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/* 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__
#include <linux/jump_label.h>
extern struct static_key_false disable_kuap_key;
extern struct static_key_false disable_kuep_key;
static __always_inline bool kuap_is_disabled(void)
{
return !IS_ENABLED(CONFIG_PPC_KUAP) || static_branch_unlikely(&disable_kuap_key);
}
static __always_inline bool kuep_is_disabled(void)
{
return !IS_ENABLED(CONFIG_PPC_KUEP) || static_branch_unlikely(&disable_kuep_key);
}
static inline void kuep_lock(void)
{
if (kuep_is_disabled())
return;
update_user_segments(mfsr(0) | SR_NX);
/*
* This isync() shouldn't be necessary as the kernel is not excepted to
* run any instruction in userspace soon after the update of segments,
* but hash based cores (at least G3) seem to exhibit a random
* behaviour when the 'isync' is not there. 603 cores don't have this
* behaviour so don't do the 'isync' as it saves several CPU cycles.
*/
if (mmu_has_feature(MMU_FTR_HPTE_TABLE))
isync(); /* Context sync required after mtsr() */
}
static inline void kuep_unlock(void)
{
if (kuep_is_disabled())
return;
update_user_segments(mfsr(0) & ~SR_NX);
/*
* This isync() shouldn't be necessary as a 'rfi' will soon be executed
* to return to userspace, but hash based cores (at least G3) seem to
* exhibit a random behaviour when the 'isync' is not there. 603 cores
* don't have this behaviour so don't do the 'isync' as it saves several
* CPU cycles.
*/
if (mmu_has_feature(MMU_FTR_HPTE_TABLE))
isync(); /* Context sync required after mtsr() */
}
#ifdef CONFIG_PPC_KUAP
#include <linux/sched.h>
#define KUAP_NONE (~0UL)
#define KUAP_ALL (~1UL)
static inline void kuap_lock_one(unsigned long addr)
{
mtsr(mfsr(addr) | SR_KS, addr);
isync(); /* Context sync required after mtsr() */
}
static inline void kuap_unlock_one(unsigned long addr)
{
mtsr(mfsr(addr) & ~SR_KS, addr);
isync(); /* Context sync required after mtsr() */
}
static inline void kuap_lock_all(void)
{
update_user_segments(mfsr(0) | SR_KS);
isync(); /* Context sync required after mtsr() */
}
static inline void kuap_unlock_all(void)
{
update_user_segments(mfsr(0) & ~SR_KS);
isync(); /* Context sync required after mtsr() */
}
void kuap_lock_all_ool(void);
void kuap_unlock_all_ool(void);
static inline void kuap_lock(unsigned long addr, bool ool)
{
if (likely(addr != KUAP_ALL))
kuap_lock_one(addr);
else if (!ool)
kuap_lock_all();
else
kuap_lock_all_ool();
}
static inline void kuap_unlock(unsigned long addr, bool ool)
{
if (likely(addr != KUAP_ALL))
kuap_unlock_one(addr);
else if (!ool)
kuap_unlock_all();
else
kuap_unlock_all_ool();
}
static inline void kuap_save_and_lock(struct pt_regs *regs)
{
unsigned long kuap = current->thread.kuap;
if (kuap_is_disabled())
return;
regs->kuap = kuap;
if (unlikely(kuap == KUAP_NONE))
return;
current->thread.kuap = KUAP_NONE;
kuap_lock(kuap, false);
}
static inline void kuap_user_restore(struct pt_regs *regs)
{
}
static inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
{
if (kuap_is_disabled())
return;
if (unlikely(kuap != KUAP_NONE)) {
current->thread.kuap = KUAP_NONE;
kuap_lock(kuap, false);
}
if (likely(regs->kuap == KUAP_NONE))
return;
current->thread.kuap = regs->kuap;
kuap_unlock(regs->kuap, false);
}
static inline unsigned long kuap_get_and_assert_locked(void)
{
unsigned long kuap = current->thread.kuap;
if (kuap_is_disabled())
return KUAP_NONE;
WARN_ON_ONCE(IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && kuap != KUAP_NONE);
return kuap;
}
static inline void kuap_assert_locked(void)
{
kuap_get_and_assert_locked();
}
static __always_inline void allow_user_access(void __user *to, const void __user *from,
u32 size, unsigned long dir)
{
if (kuap_is_disabled())
return;
BUILD_BUG_ON(!__builtin_constant_p(dir));
if (!(dir & KUAP_WRITE))
return;
current->thread.kuap = (__force u32)to;
kuap_unlock_one((__force u32)to);
}
static __always_inline void prevent_user_access(unsigned long dir)
{
u32 kuap = current->thread.kuap;
if (kuap_is_disabled())
return;
BUILD_BUG_ON(!__builtin_constant_p(dir));
if (!(dir & KUAP_WRITE))
return;
current->thread.kuap = KUAP_NONE;
kuap_lock(kuap, true);
}
static inline unsigned long prevent_user_access_return(void)
{
unsigned long flags = current->thread.kuap;
if (kuap_is_disabled())
return KUAP_NONE;
if (flags != KUAP_NONE) {
current->thread.kuap = KUAP_NONE;
kuap_lock(flags, true);
}
return flags;
}
static inline void restore_user_access(unsigned long flags)
{
if (kuap_is_disabled())
return;
if (flags != KUAP_NONE) {
current->thread.kuap = flags;
kuap_unlock(flags, true);
}
}
static inline bool
bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
{
unsigned long kuap = regs->kuap;
if (kuap_is_disabled())
return false;
if (!is_write || kuap == KUAP_ALL)
return false;
if (kuap == KUAP_NONE)
return true;
/* If faulting address doesn't match unlocked segment, unlock all */
if ((kuap ^ address) & 0xf0000000)
regs->kuap = KUAP_ALL;
return false;
}
#endif /* CONFIG_PPC_KUAP */
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */
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