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, 3 insertions, 3 deletions

diff --git a/arch/riscv/include/asm/bitops.h b/arch/riscv/include/asm/bitops.h
index d59310f74c2b..77880677b06e 100644
--- a/arch/riscv/include/asm/bitops.h
+++ b/arch/riscv/include/asm/bitops.h
@@ -45,7 +45,7 @@
 #error "Unexpected BITS_PER_LONG"
 #endif
 
-static __always_inline unsigned long variable__ffs(unsigned long word)
+static __always_inline __attribute_const__ unsigned long variable__ffs(unsigned long word)
 {
 	asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
 				      RISCV_ISA_EXT_ZBB, 1)
@@ -74,7 +74,7 @@ legacy:
 	 (unsigned long)__builtin_ctzl(word) :	\
 	 variable__ffs(word))
 
-static __always_inline unsigned long variable__fls(unsigned long word)
+static __always_inline __attribute_const__ unsigned long variable__fls(unsigned long word)
 {
 	asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
 				      RISCV_ISA_EXT_ZBB, 1)
@@ -103,7 +103,7 @@ legacy:
 	 (unsigned long)(BITS_PER_LONG - 1 - __builtin_clzl(word)) :	\
 	 variable__fls(word))
 
-static __always_inline int variable_ffs(int x)
+static __always_inline __attribute_const__ int variable_ffs(int x)
 {
 	asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
 				      RISCV_ISA_EXT_ZBB, 1)