[Qemu-devel] [PATCH] MIPS CP0 not usable in kernel mode?

[Qemu-devel] [PATCH] MIPS CP0 not usable in kernel mode?

[Stefan Weil]

Hello,

according to MIPS32 4KE User's Manual, coprocessor CP0 is
always usable when the processor is running in kernel mode.

So in kernel mode, exception "CP0 is not usable" should
not happen.

I think the boolean expression which checks for the
exception condition has to be inverted - see my patch
for translate.c.

Kind regards,
Stefan



RCS file: /sources/qemu/qemu/target-mips/translate.c,v
retrieving revision 1.11
diff -u -r1.11 translate.c
--- target-mips/translate.c    5 Dec 2005 19:59:36 -0000    1.11
+++ target-mips/translate.c    23 Mar 2006 19:25:53 -0000
@@ -1180,7 +1180,7 @@
     const unsigned char *opn = "unk";
 
     if (!(ctx->CP0_Status & (1 << CP0St_CU0)) &&
-        !(ctx->hflags & MIPS_HFLAG_UM) &&
+        (ctx->hflags & MIPS_HFLAG_UM) &&
         !(ctx->hflags & MIPS_HFLAG_ERL) &&
         !(ctx->hflags & MIPS_HFLAG_EXL)) {
         if (loglevel & CPU_LOG_TB_IN_ASM) {

//

Re: [Qemu-devel] [PATCH] MIPS CP0 not usable in kernel mode?

[Thiemo Seufer]

On Thu, Mar 23, 2006 at 08:48:25PM +0100, Stefan Weil wrote:
> Hello,
> 
> according to MIPS32 4KE User's Manual, coprocessor CP0 is
> always usable when the processor is running in kernel mode.
> 
> So in kernel mode, exception "CP0 is not usable" should
> not happen.
> 
> I think the boolean expression which checks for the
> exception condition has to be inverted - see my patch
> for translate.c.

This is correct (otherwise it wouldn't be possible to ever enable CP0).
The Linux kernel (plus qemu startup) happens to avoid this particular
case, which might explain it wasn't caught earlier.


Thiemo

[Qemu-devel] [PATCH] Fix some minor warnings from qemu-doc.texi

[Stefan Weil]

Hi,

texi2html prints several warnings when it processes qemu-doc.texi.
Some of these warnings are fixed with my patch.

Merci
Stefan

diff -u -b -B -u -r1.81 qemu-doc.texi
--- qemu-doc.texi       20 Feb 2006 00:35:00 -0000      1.81
+++ qemu-doc.texi       29 Mar 2006 12:04:36 -0000
@@ -903,7 +903,7 @@
 @example
 > ./qemu.sh
 Connected to host network interface: tun0
-Linux version 2.4.21 (bellard@voyager.localdomain) (gcc version 3.2.2 
20030222 (Red Hat Linux 3.2.2-5)) #5 Tue Nov 11 18:18:53 CET 2003
+Linux version 2.4.21 (bellard@@voyager.localdomain) (gcc version 3.2.2 
20030222 (Red Hat Linux 3.2.2-5)) #5 Tue Nov 11 18:18:53 CET 2003
 BIOS-provided physical RAM map:
  BIOS-e801: 0000000000000000 - 000000000009f000 (usable)
  BIOS-e801: 0000000000100000 - 0000000002000000 (usable)
@@ -940,7 +940,7 @@
 pty: 256 Unix98 ptys configured
 Serial driver version 5.05c (2001-07-08) with no serial options enabled
 ttyS00 at 0x03f8 (irq = 4) is a 16450
-ne.c:v1.10 9/23/94 Donald Becker (becker@scyld.com)
+ne.c:v1.10 9/23/94 Donald Becker (becker@@scyld.com)
 Last modified Nov 1, 2000 by Paul Gortmaker
 NE*000 ethercard probe at 0x300: 52 54 00 12 34 56
 eth0: NE2000 found at 0x300, using IRQ 9.
@@ -963,7 +963,7 @@
 VFS: Mounted root (ext2 filesystem).
 Freeing unused kernel memory: 64k freed

-Linux version 2.4.21 (bellard@voyager.localdomain) (gcc version 3.2.2 
20030222 (Red Hat Linux 3.2.2-5)) #5 Tue Nov 11 18:18:53 CET 2003
+Linux version 2.4.21 (bellard@@voyager.localdomain) (gcc version 3.2.2 
20030222 (Red Hat Linux 3.2.2-5)) #5 Tue Nov 11 18:18:53 CET 2003

 QEMU Linux test distribution (based on Redhat 9)

[Qemu-devel] [PATCH] Small fix for qemu-doc.texi

[Stefan Weil]

Hi,

this patch fixes 4 minor issues in qemu-doc.texi.

Kind regards,
Stefan

--- qemu-doc.texi       19 Aug 2006 16:56:18 -0000      1.105
+++ qemu-doc.texi       21 Aug 2006 16:34:23 -0000
@@ -559,8 +559,8 @@
 The TCP Net Console has two modes of operation.  It can send the serial
 I/O to a location or wait for a connection from a location.  By default
 the TCP Net Console is sent to @var{host} at the @var{port}.  If you use
-the @var{,server} option QEMU will wait for a client socket application
-to connect to the port before continuing, unless the @code{,nowait}
+the @var{server} option QEMU will wait for a client socket application
+to connect to the port before continuing, unless the @code{nowait}
 option was specified. If @var{host} is omitted, 0.0.0.0 is assumed. Only
 one TCP connection at a time is accepted. You can use @code{telnet} to
 connect to the corresponding character device.
@@ -1011,7 +1011,7 @@
 it. For example, use @file{/dev/cdrom} to access to the CDROM or
 @file{/dev/fd0} for the floppy.

-@table
+@table @code
 @item CD
 You can specify a CDROM device even if no CDROM is loaded. QEMU has
 specific code to detect CDROM insertion or removal. CDROM ejection by
@@ -1198,7 +1198,7 @@
 QEMU emulates a PCI UHCI USB controller. You can virtually plug
 virtual USB devices or real host USB devices (experimental, works only
 on Linux hosts).  Qemu will automatically create and connect virtual
USB hubs
-as neccessary to connect multiple USB devices.
+as necessary to connect multiple USB devices.

 @menu
 * usb_devices::