minix/lib/libsys/taskcall.c

/* _taskcall() is the same as _syscall() except it returns negative error
 * codes directly and not in errno.  This is a better interface for PM and
 * VFS.
 */

#include <lib.h>
#include <minix/syslib.h>

int _taskcall(who, syscallnr, msgptr)
endpoint_t who;
int syscallnr;
register message *msgptr;
{
  int status;

  msgptr->m_type = syscallnr;
  status = sendrec(who, msgptr);
  if (status != 0) return(status);
  return(msgptr->m_type);
}
Initial revision 2005-04-21 16:53:53 +02:00			`/* _taskcall() is the same as _syscall() except it returns negative error`
More cleanup to remove MM and FS references 2010-06-10 16:04:46 +02:00			`* codes directly and not in errno. This is a better interface for PM and`
			`* VFS.`
Initial revision 2005-04-21 16:53:53 +02:00			`*/`

			`#include <lib.h>`
			`#include <minix/syslib.h>`

retire PUBLIC, PRIVATE and FORWARD 2012-03-25 20:25:53 +02:00			`int _taskcall(who, syscallnr, msgptr)`
endpoint_t in syslib - headers use the endpoint_t in syslib.h and the implmentation was using int instead. Both uses endpoint_t now - every variable named like proc, proc_nr or proc_nr_e of type endpoint_t has name proc_ep now - endpoint_t defined as u32_t not int 2009-09-22 23:42:02 +02:00			`endpoint_t who;`
Initial revision 2005-04-21 16:53:53 +02:00			`int syscallnr;`
			`register message *msgptr;`
			`{`
			`int status;`

			`msgptr->m_type = syscallnr;`
SYSENTER/SYSCALL support . add cpufeature detection of both . use it for both ipc and kernelcall traps, using a register for call number . SYSENTER/SYSCALL does not save any context, therefore userland has to save it . to accomodate multiple kernel entry/exit types, the entry type is recorded in the process struct. hitherto all types were interrupt (soft int, exception, hard int); now SYSENTER/SYSCALL is new, with the difference that context is not fully restored from proc struct when running the process again. this can't be done as some information is missing. . complication: cases in which the kernel has to fully change process context (i.e. sigreturn). in that case the exit type is changed from SYSENTER/SYSEXIT to soft-int (i.e. iret) and context is fully restored from the proc struct. this does mean the PC and SP must change, as the sysenter/sysexit userland code will otherwise try to restore its own context. this is true in the sigreturn case. . override all usage by setting libc_ipc=1 2012-06-10 19:50:17 +02:00			`status = sendrec(who, msgptr);`
Initial revision 2005-04-21 16:53:53 +02:00			`if (status != 0) return(status);`
			`return(msgptr->m_type);`
			`}`