- 09 Jun, 2020 40 commits
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Christoph Hellwig authored
Allow the callers to distinguish a real unmapped address vs a range that can't be probed. Suggested-by:
Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Reviewed-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Christoph Hellwig authored
Provide arch_kernel_read and arch_kernel_write routines to implement the maccess routines without messing with set_fs and without stac/clac that opens up access to user space. [akpm@linux-foundation.org: coding style fixes] Signed-off-by:
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Christoph Hellwig authored
Provide alternative versions of probe_kernel_read, probe_kernel_write and strncpy_from_kernel_unsafe that don't need set_fs magic, but instead use arch hooks that are modelled after unsafe_{get,put}_user to access kernel memory in an exception safe way. Signed-off-by: -
Christoph Hellwig authored
Move kernel access vs user access routines together to ease upcoming ifdefs. Signed-off-by:
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Christoph Hellwig authored
Except for historical confusion in the kprobes/uprobes and bpf tracers, which has been fixed now, there is no good reason to ever allow user memory accesses from probe_kernel_read. Switch probe_kernel_read to only read from kernel memory. [akpm@linux-foundation.org: update it for "mm, dump_page(): do not crash with invalid mapping pointer"] Signed-off-by:
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Christoph Hellwig authored
All users are gone now. Signed-off-by:
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Christoph Hellwig authored
Instead of using the dangerous probe_kernel_read and strncpy_from_unsafe helpers, rework probes to try a user probe based on the address if the architecture has a common address space for kernel and userspace. [svens@linux.ibm.com:use strncpy_from_kernel_nofault() in fetch_store_string()] Link: http://lkml.kernel.org/r/20200606181903.49384-1-svens@linux.ibm.comSigned-off-by:
Sven Schnelle <svens@linux.ibm.com> Signed-off-by:
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Christoph Hellwig authored
Instead of using the dangerous probe_kernel_read and strncpy_from_unsafe helpers, rework the compat probes to check if an address is a kernel or userspace one, and then use the low-level kernel or user probe helper shared by the proper kernel and user probe helpers. This slightly changes behavior as the compat probe on a user address doesn't check the lockdown flags, just as the pure user probes do. Signed-off-by:
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Andrew Morton authored
User the proper helper for kernel or userspace addresses based on TASK_SIZE instead of the dangerous strncpy_from_unsafe function. Signed-off-by:
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Christoph Hellwig authored
User the proper helper for kernel or userspace addresses based on TASK_SIZE instead of the dangerous strncpy_from_unsafe function. Signed-off-by:
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Christoph Hellwig authored
Split out a helper to do the fault free access to the string pointer to get it out of a crazy indentation level. Signed-off-by:
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Christoph Hellwig authored
Currently architectures have to override every routine that probes kernel memory, which includes a pure read and strcpy, both in strict and not strict variants. Just provide a single arch hooks instead to make sure all architectures cover all the cases. [akpm@linux-foundation.org: fix !CONFIG_X86_64 build] Signed-off-by:
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Christoph Hellwig authored
Each of the helpers has just two callers, which also different in dealing with kernel or userspace pointers. Just open code the logic in the callers. Signed-off-by:
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Christoph Hellwig authored
This matches the naming of strnlen_user, and also makes it more clear what the function is supposed to do. Signed-off-by:
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Christoph Hellwig authored
This matches the naming of strncpy_from_user_nofault, and also makes it more clear what the function is supposed to do. Signed-off-by:
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Christoph Hellwig authored
This matches the naming of strncpy_from_user, and also makes it more clear what the function is supposed to do. Signed-off-by:
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Christoph Hellwig authored
This file now also contains several helpers for accessing user memory. Signed-off-by:
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Christoph Hellwig authored
Add proper kerneldoc comments for probe_kernel_read_strict and probe_kernel_read strncpy_from_unsafe_strict and explain the different versus the non-strict version. Signed-off-by:
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Christoph Hellwig authored
Many of the maccess routines have a copy of the kerneldoc comment in the header. Remove it as it is not useful and will get out of sync sooner or later. Signed-off-by:
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Christoph Hellwig authored
maccess tends to define lots of underscore prefixed symbols that then have other weak aliases. But except for two cases they are never actually used, so remove them. Signed-off-by:
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Christoph Hellwig authored
Patch series "clean up and streamline probe_kernel_* and friends", v4. This series start cleaning up the safe kernel and user memory probing helpers in mm/maccess.c, and then allows architectures to implement the kernel probing without overriding the address space limit and temporarily allowing access to user memory. It then switches x86 over to this new mechanism by reusing the unsafe_* uaccess logic. This version also switches to the saner copy_{from,to}_kernel_nofault naming suggested by Linus. I kept the x86 helpers as-is without calling unsage_{get,put}_user as that avoids a number of hard to trace casts, and it will still work with the asm-goto based version easily. This patch (of 20): probe_kernel_write() is not used by any modular code. [sfr@canb.auug.org.au: turns out that probe_user_write is used in modular code] Link: http://lkml.kernel.org/r/20200602195741.4faaa348@canb.auug.org.auSigned-off-by:Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by:
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Michel Lespinasse authored
Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by:
Michel Lespinasse <walken@google.com> Signed-off-by:
Vlastimil Babka <vbabka@suse.cz> Reviewed-by:
Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.comSigned-off-by:
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Michel Lespinasse authored
Convert comments that reference old mmap_sem APIs to reference corresponding new mmap locking APIs instead. Signed-off-by:
Davidlohr Bueso <dbueso@suse.de> Reviewed-by:
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Michel Lespinasse authored
Rename the mmap_sem field to mmap_lock. Any new uses of this lock should now go through the new mmap locking api. The mmap_lock is still implemented as a rwsem, though this could change in the future. [akpm@linux-foundation.org: fix it for mm-gup-might_lock_readmmap_sem-in-get_user_pages_fast.patch] Signed-off-by:
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Michel Lespinasse authored
Add new APIs to assert that mmap_sem is held. Using this instead of rwsem_is_locked and lockdep_assert_held[_write] makes the assertions more tolerant of future changes to the lock type. Signed-off-by:
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Michel Lespinasse authored
Define a new initializer for the mmap locking api. Initially this just evaluates to __RWSEM_INITIALIZER as the API is defined as wrappers around rwsem. Signed-off-by:
Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by:
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Michel Lespinasse authored
Add a couple APIs used by kernel/bpf/stackmap.c only: - mmap_read_trylock_non_owner() - mmap_read_unlock_non_owner() (may be called from a work queue). It's still not ideal that bpf/stackmap subverts the lock ownership in this way. Thanks to Peter Zijlstra for suggesting this API as the least-ugly way of addressing this in the short term. Signed-off-by:
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Michel Lespinasse authored
Add API for nested write locks and convert the few call sites doing that. Signed-off-by:
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Michel Lespinasse authored
Convert the last few remaining mmap_sem rwsem calls to use the new mmap locking API. These were missed by coccinelle for some reason (I think coccinelle does not support some of the preprocessor constructs in these files ?) [akpm@linux-foundation.org: convert linux-next leftovers] [akpm@linux-foundation.org: more linux-next leftovers] [akpm@linux-foundation.org: more linux-next leftovers] Signed-off-by:
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Michel Lespinasse authored
This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by:
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Michel Lespinasse authored
This use is converted manually ahead of the next patch in the series, as it requires including a new header which the automated conversion would miss. Signed-off-by:
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Michel Lespinasse authored
This use is converted manually ahead of the next patch in the series, as it requires including a new header which the automated conversion would miss. Signed-off-by:
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Michel Lespinasse authored
This patch series adds a new mmap locking API replacing the existing mmap_sem lock and unlocks. Initially the API is just implemente in terms of inlined rwsem calls, so it doesn't provide any new functionality. There are two justifications for the new API: - At first, it provides an easy hooking point to instrument mmap_sem locking latencies independently of any other rwsems. - In the future, it may be a starting point for replacing the rwsem implementation with a different one, such as range locks. This is something that is being explored, even though there is no wide concensus about this possible direction yet. (see https://patchwork.kernel.org/cover/11401483/) This patch (of 12): This change wraps the existing mmap_sem related rwsem calls into a new mmap locking API. There are two justifications for the new API: - At first, it provides an easy hooking point to instrument mmap_sem locking latencies independently of any other rwsems. - In the future, it may be a starting point for replacing the rwsem implementation with a different one, such as range locks. Signed-off-by:
