mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-28 04:45:12 +07:00
de78a9c42a
This patch implements a framework for Kernel Userspace Access Protection. Then subarches will have the possibility to provide their own implementation by providing setup_kuap() and allow/prevent_user_access(). Some platforms will need to know the area accessed and whether it is accessed from read, write or both. Therefore source, destination and size and handed over to the two functions. mpe: Rename to allow/prevent rather than unlock/lock, and add read/write wrappers. Drop the 32-bit code for now until we have an implementation for it. Add kuap to pt_regs for 64-bit as well as 32-bit. Don't split strings, use pr_crit_ratelimited(). Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
107 lines
2.4 KiB
C
107 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_FUTEX_H
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#define _ASM_POWERPC_FUTEX_H
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#ifdef __KERNEL__
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#include <linux/futex.h>
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#include <linux/uaccess.h>
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#include <asm/errno.h>
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#include <asm/synch.h>
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#include <asm/asm-405.h>
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#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
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__asm__ __volatile ( \
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PPC_ATOMIC_ENTRY_BARRIER \
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"1: lwarx %0,0,%2\n" \
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insn \
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PPC405_ERR77(0, %2) \
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"2: stwcx. %1,0,%2\n" \
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"bne- 1b\n" \
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PPC_ATOMIC_EXIT_BARRIER \
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"li %1,0\n" \
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"3: .section .fixup,\"ax\"\n" \
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"4: li %1,%3\n" \
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"b 3b\n" \
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".previous\n" \
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EX_TABLE(1b, 4b) \
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EX_TABLE(2b, 4b) \
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: "=&r" (oldval), "=&r" (ret) \
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: "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
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: "cr0", "memory")
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static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
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u32 __user *uaddr)
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{
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int oldval = 0, ret;
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allow_write_to_user(uaddr, sizeof(*uaddr));
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pagefault_disable();
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switch (op) {
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case FUTEX_OP_SET:
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__futex_atomic_op("mr %1,%4\n", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_ADD:
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__futex_atomic_op("add %1,%0,%4\n", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_OR:
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__futex_atomic_op("or %1,%0,%4\n", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_ANDN:
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__futex_atomic_op("andc %1,%0,%4\n", ret, oldval, uaddr, oparg);
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break;
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case FUTEX_OP_XOR:
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__futex_atomic_op("xor %1,%0,%4\n", ret, oldval, uaddr, oparg);
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break;
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default:
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ret = -ENOSYS;
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}
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pagefault_enable();
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if (!ret)
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*oval = oldval;
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prevent_write_to_user(uaddr, sizeof(*uaddr));
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return ret;
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}
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static inline int
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futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
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u32 oldval, u32 newval)
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{
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int ret = 0;
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u32 prev;
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if (!access_ok(uaddr, sizeof(u32)))
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return -EFAULT;
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allow_write_to_user(uaddr, sizeof(*uaddr));
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__asm__ __volatile__ (
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PPC_ATOMIC_ENTRY_BARRIER
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"1: lwarx %1,0,%3 # futex_atomic_cmpxchg_inatomic\n\
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cmpw 0,%1,%4\n\
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bne- 3f\n"
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PPC405_ERR77(0,%3)
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"2: stwcx. %5,0,%3\n\
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bne- 1b\n"
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PPC_ATOMIC_EXIT_BARRIER
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"3: .section .fixup,\"ax\"\n\
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4: li %0,%6\n\
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b 3b\n\
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.previous\n"
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EX_TABLE(1b, 4b)
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EX_TABLE(2b, 4b)
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: "+r" (ret), "=&r" (prev), "+m" (*uaddr)
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: "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
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: "cc", "memory");
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*uval = prev;
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prevent_write_to_user(uaddr, sizeof(*uaddr));
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return ret;
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}
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_FUTEX_H */
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