On Thu, 25 Sep 2014 17:44:12 +0800 Baoquan He <[email protected]> wrote:
> On 09/24/14 at 05:19pm, Michael Holzheu wrote: > > On Tue, 23 Sep 2014 10:40:58 +0800 > > Baoquan He <[email protected]> wrote: [snip] > > > > > > Hi Michael, > > > > > > Please alse provide a get_versiondep_info_s390x since page_offset is > > > needed in set_kcore_vmcoreinfo() and other information need it too, such > > > as VMALLOC_START/VMEMMAP_START/MODULES_VADDR, if you want to provide a > > > is_vmalloc_addr_s390x before initial() is called. > > > > Hello Baoquan, > > > > Thanks for the hint! I looked into the x86_64 implementation of > > get_versiondep_info() where version dependent constants are used > > for vmalloc_start and others. > > > > For s390x this is not so easy because vmalloc_start is dependent > > on the memory size of the system (see setup_memory_end() > > in arch/s390/kernel/setup.c). Unfortunately "info->max_mapnr" > > is not set at that time. > > I am not aware of s390 arch and memory layout. But I can explain what > those versiondep_info are used for, hope they can help. In fact in > x86_64, page_offset is got for set_kcore_vmcoreinfo(), there the > vmcoreinfo_addr need be converted to kvaddr. Since vmcoreinfo_addr is a > physical addr, we can't use it directly. And > VMALLOC_START/VMEMMAP_START/MODULES_VADDR are all used to filter this > virtual addr space region since our vmcore only care about the physical > ram addr region. > > If you need get these before they are used for s390 arch. If necessary > you can build a different code flow if you can achive the goal. All > these are all used to get dumpable load segments from kcore. Isn't this a chicken-and-egg problem? In order to determine vmalloc start I have to be able to read memory. But in order to read memory I have to call get_kcore_dump_loads() first. What about using /proc/iomem to find out if an address is a real address? The following patch seems to work for me: --- elf_info.c | 4 ++-- makedumpfile.c | 26 ++++++++++++++++++++++++++ makedumpfile.h | 1 + 3 files changed, 29 insertions(+), 2 deletions(-) --- a/elf_info.c +++ b/elf_info.c @@ -854,7 +854,7 @@ int get_kcore_dump_loads(void) for (i = 0; i < num_pt_loads; ++i) { struct pt_load_segment *p = &pt_loads[i]; - if (is_vmalloc_addr(p->virt_start)) + if (!is_real_addr(p->virt_start)) continue; loads++; } @@ -874,7 +874,7 @@ int get_kcore_dump_loads(void) for (i = 0, j = 0; i < num_pt_loads; ++i) { struct pt_load_segment *p = &pt_loads[i]; - if (is_vmalloc_addr(p->virt_start)) + if (!is_real_addr(p->virt_start)) continue; if (j >= loads) return FALSE; --- a/makedumpfile.c +++ b/makedumpfile.c @@ -9227,6 +9227,32 @@ int is_crashkernel_mem_reserved(void) return !!crash_reserved_mem_nr; } +struct addr_check { + unsigned long addr; + int found; +}; + +static int real_addr_callback(void *data, int nr, char *str, + unsigned long base, unsigned long length) +{ + struct addr_check *addr_check = data; + unsigned long addr = addr_check->addr; + + if (addr >= base && addr < base + length) { + addr_check->found = 1; + return -1; + } + return 0; +} + +int is_real_addr(unsigned long addr) +{ + struct addr_check addr_check = {addr, 0}; + + iomem_for_each_line("System RAM\n", real_addr_callback, &addr_check); + return addr_check.found; +} + static int get_page_offset(void) { struct utsname utsname; --- a/makedumpfile.h +++ b/makedumpfile.h @@ -1567,6 +1567,7 @@ int read_disk_dump_header(struct disk_du int read_kdump_sub_header(struct kdump_sub_header *kh, char *filename); void close_vmcoreinfo(void); int close_files_for_creating_dumpfile(void); +int is_real_addr(unsigned long addr); /* _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
