[Qemu-devel] [PATCH 03/34] linux-user: Support for restarting system calls

[Timothy E Baldwin]

This allows SA_RESTART to be supported along with various case
where pending signals need to be handled before a system call.

New macro TARGET_ERESTARTSYS which is the error code used by Linux
to indicate that system call should be restarted.

TARGET_QEMU_ESIGRETURN moved into errno_defs.h and renumbered to
513 which is safe from future use as a system call return value
as it is used for system call restarting in Linux and exposed only
via ptrace.

do_sigreturn() and do_rt_sigreturn() will be amended to return
-TARGET_QEMU_ESIGRETURN rather than the value of result register to
avoid confusion with -TARGET_ERESTARTSYS and cpu_loop() will be
altered to act upon the return value accordingly.

Signed-off-by: Timothy Edward Baldwin <address@hidden>
---
 linux-user/errno_defs.h     | 3 +++
 linux-user/mips/syscall.h   | 4 ----
 linux-user/mips64/syscall.h | 4 ----
 linux-user/ppc/syscall.h    | 2 --
 4 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/linux-user/errno_defs.h b/linux-user/errno_defs.h
index 8a1cf76..a385f50 100644
--- a/linux-user/errno_defs.h
+++ b/linux-user/errno_defs.h
@@ -139,3 +139,6 @@
 /* for robust mutexes */
 #define TARGET_EOWNERDEAD      130     /* Owner died */
 #define TARGET_ENOTRECOVERABLE 131     /* State not recoverable */
+
+#define TARGET_ERESTARTSYS     512  /* Restart system call */
+#define TARGET_QEMU_ESIGRETURN 513  /* Return from signal */
diff --git a/linux-user/mips/syscall.h b/linux-user/mips/syscall.h
index 35ca23b..e34f80c 100644
--- a/linux-user/mips/syscall.h
+++ b/linux-user/mips/syscall.h
@@ -220,10 +220,6 @@ struct target_pt_regs {
 #define TARGET_ENOTRECOVERABLE 166     /* State not recoverable */
 
 
-
-/* Nasty hack: define a fake errno value for use by sigreturn.  */
-#define TARGET_QEMU_ESIGRETURN 255
-
 #define UNAME_MACHINE "mips"
 #define UNAME_MINIMUM_RELEASE "2.6.32"
 
diff --git a/linux-user/mips64/syscall.h b/linux-user/mips64/syscall.h
index 6733107..33afb8d 100644
--- a/linux-user/mips64/syscall.h
+++ b/linux-user/mips64/syscall.h
@@ -217,10 +217,6 @@ struct target_pt_regs {
 #define TARGET_ENOTRECOVERABLE 166     /* State not recoverable */
 
 
-
-/* Nasty hack: define a fake errno value for use by sigreturn. */
-#define TARGET_QEMU_ESIGRETURN 255
-
 #define UNAME_MACHINE "mips64"
 #define UNAME_MINIMUM_RELEASE "2.6.32"
 
diff --git a/linux-user/ppc/syscall.h b/linux-user/ppc/syscall.h
index 0daf5cd..532cbbd 100644
--- a/linux-user/ppc/syscall.h
+++ b/linux-user/ppc/syscall.h
@@ -50,8 +50,6 @@ struct target_revectored_struct {
        abi_ulong __map[8];                     /* 256 bits */
 };
 
-/* Nasty hack: define a fake errno value for use by sigreturn.  */
-#define TARGET_QEMU_ESIGRETURN 255
 
 /*
  * flags masks
-- 
2.1.4