[COMMITTED] sparc: Fix arch_fork definition

Message ID 20180328003653.15247-1-adhemerval.zanella@linaro.org
State New
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Series
  • [COMMITTED] sparc: Fix arch_fork definition
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Commit Message

Adhemerval Zanella March 28, 2018, 12:36 a.m.
From: Adhemerval Zanella <adhemerval.zanella@linaro.org>

This patch fixes 3dc214977 for sparc.  Different than other architectures
SPARC kernel Kconfig does not define CONFIG_CLONE_BACKWARDS, however it
has the same ABI as if it did, implemented by sparc-specific code
(sparc_do_fork).

It also has a unique return value convention for clone:

   Parent -->  %o0 == child's  pid, %o1 == 0
   Child  -->  %o0 == parent's pid, %o1 == 1

Which required a special macro to correct issue the syscall
(INLINE_CLONE_SYSCALL).

Checked on sparc64-linux-gnu and sparcv9-linux-gnu.

	* sysdeps/unix/sysv/linux/arch-fork.h [__ASSUME_CLONE_BACKWARDS]
	(arch_fork): Issue INLINE_CLONE_SYSCALL if defined.
	* sysdeps/unix/sysv/linux/sparc/kernel-features.h
	(__ASSUME_CLONE_BACKWARDS): Define.
---
 ChangeLog                                       |  7 +++++++
 sysdeps/unix/sysv/linux/arch-fork.h             |  4 ++++
 sysdeps/unix/sysv/linux/sparc/kernel-features.h | 14 ++++++++++++++
 3 files changed, 25 insertions(+)

Patch

diff --git a/sysdeps/unix/sysv/linux/arch-fork.h b/sysdeps/unix/sysv/linux/arch-fork.h
index 3daa9651e5..046d9fc60d 100644
--- a/sysdeps/unix/sysv/linux/arch-fork.h
+++ b/sysdeps/unix/sysv/linux/arch-fork.h
@@ -34,7 +34,11 @@  arch_fork (void *ctid)
   const int flags = CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD;
   long int ret;
 #ifdef __ASSUME_CLONE_BACKWARDS
+# ifdef INLINE_CLONE_SYSCALL
+  ret = INLINE_CLONE_SYSCALL (flags, 0, NULL, 0, ctid);
+# else
   ret = INLINE_SYSCALL_CALL (clone, flags, 0, NULL, 0, ctid);
+# endif
 #elif defined(__ASSUME_CLONE_BACKWARDS2)
   ret = INLINE_SYSCALL_CALL (clone, 0, flags, NULL, ctid, 0);
 #elif defined(__ASSUME_CLONE_BACKWARDS3)
diff --git a/sysdeps/unix/sysv/linux/sparc/kernel-features.h b/sysdeps/unix/sysv/linux/sparc/kernel-features.h
index 2fd12cb7ce..64d714036e 100644
--- a/sysdeps/unix/sysv/linux/sparc/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/sparc/kernel-features.h
@@ -40,3 +40,17 @@ 
 
 /* sparc only supports ipc syscall.  */
 #undef __ASSUME_DIRECT_SYSVIPC_SYSCALLS
+
+/* SPARC kernel Kconfig does not define CONFIG_CLONE_BACKWARDS, however it
+   has the same ABI as if it did, implemented by sparc-specific code
+   (sparc_do_fork).
+
+   It also has a unique return value convention:
+
+     Parent -->  %o0 == child's  pid, %o1 == 0
+     Child  -->  %o0 == parent's pid, %o1 == 1
+
+   Which required a special macro to correct issue the syscall
+   (INLINE_CLONE_SYSCALL).  */
+#undef __ASSUME_CLONE_DEFAULT
+#define __ASSUME_CLONE_BACKWARDS	1