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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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3d7dfd632f
Implement user_access_save() and user_access_restore()
On 8xx and radix:
- On save, get the value of the associated special register then
prevent user access.
- On restore, set back the saved value to the associated special
register.
On book3s/32:
- On save, get the value stored in current->thread.kuap and prevent
user access.
- On restore, regenerate address range from the stored value and
reopen read/write access for that range.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/54f2f74938006b33c55a416674807b42ef222068.1579866752.git.christophe.leroy@c-s.fr
107 lines
2.6 KiB
C
107 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_KUP_H_
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#define _ASM_POWERPC_KUP_H_
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#define KUAP_READ 1
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#define KUAP_WRITE 2
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#define KUAP_READ_WRITE (KUAP_READ | KUAP_WRITE)
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/*
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* For prevent_user_access() only.
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* Use the current saved situation instead of the to/from/size params.
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* Used on book3s/32
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*/
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#define KUAP_CURRENT 4
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#ifdef CONFIG_PPC64
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#include <asm/book3s/64/kup-radix.h>
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#endif
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#ifdef CONFIG_PPC_8xx
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#include <asm/nohash/32/kup-8xx.h>
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#endif
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#ifdef CONFIG_PPC_BOOK3S_32
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#include <asm/book3s/32/kup.h>
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#endif
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#ifdef __ASSEMBLY__
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#ifndef CONFIG_PPC_KUAP
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.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3
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.endm
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.macro kuap_restore sp, current, gpr1, gpr2, gpr3
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.endm
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.macro kuap_check current, gpr
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.endm
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#endif
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#else /* !__ASSEMBLY__ */
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#include <asm/pgtable.h>
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void setup_kup(void);
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#ifdef CONFIG_PPC_KUEP
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void setup_kuep(bool disabled);
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#else
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static inline void setup_kuep(bool disabled) { }
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#endif /* CONFIG_PPC_KUEP */
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#ifdef CONFIG_PPC_KUAP
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void setup_kuap(bool disabled);
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#else
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static inline void setup_kuap(bool disabled) { }
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static inline void allow_user_access(void __user *to, const void __user *from,
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unsigned long size, unsigned long dir) { }
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static inline void prevent_user_access(void __user *to, const void __user *from,
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unsigned long size, unsigned long dir) { }
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static inline unsigned long prevent_user_access_return(void) { return 0UL; }
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static inline void restore_user_access(unsigned long flags) { }
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static inline bool
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bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
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{
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return false;
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}
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#endif /* CONFIG_PPC_KUAP */
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static inline void allow_read_from_user(const void __user *from, unsigned long size)
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{
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allow_user_access(NULL, from, size, KUAP_READ);
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}
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static inline void allow_write_to_user(void __user *to, unsigned long size)
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{
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allow_user_access(to, NULL, size, KUAP_WRITE);
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}
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static inline void allow_read_write_user(void __user *to, const void __user *from,
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unsigned long size)
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{
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allow_user_access(to, from, size, KUAP_READ_WRITE);
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}
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static inline void prevent_read_from_user(const void __user *from, unsigned long size)
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{
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prevent_user_access(NULL, from, size, KUAP_READ);
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}
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static inline void prevent_write_to_user(void __user *to, unsigned long size)
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{
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prevent_user_access(to, NULL, size, KUAP_WRITE);
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}
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static inline void prevent_read_write_user(void __user *to, const void __user *from,
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unsigned long size)
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{
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prevent_user_access(to, from, size, KUAP_READ_WRITE);
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}
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static inline void prevent_current_access_user(void)
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{
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prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT);
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_POWERPC_KUAP_H_ */
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