[PATCH 3/4] locking/atomic: Annotate generic atomics with wrapping

From: Kees Cook
Date: Wed Apr 24 2024 - 15:20:11 EST

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Because atomics depend on signed wrap-around, we need to use helpers to
perform the operations so that it is not instrumented by the signed
wrap-around sanitizer.

Refresh generated files by running scripts/atomic/gen-atomics.sh.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
---
include/asm-generic/atomic.h | 6 +++---
include/asm-generic/atomic64.h | 6 +++---
include/linux/atomic/atomic-arch-fallback.h | 19 ++++++++++---------
include/linux/atomic/atomic-instrumented.h | 3 ++-
include/linux/atomic/atomic-long.h | 3 ++-
lib/atomic64.c | 10 +++++-----
scripts/atomic/fallbacks/dec_if_positive | 2 +-
scripts/atomic/fallbacks/dec_unless_positive | 2 +-
scripts/atomic/fallbacks/fetch_add_unless | 2 +-
scripts/atomic/fallbacks/inc_unless_negative | 2 +-
scripts/atomic/gen-atomic-fallback.sh | 1 +
scripts/atomic/gen-atomic-instrumented.sh | 1 +
scripts/atomic/gen-atomic-long.sh | 1 +
13 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h
index 22142c71d35a..1b54e9b1cd02 100644
--- a/include/asm-generic/atomic.h
+++ b/include/asm-generic/atomic.h
@@ -55,7 +55,7 @@ static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \
#include <linux/irqflags.h>

#define ATOMIC_OP(op, c_op) \
-static inline void generic_atomic_##op(int i, atomic_t *v) \
+static inline void __signed_wrap generic_atomic_##op(int i, atomic_t *v)\
{ \
unsigned long flags; \
\
@@ -65,7 +65,7 @@ static inline void generic_atomic_##op(int i, atomic_t *v) \
}

#define ATOMIC_OP_RETURN(op, c_op) \
-static inline int generic_atomic_##op##_return(int i, atomic_t *v) \
+static inline int __signed_wrap generic_atomic_##op##_return(int i, atomic_t *v)\
{ \
unsigned long flags; \
int ret; \
@@ -78,7 +78,7 @@ static inline int generic_atomic_##op##_return(int i, atomic_t *v) \
}

#define ATOMIC_FETCH_OP(op, c_op) \
-static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \
+static inline int __signed_wrap generic_atomic_fetch_##op(int i, atomic_t *v)\
{ \
unsigned long flags; \
int ret; \
diff --git a/include/asm-generic/atomic64.h b/include/asm-generic/atomic64.h
index 100d24b02e52..0084867fe399 100644
--- a/include/asm-generic/atomic64.h
+++ b/include/asm-generic/atomic64.h
@@ -19,13 +19,13 @@ extern s64 generic_atomic64_read(const atomic64_t *v);
extern void generic_atomic64_set(atomic64_t *v, s64 i);

#define ATOMIC64_OP(op) \
-extern void generic_atomic64_##op(s64 a, atomic64_t *v);
+extern void __signed_wrap generic_atomic64_##op(s64 a, atomic64_t *v);

#define ATOMIC64_OP_RETURN(op) \
-extern s64 generic_atomic64_##op##_return(s64 a, atomic64_t *v);
+extern s64 __signed_wrap generic_atomic64_##op##_return(s64 a, atomic64_t *v);

#define ATOMIC64_FETCH_OP(op) \
-extern s64 generic_atomic64_fetch_##op(s64 a, atomic64_t *v);
+extern s64 __signed_wrap generic_atomic64_fetch_##op(s64 a, atomic64_t *v);

#define ATOMIC64_OPS(op) ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) ATOMIC64_FETCH_OP(op)

diff --git a/include/linux/atomic/atomic-arch-fallback.h b/include/linux/atomic/atomic-arch-fallback.h
index 956bcba5dbf2..2d2ebb4e0f8f 100644
--- a/include/linux/atomic/atomic-arch-fallback.h
+++ b/include/linux/atomic/atomic-arch-fallback.h
@@ -7,6 +7,7 @@
#define _LINUX_ATOMIC_FALLBACK_H

