Messages in this thread | | | From | Michael Holzheu <> | Subject | [PATCH v7 0/5] kdump: Allow ELF header creation in new kernel | Date | Tue, 16 Jul 2013 18:18:10 +0200 |
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Hello Andrew,
Here a new kdump patch series that we have discussed with Vivek and Hatayama during the last months.
Besides of the feature described below, this patch series also fixes a regression on s390 that was introduced with the mmap patches for /proc/vmcore (git commit 83086978c63afd7c73e1c).
See also: http://lists.infradead.org/pipermail/kexec/2013-July/009287.html
Is it somehow possible to integrate this patch series into 3.11?
ChangeLog ========= v6 => v7)
- Rebase to v3.11-rc1 - Return VM_FAULT_SIGBUS in fault handler for non s390 - Use __va() for buffer in fault handler
v5 => v6)
- Set elfcorehdr_addr to ELFCORE_ADDR_ERR after elfcorehdr_free() - Fix OLDMEM_SIZE/ZFCPDUMP_HSA_SIZE confusion - Remove return VM_FAULT_MAJOR/MINOR - Use find_or_create_page() in mmap_vmcore_fault() - Use kfree instead of vfree in elfcorehdr_free()
v4 => v5)
- Add weak function elfcorehdr_read_notes() to read ELF notes - Rename weak functions for ELF header access and use "vmcorehdr_" prefix - Generic vmcore code calls elfcorehdr_alloc() if elfcorehdr= is not specified - Add vmcore fault handler for mmap of non-resident memory regions - Add weak function remap_oldmem_pfn_range() to be used by zfcpdump for mmap
v3 => v4)
- Rebase to 3.10-rc2 + vmcore mmap patches v8
v2 => v3)
- Get rid of ELFCORE_ADDR_NEWMEM - Make read_from_crash_header() only read from kernel - Move read_from_crash_header() to weak function arch_read_from_crash_header() - Implement read_from_crash_header() strong function for s390 - Set elfcorehdr_addr to address of new ELF header
v1 => v2)
- Rebase 3.10-rc2 + vmcore mmap patches - Introduced arch_get/free_crash_header() and ELFCORE_ADDR_NEWMEM
Feature Description =================== For s390 we want to use /proc/vmcore for our SCSI stand-alone dump (zfcpdump). We have support where the first HSA_SIZE bytes are saved into a hypervisor owned memory area (HSA) before the kdump kernel is booted. When the kdump kernel starts, it is restricted to use only HSA_SIZE bytes.
The advantages of this mechanism are:
* No crashkernel memory has to be defined in the old kernel. * Early boot problems (before kexec_load has been done) can be dumped * Non-Linux systems can be dumped.
We modify the s390 copy_oldmem_page() function to read from the HSA memory if memory below HSA_SIZE bytes is requested.
Since we cannot use the kexec tool to load the kernel in this scenario, we have to build the ELF header in the 2nd (kdump/new) kernel.
So with the following patch set we would like to introduce the new function that the ELF header for /proc/vmcore can be created in the 2nd kernel memory.
The following steps are done during zfcpdump execution:
1. Production system crashes 2. User boots a SCSI disk that has been prepared with the zfcpdump tool 3. Hypervisor saves CPU state of boot CPU and HSA_SIZE bytes of memory into HSA 4. Boot loader loads kernel into low memory area 5. Kernel boots and uses only HSA_SIZE bytes of memory 6. Kernel saves registers of non-boot CPUs 7. Kernel does memory detection for dump memory map 8. Kernel creates ELF header for /proc/vmcore 9. /proc/vmcore uses this header for initialization 10. The zfcpdump user space reads /proc/vmcore to write dump to SCSI disk - copy_oldmem_page() copies from HSA for memory below HSA_SIZE - copy_oldmem_page() copies from real memory for memory above HSA_SIZE --- Jan Willeke (1): s390/vmcore: Implement remap_oldmem_pfn_range for s390
Michael Holzheu (4): vmcore: Introduce ELF header in new memory feature s390/vmcore: Use ELF header in new memory feature vmcore: Introduce remap_oldmem_pfn_range() s390/vmcore: Use vmcore for zfcpdump
arch/s390/Kconfig | 3 +- arch/s390/include/asm/sclp.h | 1 + arch/s390/kernel/crash_dump.c | 228 ++++++++++++++++++++++++++++++++++-------- drivers/s390/char/zcore.c | 6 +- fs/proc/vmcore.c | 152 ++++++++++++++++++++++++---- include/linux/crash_dump.h | 9 ++ 6 files changed, 333 insertions(+), 66 deletions(-)
-- 1.8.2.3
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