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authorVivek Goyal <vgoyal@redhat.com>2009-11-24 01:50:03 -0500
committerTejun Heo <tj@kernel.org>2009-11-25 07:49:22 -0500
commit3b034b0d084221596bf35c8d893e1d4d5477b9cc (patch)
treec3b9f33dc9fc748a9460036ae8647b16541a7547 /drivers/base
parent833af8427be4b217b5bc522f61afdbd3f1d282c2 (diff)
percpu: Fix kdump failure if booted with percpu_alloc=page
o kdump functionality reserves a per cpu area at boot time and exports the physical address of that area to user space through sys interface. This area stores some dump related information like cpu register states etc at the time of crash. o We were assuming that per cpu area always come from linearly mapped meory region and using __pa() to determine physical address. With percpu_alloc=page, per cpu area can come from vmalloc region also and __pa() breaks. o This patch implments a new function to convert per cpu address to physical address. Before the patch, crash_notes addresses looked as follows. cpu0 60fffff49800 cpu1 60fffff60800 cpu2 60fffff77800 These are bogus phsyical addresses. After the patch, address are following. cpu0 13eb44000 cpu1 13eb43000 cpu2 13eb42000 cpu3 13eb41000 These look fine. I got 4G of memory and /proc/iomem tell me following. 100000000-13fffffff : System RAM tj: * added missing asm/io.h include reported by Stephen Rothwell * repositioned per_cpu_ptr_phys() in percpu.c and added comment. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/cpu.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index e62a4ccea54d..69ee5b7517ec 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -97,7 +97,7 @@ static ssize_t show_crash_notes(struct sys_device *dev, struct sysdev_attribute
97 * boot up and this data does not change there after. Hence this 97 * boot up and this data does not change there after. Hence this
98 * operation should be safe. No locking required. 98 * operation should be safe. No locking required.
99 */ 99 */
100 addr = __pa(per_cpu_ptr(crash_notes, cpunum)); 100 addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
101 rc = sprintf(buf, "%Lx\n", addr); 101 rc = sprintf(buf, "%Lx\n", addr);
102 return rc; 102 return rc;
103} 103}