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authorLinus Torvalds <torvalds@linux-foundation.org>2015-10-07 08:52:42 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2015-10-07 08:52:42 (GMT)
commit79c7c7acd25689b1d7669bdb33fb3cb7c64541fe (patch)
treef8d5dc80466d2637c32f6be70c287986cca59273
parent3f5e4a311619533bfc742f2d8e04510334dd0dd5 (diff)
parent990486c8af044f89bddfbde1d1cf9fde449bedbf (diff)
downloadlinux-79c7c7acd25689b1d7669bdb33fb3cb7c64541fe.tar.xz
Merge branch 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile
Pull strscpy fixes from Chris Metcalf : "This patch series fixes up a couple of architecture issues where strscpy wasn't configured correctly (missing on h8300, duplicating local and asm-generic copies on powerpc and tile). It also adds a use of zero_bytemask() to the final store for strscpy to avoid writing uninitialized data to the destination. However, to make this work we had to add support for zero_bytemask() to the two architectures that didn't have it (alpha and tile), because they were providing their own local copies, but didn't provide the zero_bytemask() that was previously only required when building with CONFIG_DCACHE_WORD_ACCESS" [ Side note: there is still no actual users of strscpy except for the one preexisting use in arch/tile that predates the generic version. So this is all about fixing the infrastructure so that we eventually can start using it. - Linus ] * 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: strscpy: zero any trailing garbage bytes in the destination word-at-a-time.h: support zero_bytemask() on alpha and tile word-at-a-time.h: fix some Kbuild files
-rw-r--r--arch/alpha/include/asm/word-at-a-time.h2
-rw-r--r--arch/h8300/include/asm/Kbuild1
-rw-r--r--arch/powerpc/include/asm/Kbuild1
-rw-r--r--arch/tile/include/asm/Kbuild1
-rw-r--r--arch/tile/include/asm/word-at-a-time.h8
-rw-r--r--lib/string.c3
6 files changed, 12 insertions, 4 deletions
diff --git a/arch/alpha/include/asm/word-at-a-time.h b/arch/alpha/include/asm/word-at-a-time.h
index 6b340d0..902e6ab 100644
--- a/arch/alpha/include/asm/word-at-a-time.h
+++ b/arch/alpha/include/asm/word-at-a-time.h
@@ -52,4 +52,6 @@ static inline unsigned long find_zero(unsigned long bits)
#endif
}
+#define zero_bytemask(mask) ((2ul << (find_zero(mask) * 8)) - 1)
+
#endif /* _ASM_WORD_AT_A_TIME_H */
diff --git a/arch/h8300/include/asm/Kbuild b/arch/h8300/include/asm/Kbuild
index 70e6ae1..373cb23 100644
--- a/arch/h8300/include/asm/Kbuild
+++ b/arch/h8300/include/asm/Kbuild
@@ -73,4 +73,5 @@ generic-y += uaccess.h
generic-y += ucontext.h
generic-y += unaligned.h
generic-y += vga.h
+generic-y += word-at-a-time.h
generic-y += xor.h
diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild
index ac16629..ab9f4e0 100644
--- a/arch/powerpc/include/asm/Kbuild
+++ b/arch/powerpc/include/asm/Kbuild
@@ -7,4 +7,3 @@ generic-y += mcs_spinlock.h
generic-y += preempt.h
generic-y += rwsem.h
generic-y += vtime.h
-generic-y += word-at-a-time.h
diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild
index 0b6cacaa..ba35c41 100644
--- a/arch/tile/include/asm/Kbuild
+++ b/arch/tile/include/asm/Kbuild
@@ -40,5 +40,4 @@ generic-y += termbits.h
generic-y += termios.h
generic-y += trace_clock.h
generic-y += types.h
-generic-y += word-at-a-time.h
generic-y += xor.h
diff --git a/arch/tile/include/asm/word-at-a-time.h b/arch/tile/include/asm/word-at-a-time.h
index 9e5ce0d..b66a693 100644
--- a/arch/tile/include/asm/word-at-a-time.h
+++ b/arch/tile/include/asm/word-at-a-time.h
@@ -6,7 +6,7 @@
struct word_at_a_time { /* unused */ };
#define WORD_AT_A_TIME_CONSTANTS {}
-/* Generate 0x01 byte values for non-zero bytes using a SIMD instruction. */
+/* Generate 0x01 byte values for zero bytes using a SIMD instruction. */
static inline unsigned long has_zero(unsigned long val, unsigned long *data,
const struct word_at_a_time *c)
{
@@ -33,4 +33,10 @@ static inline long find_zero(unsigned long mask)
#endif
}
+#ifdef __BIG_ENDIAN
+#define zero_bytemask(mask) (~1ul << (63 - __builtin_clzl(mask)))
+#else
+#define zero_bytemask(mask) ((2ul << __builtin_ctzl(mask)) - 1)
+#endif
+
#endif /* _ASM_WORD_AT_A_TIME_H */
diff --git a/lib/string.c b/lib/string.c
index 8dbb7b1..84775ba 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -203,12 +203,13 @@ ssize_t strscpy(char *dest, const char *src, size_t count)
unsigned long c, data;
c = *(unsigned long *)(src+res);
- *(unsigned long *)(dest+res) = c;
if (has_zero(c, &data, &constants)) {
data = prep_zero_mask(c, data, &constants);
data = create_zero_mask(data);
+ *(unsigned long *)(dest+res) = c & zero_bytemask(data);
return res + find_zero(data);
}
+ *(unsigned long *)(dest+res) = c;
res += sizeof(unsigned long);
count -= sizeof(unsigned long);
max -= sizeof(unsigned long);