linux/arch/powerpc/include/asm/kup.h
Christophe Leroy e2fb9f5444 powerpc/32: Prepare for Kernel Userspace Access Protection
This patch adds ASM macros for saving, restoring and checking
the KUAP state, and modifies setup_32 to call them on exceptions
from kernel.

The macros are defined as empty by default for when CONFIG_PPC_KUAP
is not selected and/or for platforms which don't handle (yet) KUAP.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2019-04-21 23:11:46 +10:00

68 lines
1.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_KUP_H_
#define _ASM_POWERPC_KUP_H_
#ifdef CONFIG_PPC64
#include <asm/book3s/64/kup-radix.h>
#endif
#ifdef __ASSEMBLY__
#ifndef CONFIG_PPC_KUAP
.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3
.endm
.macro kuap_restore sp, current, gpr1, gpr2, gpr3
.endm
.macro kuap_check current, gpr
.endm
#endif
#else /* !__ASSEMBLY__ */
#include <asm/pgtable.h>
void setup_kup(void);
#ifdef CONFIG_PPC_KUEP
void setup_kuep(bool disabled);
#else
static inline void setup_kuep(bool disabled) { }
#endif /* CONFIG_PPC_KUEP */
#ifdef CONFIG_PPC_KUAP
void setup_kuap(bool disabled);
#else
static inline void setup_kuap(bool disabled) { }
static inline void allow_user_access(void __user *to, const void __user *from,
unsigned long size) { }
static inline void prevent_user_access(void __user *to, const void __user *from,
unsigned long size) { }
static inline bool bad_kuap_fault(struct pt_regs *regs, bool is_write) { return false; }
#endif /* CONFIG_PPC_KUAP */
static inline void allow_read_from_user(const void __user *from, unsigned long size)
{
allow_user_access(NULL, from, size);
}
static inline void allow_write_to_user(void __user *to, unsigned long size)
{
allow_user_access(to, NULL, size);
}
static inline void prevent_read_from_user(const void __user *from, unsigned long size)
{
prevent_user_access(NULL, from, size);
}
static inline void prevent_write_to_user(void __user *to, unsigned long size)
{
prevent_user_access(to, NULL, size);
}
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_POWERPC_KUP_H_ */