semihosting: Split out semihost_sys_lseek

Split out the non-ARM specific portions of SYS_SEEK to a
reusable function.  This handles all GuestFD.  Isolate the
curious ARM-specific return value processing to a new
callback, common_semi_seek_cb.

Expand the internal type of the offset to int64_t, and
provide the whence argument, which will be required by
m68k and nios2 semihosting.

Note that gdb_do_syscall %x reads target_ulong, not int.

Reviewed-by: Luc Michel <lmichel@kalray.eu>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/exec/gdbstub.h b/include/exec/gdbstub.h
index 95a8b7b056..b588c306cc 100644
--- a/include/exec/gdbstub.h
+++ b/include/exec/gdbstub.h
@@ -41,6 +41,11 @@
 #define GDB_ENAMETOOLONG   91
 #define GDB_EUNKNOWN       9999
 
+/* For gdb file i/o remote protocol lseek whence. */
+#define GDB_SEEK_SET  0
+#define GDB_SEEK_CUR  1
+#define GDB_SEEK_END  2
+
 /* For gdb file i/o stat/fstat. */
 typedef uint32_t gdb_mode_t;
 typedef uint32_t gdb_time_t;