projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 890274c2 ME |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | #ifndef _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H | |
| 3 | #define _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H | |
| 4 | ||
| 5 | #include <linux/const.h> | |
| 6 | ||
| 7 | #define AMR_KUAP_BLOCK_READ UL(0x4000000000000000) | |
| 8 | #define AMR_KUAP_BLOCK_WRITE UL(0x8000000000000000) | |
| 9 | #define AMR_KUAP_BLOCKED (AMR_KUAP_BLOCK_READ | AMR_KUAP_BLOCK_WRITE) | |
| 10 | #define AMR_KUAP_SHIFT 62 | |
| 11 | ||
| 12 | #ifdef __ASSEMBLY__ | |
| 13 | ||
| 14 | .macro kuap_restore_amr gpr | |
| 15 | #ifdef CONFIG_PPC_KUAP | |
| 16 | BEGIN_MMU_FTR_SECTION_NESTED(67) | |
| 17 | ld \gpr, STACK_REGS_KUAP(r1) | |
| 18 | mtspr SPRN_AMR, \gpr | |
| 19 | END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67) | |
| 20 | #endif | |
| 21 | .endm | |
| 22 | ||
| 23 | .macro kuap_check_amr gpr1, gpr2 | |
| 24 | #ifdef CONFIG_PPC_KUAP_DEBUG | |
| 25 | BEGIN_MMU_FTR_SECTION_NESTED(67) | |
| 26 | mfspr \gpr1, SPRN_AMR | |
| 27 | li \gpr2, (AMR_KUAP_BLOCKED >> AMR_KUAP_SHIFT) | |
| 28 | sldi \gpr2, \gpr2, AMR_KUAP_SHIFT | |
| 29 | 999: tdne \gpr1, \gpr2 | |
| 30 | EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE) | |
| 31 | END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67) | |
| 32 | #endif | |
| 33 | .endm | |
| 34 | ||
| 35 | .macro kuap_save_amr_and_lock gpr1, gpr2, use_cr, msr_pr_cr | |
| 36 | #ifdef CONFIG_PPC_KUAP | |
| 37 | BEGIN_MMU_FTR_SECTION_NESTED(67) | |
| 38 | .ifnb \msr_pr_cr | |
| 39 | bne \msr_pr_cr, 99f | |
| 40 | .endif | |
| 41 | mfspr \gpr1, SPRN_AMR | |
| 42 | std \gpr1, STACK_REGS_KUAP(r1) | |
| 43 | li \gpr2, (AMR_KUAP_BLOCKED >> AMR_KUAP_SHIFT) | |
| 44 | sldi \gpr2, \gpr2, AMR_KUAP_SHIFT | |
| 45 | cmpd \use_cr, \gpr1, \gpr2 | |
| 46 | beq \use_cr, 99f | |
| 47 | // We don't isync here because we very recently entered via rfid | |
| 48 | mtspr SPRN_AMR, \gpr2 | |
| 49 | isync | |
| 50 | 99: | |
| 51 | END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67) | |
| 52 | #endif | |
| 53 | .endm | |
| 54 | ||
| 55 | #else /* !__ASSEMBLY__ */ | |
| 56 | ||
| 57 | #ifdef CONFIG_PPC_KUAP | |
| 58 | ||
| 59 | #include <asm/reg.h> | |
| 60 | ||
| 61 | /* | |
| 62 | * We support individually allowing read or write, but we don't support nesting | |
| 63 | * because that would require an expensive read/modify write of the AMR. | |
| 64 | */ | |
| 65 | ||
| 66 | static inline void set_kuap(unsigned long value) | |
| 67 | { | |
| 68 | if (!mmu_has_feature(MMU_FTR_RADIX_KUAP)) | |
| 69 | return; | |
| 70 | ||
| 71 | /* | |
| 72 | * ISA v3.0B says we need a CSI (Context Synchronising Instruction) both | |
| 73 | * before and after the move to AMR. See table 6 on page 1134. | |
| 74 | */ | |
| 75 | isync(); | |
| 76 | mtspr(SPRN_AMR, value); | |
| 77 | isync(); | |
| 78 | } | |
| 79 | ||
| 80 | static inline void allow_user_access(void __user *to, const void __user *from, | |
| 81 | unsigned long size) | |
| 82 | { | |
| 83 | // This is written so we can resolve to a single case at build time | |
| 84 | if (__builtin_constant_p(to) && to == NULL) | |
| 85 | set_kuap(AMR_KUAP_BLOCK_WRITE); | |
| 86 | else if (__builtin_constant_p(from) && from == NULL) | |
| 87 | set_kuap(AMR_KUAP_BLOCK_READ); | |
| 88 | else | |
| 89 | set_kuap(0); | |
| 90 | } | |
| 91 | ||
| 92 | static inline void prevent_user_access(void __user *to, const void __user *from, | |
| 93 | unsigned long size) | |
| 94 | { | |
| 95 | set_kuap(AMR_KUAP_BLOCKED); | |
| 96 | } | |
| 97 | ||
| 5e5be3ae ME |
98 | static inline bool bad_kuap_fault(struct pt_regs *regs, bool is_write) |
| 99 | { | |
| 100 | return WARN(mmu_has_feature(MMU_FTR_RADIX_KUAP) && | |
| 101 | (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)), | |
| 102 | "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read"); | |
| 103 | } | |
| 890274c2 ME |
104 | #endif /* CONFIG_PPC_KUAP */ |
| 105 | ||
| 106 | #endif /* __ASSEMBLY__ */ | |
| 107 | ||
| 108 | #endif /* _ASM_POWERPC_BOOK3S_64_KUP_RADIX_H */ |