linux.git/arch/s390/kernel/module.c, branch v6.5

s390/module: fix rela calculation for R_390_GOTENT

2023-06-20T17:55:00+00:00

During  module load, module layout allocation occurs by initially
allowing the architecture to frob the sections. This is performed via
module_frob_arch_sections().

However, the size of each module memory types like text,data,rodata etc
are updated correctly only after layout_sections().

After calculation of required module memory sizes for each types,
move_module() is responsible for allocating the module memory for each
type from modules vaddr range.

Considering the sequence above, module_frob_arch_sections() updates the
module mod_arch_specific got_offset before module memory text type size
is fully updated in layout_sections().  Hence mod_arch_specific
got_offset points to currently zero.

As per s390 ABI,
R_390_GOTENT :  (G + O + A - P) >> 1
where
G=me->mem[MOD_TEXT].base+me->arch.got_offset
O=info->got_offset
A=rela->r_addend
P=loc

fix R_390_GOTENT calculation in apply_rela().

Note: currently this doesn't break anything because me->arch.got_offset
is zero.  However, reordering of functions in the future could break it.

Signed-off-by: Sumanth Korikkar 
Acked-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev

Merge tag 's390-6.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2023-04-30T18:43:31+00:00

Pull s390 updates from Vasily Gorbik:

 - Add support for stackleak feature. Also allow specifying
   architecture-specific stackleak poison function to enable faster
   implementation. On s390, the mvc-based implementation helps decrease
   typical overhead from a factor of 3 to just 25%

 - Convert all assembler files to use SYM* style macros, deprecating the
   ENTRY() macro and other annotations. Select ARCH_USE_SYM_ANNOTATIONS

 - Improve KASLR to also randomize module and special amode31 code base
   load addresses

 - Rework decompressor memory tracking to support memory holes and
   improve error handling

 - Add support for protected virtualization AP binding

 - Add support for set_direct_map() calls

 - Implement set_memory_rox() and noexec module_alloc()

 - Remove obsolete overriding of mem*() functions for KASAN

 - Rework kexec/kdump to avoid using nodat_stack to call purgatory

 - Convert the rest of the s390 code to use flexible-array member
   instead of a zero-length array

 - Clean up uaccess inline asm

 - Enable ARCH_HAS_MEMBARRIER_SYNC_CORE

 - Convert to using CONFIG_FUNCTION_ALIGNMENT and enable
   DEBUG_FORCE_FUNCTION_ALIGN_64B

 - Resolve last_break in userspace fault reports

 - Simplify one-level sysctl registration

 - Clean up branch prediction handling

 - Rework CPU counter facility to retrieve available counter sets just
   once

 - Other various small fixes and improvements all over the code

* tag 's390-6.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (118 commits)
  s390/stackleak: provide fast __stackleak_poison() implementation
  stackleak: allow to specify arch specific stackleak poison function
  s390: select ARCH_USE_SYM_ANNOTATIONS
  s390/mm: use VM_FLUSH_RESET_PERMS in module_alloc()
  s390: wire up memfd_secret system call
  s390/mm: enable ARCH_HAS_SET_DIRECT_MAP
  s390/mm: use BIT macro to generate SET_MEMORY bit masks
  s390/relocate_kernel: adjust indentation
  s390/relocate_kernel: use SYM* macros instead of ENTRY(), etc.
  s390/entry: use SYM* macros instead of ENTRY(), etc.
  s390/purgatory: use SYM* macros instead of ENTRY(), etc.
  s390/kprobes: use SYM* macros instead of ENTRY(), etc.
  s390/reipl: use SYM* macros instead of ENTRY(), etc.
  s390/head64: use SYM* macros instead of ENTRY(), etc.
  s390/earlypgm: use SYM* macros instead of ENTRY(), etc.
  s390/mcount: use SYM* macros instead of ENTRY(), etc.
  s390/crc32le: use SYM* macros instead of ENTRY(), etc.
  s390/crc32be: use SYM* macros instead of ENTRY(), etc.
  s390/crypto,chacha: use SYM* macros instead of ENTRY(), etc.
  s390/amode31: use SYM* macros instead of ENTRY(), etc.
  ...

s390/mm: use VM_FLUSH_RESET_PERMS in module_alloc()

2023-04-20T09:36:29+00:00

Make use of the set_direct_map() calls for module allocations.
In particular:

- All changes to read-only permissions in kernel VA mappings are also
  applied to the direct mapping. Note that execute permissions are
  intentionally not applied to the direct mapping in order to make
  sure that all allocated pages within the direct mapping stay
  non-executable

- module_alloc() passes the VM_FLUSH_RESET_PERMS to __vmalloc_node_range()
  to make sure that all implicit permission changes made to the direct
  mapping are reset when the allocated vm area is freed again

Side effects: the direct mapping will be fragmented depending on how many
vm areas with VM_FLUSH_RESET_PERMS and/or explicit page permission changes
are allocated and freed again.

For example, just after boot of a system the direct mapping statistics look
like:

$cat /proc/meminfo
...
DirectMap4k:      111628 kB
DirectMap1M:    16665600 kB
DirectMap2G:           0 kB

Acked-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/module: create module allocations without exec permissions

2023-04-13T15:36:26+00:00

This is the s390 variant of commit 7dfac3c5f40e ("arm64: module: create
module allocations without exec permissions"):

"The core code manages the executable permissions of code regions of
modules explicitly. It is no longer necessary to create the module vmalloc
regions with RWX permissions. So create them with RW- permissions instead,
which is preferred from a security perspective."

