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Diffstat (limited to '')
-rw-r--r-- | arch/powerpc/include/asm/book3s/32/kup.h | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h new file mode 100644 index 0000000000..4e14a5427a --- /dev/null +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -0,0 +1,175 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_POWERPC_BOOK3S_32_KUP_H +#define _ASM_POWERPC_BOOK3S_32_KUP_H + +#include <asm/bug.h> +#include <asm/book3s/32/mmu-hash.h> +#include <asm/mmu.h> +#include <asm/synch.h> + +#ifndef __ASSEMBLY__ + +#ifdef CONFIG_PPC_KUAP + +#include <linux/sched.h> + +#define KUAP_NONE (~0UL) + +static __always_inline void kuap_lock_one(unsigned long addr) +{ + mtsr(mfsr(addr) | SR_KS, addr); + isync(); /* Context sync required after mtsr() */ +} + +static __always_inline void kuap_unlock_one(unsigned long addr) +{ + mtsr(mfsr(addr) & ~SR_KS, addr); + isync(); /* Context sync required after mtsr() */ +} + +static __always_inline void uaccess_begin_32s(unsigned long addr) +{ + unsigned long tmp; + + asm volatile(ASM_MMU_FTR_IFSET( + "mfsrin %0, %1;" + "rlwinm %0, %0, 0, %2;" + "mtsrin %0, %1;" + "isync", "", %3) + : "=&r"(tmp) + : "r"(addr), "i"(~SR_KS), "i"(MMU_FTR_KUAP) + : "memory"); +} + +static __always_inline void uaccess_end_32s(unsigned long addr) +{ + unsigned long tmp; + + asm volatile(ASM_MMU_FTR_IFSET( + "mfsrin %0, %1;" + "oris %0, %0, %2;" + "mtsrin %0, %1;" + "isync", "", %3) + : "=&r"(tmp) + : "r"(addr), "i"(SR_KS >> 16), "i"(MMU_FTR_KUAP) + : "memory"); +} + +static __always_inline void __kuap_save_and_lock(struct pt_regs *regs) +{ + unsigned long kuap = current->thread.kuap; + + regs->kuap = kuap; + if (unlikely(kuap == KUAP_NONE)) + return; + + current->thread.kuap = KUAP_NONE; + kuap_lock_one(kuap); +} +#define __kuap_save_and_lock __kuap_save_and_lock + +static __always_inline void kuap_user_restore(struct pt_regs *regs) +{ +} + +static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap) +{ + if (unlikely(kuap != KUAP_NONE)) { + current->thread.kuap = KUAP_NONE; + kuap_lock_one(kuap); + } + + if (likely(regs->kuap == KUAP_NONE)) + return; + + current->thread.kuap = regs->kuap; + + kuap_unlock_one(regs->kuap); +} + +static __always_inline unsigned long __kuap_get_and_assert_locked(void) +{ + unsigned long kuap = current->thread.kuap; + + WARN_ON_ONCE(IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && kuap != KUAP_NONE); + + return kuap; +} +#define __kuap_get_and_assert_locked __kuap_get_and_assert_locked + +static __always_inline void allow_user_access(void __user *to, const void __user *from, + u32 size, unsigned long dir) +{ + BUILD_BUG_ON(!__builtin_constant_p(dir)); + + if (!(dir & KUAP_WRITE)) + return; + + current->thread.kuap = (__force u32)to; + uaccess_begin_32s((__force u32)to); +} + +static __always_inline void prevent_user_access(unsigned long dir) +{ + u32 kuap = current->thread.kuap; + + BUILD_BUG_ON(!__builtin_constant_p(dir)); + + if (!(dir & KUAP_WRITE)) + return; + + current->thread.kuap = KUAP_NONE; + uaccess_end_32s(kuap); +} + +static __always_inline unsigned long prevent_user_access_return(void) +{ + unsigned long flags = current->thread.kuap; + + if (flags != KUAP_NONE) { + current->thread.kuap = KUAP_NONE; + uaccess_end_32s(flags); + } + + return flags; +} + +static __always_inline void restore_user_access(unsigned long flags) +{ + if (flags != KUAP_NONE) { + current->thread.kuap = flags; + uaccess_begin_32s(flags); + } +} + +static __always_inline bool +__bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) +{ + unsigned long kuap = regs->kuap; + + if (!is_write) + return false; + if (kuap == KUAP_NONE) + return true; + + /* + * If faulting address doesn't match unlocked segment, change segment. + * In case of unaligned store crossing two segments, emulate store. + */ + if ((kuap ^ address) & 0xf0000000) { + if (!(kuap & 0x0fffffff) && address > kuap - 4 && fix_alignment(regs)) { + regs_add_return_ip(regs, 4); + emulate_single_step(regs); + } else { + regs->kuap = address; + } + } + + return false; +} + +#endif /* CONFIG_PPC_KUAP */ + +#endif /* __ASSEMBLY__ */ + +#endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */ |