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d8eebb11e9
Similar to commit eb6efdfeae ("s390/uaccess: add KMSAN support to
put_user() and get_user()") disable KMSAN instrumention for futex inline
assemblies, which contain dereferenced user pointers. With KMSAN
instrumentation this would lead to accesses of shadows for user pointers,
which should not happen.
Handle the futex operations like they copy a value (old) from user
space to kernel space.
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_S390_FUTEX_H
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#define _ASM_S390_FUTEX_H
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#include <linux/instrumented.h>
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#include <linux/uaccess.h>
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#include <linux/futex.h>
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#include <asm/asm-extable.h>
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#include <asm/mmu_context.h>
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#include <asm/errno.h>
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#define FUTEX_OP_FUNC(name, insn) \
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static uaccess_kmsan_or_inline int \
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__futex_atomic_##name(int oparg, int *old, u32 __user *uaddr) \
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{ \
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int rc, new; \
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\
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instrument_copy_from_user_before(old, uaddr, sizeof(*old)); \
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asm_inline volatile( \
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" sacf 256\n" \
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"0: l %[old],%[uaddr]\n" \
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"1:"insn \
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"2: cs %[old],%[new],%[uaddr]\n" \
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"3: jl 1b\n" \
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" lhi %[rc],0\n" \
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"4: sacf 768\n" \
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EX_TABLE_UA_FAULT(0b, 4b, %[rc]) \
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EX_TABLE_UA_FAULT(1b, 4b, %[rc]) \
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EX_TABLE_UA_FAULT(2b, 4b, %[rc]) \
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EX_TABLE_UA_FAULT(3b, 4b, %[rc]) \
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: [rc] "=d" (rc), [old] "=&d" (*old), \
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[new] "=&d" (new), [uaddr] "+Q" (*uaddr) \
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: [oparg] "d" (oparg) \
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: "cc"); \
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if (!rc) \
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instrument_copy_from_user_after(old, uaddr, sizeof(*old), 0); \
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return rc; \
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}
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FUTEX_OP_FUNC(set, "lr %[new],%[oparg]\n")
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FUTEX_OP_FUNC(add, "lr %[new],%[old]\n ar %[new],%[oparg]\n")
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FUTEX_OP_FUNC(or, "lr %[new],%[old]\n or %[new],%[oparg]\n")
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FUTEX_OP_FUNC(and, "lr %[new],%[old]\n nr %[new],%[oparg]\n")
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FUTEX_OP_FUNC(xor, "lr %[new],%[old]\n xr %[new],%[oparg]\n")
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static inline
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int arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
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{
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int old, rc;
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switch (op) {
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case FUTEX_OP_SET:
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rc = __futex_atomic_set(oparg, &old, uaddr);
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break;
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case FUTEX_OP_ADD:
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rc = __futex_atomic_add(oparg, &old, uaddr);
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break;
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case FUTEX_OP_OR:
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rc = __futex_atomic_or(oparg, &old, uaddr);
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break;
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case FUTEX_OP_ANDN:
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rc = __futex_atomic_and(~oparg, &old, uaddr);
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break;
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case FUTEX_OP_XOR:
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rc = __futex_atomic_xor(oparg, &old, uaddr);
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break;
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default:
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rc = -ENOSYS;
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}
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if (!rc)
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*oval = old;
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return rc;
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}
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static uaccess_kmsan_or_inline
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int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval)
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{
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int rc;
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instrument_copy_from_user_before(uval, uaddr, sizeof(*uval));
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asm_inline volatile(
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" sacf 256\n"
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"0: cs %[old],%[new],%[uaddr]\n"
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"1: lhi %[rc],0\n"
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"2: sacf 768\n"
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EX_TABLE_UA_FAULT(0b, 2b, %[rc])
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EX_TABLE_UA_FAULT(1b, 2b, %[rc])
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: [rc] "=d" (rc), [old] "+d" (oldval), [uaddr] "+Q" (*uaddr)
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: [new] "d" (newval)
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: "cc", "memory");
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*uval = oldval;
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instrument_copy_from_user_after(uval, uaddr, sizeof(*uval), 0);
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return rc;
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}
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#endif /* _ASM_S390_FUTEX_H */
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