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 20/30] x86, mm: remove hard-coded ASID limit checks
Date: Fri, 10 Nov 2017 11:31:44 -0800 [thread overview]
Message-ID: <20171110193144.0376C2CC@viggo.jf.intel.com> (raw)
In-Reply-To: <20171110193058.BECA7D88@viggo.jf.intel.com>
From: Dave Hansen <dave.hansen@linux.intel.com>
First, it's nice to remove the magic numbers.
Second, KAISER is going to consume half of the available ASID
space. The space is currently unused, but add a comment to spell
out this new restriction.
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/tlbflush.h | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff -puN arch/x86/include/asm/tlbflush.h~kaiser-pcid-pre-build-asids-macros arch/x86/include/asm/tlbflush.h
--- a/arch/x86/include/asm/tlbflush.h~kaiser-pcid-pre-build-asids-macros 2017-11-10 11:22:15.990244932 -0800
+++ b/arch/x86/include/asm/tlbflush.h 2017-11-10 11:22:15.994244932 -0800
@@ -74,6 +74,19 @@ static inline u64 inc_mm_tlb_gen(struct
return new_tlb_gen;
}
+/* There are 12 bits of space for ASIDS in CR3 */
+#define CR3_HW_ASID_BITS 12
+/* When enabled, KAISER consumes a single bit for user/kernel switches */
+#define KAISER_CONSUMED_ASID_BITS 0
+
+#define CR3_AVAIL_ASID_BITS (CR3_HW_ASID_BITS-KAISER_CONSUMED_ASID_BITS)
+/*
+ * ASIDs are zero-based: 0->MAX_AVAIL_ASID are valid. -1 below
+ * to account for them being zero-absed. Another -1 is because ASID 0
+ * is reserved for use by non-PCID-aware users.
+ */
+#define MAX_ASID_AVAILABLE ((1<<CR3_AVAIL_ASID_BITS) - 2)
+
/*
* If PCID is on, ASID-aware code paths put the ASID+1 into the PCID
* bits. This serves two purposes. It prevents a nasty situation in
@@ -87,7 +100,7 @@ struct pgd_t;
static inline unsigned long build_cr3(pgd_t *pgd, u16 asid)
{
if (static_cpu_has(X86_FEATURE_PCID)) {
- VM_WARN_ON_ONCE(asid > 4094);
+ VM_WARN_ON_ONCE(asid > MAX_ASID_AVAILABLE);
return __sme_pa(pgd) | (asid + 1);
} else {
VM_WARN_ON_ONCE(asid != 0);
@@ -97,7 +110,7 @@ static inline unsigned long build_cr3(pg
static inline unsigned long build_cr3_noflush(pgd_t *pgd, u16 asid)
{
- VM_WARN_ON_ONCE(asid > 4094);
+ VM_WARN_ON_ONCE(asid > MAX_ASID_AVAILABLE);
return __sme_pa(pgd) | (asid + 1) | CR3_NOFLUSH;
}
_
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next prev parent reply other threads:[~2017-11-10 19:32 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-10 19:30 [PATCH 00/30] [v3] KAISER: unmap most of the kernel from userspace page tables Dave Hansen
2017-11-10 19:31 ` [PATCH 01/30] x86, mm: do not set _PAGE_USER for init_mm " Dave Hansen
2017-11-10 19:31 ` [PATCH 02/30] x86, tlb: Make CR4-based TLB flushes more robust Dave Hansen
2017-11-10 19:31 ` [PATCH 03/30] x86/mm: Document X86_CR4_PGE toggling behavior Dave Hansen
2017-11-10 19:31 ` [PATCH 04/30] x86, kaiser: disable global pages by default with KAISER Dave Hansen
2017-11-14 19:38 ` Rik van Riel
2017-11-26 14:48 ` Ingo Molnar
2017-11-27 11:37 ` Thomas Gleixner
2017-11-27 13:20 ` [PATCH v2] x86/mm/kaiser: Disable " Ingo Molnar
2017-11-27 13:23 ` Thomas Gleixner
2017-11-27 13:27 ` Ingo Molnar
2017-11-10 19:31 ` [PATCH 05/30] x86, kaiser: prepare assembly for entry/exit CR3 switching Dave Hansen
2017-11-20 12:17 ` Thomas Gleixner
2017-11-10 19:31 ` [PATCH 06/30] x86, kaiser: introduce user-mapped per-cpu areas Dave Hansen
2017-11-10 19:31 ` [PATCH 07/30] x86, kaiser: mark per-cpu data structures required for entry/exit Dave Hansen
2017-11-10 19:31 ` [PATCH 08/30] x86, kaiser: unmap kernel from userspace page tables (core patch) Dave Hansen
2017-11-20 17:21 ` Thomas Gleixner
2017-11-22 22:45 ` Dave Hansen
