linux/arch/x86/include/asm/smpboot_hooks.h
Don Zickus 299c56966a x86: Use u32 instead of long to set reset vector back to 0
A customer of ours, complained that when setting the reset
vector back to 0, it trashed other data and hung their box.
They noticed when only 4 bytes were set to 0 instead of 8,
everything worked correctly.

Mathew pointed out:

 |
 | We're supposed to be resetting trampoline_phys_low and
 | trampoline_phys_high here, which are two 16-bit values.
 | Writing 64 bits is definitely going to overwrite space
 | that we're not supposed to be touching.
 |

So limit the area modified to u32.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Cc: <stable@kernel.org>
LKML-Reference: <1297139100-424-1-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-02-28 16:22:18 +01:00

61 lines
1.3 KiB
C

/* two abstractions specific to kernel/smpboot.c, mainly to cater to visws
* which needs to alter them. */
static inline void smpboot_clear_io_apic_irqs(void)
{
#ifdef CONFIG_X86_IO_APIC
io_apic_irqs = 0;
#endif
}
static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip)
{
CMOS_WRITE(0xa, 0xf);
local_flush_tlb();
pr_debug("1.\n");
*((volatile unsigned short *)phys_to_virt(apic->trampoline_phys_high)) =
start_eip >> 4;
pr_debug("2.\n");
*((volatile unsigned short *)phys_to_virt(apic->trampoline_phys_low)) =
start_eip & 0xf;
pr_debug("3.\n");
}
static inline void smpboot_restore_warm_reset_vector(void)
{
/*
* Install writable page 0 entry to set BIOS data area.
*/
local_flush_tlb();
/*
* Paranoid: Set warm reset code and vector here back
* to default values.
*/
CMOS_WRITE(0, 0xf);
*((volatile u32 *)phys_to_virt(apic->trampoline_phys_low)) = 0;
}
static inline void __init smpboot_setup_io_apic(void)
{
#ifdef CONFIG_X86_IO_APIC
/*
* Here we can be sure that there is an IO-APIC in the system. Let's
* go and set it up:
*/
if (!skip_ioapic_setup && nr_ioapics)
setup_IO_APIC();
else {
nr_ioapics = 0;
}
#endif
}
static inline void smpboot_clear_io_apic(void)
{
#ifdef CONFIG_X86_IO_APIC
nr_ioapics = 0;
#endif
}