Check to see if there actually is data from a previously
crashed kernel waiting. If so, Allow user-sapce tools to
grab the data (by reading /proc/kcore). When user-space
finishes dumping a section, it must release that memory
by writing to sysfs. For example,
echo "0x40000000 0x10000000" > /sys/kernel/release_region
will release 256MB starting at the 1GB. The released memory
becomes free for general use.
Signed-off-by: Linas Vepstas <[EMAIL PROTECTED]>
Signed-off-by: Manish Ahuja <[EMAIL PROTECTED]>
------
arch/powerpc/platforms/pseries/phyp_dump.c | 101 +++++++++++++++++++++++++++--
1 file changed, 96 insertions(+), 5 deletions(-)
Index: linux-2.6.24-rc3-git1/arch/powerpc/platforms/pseries/phyp_dump.c
===================================================================
--- linux-2.6.24-rc3-git1.orig/arch/powerpc/platforms/pseries/phyp_dump.c
2007-11-21 13:15:05.000000000 -0600
+++ linux-2.6.24-rc3-git1/arch/powerpc/platforms/pseries/phyp_dump.c
2007-11-21 13:24:30.000000000 -0600
@@ -12,17 +12,24 @@
*/
#include <linux/init.h>
+#include <linux/kobject.h>
#include <linux/mm.h>
+#include <linux/of.h>
#include <linux/pfn.h>
#include <linux/swap.h>
+#include <linux/sysfs.h>
#include <asm/page.h>
#include <asm/phyp_dump.h>
+#include <asm/rtas.h>
/* Global, used to communicate data between early boot and late boot */
static struct phyp_dump phyp_dump_global;
struct phyp_dump *phyp_dump_info = &phyp_dump_global;
+static int ibm_configure_kernel_dump;
+
+/* ------------------------------------------------- */
/**
* release_memory_range -- release memory previously lmb_reserved
* @start_pfn: starting physical frame number
@@ -52,18 +59,102 @@ release_memory_range(unsigned long start
}
}
-static int __init phyp_dump_setup(void)
+/* ------------------------------------------------- */
+/**
+ * sysfs_release_region -- sysfs interface to release memory range.
+ *
+ * Usage:
+ * "echo <start addr> <length> > /sys/kernel/release_region"
+ *
+ * Example:
+ * "echo 0x40000000 0x10000000 > /sys/kernel/release_region"
+ *
+ * will release 256MB starting at 1GB.
+ */
+static ssize_t
+store_release_region(struct kset *kset, const char *buf, size_t count)
{
+ unsigned long start_addr, length, end_addr;
unsigned long start_pfn, nr_pages;
+ ssize_t ret;
- /* If no memory was reserved in early boot, there is nothing to do */
- if (phyp_dump_info->init_reserve_size == 0)
- return 0;
+ ret = sscanf(buf, "%lx %lx", &start_addr, &length);
+ if (ret != 2)
+ return -EINVAL;
+
+ /* Range-check - don't free any reserved memory that
+ * wasn't reserved for phyp-dump */
+ if (start_addr < phyp_dump_info->init_reserve_start)
+ start_addr = phyp_dump_info->init_reserve_start;
+
+ end_addr = phyp_dump_info->init_reserve_start +
+ phyp_dump_info->init_reserve_size;
+ if (start_addr+length > end_addr)
+ length = end_addr - start_addr;
+
+ /* Release the region of memory assed in by user */
+ start_pfn = PFN_DOWN(start_addr);
+ nr_pages = PFN_DOWN(length);
+ release_memory_range (start_pfn, nr_pages);
+
+ return count;
+}
+
+static ssize_t
+show_release_region(struct kset * kset, char *buf)
+{
+ return sprintf(buf, "ola\n");
+}
+
+static struct subsys_attribute rr = __ATTR(release_region, 0600,
+ show_release_region,
+ store_release_region);
+
+/* ------------------------------------------------- */
+
+static void release_all (void)
+{
+ unsigned long start_pfn, nr_pages;
- /* Release memory that was reserved in early boot */
+ /* Release all memory that was reserved in early boot */
start_pfn = PFN_DOWN(phyp_dump_info->init_reserve_start);
nr_pages = PFN_DOWN(phyp_dump_info->init_reserve_size);
release_memory_range(start_pfn, nr_pages);
+}
+
+static int __init phyp_dump_setup(void)
+{
+ struct device_node *rtas;
+ const int *dump_header;
+ int header_len = 0;
+ int rc;
+
+ /* If no memory was reserved in early boot, there is nothing to do */
+ if (phyp_dump_info->init_reserve_size == 0)
+ return 0;
+
+ /* Return if phyp dump not supported */
+ ibm_configure_kernel_dump = rtas_token("ibm,configure-kernel-dump");
+ if (ibm_configure_kernel_dump == RTAS_UNKNOWN_SERVICE) {
+ release_all();
+ return -ENOSYS;
+ }
+
+ /* Is there dump data waiting for us? */
+ rtas = of_find_node_by_path("/rtas");
+ dump_header = of_get_property(rtas, "ibm,kernel-dump", &header_len);
+ if (dump_header == NULL) {
+ release_all();
+ return 0;
+ }
+
+ /* Should we create a dump_subsys, analogous to s390/ipl.c ? */
+ rc = subsys_create_file(&kernel_subsys, &rr);
+ if (rc) {
+ printk (KERN_ERR "phyp-dump: unable to create sysfs file
(%d)\n", rc);
+ release_all();
+ return 0;
+ }
return 0;
}
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