walk_page_range_novma() is rather confusing - it supports two modes, one
used often, the other used only for debugging.
The first mode is the common case of traversal of kernel page tables,
which is what nearly all callers use this for.
Secondly it provides an unusual debugging interface that allows for the
traversal of page tables in a userland range of memory even for that
memory which is not described by a VMA.
It is far from certain that such page tables should even exist, but
perhaps this is precisely why it is useful as a debugging mechanism.
As a result, this is utilised by ptdump only. Historically, things were
reversed - ptdump was the only user, and other parts of the kernel evolved
to use the kernel page table walking here.
Since we have some complicated and confusing locking rules for the novma
case, it makes sense to separate the two usages into their own functions.
Doing this also provide self-documentation as to the intent of the caller
- are they doing something rather unusual or are they simply doing a
standard kernel page table walk?
We therefore establish two separate functions - walk_page_range_debug()
for this single usage, and walk_kernel_page_table_range() for general
kernel page table walking.
The walk_page_range_debug() function is currently used to traverse both
userland and kernel mappings, so we maintain this and in the case of
kernel mappings being traversed, we have walk_page_range_debug() invoke
walk_kernel_page_table_range() internally.
We additionally make walk_page_range_debug() internal to mm.
Link: https://lkml.kernel.org/r/20250605135104.90720-1-lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Barry Song <baohua@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Now kernel_page_present() always return true for KPRANGE/XKPRANGE
addresses, this isn't correct because hibernation (ACPI S4) use it
to distinguish whether a page is saveable. If all KPRANGE/XKPRANGE
addresses are considered as saveable, then reserved memory such as
EFI_RUNTIME_SERVICES_CODE / EFI_RUNTIME_SERVICES_DATA will also be
saved and restored.
Fix this by returning true only if the KPRANGE/XKPRANGE address is in
memblock.memory.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Add an API that will allow updates of the direct/linear map for a set of
physically contiguous pages.
It will be used in the following patches.
Link: https://lkml.kernel.org/r/20241023162711.2579610-6-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Tested-by: kdevops <kdevops@lists.linux.dev>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Song Liu <song@kernel.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add set_direct_map_*() functions for setting the direct map alias for
the page to its default permissions and to an invalid state that cannot
be cached in a TLB. (See d253ca0c3 ("x86/mm/cpa: Add set_direct_map_*()
functions")) Add a similar implementation for LoongArch.
This fixes the KFENCE warnings during hibernation:
==================================================================
BUG: KFENCE: invalid read in swsusp_save+0x368/0x4d8
Invalid read at 0x00000000f7b89a3c:
swsusp_save+0x368/0x4d8
hibernation_snapshot+0x3f0/0x4e0
hibernate+0x20c/0x440
state_store+0x128/0x140
kernfs_fop_write_iter+0x160/0x260
vfs_write+0x2c0/0x520
ksys_write+0x74/0x160
do_syscall+0xb0/0x160
CPU: 0 UID: 0 PID: 812 Comm: bash Tainted: G B 6.11.0-rc1+ #1566
Tainted: [B]=BAD_PAGE
Hardware name: Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0 10/21/2022
==================================================================
Note: We can only set permissions for KVRANGE/XKVRANGE kernel addresses.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Add set_memory_ro/rw/x/nx architecture hooks to change the page
attribution.
Use own set_memory.h rather than generic set_memory.h (i.e.
include/asm-generic/set_memory.h), because we want to add other function
prototypes here.
Note: We can only set attributes for KVRANGE/XKVRANGE kernel addresses.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
