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

lib/libc/arch/i386/sys-minix/_ipc.S

@@ -9,40 +9,40 @@
 /*                           IPC assembly routines			  * */
 /**========================================================================* */
 /* all message passing routines save ebx, but destroy eax and ecx. */
-ENTRY(_send)
+ENTRY(_send_orig)
 	push	%ebp
 	movl	%esp, %ebp
 	push	%ebx
 	movl	SRC_DST(%ebp), %eax	/* eax = dest-src */
 	movl	MESSAGE(%ebp), %ebx	/* ebx = message pointer */
 	movl	$SEND, %ecx	/* _send(dest, ptr) */
-	int	$IPCVEC	/* trap to the kernel */
+	int	$IPCVEC_ORIG	/* trap to the kernel */
 	pop	%ebx
 	pop	%ebp
 	ret
 
-ENTRY(_receive)
+ENTRY(_receive_orig)
 	push	%ebp
 	movl	%esp, %ebp
 	push	%ebx
 	movl	SRC_DST(%ebp), %eax	/* eax = dest-src */
 	movl	MESSAGE(%ebp), %ebx	/* ebx = message pointer */
 	movl	$RECEIVE, %ecx	/* _receive(src, ptr) */
-	int	$IPCVEC	/* trap to the kernel */
+	int	$IPCVEC_ORIG	/* trap to the kernel */
 	movl	STATUS(%ebp), %ecx	/* ecx = status pointer */
 	movl	%ebx, (%ecx)
 	pop	%ebx
 	pop	%ebp
 	ret
 
-ENTRY(_sendrec)
+ENTRY(_sendrec_orig)
 	push	%ebp
 	movl	%esp, %ebp
 	push	%ebx
 	movl	SRC_DST(%ebp), %eax	/* eax = dest-src */
 	movl	MESSAGE(%ebp), %ebx	/* ebx = message pointer */
 	movl	$SENDREC, %ecx	/* _sendrec(srcdest, ptr) */
-	int	$IPCVEC	/* trap to the kernel */
+	int	$IPCVEC_ORIG	/* trap to the kernel */
 	pop	%ebx
 	pop	%ebp
 	ret
@@ -54,38 +54,38 @@ ENTRY(_minix_kernel_info_struct)
 	movl	$0, %eax
 	movl	$0, %ebx
 	movl	$MINIX_KERNINFO, %ecx
-	int	$IPCVEC	/* trap to the kernel */
+	int	$IPCVEC_ORIG	/* trap to the kernel */
 	movl	8(%ebp), %ecx	/* ecx = return struct ptr */
 	movl	%ebx, (%ecx)
 	pop	%ebx
 	pop	%ebp
 	ret
 
-ENTRY(_notify)
+ENTRY(_notify_orig)
 	push	%ebp
 	movl	%esp, %ebp
 	push	%ebx
 	movl	SRC_DST(%ebp), %eax	/* eax = destination  */
 	movl	$NOTIFY, %ecx	/* _notify(srcdst) */
-	int	$IPCVEC	/* trap to the kernel */
+	int	$IPCVEC_ORIG	/* trap to the kernel */
 	pop	%ebx
 	pop	%ebp
 	ret
 
-ENTRY(_sendnb)
+ENTRY(_sendnb_orig)
 	push	%ebp
 	movl	%esp, %ebp
 	push	%ebx
 	movl	SRC_DST(%ebp), %eax	/* eax = dest-src */
 	movl	MESSAGE(%ebp), %ebx	/* ebx = message pointer */
 	movl	$SENDNB, %ecx	/* _sendnb(dest, ptr) */
-	int	$IPCVEC	/* trap to the kernel */
+	int	$IPCVEC_ORIG	/* trap to the kernel */
 	pop	%ebx
 	pop	%ebp
 	ret
 
-ENTRY(_do_kernel_call)
+ENTRY(_do_kernel_call_orig)
 	/* pass the message pointer to kernel in the %eax register */
 	movl	4(%esp), %eax
-	int	$KERVEC
+	int	$KERVEC_ORIG
 	ret

lib/libc/arch/i386/sys-minix/_senda.S

@@ -4,7 +4,7 @@
 	MSGTAB = 8	/* message table */
 	TABCOUNT = 12	/* number of entries in message table */
 
-ENTRY(_senda)
+ENTRY(_senda_orig)
 	push	%ebp
 	movl	%esp, %ebp
 	push	%ebx

lib/libc/sys-minix/init.c

@@ -2,15 +2,29 @@
 #include <stdio.h>
 #include <minix/ipc.h>
 
+/* Minix kernel info, IPC functions pointers */
 struct minix_kerninfo *_minix_kerninfo = NULL;
 
 void    __minix_init(void) __attribute__((__constructor__, __used__));
 
+struct minix_ipcvecs _minix_ipcvecs = {
+	.sendrec_ptr = _sendrec_orig,
+	.send_ptr = _send_orig,
+	.notify_ptr = _notify_orig,
+	.senda_ptr = _senda_orig,
+	.sendnb_ptr = _sendnb_orig,
+	.receive_ptr = _receive_orig,
+	.do_kernel_call_ptr = _do_kernel_call_orig,
+};
+
 void __minix_init(void)
 {
 	if((_minix_kernel_info_struct(&_minix_kerninfo)) != 0
 	  || _minix_kerninfo->kerninfo_magic != KERNINFO_MAGIC) {
 		_minix_kerninfo = NULL;
-	}
+         } else if((_minix_kerninfo->ki_flags & MINIX_KIF_IPCVECS) &&
+         	_minix_kerninfo->minix_ipcvecs) {
+		_minix_ipcvecs = *_minix_kerninfo->minix_ipcvecs;
+         }
 }
 

lib/libc/sys-minix/syscall.c

@@ -11,7 +11,7 @@ int _syscall(endpoint_t who, int syscallnr, message *msgptr)
   int status;
 
   msgptr->m_type = syscallnr;
-  status = _sendrec(who, msgptr);
+  status = sendrec(who, msgptr);
   if (status != 0) {
 	/* 'sendrec' itself failed. */
 	/* XXX - strerror doesn't know all the codes */