Re: [RESEND PATCH v5 00/11] ppc64: enable kdump support for kexec_file_load syscall
On 28/07/20 8:02 am, piliu wrote: On 07/27/2020 03:36 AM, Hari Bathini wrote: Sorry! There was a gateway issue on my system while posting v5, due to which some patches did not make it through. Resending... This patch series enables kdump support for kexec_file_load system call (kexec -s -p) on PPC64. The changes are inspired from kexec-tools code but heavily modified for kernel consumption. The first patch adds a weak arch_kexec_locate_mem_hole() function to override locate memory hole logic suiting arch needs. There are some special regions in ppc64 which should be avoided while loading buffer & there are multiple callers to kexec_add_buffer making it complicated to maintain range sanity and using generic lookup at the same time. The second patch marks ppc64 specific code within arch/powerpc/kexec and arch/powerpc/purgatory to make the subsequent code changes easy to understand. The next patch adds helper function to setup different memory ranges needed for loading kdump kernel, booting into it and exporting the crashing kernel's elfcore. The fourth patch overrides arch_kexec_locate_mem_hole() function to locate memory hole for kdump segments by accounting for the special memory regions, referred to as excluded memory ranges, and sets kbuf->mem when a suitable memory region is found. The fifth patch moves walk_drmem_lmbs() out of .init section with a few changes to reuse it for setting up kdump kernel's usable memory ranges. The next patch uses walk_drmem_lmbs() to look up the LMBs and set linux,drconf-usable-memory & linux,usable-memory properties in order to restrict kdump kernel's memory usage. The seventh patch updates purgatory to setup r8 & r9 with opal base and opal entry addresses respectively to aid kernels built with CONFIG_PPC_EARLY_DEBUG_OPAL enabled. The next patch setups up backup region as a kexec segment while loading kdump kernel and teaches purgatory to copy data from source to destination. Patch 09 builds the elfcore header for the running kernel & passes the info to kdump kernel via "elfcorehdr=" parameter to export as /proc/vmcore file. The next patch sets up the memory reserve map for the kexec kernel and also claims kdump support for kdump as all the necessary changes are added. The last patch fixes a lookup issue for `kexec -l -s` case when memory is reserved for crashkernel. Tested the changes successfully on P8, P9 lpars, couple of OpenPOWER boxes, one with secureboot enabled, KVM guest and a simulator. v4 -> v5: * Dropped patches 07/12 & 08/12 and updated purgatory to do everything in assembly. Hello Pingfan, Sorry, I missed out on responding to this. I guess you achieve this by carefully selecting instruction to avoid relocation issue, right? Yes. No far branching or reference to data from elsewhere. Thanks Hari ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
Re: [RESEND PATCH v5 00/11] ppc64: enable kdump support for kexec_file_load syscall
On 07/27/2020 03:36 AM, Hari Bathini wrote: > Sorry! There was a gateway issue on my system while posting v5, due to > which some patches did not make it through. Resending... > > This patch series enables kdump support for kexec_file_load system > call (kexec -s -p) on PPC64. The changes are inspired from kexec-tools > code but heavily modified for kernel consumption. > > The first patch adds a weak arch_kexec_locate_mem_hole() function to > override locate memory hole logic suiting arch needs. There are some > special regions in ppc64 which should be avoided while loading buffer > & there are multiple callers to kexec_add_buffer making it complicated > to maintain range sanity and using generic lookup at the same time. > > The second patch marks ppc64 specific code within arch/powerpc/kexec > and arch/powerpc/purgatory to make the subsequent code changes easy > to understand. > > The next patch adds helper function to setup different memory ranges > needed for loading kdump kernel, booting into it and exporting the > crashing kernel's elfcore. > > The fourth patch overrides arch_kexec_locate_mem_hole() function to > locate memory hole for kdump segments by accounting for the special > memory regions, referred to as excluded memory ranges, and sets > kbuf->mem when a suitable memory region is found. > > The fifth patch moves walk_drmem_lmbs() out of .init section with > a few changes to reuse it for setting up kdump kernel's usable memory > ranges. The next patch uses walk_drmem_lmbs() to look up the LMBs > and set linux,drconf-usable-memory & linux,usable-memory properties > in order to restrict kdump kernel's memory usage. > > The seventh patch updates purgatory to setup r8 & r9 with opal base > and opal entry addresses respectively to aid kernels built with > CONFIG_PPC_EARLY_DEBUG_OPAL enabled. The next patch setups up backup > region as a kexec segment while loading kdump kernel and teaches > purgatory to copy data from source to destination. > > Patch 09 builds the elfcore header for the running kernel & passes > the info to kdump kernel via "elfcorehdr=" parameter to export as > /proc/vmcore file. The next patch sets up the memory reserve map > for the kexec kernel and also claims kdump support for kdump as > all the necessary changes are added. > > The last patch fixes a lookup issue for `kexec -l -s` case when > memory is reserved for crashkernel. > > Tested the changes successfully on P8, P9 lpars, couple of OpenPOWER > boxes, one with secureboot enabled, KVM guest and a simulator. > > v4 -> v5: > * Dropped patches 07/12 & 08/12 and updated purgatory to do everything > in assembly. I guess you achieve this by carefully selecting instruction to avoid relocation issue, right? Thanks, Pingfan ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
