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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>
#ifdef __ASSEMBLY__
#ifdef CONFIG_PPC_KUAP
.macro kuap_update_sr gpr1, gpr2, gpr3 /* NEVER use r0 as gpr2 due to addis */
101: mtsrin \gpr1, \gpr2
addi \gpr1, \gpr1, 0x111 /* next VSID */
rlwinm \gpr1, \gpr1, 0, 0xf0ffffff /* clear VSID overflow */
addis \gpr2, \gpr2, 0x1000 /* address of next segment */
cmplw \gpr2, \gpr3
blt- 101b
isync
.endm
.macro kuap_save_and_lock sp, thread, gpr1, gpr2, gpr3
lwz \gpr2, KUAP(\thread)
rlwinm. \gpr3, \gpr2, 28, 0xf0000000
stw \gpr2, STACK_REGS_KUAP(\sp)
beq+ 102f
li \gpr1, 0
stw \gpr1, KUAP(\thread)
mfsrin \gpr1, \gpr2
oris \gpr1, \gpr1, SR_KS@h /* set Ks */
kuap_update_sr \gpr1, \gpr2, \gpr3
102:
.endm
.macro kuap_restore sp, current, gpr1, gpr2, gpr3
lwz \gpr2, STACK_REGS_KUAP(\sp)
rlwinm. \gpr3, \gpr2, 28, 0xf0000000
stw \gpr2, THREAD + KUAP(\current)
beq+ 102f
mfsrin \gpr1, \gpr2
rlwinm \gpr1, \gpr1, 0, ~SR_KS /* Clear Ks */
kuap_update_sr \gpr1, \gpr2, \gpr3
102:
.endm
.macro kuap_check current, gpr
#ifdef CONFIG_PPC_KUAP_DEBUG
lwz \gpr, THREAD + KUAP(\current)
999: twnei \gpr, 0
EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE)
#endif
.endm
#endif /* CONFIG_PPC_KUAP */
#else /* !__ASSEMBLY__ */
#ifdef CONFIG_PPC_KUAP
#include <linux/sched.h>
static inline void kuap_update_sr(u32 sr, u32 addr, u32 end)
{
addr &= 0xf0000000; /* align addr to start of segment */
barrier(); /* make sure thread.kuap is updated before playing with SRs */
while (addr < end) {
mtsr(sr, addr);
sr += 0x111; /* next VSID */
sr &= 0xf0ffffff; /* clear VSID overflow */
addr += 0x10000000; /* address of next segment */
}
isync(); /* Context sync required after mtsr() */
}
static __always_inline void allow_user_access(void __user *to, const void __user *from,
u32 size, unsigned long dir)
{
u32 addr, end;
BUILD_BUG_ON(!__builtin_constant_p(dir));
BUILD_BUG_ON(dir & ~KUAP_READ_WRITE);
if (!(dir & KUAP_WRITE))
return;
addr = (__force u32)to;
if (unlikely(addr >= TASK_SIZE || !size))
return;
end = min(addr + size, TASK_SIZE);
current->thread.kuap = (addr & 0xf0000000) | ((((end - 1) >> 28) + 1) & 0xf);
kuap_update_sr(mfsr(addr) & ~SR_KS, addr, end); /* Clear Ks */
}
static __always_inline void prevent_user_access(void __user *to, const void __user *from,
u32 size, unsigned long dir)
{
u32 addr, end;
BUILD_BUG_ON(!__builtin_constant_p(dir));
if (dir & KUAP_CURRENT_WRITE) {
u32 kuap = current->thread.kuap;
if (unlikely(!kuap))
return;
addr = kuap & 0xf0000000;
end = kuap << 28;
} else if (dir & KUAP_WRITE) {
addr = (__force u32)to;
end = min(addr + size, TASK_SIZE);
if (unlikely(addr >= TASK_SIZE || !size))
return;
} else {
return;
}
current->thread.kuap = 0;
kuap_update_sr(mfsr(addr) | SR_KS, addr, end); /* set Ks */
}
static inline unsigned long prevent_user_access_return(void)
{
unsigned long flags = current->thread.kuap;
unsigned long addr = flags & 0xf0000000;
unsigned long end = flags << 28;
void __user *to = (__force void __user *)addr;
if (flags)
prevent_user_access(to, to, end - addr, KUAP_READ_WRITE);
return flags;
}
static inline void restore_user_access(unsigned long flags)
{
unsigned long addr = flags & 0xf0000000;
unsigned long end = flags << 28;
void __user *to = (__force void __user *)addr;
if (flags)
allow_user_access(to, to, end - addr, KUAP_READ_WRITE);
}
static inline bool
bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
{
unsigned long begin = regs->kuap & 0xf0000000;
unsigned long end = regs->kuap << 28;
return is_write && (address < begin || address >= end);
}
#endif /* CONFIG_PPC_KUAP */
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */
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