lkml.org 
[lkml]   [2009]   [May]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] x86: read apic id if it is not acpi_lapic

Ed found that on 32bit, boot_cpu_physical_apicid is not read right,
when mptable is broken.

interesting, actually three path
1. acpi: at that time, at that time that is already read from reg.
2. mptable: that only read from mptable.
3. no madt, and no mptable, that use default apic id 0 for 64bit, -1 for 32bit

so could read that apic id for 2/3 path.

also could avoid set fixmap that lapic two times when acpi_lapic is used.
and need to move cpu_has_apic earlier and call apic_disable()

Reported-by: Ed Swierk <eswierk@aristanetworks.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>

---
arch/x86/kernel/apic/apic.c | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)
Index: linux-2.6/arch/x86/kernel/apic/apic.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic/apic.c
+++ linux-2.6/arch/x86/kernel/apic/apic.c
@@ -1574,6 +1574,8 @@ void __init early_init_lapic_mapping(voi
*/
void __init init_apic_mappings(void)
{
+ unsigned int new_apicid;
+
if (x2apic_mode) {
boot_cpu_physical_apicid = read_apic_id();
return;
@@ -1590,21 +1592,32 @@ void __init init_apic_mappings(void)
} else
apic_phys = mp_lapic_addr;

- set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
+ /* lets check if we may to NOP'ify apic operations */
+ if (!cpu_has_apic) {
+ pr_info("APIC: disable apic facility\n");
+ apic_disable();
+ return;
+ }
+
+ /*
+ * acpi lapic path already map that address in
+ * acpi_register_lapic_address()
+ */
apic_printk(APIC_VERBOSE, "mapped APIC to %08lx (%08lx)\n",
APIC_BASE, apic_phys);
+ if (acpi_lapic)
+ return;

+ set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
/*
* Fetch the APIC ID of the BSP in case we have a
* default configuration (or the MP table is broken).
*/
- if (boot_cpu_physical_apicid == -1U)
- boot_cpu_physical_apicid = read_apic_id();
-
- /* lets check if we may to NOP'ify apic operations */
- if (!cpu_has_apic) {
- pr_info("APIC: disable apic facility\n");
- apic_disable();
+ new_apicid = read_apic_id();
+ if (boot_cpu_physical_apicid != new_apicid) {
+ boot_cpu_physical_apicid = new_apicid;
+ apic_version[new_apicid] =
+ GET_APIC_VERSION(apic_read(APIC_LVR));
}
}


\
 
 \ /
  Last update: 2009-05-02 06:51    [from the cache]
©2003-2011 Jasper Spaans