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OpenCloudOS-Kernel/arch/x86/mm
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Linus Torvalds 798dec3304 x86-64: mm: clarify the 'positive addresses' user address rules 
Dave Hansen found the "(long) addr >= 0" code in the x86-64 access_ok
checks somewhat confusing, and suggested using a helper to clarify what
the code is doing.

So this does exactly that: clarifying what the sign bit check is all
about, by adding a helper macro that makes it clear what it is testing.

This also adds some explicit comments talking about how even with LAM
enabled, any addresses with the sign bit will still GP-fault in the
non-canonical region just above the sign bit.

This is all what allows us to do the user address checks with just the
sign bit, and furthermore be a bit cavalier about accesses that might be
done with an additional offset even past that point.

(And yes, this talks about 'positive' even though zero is also a valid
user address and so technically we should call them 'non-negative'.  But
I don't think using 'non-negative' ends up being more understandable).

Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2023-05-03 10:37:22 -07:00
..
pat - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of 2023-04-27 19:42:02 -07:00
Makefile x86: kmsan: handle CPU entry area 2022-10-03 14:03:26 -07:00
amdtopology.c x86/mm: Replace nodes_weight() with nodes_empty() where appropriate 2022-04-10 22:35:38 +02:00
cpu_entry_area.c x86/mm: Do not shuffle CPU entry areas without KASLR 2023-03-22 10:42:47 -07:00
debug_pagetables.c x86/mm/dump_pagetables: remove MODULE_LICENSE in non-modules 2023-04-13 13:13:54 -07:00
dump_pagetables.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
extable.c x86-64: mm: clarify the 'positive addresses' user address rules 2023-05-03 10:37:22 -07:00
fault.c x86/mm: try VMA lock-based page fault handling first 2023-04-05 20:03:01 -07:00
highmem_32.c x86/mm/highmem: Use generic kmap atomic implementation 2020-11-06 23:14:55 +01:00
hugetlbpage.c arch/x86/mm/hugetlbpage.c: pud_huge() returns 0 when using 2-level paging 2022-11-08 15:57:25 -08:00
ident_map.c x86/mm/ident_map: Check for errors from ident_pud_init() 2020-10-28 14:48:30 +01:00
init.c Add support for new Linear Address Masking CPU feature. This is similar 2023-04-28 09:43:49 -07:00
init_32.c x86: mm: rename __is_kernel_text() to is_x86_32_kernel_text() 2021-11-09 10:02:51 -08:00
init_64.c mm/sparse-vmemmap: generalise vmemmap_populate_hugepages() 2022-12-11 18:12:12 -08:00
iomap_32.c io-mapping: Cleanup atomic iomap 2020-11-06 23:14:58 +01:00
ioremap.c x86/ioremap: Add hypervisor callback for private MMIO mapping in coco VM 2023-03-26 23:42:40 +02:00
kasan_init_64.c x86/kasan: Populate shadow for shared chunk of the CPU entry area 2022-12-15 10:37:28 -08:00
kaslr.c x86: Fix various typos in comments 2021-03-18 15:31:53 +01:00
kmmio.c x86/mm/kmmio: Remove redundant preempt_disable() 2022-12-12 10:54:48 -05:00
kmsan_shadow.c x86: kmsan: handle CPU entry area 2022-10-03 14:03:26 -07:00
maccess.c x86: Share definition of __is_canonical_address() 2022-02-02 13:11:42 +01:00
mem_encrypt.c virtio: replace arch_has_restricted_virtio_memory_access() 2022-06-06 08:22:01 +02:00
mem_encrypt_amd.c x86/mm: Handle decryption/re-encryption of bss_decrypted consistently 2023-03-27 09:23:21 +02:00
mem_encrypt_boot.S x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros 2022-12-15 10:37:27 -08:00
mem_encrypt_identity.c x86/mm: Fix use of uninitialized buffer in sme_enable() 2023-03-16 12:22:25 +01:00
mm_internal.h x86/mm: thread pgprot_t through init_memory_mapping() 2020-04-10 15:36:21 -07:00
mmap.c x86/mm/mmap: Fix -Wmissing-prototypes warnings 2020-04-22 20:19:48 +02:00
mmio-mod.c x86: Replace cpumask_weight() with cpumask_empty() where appropriate 2022-04-10 22:35:38 +02:00
numa.c x86/numa: Use cpumask_available instead of hardcoded NULL check 2022-08-03 11:44:57 +02:00
numa_32.c x86/mm: Drop deprecated DISCONTIGMEM support for 32-bit 2020-05-28 18:34:30 +02:00
numa_64.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
numa_emulation.c x86/mm: Replace nodes_weight() with nodes_empty() where appropriate 2022-04-10 22:35:38 +02:00
numa_internal.h
…
pf_in.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
pf_in.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
pgprot.c x86/mm: move protection_map[] inside the platform 2022-07-17 17:14:38 -07:00
pgtable.c mm/pgtable: Fix multiple -Wstringop-overflow warnings 2022-12-01 08:50:38 -08:00
pgtable_32.c mm: remove unneeded includes of <asm/pgalloc.h> 2020-08-07 11:33:26 -07:00
physaddr.c mm, x86/mm: Untangle address space layout definitions from basic pgtable type definitions 2019-12-10 10:12:55 +01:00
physaddr.h
…
pkeys.c x86/pkeys: Clarify PKRU_AD_KEY macro 2022-06-07 16:06:33 -07:00
pti.c x86/mm: Remove P*D_PAGE_MASK and P*D_PAGE_SIZE macros 2022-12-15 10:37:27 -08:00
srat.c
…
testmmiotrace.c remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
tlb.c Add support for new Linear Address Masking CPU feature. This is similar 2023-04-28 09:43:49 -07:00