 2017-11-23 0:34 ` Dave Hansen 2017-11-23 3:31 ` Andy Lutomirski 2017-11-23 3:31 ` Andy Lutomirski 2017-11-23 15:37 ` Dave Hansen 2017-11-23 15:37 ` Dave Hansen 2017-11-23 15:55 ` Andy Lutomirski 2017-11-23 15:55 ` Andy Lutomirski 2017-11-23 0:35 ` [PATCH 12/23] x86, kaiser: map virtually-addressed performance monitoring buffers Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 0:35 ` [PATCH 13/23] x86, mm: Move CR3 construction functions Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 0:35 ` [PATCH 14/23] x86, mm: remove hard-coded ASID limit checks Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 0:35 ` [PATCH 15/23] x86, mm: put mmu-to-h/w ASID translation in one place Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 0:35 ` [PATCH 16/23] x86, pcid, kaiser: allow flushing for future ASID switches Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 0:35 ` [PATCH 17/23] x86, kaiser: use PCID feature to make user and kernel switches faster Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 0:35 ` [PATCH 18/23] x86, kaiser: disable native VSYSCALL Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 0:35 ` [PATCH 19/23] x86, kaiser: add debugfs file to turn KAISER on/off at runtime Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 0:35 ` [PATCH 20/23] x86, kaiser: add a function to check for KAISER being enabled Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-25 1:23 ` Eduardo Valentin 2017-11-25 1:23 ` Eduardo Valentin 2017-11-23 0:35 ` [PATCH 21/23] x86, kaiser: un-poison PGDs at runtime Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-25 1:17 ` Eduardo Valentin 2017-11-25 1:17 ` Eduardo Valentin 2017-11-23 0:35 ` [PATCH 22/23] x86, kaiser: allow KAISER to be enabled/disabled " Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 0:35 ` [PATCH 23/23] x86, kaiser: add Kconfig Dave Hansen 2017-11-23 0:35 ` Dave Hansen 2017-11-23 7:23 ` [PATCH 00/23] [v4] KAISER: unmap most of the kernel from userspace page tables Ingo Molnar 2017-11-23 7:23 ` Ingo Molnar 2017-11-23 7:27 ` Ingo Molnar 2017-11-23 7:27 ` Ingo Molnar 2017-11-23 7:32 ` Ingo Molnar 2017-11-23 7:32 ` Ingo Molnar 2017-11-23 15:02 ` Dave Hansen 2017-11-23 15:02 ` Dave Hansen 2017-11-23 16:20 ` Dave Hansen 2017-11-23 16:20 ` Dave Hansen 2017-11-24 6:35 ` Ingo Molnar 2017-11-24 6:35 ` Ingo Molnar 2017-11-24 6:41 ` Dave Hansen 2017-11-24 6:41 ` Dave Hansen 2017-11-24 7:33 ` Ingo Molnar 2017-11-24 7:33 ` Ingo Molnar
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