111 lines
2.9 KiB
C
111 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H
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#define _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H
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#include <linux/const.h>
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#define AMR_KUAP_BLOCK_READ UL(0x4000000000000000)
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#define AMR_KUAP_BLOCK_WRITE UL(0x8000000000000000)
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#define AMR_KUAP_BLOCKED (AMR_KUAP_BLOCK_READ | AMR_KUAP_BLOCK_WRITE)
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#define AMR_KUAP_SHIFT 62
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#ifdef __ASSEMBLY__
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.macro kuap_restore_amr gpr
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#ifdef CONFIG_PPC_KUAP
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BEGIN_MMU_FTR_SECTION_NESTED(67)
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ld \gpr, STACK_REGS_KUAP(r1)
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mtspr SPRN_AMR, \gpr
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END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67)
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#endif
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.endm
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.macro kuap_check_amr gpr1, gpr2
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#ifdef CONFIG_PPC_KUAP_DEBUG
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BEGIN_MMU_FTR_SECTION_NESTED(67)
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mfspr \gpr1, SPRN_AMR
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li \gpr2, (AMR_KUAP_BLOCKED >> AMR_KUAP_SHIFT)
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sldi \gpr2, \gpr2, AMR_KUAP_SHIFT
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999: tdne \gpr1, \gpr2
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EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE)
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END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67)
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#endif
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.endm
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.macro kuap_save_amr_and_lock gpr1, gpr2, use_cr, msr_pr_cr
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#ifdef CONFIG_PPC_KUAP
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BEGIN_MMU_FTR_SECTION_NESTED(67)
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.ifnb \msr_pr_cr
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bne \msr_pr_cr, 99f
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.endif
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mfspr \gpr1, SPRN_AMR
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std \gpr1, STACK_REGS_KUAP(r1)
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li \gpr2, (AMR_KUAP_BLOCKED >> AMR_KUAP_SHIFT)
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sldi \gpr2, \gpr2, AMR_KUAP_SHIFT
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cmpd \use_cr, \gpr1, \gpr2
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beq \use_cr, 99f
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// We don't isync here because we very recently entered via rfid
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mtspr SPRN_AMR, \gpr2
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isync
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99:
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END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67)
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#endif
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.endm
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#else /* !__ASSEMBLY__ */
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#ifdef CONFIG_PPC_KUAP
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#include <asm/reg.h>
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/*
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* We support individually allowing read or write, but we don't support nesting
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* because that would require an expensive read/modify write of the AMR.
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*/
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static inline void set_kuap(unsigned long value)
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{
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if (!early_mmu_has_feature(MMU_FTR_RADIX_KUAP))
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return;
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/*
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* ISA v3.0B says we need a CSI (Context Synchronising Instruction) both
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* before and after the move to AMR. See table 6 on page 1134.
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*/
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isync();
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mtspr(SPRN_AMR, value);
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isync();
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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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// This is written so we can resolve to a single case at build time
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BUILD_BUG_ON(!__builtin_constant_p(dir));
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if (dir == KUAP_READ)
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set_kuap(AMR_KUAP_BLOCK_WRITE);
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else if (dir == KUAP_WRITE)
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set_kuap(AMR_KUAP_BLOCK_READ);
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else
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set_kuap(0);
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}
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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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{
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set_kuap(AMR_KUAP_BLOCKED);
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}
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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 WARN(mmu_has_feature(MMU_FTR_RADIX_KUAP) &&
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(regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)),
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"Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read");
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}
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#endif /* CONFIG_PPC_KUAP */
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H */
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