Re: [PATCH v2 40/43] powerpc/64s: Make kuap_check_amr() and kuap_get_and_check_amr() generic

[Christophe Leroy]

Le 10/03/2021 à 02:37, Nicholas Piggin a écrit :

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,

Ok, renamed kuap_assert_locked() and kuap_get_and_assert_locked()

Reviewed-by: Nicholas Piggin <npig...@gmail.com>

Signed-off-by: Christophe Leroy <christophe.le...@csgroup.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