#include <linux/compiler.h>
+#include <linux/overflow.h>

#if defined(arch_xchg)
#define raw_xchg arch_xchg
@@ -2428,7 +2429,7 @@ raw_atomic_fetch_add_unless(atomic_t *v, int a, int u)
do {
if (unlikely(c == u))
break;
- } while (!raw_atomic_try_cmpxchg(v, &c, c + a));
+ } while (!raw_atomic_try_cmpxchg(v, &c, wrapping_add(int, c, a)));

return c;
#endif
@@ -2500,7 +2501,7 @@ raw_atomic_inc_unless_negative(atomic_t *v)
do {
if (unlikely(c < 0))
return false;
- } while (!raw_atomic_try_cmpxchg(v, &c, c + 1));
+ } while (!raw_atomic_try_cmpxchg(v, &c, wrapping_add(int, c, 1)));

return true;
#endif
@@ -2528,7 +2529,7 @@ raw_atomic_dec_unless_positive(atomic_t *v)
do {
if (unlikely(c > 0))
return false;
- } while (!raw_atomic_try_cmpxchg(v, &c, c - 1));
+ } while (!raw_atomic_try_cmpxchg(v, &c, wrapping_sub(int, c, 1)));

return true;
#endif
@@ -2554,7 +2555,7 @@ raw_atomic_dec_if_positive(atomic_t *v)
int dec, c = raw_atomic_read(v);

do {
- dec = c - 1;
+ dec = wrapping_sub(int, c, 1);
if (unlikely(dec < 0))
break;
} while (!raw_atomic_try_cmpxchg(v, &c, dec));
@@ -4554,7 +4555,7 @@ raw_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
do {
if (unlikely(c == u))
break;
- } while (!raw_atomic64_try_cmpxchg(v, &c, c + a));
+ } while (!raw_atomic64_try_cmpxchg(v, &c, wrapping_add(s64, c, a)));

return c;
#endif
@@ -4626,7 +4627,7 @@ raw_atomic64_inc_unless_negative(atomic64_t *v)
do {
if (unlikely(c < 0))
return false;
- } while (!raw_atomic64_try_cmpxchg(v, &c, c + 1));
+ } while (!raw_atomic64_try_cmpxchg(v, &c, wrapping_add(s64, c, 1)));

return true;
#endif
@@ -4654,7 +4655,7 @@ raw_atomic64_dec_unless_positive(atomic64_t *v)
do {
if (unlikely(c > 0))
return false;
- } while (!raw_atomic64_try_cmpxchg(v, &c, c - 1));
+ } while (!raw_atomic64_try_cmpxchg(v, &c, wrapping_sub(s64, c, 1)));

return true;
#endif
@@ -4680,7 +4681,7 @@ raw_atomic64_dec_if_positive(atomic64_t *v)
s64 dec, c = raw_atomic64_read(v);

do {
- dec = c - 1;
+ dec = wrapping_sub(s64, c, 1);
if (unlikely(dec < 0))
break;
} while (!raw_atomic64_try_cmpxchg(v, &c, dec));
@@ -4690,4 +4691,4 @@ raw_atomic64_dec_if_positive(atomic64_t *v)
}

#endif /* _LINUX_ATOMIC_FALLBACK_H */
-// 14850c0b0db20c62fdc78ccd1d42b98b88d76331
+// 1278e3a674d0a36c2f0eb9f5fd0ddfcbf3690406
diff --git a/include/linux/atomic/atomic-instrumented.h b/include/linux/atomic/atomic-instrumented.h
index debd487fe971..af103189bd7d 100644
--- a/include/linux/atomic/atomic-instrumented.h
+++ b/include/linux/atomic/atomic-instrumented.h
@@ -15,6 +15,7 @@
#include <linux/build_bug.h>
#include <linux/compiler.h>
#include <linux/instrumented.h>
+#include <linux/overflow.h>

/**
* atomic_read() - atomic load with relaxed ordering
@@ -5050,4 +5051,4 @@ atomic_long_dec_if_positive(atomic_long_t *v)

