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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__
#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 */
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