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linux-next/arch/i386/kernel/cpu/nexgen.c
Chuck Ebbert fe38d8553c [PATCH] i386 cpu hotplug: don't access freed memory
i386 CPU init code accesses freed init memory when booting a newly-started
processor after CPU hotplug.  The cpu_devs array is searched to find the
vendor and it contains pointers to freed data.

Fix that by:

        1. Zeroing entries for freed vendor data after bootup.
        2. Changing Transmeta, NSC and UMC to all __init[data].
        3. Printing a warning (once only) and setting this_cpu
           to a safe default when the vendor is not found.

This does not change behavior for AMD systems.  They were broken already
but no error was reported.

Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-05 11:06:53 -08:00

72 lines
1.4 KiB
C

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <asm/processor.h>
#include "cpu.h"
/*
* Detect a NexGen CPU running without BIOS hypercode new enough
* to have CPUID. (Thanks to Herbert Oppmann)
*/
static int __init deep_magic_nexgen_probe(void)
{
int ret;
__asm__ __volatile__ (
" movw $0x5555, %%ax\n"
" xorw %%dx,%%dx\n"
" movw $2, %%cx\n"
" divw %%cx\n"
" movl $0, %%eax\n"
" jnz 1f\n"
" movl $1, %%eax\n"
"1:\n"
: "=a" (ret) : : "cx", "dx" );
return ret;
}
static void __init init_nexgen(struct cpuinfo_x86 * c)
{
c->x86_cache_size = 256; /* A few had 1 MB... */
}
static void __init nexgen_identify(struct cpuinfo_x86 * c)
{
/* Detect NexGen with old hypercode */
if ( deep_magic_nexgen_probe() ) {
strcpy(c->x86_vendor_id, "NexGenDriven");
}
generic_identify(c);
}
static struct cpu_dev nexgen_cpu_dev __initdata = {
.c_vendor = "Nexgen",
.c_ident = { "NexGenDriven" },
.c_models = {
{ .vendor = X86_VENDOR_NEXGEN,
.family = 5,
.model_names = { [1] = "Nx586" }
},
},
.c_init = init_nexgen,
.c_identify = nexgen_identify,
};
int __init nexgen_init_cpu(void)
{
cpu_devs[X86_VENDOR_NEXGEN] = &nexgen_cpu_dev;
return 0;
}
//early_arch_initcall(nexgen_init_cpu);
static int __init nexgen_exit_cpu(void)
{
cpu_devs[X86_VENDOR_NEXGEN] = NULL;
return 0;
}
late_initcall(nexgen_exit_cpu);