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, 7 insertions, 7 deletions

diff --git a/arch/alpha/include/asm/bitops.h b/arch/alpha/include/asm/bitops.h
index 3e33621922c3..76e4343c090f 100644
--- a/arch/alpha/include/asm/bitops.h
+++ b/arch/alpha/include/asm/bitops.h
@@ -328,7 +328,7 @@ static inline unsigned long ffz_b(unsigned long x)
 	return sum;
 }
 
-static inline unsigned long ffz(unsigned long word)
+static inline unsigned long __attribute_const__ ffz(unsigned long word)
 {
 #if defined(CONFIG_ALPHA_EV6) && defined(CONFIG_ALPHA_EV67)
 	/* Whee.  EV67 can calculate it directly.  */
@@ -348,7 +348,7 @@ static inline unsigned long ffz(unsigned long word)
 /*
  * __ffs = Find First set bit in word.  Undefined if no set bit exists.
  */
-static inline unsigned long __ffs(unsigned long word)
+static inline __attribute_const__ unsigned long __ffs(unsigned long word)
 {
 #if defined(CONFIG_ALPHA_EV6) && defined(CONFIG_ALPHA_EV67)
 	/* Whee.  EV67 can calculate it directly.  */
@@ -373,7 +373,7 @@ static inline unsigned long __ffs(unsigned long word)
  * differs in spirit from the above __ffs.
  */
 
-static inline int ffs(int word)
+static inline __attribute_const__ int ffs(int word)
 {
 	int result = __ffs(word) + 1;
 	return word ? result : 0;
@@ -383,14 +383,14 @@ static inline int ffs(int word)
  * fls: find last bit set.
  */
 #if defined(CONFIG_ALPHA_EV6) && defined(CONFIG_ALPHA_EV67)
-static inline int fls64(unsigned long word)
+static inline __attribute_const__ int fls64(unsigned long word)
 {
 	return 64 - __kernel_ctlz(word);
 }
 #else
 extern const unsigned char __flsm1_tab[256];
 
-static inline int fls64(unsigned long x)
+static inline __attribute_const__ int fls64(unsigned long x)
 {
 	unsigned long t, a, r;
 
@@ -403,12 +403,12 @@ static inline int fls64(unsigned long x)
 }
 #endif
 
-static inline unsigned long __fls(unsigned long x)
+static inline __attribute_const__ unsigned long __fls(unsigned long x)
 {
 	return fls64(x) - 1;
 }
 
-static inline int fls(unsigned int x)
+static inline __attribute_const__ int fls(unsigned int x)
 {
 	return fls64(x);
 }