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Mike Rapoport authored
All architectures define pte_index() as (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1) and all architectures define pte_offset_kernel() as an entry in the array of PTEs indexed by the pte_index(). For the most architectures the pte_offset_kernel() implementation relies on the availability of pmd_page_vaddr() that converts a PMD entry value to the virtual address of the page containing PTEs array. Let's move x86 definitions of the PTE accessors to the generic place in <linux/pgtable.h> and then simply drop the respective definitions from the other architectures. The architectures that didn't provide pmd_page_vaddr() are updated to have that defined. The generic implementation of pte_offset_kernel() can be overridden by an architecture and alpha makes use of this because it has special ordering requirements for its version of pte_offset_kernel(). [rppt@linux.ibm.com: v2] Link: http://lkml.kernel.org/r/20200514170327.31389-11-rppt@kernel.org [rppt@linux.ibm.com: update] Link: http://lkml.kernel.org/r/20200514170327.31389-12-rppt@kernel.org [rppt@linux.ibm.com: update] Link: http://lkml.kernel.org/r/20200514170327.31389-13-rppt@kernel.org [akpm@linux-foundation.org: fix x86 warning] [sfr@canb.auug.org.au: fix powerpc build] Link: http://lkml.kernel.org/r/20200607153443.GB738695@linux.ibm.comSigned-off-by:
Mike Rapoport <rppt@linux.ibm.com> Signed-off-by:
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Mike Rapoport authored
The powerpc 32-bit implementation of pgtable has nice shortcuts for accessing kernel PMD and PTE for a given virtual address. Make these helpers available for all architectures. [rppt@linux.ibm.com: microblaze: fix page table traversal in setup_rt_frame()] Link: http://lkml.kernel.org/r/20200518191511.GD1118872@kernel.org [akpm@linux-foundation.org: s/pmd_ptr_k/pmd_off_k/ in various powerpc places] Signed-off-by:
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Mike Rapoport authored
There are three cases for the trampoline initialization: * 32-bit does nothing * 64-bit with kaslr disabled simply copies a PGD entry from the direct map to the trampoline PGD * 64-bit with kaslr enabled maps the real mode trampoline at PUD level These cases are currently differentiated by a bunch of ifdefs inside asm/include/pgtable.h and the case of 64-bits with kaslr on uses pgd_index() helper. Replacing the ifdefs with a static function in arch/x86/mm/init.c gives clearer code and allows moving pgd_index() to the generic implementation in include/linux/pgtable.h [rppt@linux.ibm.com: take CONFIG_RANDOMIZE_MEMORY into account in kaslr_enabled()] Link: http://lkml.kernel.org/r/20200525104045.GB13212@linux.ibm.comSigned-off-by:
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Mike Rapoport authored
The cache_page() and nocache_page() functions are only used by the motorola MMU variant for setting caching attributes for the page table pages. Move the definitions of these functions from arch/m68k/include/asm/motorola_pgtable.h closer to their usage in arch/m68k/mm/motorola.c and drop unused definition in arch/m68k/include/asm/mcf_pgtable.h. Signed-off-by:
Greg Ungerer <gerg@linux-m68k.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.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: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-7-rppt@kernel.orgSigned-off-by:
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Mike Rapoport authored
The comment about page table allocation functions resides in include/asm/motorola_pgtable.h while the functions live in include/asm/motorola_pgaloc.h. Move the comment close to the code. Signed-off-by:
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Mike Rapoport authored
All architectures use pXd_index() to get an entry in the page table page corresponding to a virtual address. Align csky with other architectures. Signed-off-by:
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Mike Rapoport authored
The replacement of <asm/pgrable.h> with <linux/pgtable.h> made the include of the latter in the middle of asm includes. Fix this up with the aid of the below script and manual adjustments here and there. import sys import re if len(sys.argv) is not 3: print "USAGE: %s <file> <header>" % (sys.argv[0]) sys.exit(1) hdr_to_move="#include <linux/%s>" % sys.argv[2] moved = False in_hdrs = False with open(sys.argv[1], "r") as f: lines = f.readlines() for _line in lines: line = _line.rstrip(' ') if line == hdr_to_move: continue if line.startswith("#include <linux/"): in_hdrs = True elif not moved and in_hdrs: moved = True print hdr_to_move print line Signed-off-by:
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