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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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
112 lines
2.3 KiB
C
112 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_KUP_BOOKE_H_
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#define _ASM_POWERPC_KUP_BOOKE_H_
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#include <asm/bug.h>
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#include <asm/mmu.h>
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#ifdef CONFIG_PPC_KUAP
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#ifdef __ASSEMBLY__
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.macro kuap_check_amr gpr1, gpr2
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.endm
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#else
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#include <linux/sched.h>
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#include <asm/reg.h>
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static __always_inline void __kuap_lock(void)
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{
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mtspr(SPRN_PID, 0);
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isync();
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}
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#define __kuap_lock __kuap_lock
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static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
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{
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regs->kuap = mfspr(SPRN_PID);
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mtspr(SPRN_PID, 0);
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isync();
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}
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#define __kuap_save_and_lock __kuap_save_and_lock
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static __always_inline void kuap_user_restore(struct pt_regs *regs)
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{
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if (kuap_is_disabled())
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return;
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mtspr(SPRN_PID, current->thread.pid);
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/* Context synchronisation is performed by rfi */
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}
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static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
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{
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if (regs->kuap)
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mtspr(SPRN_PID, current->thread.pid);
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/* Context synchronisation is performed by rfi */
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}
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#ifdef CONFIG_PPC_KUAP_DEBUG
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static __always_inline unsigned long __kuap_get_and_assert_locked(void)
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{
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WARN_ON_ONCE(mfspr(SPRN_PID));
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return 0;
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}
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#define __kuap_get_and_assert_locked __kuap_get_and_assert_locked
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#endif
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static __always_inline void uaccess_begin_booke(unsigned long val)
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{
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asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
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"i"(SPRN_PID), "r"(val), "i"(MMU_FTR_KUAP) : "memory");
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}
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static __always_inline void uaccess_end_booke(void)
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{
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asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
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"i"(SPRN_PID), "r"(0), "i"(MMU_FTR_KUAP) : "memory");
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}
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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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{
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uaccess_begin_booke(current->thread.pid);
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}
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static __always_inline void prevent_user_access(unsigned long dir)
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{
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uaccess_end_booke();
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}
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static __always_inline unsigned long prevent_user_access_return(void)
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{
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unsigned long flags = mfspr(SPRN_PID);
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uaccess_end_booke();
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return flags;
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}
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static __always_inline void restore_user_access(unsigned long flags)
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{
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if (flags)
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uaccess_begin_booke(current->thread.pid);
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}
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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 !regs->kuap;
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* CONFIG_PPC_KUAP */
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#endif /* _ASM_POWERPC_KUP_BOOKE_H_ */
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