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powerpc/32s: Create C version of kuap save/restore/check helpers

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In preparation of porting PPC32 to C syscall entry/exit,
create C version of kuap_save_and_lock() and kuap_user_restore() and
kuap_kernel_restore() and kuap_assert_locked() and
kuap_get_and_assert_locked() on book3s/32.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2be8fb729da4a0f9863b25e1b9d547174fcd5056.1615552867.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2021-03-12 12:50:49 +00:00 committed by Michael Ellerman
parent ad2d234477
commit 21eb58ae4f
1 changed files with 45 additions and 0 deletions
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45
arch/powerpc/include/asm/book3s/32/kup.h
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@ -72,6 +72,51 @@ static inline void kuap_update_sr(u32 sr, u32 addr, u32 end)
isync(); /* Context sync required after mtsr() */
}
static inline void kuap_save_and_lock(struct pt_regs *regs)
{
unsigned long kuap = current->thread.kuap;
u32 addr = kuap & 0xf0000000;
u32 end = kuap << 28;
regs->kuap = kuap;
if (unlikely(!kuap))
return;
current->thread.kuap = 0;
kuap_update_sr(mfsr(addr) | SR_KS, addr, end); /* Set Ks */
}
static inline void kuap_user_restore(struct pt_regs *regs)
{
}
static inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
{
u32 addr = regs->kuap & 0xf0000000;
u32 end = regs->kuap << 28;
current->thread.kuap = regs->kuap;
if (unlikely(regs->kuap == kuap))
return;
kuap_update_sr(mfsr(addr) & ~SR_KS, addr, end); /* Clear Ks */
}
static 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 != 0);
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)
{