#endif /* _LINUX_ATOMIC_INSTRUMENTED_H */
-// ce5b65e0f1f8a276268b667194581d24bed219d4
+// b9cd8314e11c4c818fb469dbd18c7390fcaf9b3c
diff --git a/include/linux/atomic/atomic-long.h b/include/linux/atomic/atomic-long.h
index 3ef844b3ab8a..07c1625a2d92 100644
--- a/include/linux/atomic/atomic-long.h
+++ b/include/linux/atomic/atomic-long.h
@@ -7,6 +7,7 @@
#define _LINUX_ATOMIC_LONG_H

#include <linux/compiler.h>
+#include <linux/overflow.h>
#include <asm/types.h>

#ifdef CONFIG_64BIT
@@ -1809,4 +1810,4 @@ raw_atomic_long_dec_if_positive(atomic_long_t *v)
}

#endif /* _LINUX_ATOMIC_LONG_H */
-// 1c4a26fc77f345342953770ebe3c4d08e7ce2f9a
+// 01a5fe70d091e84c1de5eea7e9c09ebeaf7799b3
diff --git a/lib/atomic64.c b/lib/atomic64.c
index caf895789a1e..25cc8993d7da 100644
--- a/lib/atomic64.c
+++ b/lib/atomic64.c
@@ -67,7 +67,7 @@ void generic_atomic64_set(atomic64_t *v, s64 i)
EXPORT_SYMBOL(generic_atomic64_set);

#define ATOMIC64_OP(op, c_op) \
-void generic_atomic64_##op(s64 a, atomic64_t *v) \
+void __signed_wrap generic_atomic64_##op(s64 a, atomic64_t *v) \
{ \
unsigned long flags; \
raw_spinlock_t *lock = lock_addr(v); \
@@ -79,7 +79,7 @@ void generic_atomic64_##op(s64 a, atomic64_t *v) \
EXPORT_SYMBOL(generic_atomic64_##op);

#define ATOMIC64_OP_RETURN(op, c_op) \
-s64 generic_atomic64_##op##_return(s64 a, atomic64_t *v) \
+s64 __signed_wrap generic_atomic64_##op##_return(s64 a, atomic64_t *v) \
{ \
unsigned long flags; \
raw_spinlock_t *lock = lock_addr(v); \
@@ -93,7 +93,7 @@ s64 generic_atomic64_##op##_return(s64 a, atomic64_t *v) \
EXPORT_SYMBOL(generic_atomic64_##op##_return);

#define ATOMIC64_FETCH_OP(op, c_op) \
-s64 generic_atomic64_fetch_##op(s64 a, atomic64_t *v) \
+s64 __signed_wrap generic_atomic64_fetch_##op(s64 a, atomic64_t *v) \
{ \
unsigned long flags; \
raw_spinlock_t *lock = lock_addr(v); \
@@ -135,7 +135,7 @@ s64 generic_atomic64_dec_if_positive(atomic64_t *v)
s64 val;

raw_spin_lock_irqsave(lock, flags);
- val = v->counter - 1;
+ val = wrapping_sub(typeof(val), v->counter, 1);
if (val >= 0)
v->counter = val;
raw_spin_unlock_irqrestore(lock, flags);
@@ -181,7 +181,7 @@ s64 generic_atomic64_fetch_add_unless(atomic64_t *v, s64 a, s64 u)
raw_spin_lock_irqsave(lock, flags);
val = v->counter;
if (val != u)
- v->counter += a;
+ wrapping_assign_add(v->counter, a);
raw_spin_unlock_irqrestore(lock, flags);

return val;
diff --git a/scripts/atomic/fallbacks/dec_if_positive b/scripts/atomic/fallbacks/dec_if_positive
index f65c11b4b85b..910a6d4ef398 100755
--- a/scripts/atomic/fallbacks/dec_if_positive
+++ b/scripts/atomic/fallbacks/dec_if_positive
@@ -2,7 +2,7 @@ cat <<EOF
${int} dec, c = raw_${atomic}_read(v);

