ia64/linux-2.6.18-xen.hg

view arch/m68k/mm/hwtest.c @ 452:c7ed6fe5dca0

kexec: dont initialise regions in reserve_memory()

There is no need to initialise efi_memmap_res and boot_param_res in
reserve_memory() for the initial xen domain as it is done in
machine_kexec_setup_resources() using values from the kexec hypercall.

Signed-off-by: Simon Horman <horms@verge.net.au>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Feb 28 10:55:18 2008 +0000 (2008-02-28)
parents 831230e53067
children
line source
1 /* Tests for presence or absence of hardware registers.
2 * This code was originally in atari/config.c, but I noticed
3 * that it was also in drivers/nubus/nubus.c and I wanted to
4 * use it in hp300/config.c, so it seemed sensible to pull it
5 * out into its own file.
6 *
7 * The test is for use when trying to read a hardware register
8 * that isn't present would cause a bus error. We set up a
9 * temporary handler so that this doesn't kill the kernel.
10 *
11 * There is a test-by-reading and a test-by-writing; I present
12 * them here complete with the comments from the original atari
13 * config.c...
14 * -- PMM <pmaydell@chiark.greenend.org.uk>, 05/1998
15 */
17 /* This function tests for the presence of an address, specially a
18 * hardware register address. It is called very early in the kernel
19 * initialization process, when the VBR register isn't set up yet. On
20 * an Atari, it still points to address 0, which is unmapped. So a bus
21 * error would cause another bus error while fetching the exception
22 * vector, and the CPU would do nothing at all. So we needed to set up
23 * a temporary VBR and a vector table for the duration of the test.
24 */
26 #include <linux/module.h>
28 int hwreg_present( volatile void *regp )
29 {
30 int ret = 0;
31 long save_sp, save_vbr;
32 long tmp_vectors[3];
34 __asm__ __volatile__
35 ( "movec %/vbr,%2\n\t"
36 "movel #Lberr1,%4@(8)\n\t"
37 "movec %4,%/vbr\n\t"
38 "movel %/sp,%1\n\t"
39 "moveq #0,%0\n\t"
40 "tstb %3@\n\t"
41 "nop\n\t"
42 "moveq #1,%0\n"
43 "Lberr1:\n\t"
44 "movel %1,%/sp\n\t"
45 "movec %2,%/vbr"
46 : "=&d" (ret), "=&r" (save_sp), "=&r" (save_vbr)
47 : "a" (regp), "a" (tmp_vectors)
48 );
50 return( ret );
51 }
52 EXPORT_SYMBOL(hwreg_present);
54 /* Basically the same, but writes a value into a word register, protected
55 * by a bus error handler. Returns 1 if successful, 0 otherwise.
56 */
58 int hwreg_write( volatile void *regp, unsigned short val )
59 {
60 int ret;
61 long save_sp, save_vbr;
62 long tmp_vectors[3];
64 __asm__ __volatile__
65 ( "movec %/vbr,%2\n\t"
66 "movel #Lberr2,%4@(8)\n\t"
67 "movec %4,%/vbr\n\t"
68 "movel %/sp,%1\n\t"
69 "moveq #0,%0\n\t"
70 "movew %5,%3@\n\t"
71 "nop \n\t" /* If this nop isn't present, 'ret' may already be
72 * loaded with 1 at the time the bus error
73 * happens! */
74 "moveq #1,%0\n"
75 "Lberr2:\n\t"
76 "movel %1,%/sp\n\t"
77 "movec %2,%/vbr"
78 : "=&d" (ret), "=&r" (save_sp), "=&r" (save_vbr)
79 : "a" (regp), "a" (tmp_vectors), "g" (val)
80 );
82 return( ret );
83 }
84 EXPORT_SYMBOL(hwreg_write);