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powerpc/kuap: Prepare for supporting KUAP on BOOK3E/64 

Also call kuap_lock() and kuap_save_and_lock() from
interrupt functions with CONFIG_PPC64.

For book3s/64 we keep them empty as it is done in assembly.

Also do the locked assert when switching task unless it is
book3s/64.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1cbf94e26e6d6e2e028fd687588a7e6622d454a6.1634627931.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2021-10-19 09:29:26 +02:00 committed by Michael Ellerman
parent 047a6fd401
commit 42e03bc524
4 changed files with 14 additions and 5 deletions
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9
arch/powerpc/include/asm/book3s/64/kup.h
View File

@ -298,6 +298,15 @@ static inline unsigned long __kuap_get_and_assert_locked(void)
return amr;
}
/* Do nothing, book3s/64 does that in ASM */
static inline void __kuap_lock(void)
{
}
static inline void __kuap_save_and_lock(struct pt_regs *regs)
{
}
/*
* We support individually allowing read or write, but we don't support nesting
* because that would require an expensive read/modify write of the AMR.

2
arch/powerpc/include/asm/interrupt.h
View File

@ -154,12 +154,14 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
if (user_mode(regs)) {
kuap_lock();
CT_WARN_ON(ct_state() != CONTEXT_USER);
user_exit_irqoff();
account_cpu_user_entry();
account_stolen_time();
} else {
kuap_save_and_lock(regs);
/*
* CT_WARN_ON comes here via program_check_exception,
* so avoid recursion.

2
arch/powerpc/include/asm/kup.h
View File

@ -91,7 +91,6 @@ static __always_inline void kuap_assert_locked(void)
__kuap_get_and_assert_locked();
}
#ifdef CONFIG_PPC32
static __always_inline void kuap_lock(void)
{
if (kuap_is_disabled())
@ -107,7 +106,6 @@ static __always_inline void kuap_save_and_lock(struct pt_regs *regs)
__kuap_save_and_lock(regs);
}
#endif
static __always_inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long amr)
{

6
arch/powerpc/kernel/process.c
View File

@ -1315,9 +1315,9 @@ struct task_struct *__switch_to(struct task_struct *prev,
set_return_regs_changed(); /* _switch changes stack (and regs) */
#ifdef CONFIG_PPC32
kuap_assert_locked();
#endif
if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
kuap_assert_locked();
last = _switch(old_thread, new_thread);
/*