fls: change parameter to unsigned int

When testing in userspace, UBSAN pointed out that shifting into the sign
bit is undefined behaviour.  It doesn't really make sense to ask for the
highest set bit of a negative value, so just turn the argument type into
an unsigned int.

Some architectures (eg ppc) already had it declared as an unsigned int,
so I don't expect too many problems.

Link: http://lkml.kernel.org/r/20181105221117.31828-1-willy@infradead.org
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/alpha/include/asm/bitops.h b/arch/alpha/include/asm/bitops.h
index ca43f4d..5adca78 100644 (file)
--- a/arch/alpha/include/asm/bitops.h
+++ b/arch/alpha/include/asm/bitops.h
@@ -391,9 +391,9 @@ static inline unsigned long __fls(unsigned long x)
        return fls64(x) - 1;
 }
 
-static inline int fls(int x)
+static inline int fls(unsigned int x)
 {
-       return fls64((unsigned int) x);
+       return fls64(x);
 }
 
 /*

diff --git a/arch/arc/include/asm/bitops.h b/arch/arc/include/asm/bitops.h
index 8da87fe..ee92461 100644 (file)
--- a/arch/arc/include/asm/bitops.h
+++ b/arch/arc/include/asm/bitops.h
@@ -278,7 +278,7 @@ static inline __attribute__ ((const)) int clz(unsigned int x)
        return res;
 }
 
-static inline int constant_fls(int x)
+static inline int constant_fls(unsigned int x)
 {
        int r = 32;
 
@@ -312,7 +312,7 @@ static inline int constant_fls(int x)
  * @result: [1-32]
  * fls(1) = 1, fls(0x80000000) = 32, fls(0) = 0
  */
-static inline __attribute__ ((const)) int fls(unsigned long x)
+static inline __attribute__ ((const)) int fls(unsigned int x)
 {
        if (__builtin_constant_p(x))
               return constant_fls(x);

diff --git a/arch/c6x/include/asm/bitops.h b/arch/c6x/include/asm/bitops.h
index f0ab012..8b68234 100644 (file)
--- a/arch/c6x/include/asm/bitops.h
+++ b/arch/c6x/include/asm/bitops.h
@@ -54,7 +54,7 @@ static inline unsigned long __ffs(unsigned long x)
  * This is defined the same way as ffs.
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
-static inline int fls(int x)
+static inline int fls(unsigned int x)
 {
        if (!x)
                return 0;

diff --git a/arch/csky/include/asm/bitops.h b/arch/csky/include/asm/bitops.h
index 335f288..43b9838 100644 (file)
--- a/arch/csky/include/asm/bitops.h
+++ b/arch/csky/include/asm/bitops.h
@@ -40,7 +40,7 @@ static __always_inline unsigned long __ffs(unsigned long x)
 /*
  * asm-generic/bitops/fls.h
  */
-static __always_inline int fls(int x)
+static __always_inline int fls(unsigned int x)
 {
        asm volatile(
                "ff1 %0\n"

diff --git a/arch/hexagon/include/asm/bitops.h b/arch/hexagon/include/asm/bitops.h
index 2691a18..bee9742 100644 (file)
--- a/arch/hexagon/include/asm/bitops.h
+++ b/arch/hexagon/include/asm/bitops.h
@@ -211,7 +211,7 @@ static inline long ffz(int x)
  * This is defined the same way as ffs.
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
-static inline int fls(int x)
+static inline int fls(unsigned int x)
 {
        int r;
 

diff --git a/arch/ia64/include/asm/bitops.h b/arch/ia64/include/asm/bitops.h
index 56a774b..2f24ee6 100644 (file)
--- a/arch/ia64/include/asm/bitops.h
+++ b/arch/ia64/include/asm/bitops.h
@@ -388,8 +388,7 @@ ia64_fls (unsigned long x)
  * Find the last (most significant) bit set.  Returns 0 for x==0 and
  * bits are numbered from 1..32 (e.g., fls(9) == 4).
  */
-static inline int
-fls (int t)
+static inline int fls(unsigned int t)
 {
        unsigned long x = t & 0xffffffffu;
 

diff --git a/arch/m68k/include/asm/bitops.h b/arch/m68k/include/asm/bitops.h
index d979f38..10133a9 100644 (file)
--- a/arch/m68k/include/asm/bitops.h
+++ b/arch/m68k/include/asm/bitops.h
@@ -502,7 +502,7 @@ static inline unsigned long __ffs(unsigned long x)
 /*
  *     fls: find last bit set.
  */
-static inline int fls(int x)
+static inline int fls(unsigned int x)
 {
        int cnt;
 

diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h
index f2a840f..c467595 100644 (file)
--- a/arch/mips/include/asm/bitops.h
+++ b/arch/mips/include/asm/bitops.h
@@ -555,7 +555,7 @@ static inline unsigned long __ffs(unsigned long word)
  * This is defined the same way as ffs.
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
-static inline int fls(int x)
+static inline int fls(unsigned int x)
 {
        int r;
 

diff --git a/arch/openrisc/include/asm/bitops/fls.h b/arch/openrisc/include/asm/bitops/fls.h
index 9efbf9a..57de5a1 100644 (file)
--- a/arch/openrisc/include/asm/bitops/fls.h
+++ b/arch/openrisc/include/asm/bitops/fls.h
@@ -15,7 +15,7 @@
 
 #ifdef CONFIG_OPENRISC_HAVE_INST_FL1
 
-static inline int fls(int x)
+static inline int fls(unsigned int x)
 {
        int ret;
 

diff --git a/arch/parisc/include/asm/bitops.h b/arch/parisc/include/asm/bitops.h
index 53252d4..a09eaeb 100644 (file)
--- a/arch/parisc/include/asm/bitops.h
+++ b/arch/parisc/include/asm/bitops.h
@@ -188,7 +188,7 @@ static __inline__ int ffs(int x)
  * fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
 
-static __inline__ int fls(int x)
+static __inline__ int fls(unsigned int x)
 {
        int ret;
        if (!x)

diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h
index 86e5b2f..d1f8a4d 100644 (file)
--- a/arch/s390/include/asm/bitops.h
+++ b/arch/s390/include/asm/bitops.h
@@ -397,9 +397,9 @@ static inline int fls64(unsigned long word)
  * This is defined the same way as ffs.
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
-static inline int fls(int word)
+static inline int fls(unsigned int word)
 {
-       return fls64((unsigned int)word);
+       return fls64(word);
 }
 
 #else /* CONFIG_HAVE_MARCH_Z9_109_FEATURES */

diff --git a/arch/unicore32/include/asm/bitops.h b/arch/unicore32/include/asm/bitops.h
index c0cbdbe..de58537 100644 (file)
--- a/arch/unicore32/include/asm/bitops.h
+++ b/arch/unicore32/include/asm/bitops.h
@@ -22,7 +22,7 @@
  * the cntlz instruction for much better code efficiency.
  */
 
-static inline int fls(int x)
+static inline int fls(unsigned int x)
 {
        int ret;
 

diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 124f919..ad7b210 100644 (file)
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -448,7 +448,7 @@ static __always_inline int ffs(int x)
  * set bit if value is nonzero. The last (most significant) bit is
  * at position 32.
  */
-static __always_inline int fls(int x)
+static __always_inline int fls(unsigned int x)
 {
        int r;
 

diff --git a/include/asm-generic/bitops/builtin-fls.h b/include/asm-generic/bitops/builtin-fls.h
index 62daf94..c8455cc 100644 (file)
--- a/include/asm-generic/bitops/builtin-fls.h
+++ b/include/asm-generic/bitops/builtin-fls.h
@@ -9,7 +9,7 @@
  * This is defined the same way as ffs.
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
-static __always_inline int fls(int x)
+static __always_inline int fls(unsigned int x)
 {
        return x ? sizeof(x) * 8 - __builtin_clz(x) : 0;
 }

diff --git a/include/asm-generic/bitops/fls.h b/include/asm-generic/bitops/fls.h
index 753aeca..b168bb1 100644 (file)
--- a/include/asm-generic/bitops/fls.h
+++ b/include/asm-generic/bitops/fls.h
@@ -10,7 +10,7 @@
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
 
-static __always_inline int fls(int x)
+static __always_inline int fls(unsigned int x)
 {
        int r = 32;
 

diff --git a/tools/include/asm-generic/bitops/fls.h b/tools/include/asm-generic/bitops/fls.h
index 753aeca..b168bb1 100644 (file)
--- a/tools/include/asm-generic/bitops/fls.h
+++ b/tools/include/asm-generic/bitops/fls.h
@@ -10,7 +10,7 @@
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
 
-static __always_inline int fls(int x)
+static __always_inline int fls(unsigned int x)
 {
        int r = 32;