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]> ------ 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; } _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev