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path: root/arch/powerpc/kernel/fadump.c
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2012-04-02powerpc: Fix fallout from system.h split upStephen Rothwell
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-23fadump: Invalidate registration and release reserved memory for general use.Mahesh Salgaonkar
This patch introduces an sysfs interface '/sys/kernel/fadump_release_mem' to invalidate the last fadump registration, invalidate '/proc/vmcore', release the reserved memory for general use and re-register for future kernel dump. Once the dump is copied to the disk, unlike phyp dump, the userspace tool can release all the memory reserved for dump with one single operation of echo 1 to '/sys/kernel/fadump_release_mem'. Release the reserved memory region excluding the size of the memory required for future kernel dump registration. And therefore, unlike kdump, Fadump doesn't need a 2nd reboot to get back the system to the production configuration. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-23fadump: Add PT_NOTE program header for vmcoreinfoMahesh Salgaonkar
Introduce a PT_NOTE program header that points to physical address of vmcoreinfo_note buffer declared in kernel/kexec.c. The vmcoreinfo note buffer is populated during crash_fadump() at the time of system crash. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-23fadump: Convert firmware-assisted cpu state dump data into elf notes.Mahesh Salgaonkar
When registered for firmware assisted dump on powerpc, firmware preserves the registers for the active CPUs during a system crash. This patch reads the cpu register data stored in Firmware-assisted dump format (except for crashing cpu) and converts it into elf notes and updates the PT_NOTE program header accordingly. The exact register state for crashing cpu is saved to fadump crash info structure in scratch area during crash_fadump() and read during second kernel boot. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-23fadump: Initialize elfcore header and add PT_LOAD program headers.Mahesh Salgaonkar
Build the crash memory range list by traversing through system memory during the first kernel before we register for firmware-assisted dump. After the successful dump registration, initialize the elfcore header and populate PT_LOAD program headers with crash memory ranges. The elfcore header is saved in the scratch area within the reserved memory. The scratch area starts at the end of the memory reserved for saving RMR region contents. The scratch area contains fadump crash info structure that contains magic number for fadump validation and physical address where the eflcore header can be found. This structure will also be used to pass some important crash info data to the second kernel which will help second kernel to populate ELF core header with correct data before it gets exported through /proc/vmcore. Since the firmware preserves the entire partition memory at the time of crash the contents of the scratch area will be preserved till second kernel boot. Since the memory dump exported through /proc/vmcore is in ELF format similar to kdump, it will help us to reuse the kdump infrastructure for dump capture and filtering. Unlike phyp dump, userspace tool does not need to refer any sysfs interface while reading /proc/vmcore. NOTE: The current design implementation does not address a possibility of introducing additional fields (in future) to this structure without affecting compatibility. It's on TODO list to come up with better approach to address this. Reserved dump area start => +-------------------------------------+ | CPU state dump data | +-------------------------------------+ | HPTE region data | +-------------------------------------+ | RMR region data | Scratch area start => +-------------------------------------+ | fadump crash info structure { | | magic nummber | +------|---- elfcorehdr_addr | | | } | +----> +-------------------------------------+ | ELF core header | Reserved dump area end => +-------------------------------------+ Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-23fadump: Register for firmware assisted dump.Mahesh Salgaonkar
On 2012-02-20 11:02:51 Mon, Paul Mackerras wrote: > On Thu, Feb 16, 2012 at 04:44:30PM +0530, Mahesh J Salgaonkar wrote: > > If I have read the code correctly, we are going to get this printk on > non-pSeries machines or on older pSeries machines, even if the user > has not put the fadump=on option on the kernel command line. The > printk will be annoying since there is no actual error condition. It > seems to me that the condition for the printk should include > fw_dump.fadump_enabled. In other words you should probably add > > if (!fw_dump.fadump_enabled) > return 0; > > at the beginning of the function. Hi Paul, Thanks for pointing it out. Please find the updated patch below. The existing patches above this (4/10 through 10/10) cleanly applies on this update. Thanks, -Mahesh. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-23fadump: Reserve the memory for firmware assisted dump.Mahesh Salgaonkar
Reserve the memory during early boot to preserve CPU state data, HPTE region and RMA (real mode area) region data in case of kernel crash. At the time of crash, powerpc firmware will store CPU state data, HPTE region data and move RMA region data to the reserved memory area. If the firmware-assisted dump fails to reserve the memory, then fallback to existing kexec-based kdump. Most of the code implementation to reserve memory has been adapted from phyp assisted dump implementation written by Linas Vepstas and Manish Ahuja This patch also introduces a config option CONFIG_FA_DUMP for firmware assisted dump feature on Powerpc (ppc64) architecture. Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>