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x86: apic - introduce imcr_ helpers

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Impact: cleanup

Distinguish port writting magic into helpers with comments.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <20090412165058.535921550@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Cyrill Gorcunov 2009-04-12 20:47:40 +04:00 committed by Ingo Molnar
parent edea7148a8
commit c0eaa4536f
1 changed files with 25 additions and 4 deletions
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29
arch/x86/kernel/apic/apic.c
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@ -98,6 +98,29 @@ early_param("lapic", parse_lapic);
/* Local APIC was disabled by the BIOS and enabled by the kernel */
static int enabled_via_apicbase;
/*
* Handle interrupt mode configuration register (IMCR).
* This register controls whether the interrupt signals
* that reach the BSP come from the master PIC or from the
* local APIC. Before entering Symmetric I/O Mode, either
* the BIOS or the operating system must switch out of
* PIC Mode by changing the IMCR.
*/
static inline imcr_pic_to_apic(void)
{
/* select IMCR register */
outb(0x70, 0x22);
/* NMI and 8259 INTR go through APIC */
outb(0x01, 0x23);
}
static inline imcr_apic_to_pic(void)
{
/* select IMCR register */
outb(0x70, 0x22);
/* NMI and 8259 INTR go directly to BSP */
outb(0x00, 0x23);
}
#endif
#ifdef CONFIG_X86_64
@ -1727,8 +1750,7 @@ void __init connect_bsp_APIC(void)
*/
apic_printk(APIC_VERBOSE, "leaving PIC mode, "
"enabling APIC mode.\n");
outb(0x70, 0x22);
outb(0x01, 0x23);
imcr_pic_to_apic();
}
#endif
if (apic->enable_apic_mode)
@ -1756,8 +1778,7 @@ void disconnect_bsp_APIC(int virt_wire_setup)
*/
apic_printk(APIC_VERBOSE, "disabling APIC mode, "
"entering PIC mode.\n");
outb(0x70, 0x22);
outb(0x00, 0x23);
imcr_apic_to_pic();
return;
}
#endif