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 ca43f4d0b93751b3cb262889fb638cf9c07a7011..5adca78830b5e9a3349e5fb410188b0eb98e3bd3 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 8da87feec59aab58a1309fbd5f92fb12b72d8799..ee9246184033b3138f8d09878fc7763502b11e5c 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 f0ab012401b67c10d6717cab8aa52f6987ba0ba3..8b68234ace181bbacdbf9c709d86051fc09b11de 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 335f2883fb1ee85aef5e6e4800f763c975047743..43b9838bff63d153a1942c1d292f8bc81af70599 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 2691a1857d203db2522ae178fe744225c71d2da9..bee97426238705e78fca708d3d0d0c4b965cdb60 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 56a774bf13fa73fe3b9523f1d1f25bd3237f0243..2f24ee6459d20ff49e07ebdb1aa5c137c85e1953 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 d979f38af751cfeaa8a83cfc7389b15088ef3e21..10133a968c8e150b10d6cd0a9e778701bbaff882 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 f2a840fb6a9af6739a792359b3224f5b46d231f0..c4675957b21bca1e5be2cddd37f8af71a24eb6b9 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 9efbf9ad86c409bb8a6671e4a49ea50e2ec35bde..57de5a1115bfd99ea57a208e50057af2afe0b924 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 53252d4f9a570c7a7ee889bbba7cb167d9bef2f9..a09eaebfdfd07f8caff2dbc2b77fa315770f10e0 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 86e5b2fdee3c8ee1b6da3f290de5be4b4460734c..d1f8a4d94cca02269841b6b6e0928ac699089b6b 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 c0cbdbe1716809115431e0c999363e37f7156d65..de5853761c22ca0b6485f12a06c73f25bb320286 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 124f9195eb3ef5545f96fbb111ee4a111de5f0d0..ad7b210aa3f621c5902f4f077eab0932b4924593 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 62daf940989df977d94be029beafcca21a777338..c8455cc28841afe18cfa24f7c24280836bfc58b7 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 753aecaab641a82d7f218988fcebe0751f7149ff..b168bb10e1be17bb6394e749c238da3940ea3a01 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 753aecaab641a82d7f218988fcebe0751f7149ff..b168bb10e1be17bb6394e749c238da3940ea3a01 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;