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authorLinus Torvalds <torvalds@linux-foundation.org>2016-01-21 13:02:41 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-21 13:02:41 -0800
commit404a47410c26a115123885977053e9a1a4460929 (patch)
tree2056ef0fa74f6042606a10b8e7e4c191789b6584 /lib
parenteae21770b4fed5597623aad0d618190fa60426ff (diff)
parent9fd4470ff4974c41b1db43c3b355b9085af9c12a (diff)
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Merge branch 'uaccess' (batched user access infrastructure)
Expose an interface to allow users to mark several accesses together as being user space accesses, allowing batching of the surrounding user space access markers (SMAP on x86, PAN on arm64, domain register switching on arm). This is currently only used for the user string lenth and copying functions, where the SMAP overhead on x86 drowned the actual user accesses (only noticeable on newer microarchitectures that support SMAP in the first place, of course). * user access batching branch: Use the new batched user accesses in generic user string handling Add 'unsafe' user access functions for batched accesses x86: reorganize SMAP handling in user space accesses
Diffstat (limited to 'lib')
-rw-r--r--lib/strncpy_from_user.c11
-rw-r--r--lib/strnlen_user.c18
2 files changed, 22 insertions, 7 deletions
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index e0af6ff73d14..33840324138c 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -39,7 +39,7 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long
unsigned long c, data;
/* Fall back to byte-at-a-time if we get a page fault */
- if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
+ if (unlikely(unsafe_get_user(c,(unsigned long __user *)(src+res))))
break;
*(unsigned long *)(dst+res) = c;
if (has_zero(c, &data, &constants)) {
@@ -55,7 +55,7 @@ byte_at_a_time:
while (max) {
char c;
- if (unlikely(__get_user(c,src+res)))
+ if (unlikely(unsafe_get_user(c,src+res)))
return -EFAULT;
dst[res] = c;
if (!c)
@@ -107,7 +107,12 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
src_addr = (unsigned long)src;
if (likely(src_addr < max_addr)) {
unsigned long max = max_addr - src_addr;
- return do_strncpy_from_user(dst, src, count, max);
+ long retval;
+
+ user_access_begin();
+ retval = do_strncpy_from_user(dst, src, count, max);
+ user_access_end();
+ return retval;
}
return -EFAULT;
}
diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c
index 3a5f2b366d84..2625943625d7 100644
--- a/lib/strnlen_user.c
+++ b/lib/strnlen_user.c
@@ -45,7 +45,7 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
src -= align;
max += align;
- if (unlikely(__get_user(c,(unsigned long __user *)src)))
+ if (unlikely(unsafe_get_user(c,(unsigned long __user *)src)))
return 0;
c |= aligned_byte_mask(align);
@@ -61,7 +61,7 @@ static inline long do_strnlen_user(const char __user *src, unsigned long count,
if (unlikely(max <= sizeof(unsigned long)))
break;
max -= sizeof(unsigned long);
- if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
+ if (unlikely(unsafe_get_user(c,(unsigned long __user *)(src+res))))
return 0;
}
res -= align;
@@ -112,7 +112,12 @@ long strnlen_user(const char __user *str, long count)
src_addr = (unsigned long)str;
if (likely(src_addr < max_addr)) {
unsigned long max = max_addr - src_addr;
- return do_strnlen_user(str, count, max);
+ long retval;
+
+ user_access_begin();
+ retval = do_strnlen_user(str, count, max);
+ user_access_end();
+ return retval;
}
return 0;
}
@@ -141,7 +146,12 @@ long strlen_user(const char __user *str)
src_addr = (unsigned long)str;
if (likely(src_addr < max_addr)) {
unsigned long max = max_addr - src_addr;
- return do_strnlen_user(str, ~0ul, max);
+ long retval;
+
+ user_access_begin();
+ retval = do_strnlen_user(str, ~0ul, max);
+ user_access_end();
+ return retval;
}
return 0;
}