linux.git/arch/s390, branch vsnprintf

s390/mm: Consider KMSAN modules metadata for paging levels

2024-12-15T22:35:09+00:00

The calculation determining whether to use three- or four-level paging
didn't account for KMSAN modules metadata. Include this metadata in the
virtual memory size calculation to ensure correct paging mode selection
and avoiding potentially unnecessary physical memory size limitations.

Fixes: 65ca73f9fb36 ("s390/mm: define KMSAN metadata for vmalloc and modules")
Acked-by: Heiko Carstens 
Reviewed-by: Alexander Gordeev 
Reviewed-by: Ilya Leoshkevich 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Alexander Gordeev

s390/ipl: Fix never less than zero warning

2024-12-11T17:05:49+00:00

DEFINE_IPL_ATTR_STR_RW() macro produces "unsigned 'len' is never less
than zero." warning when sys_vmcmd_on_*_store() callbacks are defined.

Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202412081614.5uel8F6W-lkp@intel.com/
Fixes: 247576bf624a ("s390/ipl: Do not accept z/VM CP diag X'008' cmds longer than max length")
Reviewed-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev

s390/mm: Fix DirectMap accounting

2024-12-10T14:40:41+00:00

With uncoupling of physical and virtual address spaces population of
the identity mapping was changed to use the type POPULATE_IDENTITY
instead of POPULATE_DIRECT. This breaks DirectMap accounting:

> cat /proc/meminfo
DirectMap4k:       55296 kB
DirectMap1M:    18446744073709496320 kB

Adjust all locations of update_page_count() in vmem.c to use
POPULATE_IDENTITY instead of POPULATE_DIRECT as well. With this
accounting is correct again:

> cat /proc/meminfo
DirectMap4k:       54264 kB
DirectMap1M:     8334336 kB

Fixes: c98d2ecae08f ("s390/mm: Uncouple physical vs virtual address spaces")
Cc: stable@vger.kernel.org
Reviewed-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev

module: Convert symbol namespace to string literal

2024-12-02T19:34:44+00:00

Clean up the existing export namespace code along the same lines of
commit 33def8498fdd ("treewide: Convert macro and uses of __section(foo)
to __section("foo")") and for the same reason, it is not desired for the
namespace argument to be a macro expansion itself.

Scripted using

  git grep -l -e MODULE_IMPORT_NS -e EXPORT_SYMBOL_NS | while read file;
  do
    awk -i inplace '
      /^#define EXPORT_SYMBOL_NS/ {
        gsub(/__stringify\(ns\)/, "ns");
        print;
        next;
      }
      /^#define MODULE_IMPORT_NS/ {
        gsub(/__stringify\(ns\)/, "ns");
        print;
        next;
      }
      /MODULE_IMPORT_NS/ {
        $0 = gensub(/MODULE_IMPORT_NS\(([^)]*)\)/, "MODULE_IMPORT_NS(\"\\1\")", "g");
      }
      /EXPORT_SYMBOL_NS/ {
        if ($0 ~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+),/) {
  	if ($0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/ &&
  	    $0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(\)/ &&
  	    $0 !~ /^my/) {
  	  getline line;
  	  gsub(/[[:space:]]*\\$/, "");
  	  gsub(/[[:space:]]/, "", line);
  	  $0 = $0 " " line;
  	}

  	$0 = gensub(/(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/,
  		    "\\1(\\2, \"\\3\")", "g");
        }
      }
      { print }' $file;
  done

Requested-by: Masahiro Yamada 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://mail.google.com/mail/u/2/#inbox/FMfcgzQXKWgMmjdFwwdsfgxzKpVHWPlc
Acked-by: Greg KH 
Signed-off-by: Linus Torvalds

Merge tag 's390-6.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2024-11-29T18:40:52+00:00

Pull more s390 updates from Heiko Carstens:

 - Add swap entry for hugetlbfs support

 - Add PTE_MARKER support for hugetlbs mappings; this fixes a regression
   (possible page fault loop) which was introduced when support for
   UFFDIO_POISON for hugetlbfs was added

 - Add ARCH_HAS_PREEMPT_LAZY and PREEMPT_DYNAMIC support

 - Mark IRQ entries in entry code, so that stack tracers can filter out
   the non-IRQ parts of stack traces. This fixes stack depot capacity
   limit warnings, since without filtering the number of unique stack
   traces is huge

