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Date:   Fri,  3 May 2019 12:12:24 -0700
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Subject: [PATCH v2 2/3] arm64: use the correct function type in SYSCALL_DEFINE0
From:   Sami Tolvanen <samitolvanen@google.com>
To:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Mark Rutland <mark.rutland@arm.com>
Cc:     Kees Cook <keescook@chromium.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Sami Tolvanen <samitolvanen@google.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Although a syscall defined using SYSCALL_DEFINE0 doesn't accept
parameters, use the correct function type to avoid indirect call
type mismatches with Control-Flow Integrity checking.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/arm64/include/asm/syscall_wrapper.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h
index a4477e515b798..507d0ee6bc690 100644
--- a/arch/arm64/include/asm/syscall_wrapper.h
+++ b/arch/arm64/include/asm/syscall_wrapper.h
@@ -30,10 +30,10 @@
 	}										\
 	static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
 
-#define COMPAT_SYSCALL_DEFINE0(sname)					\
-	asmlinkage long __arm64_compat_sys_##sname(void);		\
-	ALLOW_ERROR_INJECTION(__arm64_compat_sys_##sname, ERRNO);	\
-	asmlinkage long __arm64_compat_sys_##sname(void)
+#define COMPAT_SYSCALL_DEFINE0(sname)							\
+	asmlinkage long __arm64_compat_sys_##sname(const struct pt_regs *__unused);	\
+	ALLOW_ERROR_INJECTION(__arm64_compat_sys_##sname, ERRNO);			\
+	asmlinkage long __arm64_compat_sys_##sname(const struct pt_regs *__unused)
 
 #define COND_SYSCALL_COMPAT(name) \
 	cond_syscall(__arm64_compat_sys_##name);
@@ -62,11 +62,11 @@
 	static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
 
 #ifndef SYSCALL_DEFINE0
-#define SYSCALL_DEFINE0(sname)					\
-	SYSCALL_METADATA(_##sname, 0);				\
-	asmlinkage long __arm64_sys_##sname(void);		\
-	ALLOW_ERROR_INJECTION(__arm64_sys_##sname, ERRNO);	\
-	asmlinkage long __arm64_sys_##sname(void)
+#define SYSCALL_DEFINE0(sname)							\
+	SYSCALL_METADATA(_##sname, 0);						\
+	asmlinkage long __arm64_sys_##sname(const struct pt_regs *__unused);	\
+	ALLOW_ERROR_INJECTION(__arm64_sys_##sname, ERRNO);			\
+	asmlinkage long __arm64_sys_##sname(const struct pt_regs *__unused)
 #endif
 
 #ifndef COND_SYSCALL
-- 
2.21.0.1020.gf2820cf01a-goog