3a24ea0df8
To avoid a useless nop on top of every uaccess enable/disable and make life easier for objtool, replace static branches by ASM feature fixups that will nop KUAP enabling instructions out in the unlikely case KUAP is disabled at boottime. Leave it as is on book3s/64 for now, it will be handled later when objtool is activated on PPC64. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/671948788024fd890ec4ed175bc332dab8664ea5.1689091022.git.christophe.leroy@csgroup.eu
187 lines
4.2 KiB
C
187 lines
4.2 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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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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static __always_inline bool kuap_is_disabled(void);
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#endif
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#ifdef CONFIG_PPC_BOOK3S_64
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#include <asm/book3s/64/kup.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_BOOKE_OR_40x
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#include <asm/nohash/kup-booke.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_check_amr gpr1, gpr2
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.endm
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#endif
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#else /* !__ASSEMBLY__ */
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extern bool disable_kuep;
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extern bool disable_kuap;
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#include <linux/pgtable.h>
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void setup_kup(void);
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void setup_kuep(bool disabled);
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#ifdef CONFIG_PPC_KUAP
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void setup_kuap(bool disabled);
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static __always_inline bool kuap_is_disabled(void)
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{
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return !mmu_has_feature(MMU_FTR_KUAP);
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}
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#else
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static inline void setup_kuap(bool disabled) { }
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static __always_inline bool kuap_is_disabled(void) { return true; }
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static __always_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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static __always_inline void kuap_user_restore(struct pt_regs *regs) { }
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static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr) { }
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/*
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* book3s/64/kup-radix.h defines these functions for the !KUAP case to flush
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* the L1D cache after user accesses. Only include the empty stubs for other
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* platforms.
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*/
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#ifndef CONFIG_PPC_BOOK3S_64
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static __always_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 __always_inline void prevent_user_access(unsigned long dir) { }
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static __always_inline unsigned long prevent_user_access_return(void) { return 0UL; }
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static __always_inline void restore_user_access(unsigned long flags) { }
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#endif /* CONFIG_PPC_BOOK3S_64 */
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#endif /* CONFIG_PPC_KUAP */
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static __always_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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if (kuap_is_disabled())
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return false;
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return __bad_kuap_fault(regs, address, is_write);
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}
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static __always_inline void kuap_lock(void)
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{
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#ifdef __kuap_lock
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if (kuap_is_disabled())
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return;
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__kuap_lock();
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#endif
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}
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static __always_inline void kuap_save_and_lock(struct pt_regs *regs)
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{
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#ifdef __kuap_save_and_lock
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if (kuap_is_disabled())
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return;
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__kuap_save_and_lock(regs);
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#endif
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}
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static __always_inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long amr)
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{
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if (kuap_is_disabled())
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return;
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__kuap_kernel_restore(regs, amr);
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}
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static __always_inline unsigned long kuap_get_and_assert_locked(void)
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{
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#ifdef __kuap_get_and_assert_locked
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if (!kuap_is_disabled())
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return __kuap_get_and_assert_locked();
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#endif
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return 0;
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}
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static __always_inline void kuap_assert_locked(void)
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{
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if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG))
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kuap_get_and_assert_locked();
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}
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static __always_inline void allow_read_from_user(const void __user *from, unsigned long size)
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{
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barrier_nospec();
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allow_user_access(NULL, from, size, KUAP_READ);
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}
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static __always_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 __always_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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barrier_nospec();
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allow_user_access(to, from, size, KUAP_READ_WRITE);
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}
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static __always_inline void prevent_read_from_user(const void __user *from, unsigned long size)
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{
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prevent_user_access(KUAP_READ);
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}
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static __always_inline void prevent_write_to_user(void __user *to, unsigned long size)
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{
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prevent_user_access(KUAP_WRITE);
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}
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static __always_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(KUAP_READ_WRITE);
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}
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static __always_inline void prevent_current_access_user(void)
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{
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prevent_user_access(KUAP_READ_WRITE);
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}
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static __always_inline void prevent_current_read_from_user(void)
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{
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prevent_user_access(KUAP_READ);
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}
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static __always_inline void prevent_current_write_to_user(void)
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{
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prevent_user_access(KUAP_WRITE);
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_POWERPC_KUAP_H_ */
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