linux-kernel - [RFC PATCH v3 02/15] powerpc/radix: Make kuap_check_amr() and kuap_restore

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Date:   Mon,  6 Apr 2020 18:16:38 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
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: [RFC PATCH v3 02/15] powerpc/radix: Make kuap_check_amr() and
 kuap_restore_amr() generic

In preparation of porting powerpc32 to C syscall entry/exit,
rename kuap_check_amr() and kuap_restore_amr() as kuap_check()
and kuap_restore(), and move the stub for when CONFIG_PPC_KUAP is
not selected in the generic asm/kup.h

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/include/asm/book3s/64/kup-radix.h | 12 ++----------
 arch/powerpc/include/asm/kup.h                 |  2 ++
 arch/powerpc/kernel/syscall_64.c               | 10 +++++-----
 3 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h b/arch/powerpc/include/asm/book3s/64/kup-radix.h
index 3bcef989a35d..1f2716a0dcd8 100644
--- a/arch/powerpc/include/asm/book3s/64/kup-radix.h
+++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h
@@ -60,13 +60,13 @@
 #include <asm/mmu.h>
 #include <asm/ptrace.h>
 
-static inline void kuap_restore_amr(struct pt_regs *regs)
+static inline void kuap_restore(struct pt_regs *regs)
 {
 	if (mmu_has_feature(MMU_FTR_RADIX_KUAP))
 		mtspr(SPRN_AMR, regs->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_RADIX_KUAP))
 		WARN_ON_ONCE(mfspr(SPRN_AMR) != AMR_KUAP_BLOCKED);
@@ -141,14 +141,6 @@ bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
 		    (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)),
 		    "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read");
 }
-#else /* CONFIG_PPC_KUAP */
-static inline void kuap_restore_amr(struct pt_regs *regs)
-{
-}
-
-static inline void kuap_check_amr(void)
-{
-}
 #endif /* CONFIG_PPC_KUAP */
 
 #endif /* __ASSEMBLY__ */
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index 92bcd1a26d73..1100c13b6d9e 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -62,6 +62,8 @@ bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
 {
 	return false;
 }
+static inline void kuap_restore(struct pt_regs *regs) { }
+static inline void kuap_check(void) { }
 #endif /* CONFIG_PPC_KUAP */
 
 static inline void allow_read_from_user(const void __user *from, unsigned long size)
diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
index f021db893ec2..4c46f3aefaf8 100644
--- a/arch/powerpc/kernel/syscall_64.c
+++ b/arch/powerpc/kernel/syscall_64.c
@@ -2,7 +2,7 @@
 
 #include <linux/err.h>
 #include <asm/asm-prototypes.h>
-#include <asm/book3s/64/kup-radix.h>
+#include <asm/kup.h>
 #include <asm/cputime.h>
 #include <asm/hw_irq.h>
 #include <asm/kprobes.h>
@@ -48,7 +48,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
 	}
 #endif
 
-	kuap_check_amr();
+	kuap_check();
 
 	/*
 	 * This is not required for the syscall exit path, but makes the
@@ -220,7 +220,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
 	local_paca->tm_scratch = regs->msr;
 #endif
 
-	kuap_check_amr();
+	kuap_check();
 
 	account_cpu_user_exit();
 
@@ -300,7 +300,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
 	local_paca->tm_scratch = regs->msr;
 #endif
 
-	kuap_check_amr();
+	kuap_check();
 
 	account_cpu_user_exit();
 
@@ -370,7 +370,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 	 * We don't need to restore AMR on the way back to userspace for KUAP.
 	 * The value of AMR only matters while we're in the kernel.
 	 */
-	kuap_restore_amr(regs);
+	kuap_restore(regs);
 
 	return ret;
 }
-- 
2.25.0