 - In PCI code fix leak of struct zpci_dev object, and fix potential
   double remove of hotplug slot

 - Fix pagefault_disable() / pagefault_enable() unbalance in
   arch_stack_user_walk_common()

 - A couple of inline assembly optimizations, more cmpxchg() to
   try_cmpxchg() conversions, and removal of usages of xchg() and
   cmpxchg() on one and two byte memory areas

 - Various other small improvements and cleanups

* tag 's390-6.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (27 commits)
  Revert "s390/mm: Allow large pages for KASAN shadow mapping"
  s390/spinlock: Use flag output constraint for arch_cmpxchg_niai8()
  s390/spinlock: Use R constraint for arch_load_niai4()
  s390/spinlock: Generate shorter code for arch_spin_unlock()
  s390/spinlock: Remove condition code clobber from arch_spin_unlock()
  s390/spinlock: Use symbolic names in inline assemblies
  s390: Support PREEMPT_DYNAMIC
  s390/pci: Fix potential double remove of hotplug slot
  s390/pci: Fix leak of struct zpci_dev when zpci_add_device() fails
  s390/mm/hugetlbfs: Add missing includes
  s390/mm: Add PTE_MARKER support for hugetlbfs mappings
  s390/mm: Introduce region-third and segment table swap entries
  s390/mm: Introduce region-third and segment table entry present bits
  s390/mm: Rearrange region-third and segment table entry SW bits
  KVM: s390: Increase size of union sca_utility to four bytes
  KVM: s390: Remove one byte cmpxchg() usage
  KVM: s390: Use try_cmpxchg() instead of cmpxchg() loops
  s390/ap: Replace xchg() with WRITE_ONCE()
  s390/mm: Allow large pages for KASAN shadow mapping
  s390: Add ARCH_HAS_PREEMPT_LAZY support
  ...

Revert "s390/mm: Allow large pages for KASAN shadow mapping"

2024-11-29T12:41:11+00:00

This reverts commit ff123eb7741638d55abf82fac090bb3a543c1e74.

Allowing large pages for KASAN shadow mappings isn't inherently wrong,
but adding POPULATE_KASAN_MAP_SHADOW to large_allowed() exposes an issue
in can_large_pud() and can_large_pmd().

Since commit d8073dc6bc04 ("s390/mm: Allow large pages only for aligned
physical addresses"), both can_large_pud() and can_large_pmd() call _pa()
to check if large page physical addresses are aligned. However, _pa()
has a side effect: it allocates memory in POPULATE_KASAN_MAP_SHADOW
mode. This results in massive memory leaks.

The proper fix would be to address both large_allowed() and _pa()'s side
effects, but for now, revert this change to avoid the leaks.

Fixes: ff123eb77416 ("s390/mm: Allow large pages for KASAN shadow mapping")
Signed-off-by: Vasily Gorbik 
Signed-off-by: Heiko Carstens

s390/spinlock: Use flag output constraint for arch_cmpxchg_niai8()

2024-11-28T13:14:34+00:00

Add a new variant of arch_cmpxchg_niai8() which makes use of the flag
output constraint, which allows the compiler to generate slightly better
code. Also rename arch_cmpxchg_niai8() to arch_try_cmpxchg_niai8() which
reflects the purpose of the function and makes it consistent with other
"try" variants.

Signed-off-by: Heiko Carstens

s390/spinlock: Use R constraint for arch_load_niai4()

2024-11-28T13:12:05+00:00

The load instruction used within arch_load_niai4() has a short displacement
and index register. Therefore use the R constraint to reflect this.
The used Q constraint does consider an index register.

Signed-off-by: Heiko Carstens

s390/spinlock: Generate shorter code for arch_spin_unlock()

2024-11-28T13:12:04+00:00

Use mvhhi instead of sth to write a zero to spinlocks. Compared to the
sth variant this avoids the load of zero to a register, and reduces
register pressure.

Signed-off-by: Heiko Carstens

s390/spinlock: Remove condition code clobber from arch_spin_unlock()

2024-11-28T13:12:04+00:00

Both instructions in arch_spin_unlock() do not clobber the condition
code. Therefore remove the condition code clobber from the inline assembly.

Signed-off-by: Heiko Carstens