From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirsky <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@intel.com>,
Borislav Petkov <bpetkov@suse.de>,
Greg KH <gregkh@linuxfoundation.org>,
keescook@google.com, hughd@google.com,
Brian Gerst <brgerst@gmail.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
Rik van Riel <riel@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
David Laight <David.Laight@aculab.com>,
Eduardo Valentin <eduval@amazon.com>,
aliguori@amazon.com, Will Deacon <will.deacon@arm.com>,
daniel.gruss@iaik.tugraz.at,
Dave Hansen <dave.hansen@linux.intel.com>,
Ingo Molnar <mingo@kernel.org>,
moritz.lipp@iaik.tugraz.at, linux-mm@kvack.org,
Borislav Petkov <bp@alien8.de>,
michael.schwarz@iaik.tugraz.at,
richard.fellner@student.tugraz.at
Subject: [PATCH 9/9] x86/doc: Remove obvious weirdness
Date: Tue, 05 Dec 2017 13:34:54 +0100 [thread overview]
Message-ID: <20171205123820.337227593@infradead.org> (raw)
In-Reply-To: <20171205123444.990868007@infradead.org>
[-- Attachment #1: peterz-mm-doc.patch --]
[-- Type: text/plain, Size: 2144 bytes --]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
Documentation/x86/x86_64/mm.txt | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -1,6 +1,4 @@
-<previous description obsolete, deleted>
-
Virtual memory map with 4 level page tables:
0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm
@@ -47,8 +45,9 @@ ffffffffffe00000 - ffffffffffffffff (=2
Architecture defines a 64-bit virtual address. Implementations can support
less. Currently supported are 48- and 57-bit virtual addresses. Bits 63
-through to the most-significant implemented bit are set to either all ones
-or all zero. This causes hole between user space and kernel addresses.
+through to the most-significant implemented bit are sign extended.
+This causes hole between user space and kernel addresses if you interpret them
+as unsigned.
The direct mapping covers all memory in the system up to the highest
memory address (this means in some cases it can also include PCI memory
@@ -58,9 +57,6 @@ vmalloc space is lazily synchronized int
the processes using the page fault handler, with init_top_pgt as
reference.
-Current X86-64 implementations support up to 46 bits of address space (64 TB),
-which is our current limit. This expands into MBZ space in the page tables.
-
We map EFI runtime services in the 'efi_pgd' PGD in a 64Gb large virtual
memory window (this size is arbitrary, it can be raised later if needed).
The mappings are not part of any other kernel PGD and are only available
@@ -72,5 +68,3 @@ following fixmap section.
Note that if CONFIG_RANDOMIZE_MEMORY is enabled, the direct mapping of all
physical memory, vmalloc/ioremap space and virtual memory map are randomized.
Their order is preserved but their base will be offset early at boot time.
-
--Andi Kleen, Jul 2004
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prev parent reply other threads:[~2017-12-05 12:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-05 12:34 [PATCH 0/9] Clarify/cleanup/fix tlbflush API/usage Peter Zijlstra
2017-12-05 12:34 ` [PATCH 1/9] x86/mm: Remove superfluous barriers Peter Zijlstra
2017-12-05 12:34 ` [PATCH 2/9] x86/mm: Create asm/invpcid.h Peter Zijlstra
2017-12-05 12:34 ` [PATCH 3/9] x86/mm: Address feedback Peter Zijlstra
2017-12-05 12:34 ` [PATCH 4/9] x86/mm: Use __flush_tlb_one() for kernel memory Peter Zijlstra
2017-12-05 12:34 ` [PATCH 5/9] x86/uv: Use the right tlbflush API Peter Zijlstra
2017-12-05 21:09 ` Andrew Banman
2017-12-05 21:27 ` Peter Zijlstra
2017-12-05 23:04 ` Andrew Banman
2017-12-05 12:34 ` [PATCH 6/9] x86/microcode: Dont abuse the tlbflush interface Peter Zijlstra
2017-12-05 12:34 ` [PATCH 7/9] x86/mm: Clarify which functions are supposed to flush what Peter Zijlstra
2017-12-05 12:34 ` [PATCH 8/9] x86/mm: Clarify the whole ASID/kernel PCID/user PCID naming Peter Zijlstra
2017-12-05 12:34 ` Peter Zijlstra [this message]
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