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From:   Arnd Bergmann <arnd@arndb.de>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Jeremy Kerr <jk@ozlabs.org>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        linuxppc-dev@lists.ozlabs.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] fixup! signal: factor copy_siginfo_to_external32 from copy_siginfo_to_user32
Date:   Tue, 28 Apr 2020 21:56:26 +0200
Message-Id: <20200428195645.1365019-1-arnd@arndb.de>
In-Reply-To: <20200428074827.GA19846@lst.de>
References: <20200428074827.GA19846@lst.de>
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Sender: linux-kernel-owner@vger.kernel.org
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I think I found a way to improve the x32 handling:

This is a simplification over Christoph's "[PATCH 2/7] signal: factor
copy_siginfo_to_external32 from copy_siginfo_to_user32", reducing the
x32 specifics in the common code to a single #ifdef/#endif check, in
order to keep it more readable for everyone else.

Christoph, if you like it, please fold into your patch.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/x86/include/asm/compat.h | 10 ++++++++++
 arch/x86/kernel/signal.c      | 23 +++++++++++++++++++++++
 kernel/signal.c               | 15 ++-------------
 3 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index 52e9f3480f69..9341ea3da757 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -214,7 +214,17 @@ static inline bool in_compat_syscall(void)
 #endif
 
 struct compat_siginfo;
+#ifdef CONFIG_X86_X32_ABI
 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
 		const kernel_siginfo_t *from, bool x32_ABI);
+#else
+int copy_siginfo_to_user32(struct compat_siginfo __user *to,
+		const kernel_siginfo_t *from);
+static inline int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
+		const kernel_siginfo_t *from, bool x32_ABI)
+{
+	return copy_siginfo_to_user32(to, from);
+}
+#endif
 
 #endif /* _ASM_X86_COMPAT_H */
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 83b74fb38c8f..0e166571d28b 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -511,6 +511,29 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
 }
 #endif /* CONFIG_X86_32 */
 
+#ifdef CONFIG_X86_X32_ABI
+int copy_siginfo_to_user32(struct compat_siginfo __user *to,
+			   const struct kernel_siginfo *from)
+{
+	return __copy_siginfo_to_user32(to, from, in_x32_syscall());
+}
+
+int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
+			     const struct kernel_siginfo *from, bool x32_ABI)
+{
+	struct compat_siginfo new;
+
+	copy_siginfo_to_external32(&new, from);
+	if (x32_ABI && from->si_signo == SIGCHLD) {
+		new._sifields._sigchld_x32._utime = from->si_utime;
+		new._sifields._sigchld_x32._stime = from->si_stime;
+	}
+	if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
+		return -EFAULT;
+	return 0;
+}
+#endif
+
 static int x32_setup_rt_frame(struct ksignal *ksig,
 			      compat_sigset_t *set,
 			      struct pt_regs *regs)
diff --git a/kernel/signal.c b/kernel/signal.c
index 1a81602050b4..935facca4860 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3318,29 +3318,18 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
 	}
 }
 
+#ifndef CONFIG_X86_X32_ABI
 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
 			   const struct kernel_siginfo *from)
-#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
-{
-	return __copy_siginfo_to_user32(to, from, in_x32_syscall());
-}
-int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
-			     const struct kernel_siginfo *from, bool x32_ABI)
-#endif
 {
 	struct compat_siginfo new;
 
 	copy_siginfo_to_external32(&new, from);
-#ifdef CONFIG_X86_X32_ABI
-	if (x32_ABI && from->si_signo == SIGCHLD) {
-		new._sifields._sigchld_x32._utime = from->si_utime;
-		new._sifields._sigchld_x32._stime = from->si_stime;
-	}
-#endif
 	if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
 		return -EFAULT;
 	return 0;
 }
+#endif
 
 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
 					 const struct compat_siginfo *from)
-- 
2.26.0