Reviewed-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/ftrace: do not assume module_alloc() returns executable memory

2023-04-13T15:36:26+00:00

The ftrace code assumes at two places that module_alloc() returns
executable memory. While this is currently true, this will be changed
with a subsequent patch to follow other architectures which implement
ARCH_HAS_STRICT_MODULE_RWX.

Acked-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/kaslr: randomize module base load address

2023-04-13T15:36:26+00:00

Randomize the load address of modules in the kernel to make KASLR effective
for modules.
This is the s390 variant of commit e2b32e678513 ("x86, kaslr: randomize
module base load address").

Reviewed-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

module: replace module_layout with module_memory

2023-03-09T20:55:15+00:00

module_layout manages different types of memory (text, data, rodata, etc.)
in one allocation, which is problematic for some reasons:

1. It is hard to enable CONFIG_STRICT_MODULE_RWX.
2. It is hard to use huge pages in modules (and not break strict rwx).
3. Many archs uses module_layout for arch-specific data, but it is not
   obvious how these data are used (are they RO, RX, or RW?)

Improve the scenario by replacing 2 (or 3) module_layout per module with
up to 7 module_memory per module:

        MOD_TEXT,
        MOD_DATA,
        MOD_RODATA,
        MOD_RO_AFTER_INIT,
        MOD_INIT_TEXT,
        MOD_INIT_DATA,
        MOD_INIT_RODATA,

and allocating them separately. This adds slightly more entries to
mod_tree (from up to 3 entries per module, to up to 7 entries per
module). However, this at most adds a small constant overhead to
__module_address(), which is expected to be fast.

Various archs use module_layout for different data. These data are put
into different module_memory based on their location in module_layout.
IOW, data that used to go with text is allocated with MOD_MEM_TYPE_TEXT;
data that used to go with data is allocated with MOD_MEM_TYPE_DATA, etc.

module_memory simplifies quite some of the module code. For example,
ARCH_WANTS_MODULES_DATA_IN_VMALLOC is a lot cleaner, as it just uses a
different allocator for the data. kernel/module/strict_rwx.c is also
much cleaner with module_memory.

Signed-off-by: Song Liu 
Cc: Luis Chamberlain 
Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Guenter Roeck 
Cc: Christophe Leroy 
Reviewed-by: Thomas Gleixner 
Reviewed-by: Christophe Leroy 
Reviewed-by: Luis Chamberlain 
Signed-off-by: Luis Chamberlain

jump_label: mips: move module NOP patching into arch code

2022-06-24T07:48:55+00:00

MIPS is the only remaining architecture that needs to patch jump label
NOP encodings to initialize them at load time. So let's move the module
patching part of that from generic code into arch/mips, and drop it from
the others.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20220615154142.1574619-3-ardb@kernel.org

Merge branch 'akpm' (patches from Andrew)

2022-03-25T17:21:20+00:00

Merge yet more updates from Andrew Morton:
 "This is the material which was staged after willystuff in linux-next.

  Subsystems affected by this patch series: mm (debug, selftests,
  pagecache, thp, rmap, migration, kasan, hugetlb, pagemap, madvise),
  and selftests"

* emailed patches from Andrew Morton : (113 commits)
  selftests: kselftest framework: provide "finished" helper
  mm: madvise: MADV_DONTNEED_LOCKED
  mm: fix race between MADV_FREE reclaim and blkdev direct IO read
  mm: generalize ARCH_HAS_FILTER_PGPROT
  mm: unmap_mapping_range_tree() with i_mmap_rwsem shared
  mm: warn on deleting redirtied only if accounted
  mm/huge_memory: remove stale locking logic from __split_huge_pmd()
  mm/huge_memory: remove stale page_trans_huge_mapcount()
  mm/swapfile: remove stale reuse_swap_page()
  mm/khugepaged: remove reuse_swap_page() usage
  mm/huge_memory: streamline COW logic in do_huge_pmd_wp_page()
  mm: streamline COW logic in do_swap_page()
  mm: slightly clarify KSM logic in do_swap_page()
  mm: optimize do_wp_page() for fresh pages in local LRU pagevecs
  mm: optimize do_wp_page() for exclusive pages in the swapcache
  mm/huge_memory: make is_transparent_hugepage() static
  userfaultfd/selftests: enable hugetlb remap and remove event testing
  selftests/vm: add hugetlb madvise MADV_DONTNEED MADV_REMOVE test
  mm: enable MADV_DONTNEED for hugetlb mappings
  kasan: disable LOCKDEP when printing reports
  ...

kasan, x86, arm64, s390: rename functions for modules shadow

2022-03-25T02:06:47+00:00

Rename kasan_free_shadow to kasan_free_module_shadow and
kasan_module_alloc to kasan_alloc_module_shadow.

These functions are used to allocate/free shadow memory for kernel modules
when KASAN_VMALLOC is not enabled.  The new names better reflect their
purpose.

Also reword the comment next to their declaration to improve clarity.

Link: https://lkml.kernel.org/r/36db32bde765d5d0b856f77d2d806e838513fe84.1643047180.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Acked-by: Catalin Marinas 
Acked-by: Marco Elver 
Cc: Alexander Potapenko 
Cc: Andrey Ryabinin 
Cc: Dmitry Vyukov 
Cc: Evgenii Stepanov 
Cc: Mark Rutland 
Cc: Peter Collingbourne 
Cc: Vincenzo Frascino 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds