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authorLinus Torvalds <torvalds@linux-foundation.org>2020-03-30 16:17:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-03-30 16:17:15 -0700
commit4b9fd8a829a1eec7442e38afff21d610604de56a (patch)
tree32757737b7eecbe8c5be7606d8dcec883d39f1e6 /arch/x86/include/asm
parenta776c270a0b2fad6715cb714187e4290cadb9237 (diff)
parentf1e67e355c2aafeddf1eac31335709236996d2fe (diff)
downloadlinux-4b9fd8a829a1eec7442e38afff21d610604de56a.tar.bz2
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar: "The main changes in this cycle were: - Continued user-access cleanups in the futex code. - percpu-rwsem rewrite that uses its own waitqueue and atomic_t instead of an embedded rwsem. This addresses a couple of weaknesses, but the primary motivation was complications on the -rt kernel. - Introduce raw lock nesting detection on lockdep (CONFIG_PROVE_RAW_LOCK_NESTING=y), document the raw_lock vs. normal lock differences. This too originates from -rt. - Reuse lockdep zapped chain_hlocks entries, to conserve RAM footprint on distro-ish kernels running into the "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" depletion of the lockdep chain-entries pool. - Misc cleanups, smaller fixes and enhancements - see the changelog for details" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits) fs/buffer: Make BH_Uptodate_Lock bit_spin_lock a regular spinlock_t thermal/x86_pkg_temp: Make pkg_temp_lock a raw_spinlock_t Documentation/locking/locktypes: Minor copy editor fixes Documentation/locking/locktypes: Further clarifications and wordsmithing m68knommu: Remove mm.h include from uaccess_no.h x86: get rid of user_atomic_cmpxchg_inatomic() generic arch_futex_atomic_op_inuser() doesn't need access_ok() x86: don't reload after cmpxchg in unsafe_atomic_op2() loop x86: convert arch_futex_atomic_op_inuser() to user_access_begin/user_access_end() objtool: whitelist __sanitizer_cov_trace_switch() [parisc, s390, sparc64] no need for access_ok() in futex handling sh: no need of access_ok() in arch_futex_atomic_op_inuser() futex: arch_futex_atomic_op_inuser() calling conventions change completion: Use lockdep_assert_RT_in_threaded_ctx() in complete_all() lockdep: Add posixtimer context tracing bits lockdep: Annotate irq_work lockdep: Add hrtimer context tracing bits lockdep: Introduce wait-type checks completion: Use simple wait queues sched/swait: Prepare usage in completions ...
Diffstat (limited to 'arch/x86/include/asm')
-rw-r--r--arch/x86/include/asm/futex.h99
-rw-r--r--arch/x86/include/asm/uaccess.h93
2 files changed, 63 insertions, 129 deletions
diff --git a/arch/x86/include/asm/futex.h b/arch/x86/include/asm/futex.h
index 13c83fe97988..f9c00110a69a 100644
--- a/arch/x86/include/asm/futex.h
+++ b/arch/x86/include/asm/futex.h
@@ -12,76 +12,103 @@
#include <asm/processor.h>
#include <asm/smap.h>
-#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
- asm volatile("\t" ASM_STAC "\n" \
- "1:\t" insn "\n" \
- "2:\t" ASM_CLAC "\n" \
+#define unsafe_atomic_op1(insn, oval, uaddr, oparg, label) \
+do { \
+ int oldval = 0, ret; \
+ asm volatile("1:\t" insn "\n" \
+ "2:\n" \
"\t.section .fixup,\"ax\"\n" \
"3:\tmov\t%3, %1\n" \
"\tjmp\t2b\n" \
"\t.previous\n" \
_ASM_EXTABLE_UA(1b, 3b) \
: "=r" (oldval), "=r" (ret), "+m" (*uaddr) \
- : "i" (-EFAULT), "0" (oparg), "1" (0))
+ : "i" (-EFAULT), "0" (oparg), "1" (0)); \
+ if (ret) \
+ goto label; \
+ *oval = oldval; \
+} while(0)
-#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
- asm volatile("\t" ASM_STAC "\n" \
- "1:\tmovl %2, %0\n" \
- "\tmovl\t%0, %3\n" \
+
+#define unsafe_atomic_op2(insn, oval, uaddr, oparg, label) \
+do { \
+ int oldval = 0, ret, tem; \
+ asm volatile("1:\tmovl %2, %0\n" \
+ "2:\tmovl\t%0, %3\n" \
"\t" insn "\n" \
- "2:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \
- "\tjnz\t1b\n" \
- "3:\t" ASM_CLAC "\n" \
+ "3:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \
+ "\tjnz\t2b\n" \
+ "4:\n" \
"\t.section .fixup,\"ax\"\n" \
- "4:\tmov\t%5, %1\n" \
- "\tjmp\t3b\n" \
+ "5:\tmov\t%5, %1\n" \
+ "\tjmp\t4b\n" \
"\t.previous\n" \
- _ASM_EXTABLE_UA(1b, 4b) \
- _ASM_EXTABLE_UA(2b, 4b) \
+ _ASM_EXTABLE_UA(1b, 5b) \
+ _ASM_EXTABLE_UA(3b, 5b) \
: "=&a" (oldval), "=&r" (ret), \
"+m" (*uaddr), "=&r" (tem) \
- : "r" (oparg), "i" (-EFAULT), "1" (0))
+ : "r" (oparg), "i" (-EFAULT), "1" (0)); \
+ if (ret) \
+ goto label; \
+ *oval = oldval; \
+} while(0)
-static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
+static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
u32 __user *uaddr)
{
- int oldval = 0, ret, tem;
-
- pagefault_disable();
+ if (!user_access_begin(uaddr, sizeof(u32)))
+ return -EFAULT;
switch (op) {
case FUTEX_OP_SET:
- __futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
+ unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault);
break;
case FUTEX_OP_ADD:
- __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
- uaddr, oparg);
+ unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval,
+ uaddr, oparg, Efault);
break;
case FUTEX_OP_OR:
- __futex_atomic_op2("orl %4, %3", ret, oldval, uaddr, oparg);
+ unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault);
break;
case FUTEX_OP_ANDN:
- __futex_atomic_op2("andl %4, %3", ret, oldval, uaddr, ~oparg);
+ unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault);
break;
case FUTEX_OP_XOR:
- __futex_atomic_op2("xorl %4, %3", ret, oldval, uaddr, oparg);
+ unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault);
break;
default:
- ret = -ENOSYS;
+ user_access_end();
+ return -ENOSYS;
}
-
- pagefault_enable();
-
- if (!ret)
- *oval = oldval;
-
- return ret;
+ user_access_end();
+ return 0;
+Efault:
+ user_access_end();
+ return -EFAULT;
}
static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
- return user_atomic_cmpxchg_inatomic(uval, uaddr, oldval, newval);
+ int ret = 0;
+
+ if (!user_access_begin(uaddr, sizeof(u32)))
+ return -EFAULT;
+ asm volatile("\n"
+ "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"
+ "2:\n"
+ "\t.section .fixup, \"ax\"\n"
+ "3:\tmov %3, %0\n"
+ "\tjmp 2b\n"
+ "\t.previous\n"
+ _ASM_EXTABLE_UA(1b, 3b)
+ : "+r" (ret), "=a" (oldval), "+m" (*uaddr)
+ : "i" (-EFAULT), "r" (newval), "1" (oldval)
+ : "memory"
+ );
+ user_access_end();
+ *uval = oldval;
+ return ret;
}
#endif
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 61d93f062a36..ea6fc643ccfe 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -584,99 +584,6 @@ extern __must_check long strnlen_user(const char __user *str, long n);
unsigned long __must_check clear_user(void __user *mem, unsigned long len);
unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
-extern void __cmpxchg_wrong_size(void)
- __compiletime_error("Bad argument size for cmpxchg");
-
-#define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size) \
-({ \
- int __ret = 0; \
- __typeof__(*(ptr)) __old = (old); \
- __typeof__(*(ptr)) __new = (new); \
- __uaccess_begin_nospec(); \
- switch (size) { \
- case 1: \
- { \
- asm volatile("\n" \
- "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n" \
- "2:\n" \
- "\t.section .fixup, \"ax\"\n" \
- "3:\tmov %3, %0\n" \
- "\tjmp 2b\n" \
- "\t.previous\n" \
- _ASM_EXTABLE_UA(1b, 3b) \
- : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
- : "i" (-EFAULT), "q" (__new), "1" (__old) \
- : "memory" \
- ); \
- break; \
- } \
- case 2: \
- { \
- asm volatile("\n" \
- "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n" \
- "2:\n" \
- "\t.section .fixup, \"ax\"\n" \
- "3:\tmov %3, %0\n" \
- "\tjmp 2b\n" \
- "\t.previous\n" \
- _ASM_EXTABLE_UA(1b, 3b) \
- : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
- : "i" (-EFAULT), "r" (__new), "1" (__old) \
- : "memory" \
- ); \
- break; \
- } \
- case 4: \
- { \
- asm volatile("\n" \
- "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" \
- "2:\n" \
- "\t.section .fixup, \"ax\"\n" \
- "3:\tmov %3, %0\n" \
- "\tjmp 2b\n" \
- "\t.previous\n" \
- _ASM_EXTABLE_UA(1b, 3b) \
- : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
- : "i" (-EFAULT), "r" (__new), "1" (__old) \
- : "memory" \
- ); \
- break; \
- } \
- case 8: \
- { \
- if (!IS_ENABLED(CONFIG_X86_64)) \
- __cmpxchg_wrong_size(); \
- \
- asm volatile("\n" \
- "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n" \
- "2:\n" \
- "\t.section .fixup, \"ax\"\n" \
- "3:\tmov %3, %0\n" \
- "\tjmp 2b\n" \
- "\t.previous\n" \
- _ASM_EXTABLE_UA(1b, 3b) \
- : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \
- : "i" (-EFAULT), "r" (__new), "1" (__old) \
- : "memory" \
- ); \
- break; \
- } \
- default: \
- __cmpxchg_wrong_size(); \
- } \
- __uaccess_end(); \
- *(uval) = __old; \
- __ret; \
-})
-
-#define user_atomic_cmpxchg_inatomic(uval, ptr, old, new) \
-({ \
- access_ok((ptr), sizeof(*(ptr))) ? \
- __user_atomic_cmpxchg_inatomic((uval), (ptr), \
- (old), (new), sizeof(*(ptr))) : \
- -EFAULT; \
-})
-
/*
* movsl can be slow when source and dest are not both 8-byte aligned
*/