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Message-Id: <1615340152.vcj9lsklbx.astroid@bobo.none>
Date: Wed, 10 Mar 2021 11:37:19 +1000
From: Nicholas Piggin <npiggin@...il.com>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Michael Ellerman <mpe@...erman.id.au>,
Paul Mackerras <paulus@...ba.org>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v2 40/43] powerpc/64s: Make kuap_check_amr() and
kuap_get_and_check_amr() generic
Excerpts from Christophe Leroy's message of March 9, 2021 10:10 pm:
> In preparation of porting powerpc32 to C syscall entry/exit,
> rename kuap_check_amr() and kuap_get_and_check_amr() as kuap_check()
> and kuap_get_and_check(), and move in the generic asm/kup.h the stub
> for when CONFIG_PPC_KUAP is not selected.
Looks pretty straightforward to me.
While you're renaming things, could kuap_check_amr() be changed to
kuap_assert_locked() or similar? Otherwise,
Reviewed-by: Nicholas Piggin <npiggin@...il.com>
>
> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
> ---
> arch/powerpc/include/asm/book3s/64/kup.h | 24 ++----------------------
> arch/powerpc/include/asm/kup.h | 10 +++++++++-
> arch/powerpc/kernel/interrupt.c | 12 ++++++------
> arch/powerpc/kernel/irq.c | 2 +-
> 4 files changed, 18 insertions(+), 30 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
> index 8bd905050896..d9b07e9998be 100644
> --- a/arch/powerpc/include/asm/book3s/64/kup.h
> +++ b/arch/powerpc/include/asm/book3s/64/kup.h
> @@ -287,7 +287,7 @@ static inline void kuap_kernel_restore(struct pt_regs *regs,
> */
> }
>
> -static inline unsigned long kuap_get_and_check_amr(void)
> +static inline unsigned long kuap_get_and_check(void)
> {
> if (mmu_has_feature(MMU_FTR_BOOK3S_KUAP)) {
> unsigned long amr = mfspr(SPRN_AMR);
> @@ -298,27 +298,7 @@ static inline unsigned long kuap_get_and_check_amr(void)
> return 0;
> }
>
> -#else /* CONFIG_PPC_PKEY */
> -
> -static inline void kuap_user_restore(struct pt_regs *regs)
> -{
> -}
> -
> -static inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long amr)
> -{
> -}
> -
> -static inline unsigned long kuap_get_and_check_amr(void)
> -{
> - return 0;
> -}
> -
> -#endif /* CONFIG_PPC_PKEY */
> -
> -
> -#ifdef CONFIG_PPC_KUAP
> -
> -static inline void kuap_check_amr(void)
> +static inline void kuap_check(void)
> {
> if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && mmu_has_feature(MMU_FTR_BOOK3S_KUAP))
> WARN_ON_ONCE(mfspr(SPRN_AMR) != AMR_KUAP_BLOCKED);
> diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
> index 25671f711ec2..b7efa46b3109 100644
> --- a/arch/powerpc/include/asm/kup.h
> +++ b/arch/powerpc/include/asm/kup.h
> @@ -74,7 +74,15 @@ bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
> return false;
> }
>
> -static inline void kuap_check_amr(void) { }
> +static inline void kuap_check(void) { }
> +static inline void kuap_save_and_lock(struct pt_regs *regs) { }
> +static inline void kuap_user_restore(struct pt_regs *regs) { }
> +static inline void kuap_kernel_restore(struct pt_regs *regs, unsigned long amr) { }
> +
> +static inline unsigned long kuap_get_and_check(void)
> +{
> + return 0;
> +}
>
> /*
> * book3s/64/kup-radix.h defines these functions for the !KUAP case to flush
> diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
> index 727b7848c9cc..40ed55064e54 100644
> --- a/arch/powerpc/kernel/interrupt.c
> +++ b/arch/powerpc/kernel/interrupt.c
> @@ -76,7 +76,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
> } else
> #endif
> #ifdef CONFIG_PPC64
> - kuap_check_amr();
> + kuap_check();
> #endif
>
> booke_restore_dbcr0();
> @@ -254,7 +254,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
> CT_WARN_ON(ct_state() == CONTEXT_USER);
>
> #ifdef CONFIG_PPC64
> - kuap_check_amr();
> + kuap_check();
> #endif
>
> regs->result = r3;
> @@ -380,7 +380,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
> * AMR can only have been unlocked if we interrupted the kernel.
> */
> #ifdef CONFIG_PPC64
> - kuap_check_amr();
> + kuap_check();
> #endif
>
> local_irq_save(flags);
> @@ -451,7 +451,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
> unsigned long flags;
> unsigned long ret = 0;
> #ifdef CONFIG_PPC64
> - unsigned long amr;
> + unsigned long kuap;
> #endif
>
> if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x) &&
> @@ -467,7 +467,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
> CT_WARN_ON(ct_state() == CONTEXT_USER);
>
> #ifdef CONFIG_PPC64
> - amr = kuap_get_and_check_amr();
> + kuap = kuap_get_and_check();
> #endif
>
> if (unlikely(current_thread_info()->flags & _TIF_EMULATE_STACK_STORE)) {
> @@ -511,7 +511,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
> * value from the check above.
> */
> #ifdef CONFIG_PPC64
> - kuap_kernel_restore(regs, amr);
> + kuap_kernel_restore(regs, kuap);
> #endif
>
> return ret;
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index d71fd10a1dd4..3b18d2b2c702 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -282,7 +282,7 @@ static inline void replay_soft_interrupts_irqrestore(void)
> * and re-locking AMR but we shouldn't get here in the first place,
> * hence the warning.
> */
> - kuap_check_amr();
> + kuap_check();
>
> if (kuap_state != AMR_KUAP_BLOCKED)
> set_kuap(AMR_KUAP_BLOCKED);
> --
> 2.25.0
>
>
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