[tip:irq/numa] x86: read apic ID in the !acpi_lapic case

tip-bot for Yinghai Lu
2009-05-12T10:37:29Z

Commit-ID: 4797f6b021a3fa399942245d07a1feb30df81bb8
Gitweb: http://git.kernel.org/tip/4797f6b021a3fa399942245d07a1feb30df81bb8
Author: Yinghai Lu <yinghai@kernel.org>
AuthorDate: Sat, 2 May 2009 10:40:57 -0700
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 12 May 2009 12:22:06 +0200

x86: read apic ID in the !acpi_lapic case

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

Interestingly, actually three paths use/set it:

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

so we could read the apic id for the 2/3 path. We trust the hardware
register more than we trust a BIOS data structure (the mptable).

We can also avoid the double set_fixmap() when acpi_lapic
is used, and also need to move cpu_has_apic earlier and
call apic_disable().

Also when need to update the apic id, we'd better read and
set the apic version as well - so that quirks are applied precisely.

v2: make path 3 with 64bit, use -1 as apic id, so could read it later.
v3: fix whitespace problem pointed out by Ed Swierk
v5: fix boot crash

[ Impact: get correct apic id for bsp other than acpi path ]

Reported-by: Ed Swierk <eswierk@aristanetworks.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <49FC85A9.2070702@kernel.org>
[ v4: sanity-check in the ACPI case too ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
arch/x86/include/asm/smp.h | 2 +-
arch/x86/kernel/apic/apic.c | 46 +++++++++++++++++++--------------------
arch/x86/kernel/apic/io_apic.c | 5 ++++
3 files changed, 28 insertions(+), 25 deletions(-)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 19e0d88..6a84ed1 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -180,7 +180,7 @@ extern int safe_smp_processor_id(void);
static inline int logical_smp_processor_id(void)
{
/* we don't want to mark this access volatile - bad code generation */
- return GET_APIC_LOGICAL_ID(*(u32 *)(APIC_BASE + APIC_LDR));
+ return GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
}

#endif
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 07cffc1..b0fd264 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -242,17 +242,24 @@ static int modern_apic(void)
* bare function to substitute write operation
* and it's _that_ fast :)
*/
-void native_apic_write_dummy(u32 reg, u32 v)
+static void native_apic_write_dummy(u32 reg, u32 v)
{
WARN_ON_ONCE((cpu_has_apic || !disable_apic));
}

+static u32 native_apic_read_dummy(u32 reg)
+{
+ WARN_ON_ONCE((cpu_has_apic || !disable_apic));
+ return 0;
+}
+
/*
- * right after this call apic->write doesn't do anything
+ * right after this call apic->write/read doesn't do anything
* note that there is no restore operation it works one way
*/
void apic_disable(void)
{
+ apic->read = native_apic_read_dummy;
apic->write = native_apic_write_dummy;
}

@@ -1576,32 +1583,23 @@ void __init init_apic_mappings(void)
return;
}

- /*
- * If no local APIC can be found then set up a fake all
- * zeroes page to simulate the local APIC and another
- * one for the IO-APIC.
- */
+ /* If no local APIC can be found return early */
if (!smp_found_config && detect_init_APIC()) {
- apic_phys = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
- apic_phys = __pa(apic_phys);
- } else
+ /* lets NOP'ify apic operations */
+ pr_info("APIC: disable apic facility\n");
+ apic_disable();
+ } else {
apic_phys = mp_lapic_addr;

- /*
- * acpi lapic path already maps that address in
- * acpi_register_lapic_address()
- */
- if (!acpi_lapic)
- set_fixmap_nocache(FIX_APIC_BASE, apic_phys);
-
- apic_printk(APIC_VERBOSE, "mapped APIC to %08lx (%08lx)\n",
- APIC_BASE, apic_phys);
+ /*
+ * acpi lapic path already maps that address in
+ * acpi_register_lapic_address()
+ */
+ if (!acpi_lapic)
+ set_fixmap_nocache(FIX_APIC_BASE, apic_phys);

- /* lets check if we may NOP'ify apic operations */
- if (!cpu_has_apic) {
- pr_info("APIC: disable apic facility\n");
- apic_disable();
- return;
+ apic_printk(APIC_VERBOSE, "mapped APIC to %08lx (%08lx)\n",
+ APIC_BASE, apic_phys);
}

/*
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 1f3d366..74d2b48 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1878,6 +1878,11 @@ __apicdebuginit(void) print_PIC(void)
__apicdebuginit(int) print_all_ICs(void)
{
print_PIC();
+
+ /* don't print out if apic is not there */
+ if (!cpu_has_apic || disable_apic)
+ return 0;
+
print_all_local_APICs();
print_IO_APIC();