[lxc-devel] [lxc/master] raw_syscalls: lxc_raw_clone() account for different trap number on 32bit SPARC

[brauner on Github]

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From 6dfb146378f24768980d6c1d600e6b2f44075d51 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at ubuntu.com>
Date: Tue, 16 Apr 2019 23:32:03 +0200
Subject: [PATCH] raw_syscalls: lxc_raw_clone()

Account for different trap number on 32bit SPARC.

Link: https://bugs.gentoo.org/656368
Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
 src/lxc/raw_syscalls.c | 42 ++++++++++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/src/lxc/raw_syscalls.c b/src/lxc/raw_syscalls.c
index 4ac51ac253..a4db306919 100644
--- a/src/lxc/raw_syscalls.c
+++ b/src/lxc/raw_syscalls.c
@@ -47,7 +47,7 @@ pid_t lxc_raw_clone(unsigned long flags)
 	/* On s390/s390x and cris the order of the first and second arguments
 	 * of the system call is reversed.
 	 */
-	return (int)syscall(__NR_clone, NULL, flags | SIGCHLD);
+	return syscall(__NR_clone, NULL, flags | SIGCHLD);
 #elif defined(__sparc__) && defined(__arch64__)
 	{
 		/*
@@ -55,28 +55,38 @@ pid_t lxc_raw_clone(unsigned long flags)
 		 * boolean flag whether this is the child or the parent in %o1.
 		 * Inline assembly is needed to get the flag returned in %o1.
 		 */
-		int in_child;
-		int child_pid;
-		asm volatile("mov %2, %%g1\n\t"
-			     "mov %3, %%o0\n\t"
-			     "mov 0 , %%o1\n\t"
-			     "t 0x6d\n\t"
-			     "mov %%o1, %0\n\t"
-			     "mov %%o0, %1"
-			     : "=r"(in_child), "=r"(child_pid)
-			     : "i"(__NR_clone), "r"(flags | SIGCHLD)
-			     : "%o1", "%o0", "%g1");
+		int child_pid, in_child, ret;
+
+                asm volatile("mov %3, %%g1\n\t"
+                             "mov %4, %%o0\n\t"
+                             "mov 0 , %%o1\n\t"
+#if defined(__arch64__)
+                             "t 0x6d\n\t"
+#else
+                             "t 0x10\n\t"
+#endif
+                             "addx %%g0, 0, %2\n\t"
+                             "mov %%o1, %0\n\t"
+                             "mov %%o0, %1" :
+                             "=r"(in_child), "=r"(child_pid), "=r"(ret) :
+                             "i"(__NR_clone), "r"(flags | SIGCHLD) :
+                             "%o1", "%o0", "%g1", "cc" );
+
+		if (ret) {
+			errno = child_pid;
+			return -1;
+		}
 
 		if (in_child)
 			return 0;
-		else
-			return child_pid;
+
+		return child_pid;
 	}
 #elif defined(__ia64__)
 	/* On ia64 the stack and stack size are passed as separate arguments. */
-	return (int)syscall(__NR_clone, flags | SIGCHLD, NULL, prctl_arg(0));
+	return syscall(__NR_clone, flags | SIGCHLD, NULL, prctl_arg(0));
 #else
-	return (int)syscall(__NR_clone, flags | SIGCHLD, NULL);
+	return syscall(__NR_clone, flags | SIGCHLD, NULL);
 #endif
 }