Merge tag 'ffs-const-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull ffs const-attribute cleanups from Kees Cook:
 "While working on various hardening refactoring a while back we
  encountered inconsistencies in the application of __attribute_const__
  on the ffs() family of functions.

  This series fixes this across all archs and adds KUnit tests.

  Notably, this found a theoretical underflow in PCI (also fixed here)
  and uncovered an inefficiency in ARC (fixed in the ARC arch PR). I
  kept the series separate from the general hardening PR since it is a
  stand-alone "topic".

   - PCI: Fix theoretical underflow in use of ffs().

   - Universally apply __attribute_const__ to all architecture's
     ffs()-family of functions.

   - Add KUnit tests for ffs() behavior and const-ness"

* tag 'ffs-const-v6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  KUnit: ffs: Validate all the __attribute_const__ annotations
  sparc: Add __attribute_const__ to ffs()-family implementations
  xtensa: Add __attribute_const__ to ffs()-family implementations
  s390: Add __attribute_const__ to ffs()-family implementations
  parisc: Add __attribute_const__ to ffs()-family implementations
  mips: Add __attribute_const__ to ffs()-family implementations
  m68k: Add __attribute_const__ to ffs()-family implementations
  openrisc: Add __attribute_const__ to ffs()-family implementations
  riscv: Add __attribute_const__ to ffs()-family implementations
  hexagon: Add __attribute_const__ to ffs()-family implementations
  alpha: Add __attribute_const__ to ffs()-family implementations
  sh: Add __attribute_const__ to ffs()-family implementations
  powerpc: Add __attribute_const__ to ffs()-family implementations
  x86: Add __attribute_const__ to ffs()-family implementations
  csky: Add __attribute_const__ to ffs()-family implementations
  bitops: Add __attribute_const__ to generic ffs()-family implementations
  KUnit: Introduce ffs()-family tests
  PCI: Test for bit underflow in pcie_set_readrq()

1 files changed, 4 insertions, 4 deletions

diff --git a/lib/clz_ctz.c b/lib/clz_ctz.c
index fb8c0c5c2bd2..8778ec44bf63 100644
--- a/lib/clz_ctz.c
+++ b/lib/clz_ctz.c
@@ -15,28 +15,28 @@
 #include <linux/kernel.h>
 
 int __weak __ctzsi2(int val);
-int __weak __ctzsi2(int val)
+int __weak __attribute_const__ __ctzsi2(int val)
 {
 	return __ffs(val);
 }
 EXPORT_SYMBOL(__ctzsi2);
 
 int __weak __clzsi2(int val);
-int __weak __clzsi2(int val)
+int __weak __attribute_const__ __clzsi2(int val)
 {
 	return 32 - fls(val);
 }
 EXPORT_SYMBOL(__clzsi2);
 
 int __weak __clzdi2(u64 val);
-int __weak __clzdi2(u64 val)
+int __weak __attribute_const__ __clzdi2(u64 val)
 {
 	return 64 - fls64(val);
 }
 EXPORT_SYMBOL(__clzdi2);
 
 int __weak __ctzdi2(u64 val);
-int __weak __ctzdi2(u64 val)
+int __weak __attribute_const__ __ctzdi2(u64 val)
 {
 	return __ffs64(val);
 }