do {
- dec = c - 1;
+ dec = wrapping_sub(${int}, c, 1);
if (unlikely(dec < 0))
break;
} while (!raw_${atomic}_try_cmpxchg(v, &c, dec));
diff --git a/scripts/atomic/fallbacks/dec_unless_positive b/scripts/atomic/fallbacks/dec_unless_positive
index d025361d7b85..327451527825 100755
--- a/scripts/atomic/fallbacks/dec_unless_positive
+++ b/scripts/atomic/fallbacks/dec_unless_positive
@@ -4,7 +4,7 @@ cat <<EOF
do {
if (unlikely(c > 0))
return false;
- } while (!raw_${atomic}_try_cmpxchg(v, &c, c - 1));
+ } while (!raw_${atomic}_try_cmpxchg(v, &c, wrapping_sub(${int}, c, 1)));

return true;
EOF
diff --git a/scripts/atomic/fallbacks/fetch_add_unless b/scripts/atomic/fallbacks/fetch_add_unless
index 8db7e9e17fac..a9a11675a4d7 100755
--- a/scripts/atomic/fallbacks/fetch_add_unless
+++ b/scripts/atomic/fallbacks/fetch_add_unless
@@ -4,7 +4,7 @@ cat << EOF
do {
if (unlikely(c == u))
break;
- } while (!raw_${atomic}_try_cmpxchg(v, &c, c + a));
+ } while (!raw_${atomic}_try_cmpxchg(v, &c, wrapping_add(${int}, c, a)));

return c;
EOF
diff --git a/scripts/atomic/fallbacks/inc_unless_negative b/scripts/atomic/fallbacks/inc_unless_negative
index 7b4b09868842..0275d3c683eb 100755
--- a/scripts/atomic/fallbacks/inc_unless_negative
+++ b/scripts/atomic/fallbacks/inc_unless_negative
@@ -4,7 +4,7 @@ cat <<EOF
do {
if (unlikely(c < 0))
return false;
- } while (!raw_${atomic}_try_cmpxchg(v, &c, c + 1));
+ } while (!raw_${atomic}_try_cmpxchg(v, &c, wrapping_add(${int}, c, 1)));

return true;
EOF
diff --git a/scripts/atomic/gen-atomic-fallback.sh b/scripts/atomic/gen-atomic-fallback.sh
index f80d69cfeb1f..60f5adf3a022 100755
--- a/scripts/atomic/gen-atomic-fallback.sh
+++ b/scripts/atomic/gen-atomic-fallback.sh
@@ -297,6 +297,7 @@ cat << EOF
#define _LINUX_ATOMIC_FALLBACK_H

#include <linux/compiler.h>
+#include <linux/overflow.h>

EOF

diff --git a/scripts/atomic/gen-atomic-instrumented.sh b/scripts/atomic/gen-atomic-instrumented.sh
index 592f3ec89b5f..fbc6c2f0abd3 100755
--- a/scripts/atomic/gen-atomic-instrumented.sh
+++ b/scripts/atomic/gen-atomic-instrumented.sh
@@ -146,6 +146,7 @@ cat << EOF
#include <linux/build_bug.h>
#include <linux/compiler.h>
#include <linux/instrumented.h>
+#include <linux/overflow.h>

EOF

diff --git a/scripts/atomic/gen-atomic-long.sh b/scripts/atomic/gen-atomic-long.sh
index 9826be3ba986..ae6d549c9079 100755
--- a/scripts/atomic/gen-atomic-long.sh
+++ b/scripts/atomic/gen-atomic-long.sh
@@ -75,6 +75,7 @@ cat << EOF
#define _LINUX_ATOMIC_LONG_H

#include <linux/compiler.h>
+#include <linux/overflow.h>
#include <asm/types.h>

#ifdef CONFIG_64BIT
--
2.34.1

Next message: Konstantin Pugin: "[PATCH v8 1/3] serial: sc16is7xx: announce support of SER_RS485_RTS_ON_SEND"
Previous message: Rob Herring: "Re: [PATCH V2 1/3] dt-bindings: serial: cdsn,uart: Add optional reset property"
In reply to: Kees Cook: "[PATCH 2/4] arm64: atomics: lse: Silence intentional wrapping addition"
Next in thread: David Howells: "Re: [PATCH 1/4] locking/atomic/x86: Silence intentional wrapping addition"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]