2017-11-22 22:50 ` Dave Hansen
2017-11-22 22:54 ` Dave Hansen
2017-11-22 23:11 ` Dave Hansen
2017-11-10 19:31 ` [PATCH 09/30] x86, kaiser: only populate shadow page tables for userspace Dave Hansen
2017-11-20 20:12 ` Thomas Gleixner
2017-11-21 7:05 ` Ingo Molnar
2017-11-21 22:09 ` Dave Hansen
2017-11-22 3:44 ` Andy Lutomirski
2017-11-22 23:30 ` Dave Hansen
2017-11-10 19:31 ` [PATCH 10/30] x86, kaiser: allow NX poison to be set in p4d/pgd Dave Hansen
2017-11-10 19:31 ` [PATCH 11/30] x86, kaiser: make sure static PGDs are 8k in size Dave Hansen
2017-11-10 19:31 ` [PATCH 12/30] x86, kaiser: map GDT into user page tables Dave Hansen
2017-11-20 20:22 ` Thomas Gleixner
2017-11-20 20:46 ` Andy Lutomirski
2017-11-20 20:55 ` Thomas Gleixner
2017-11-21 21:19 ` Dave Hansen
2017-11-21 22:46 ` Andy Lutomirski
2017-11-21 23:17 ` Dave Hansen
2017-11-21 23:32 ` Andy Lutomirski
2017-11-21 23:42 ` Dave Hansen
2017-11-22 0:17 ` Andy Lutomirski
2017-11-22 0:37 ` Dave Hansen
2017-11-21 22:12 ` Dave Hansen
2017-11-10 19:31 ` [PATCH 13/30] x86, kaiser: map dynamically-allocated LDTs Dave Hansen
2017-11-10 19:31 ` [PATCH 14/30] x86, kaiser: map espfix structures Dave Hansen
2017-11-10 19:31 ` [PATCH 15/30] x86, kaiser: map entry stack variables Dave Hansen
2017-11-10 19:31 ` [PATCH 16/30] x86, kaiser: map trace interrupt entry Dave Hansen
2017-11-10 19:31 ` [PATCH 17/30] x86, kaiser: map debug IDT tables Dave Hansen
2017-11-20 20:40 ` Thomas Gleixner
2017-11-21 22:16 ` Dave Hansen
2017-11-20 20:44 ` Andy Lutomirski
2017-11-20 20:54 ` Thomas Gleixner
2017-11-10 19:31 ` [PATCH 18/30] x86, kaiser: map virtually-addressed performance monitoring buffers Dave Hansen
2017-11-14 18:20 ` Peter Zijlstra
2017-11-14 18:28 ` Dave Hansen
2017-11-14 19:10 ` Hugh Dickins
2017-11-14 19:24 ` Andy Lutomirski
2017-11-15 9:41 ` Peter Zijlstra
2017-11-10 19:31 ` [PATCH 19/30] x86, mm: Move CR3 construction functions Dave Hansen
2017-11-10 19:31 ` Dave Hansen [this message]
2017-11-20 20:47 ` [PATCH 20/30] x86, mm: remove hard-coded ASID limit checks Thomas Gleixner
2017-11-10 19:31 ` [PATCH 21/30] x86, mm: put mmu-to-h/w ASID translation in one place Dave Hansen
2017-11-10 22:03 ` Andy Lutomirski
2017-11-10 22:09 ` Dave Hansen
2017-11-10 22:10 ` Andy Lutomirski
2017-11-10 19:31 ` [PATCH 22/30] x86, pcid, kaiser: allow flushing for future ASID switches Dave Hansen
2017-11-10 19:31 ` [PATCH 23/30] x86, kaiser: use PCID feature to make user and kernel switches faster Dave Hansen
2017-11-16 19:19 ` Andrea Arcangeli
2017-11-16 19:25 ` Dave Hansen
2017-11-10 19:31 ` [PATCH 24/30] x86, kaiser: disable native VSYSCALL Dave Hansen
2017-11-10 19:31 ` [PATCH 25/30] x86, kaiser: add debugfs file to turn KAISER on/off at runtime Dave Hansen
2017-11-10 19:31 ` [PATCH 26/30] x86, kaiser: add a function to check for KAISER being enabled Dave Hansen
2017-11-10 19:31 ` [PATCH 27/30] x86, kaiser: un-poison PGDs at runtime Dave Hansen
2017-11-10 19:31 ` [PATCH 28/30] x86, kaiser: allow KAISER to be enabled/disabled " Dave Hansen
2017-11-10 19:32 ` [PATCH 29/30] x86, kaiser: add Kconfig Dave Hansen
2017-11-10 19:32 ` [PATCH 30/30] x86, kaiser, xen: Dynamically disable KAISER when running under Xen PV Dave Hansen
2017-11-20 16:02 ` [PATCH 00/30] [v3] KAISER: unmap most of the kernel from userspace page tables Juerg Haefliger
-- strict thread matches above, loose matches on Subject: below --
2017-11-08 19:46 [PATCH 00/30] [v2] " Dave Hansen
2017-11-08 19:47 ` [PATCH 20/30] x86, mm: remove hard-coded ASID limit checks Dave Hansen
2017-11-10 12:20 ` Peter Zijlstra
2017-11-10 18:41 ` Dave Hansen
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