linux-kernel - [PATCH v4 05/23] powerpc/64s: Make kuap_check_amr() and kuap_get_and_check

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Message-Id: <0f0efde4b821684f848a644c9b8eb3cf39852382.1611585031.git.christophe.leroy@csgroup.eu>
Date:   Mon, 25 Jan 2021 14:48:17 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, npiggin@...il.com,
        msuchanek@...e.de
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v4 05/23] powerpc/64s: Make kuap_check_amr() and
 kuap_get_and_check_amr() generic

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.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/include/asm/book3s/64/kup.h | 24 ++----------------------
 arch/powerpc/include/asm/kup.h           |  9 ++++++++-
 arch/powerpc/kernel/syscall_64.c         | 12 ++++++------
 3 files changed, 16 insertions(+), 29 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
index f50f72e535aa..1507681ad4ef 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -281,7 +281,7 @@ 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);
@@ -292,27 +292,7 @@ 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 bf221a2a523e..6ef9f9cfbed0 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -66,7 +66,14 @@ 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_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/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
index 32f72965da26..b627a6384029 100644
--- a/arch/powerpc/kernel/syscall_64.c
+++ b/arch/powerpc/kernel/syscall_64.c
@@ -65,7 +65,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
 			isync();
 	} else
 #endif
-		kuap_check_amr();
+		kuap_check();
 
 	account_cpu_user_entry();
 
@@ -181,7 +181,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
 
 	CT_WARN_ON(ct_state() == CONTEXT_USER);
 
-	kuap_check_amr();
+	kuap_check();
 
 	regs->result = r3;
 
@@ -303,7 +303,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
 	 * We don't need to restore AMR on the way back to userspace for KUAP.
 	 * AMR can only have been unlocked if we interrupted the kernel.
 	 */
-	kuap_check_amr();
+	kuap_check();
 
 	local_irq_save(flags);
 
@@ -381,7 +381,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 	unsigned long *ti_flagsp = &current_thread_info()->flags;
 	unsigned long flags;
 	unsigned long ret = 0;
-	unsigned long amr;
+	unsigned long kuap;
 
 	if (IS_ENABLED(CONFIG_PPC_BOOK3S) && unlikely(!(regs->msr & MSR_RI)))
 		unrecoverable_exception(regs);
@@ -394,7 +394,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 	if (TRAP(regs) != 0x700)
 		CT_WARN_ON(ct_state() == CONTEXT_USER);
 
-	amr = kuap_get_and_check_amr();
+	kuap = kuap_get_and_check();
 
 	if (unlikely(*ti_flagsp & _TIF_EMULATE_STACK_STORE)) {
 		clear_bits(_TIF_EMULATE_STACK_STORE, ti_flagsp);
@@ -446,7 +446,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 	 * which would cause Read-After-Write stalls. Hence, we take the AMR
 	 * value from the check above.
 	 */
-	kuap_kernel_restore(regs, amr);
+	kuap_kernel_restore(regs, kuap);
 
 	return ret;
 }
-- 
2.25.0