[RESEND PATCH v5 00/11] ppc64: enable kdump support for kexec_file_load syscall
Sorry! There was a gateway issue on my system while posting v5, due to which some patches did not make it through. Resending... This patch series enables kdump support for kexec_file_load system call (kexec -s -p) on PPC64. The changes are inspired from kexec-tools code but heavily modified for kernel consumption. The first patch adds a weak arch_kexec_locate_mem_hole() function to override locate memory hole logic suiting arch needs. There are some special regions in ppc64 which should be avoided while loading buffer & there are multiple callers to kexec_add_buffer making it complicated to maintain range sanity and using generic lookup at the same time. The second patch marks ppc64 specific code within arch/powerpc/kexec and arch/powerpc/purgatory to make the subsequent code changes easy to understand. The next patch adds helper function to setup different memory ranges needed for loading kdump kernel, booting into it and exporting the crashing kernel's elfcore. The fourth patch overrides arch_kexec_locate_mem_hole() function to locate memory hole for kdump segments by accounting for the special memory regions, referred to as excluded memory ranges, and sets kbuf->mem when a suitable memory region is found. The fifth patch moves walk_drmem_lmbs() out of .init section with a few changes to reuse it for setting up kdump kernel's usable memory ranges. The next patch uses walk_drmem_lmbs() to look up the LMBs and set linux,drconf-usable-memory & linux,usable-memory properties in order to restrict kdump kernel's memory usage. The seventh patch updates purgatory to setup r8 & r9 with opal base and opal entry addresses respectively to aid kernels built with CONFIG_PPC_EARLY_DEBUG_OPAL enabled. The next patch setups up backup region as a kexec segment while loading kdump kernel and teaches purgatory to copy data from source to destination. Patch 09 builds the elfcore header for the running kernel & passes the info to kdump kernel via "elfcorehdr=" parameter to export as /proc/vmcore file. The next patch sets up the memory reserve map for the kexec kernel and also claims kdump support for kdump as all the necessary changes are added. The last patch fixes a lookup issue for `kexec -l -s` case when memory is reserved for crashkernel. Tested the changes successfully on P8, P9 lpars, couple of OpenPOWER boxes, one with secureboot enabled, KVM guest and a simulator. v4 -> v5: * Dropped patches 07/12 & 08/12 and updated purgatory to do everything in assembly. * Added a new patch (which was part of patch 08/12 in v4) to update r8 & r9 registers with opal base & opal entry addresses as it is expected on kernels built with CONFIG_PPC_EARLY_DEBUG_OPAL enabled. * Fixed kexec load issue on KVM guest. v3 -> v4: * Updated get_node_path() function to be iterative instead of a recursive one. * Added comment explaining why low memory is added to kdump kernel's usable memory ranges though it doesn't fall in crashkernel region. * Fixed stack_buf to be quadword aligned in accordance with ABI. * Added missing of_node_put() in setup_purgatory_ppc64(). * Added a FIXME tag to indicate issue in adding opal/rtas regions to core image. v2 -> v3: * Fixed TOC pointer calculation for purgatory by using section info that has relocations applied. * Fixed arch_kexec_locate_mem_hole() function to fallback to generic kexec_locate_mem_hole() lookup if exclude ranges list is empty. * Dropped check for backup_start in trampoline_64.S as purgatory() function takes care of it anyway. v1 -> v2: * Introduced arch_kexec_locate_mem_hole() for override and dropped weak arch_kexec_add_buffer(). * Addressed warnings reported by lkp. * Added patch to address kexec load issue when memory is reserved for crashkernel. * Used the appropriate license header for the new files added. * Added an option to merge ranges to minimize reallocations while adding memory ranges. * Dropped within_crashkernel parameter for add_opal_mem_range() & add_rtas_mem_range() functions as it is not really needed. --- Hari Bathini (11): kexec_file: allow archs to handle special regions while locating memory hole powerpc/kexec_file: mark PPC64 specific code powerpc/kexec_file: add helper functions for getting memory ranges ppc64/kexec_file: avoid stomping memory used by special regions powerpc/drmem: make lmb walk a bit more flexible ppc64/kexec_file: restrict memory usage of kdump kernel ppc64/kexec_file: enable early kernel's OPAL calls ppc64/kexec_file: setup backup region for kdump kernel ppc64/kexec_file: prepare elfcore header for crashing kernel ppc64/kexec_file: add appropriate regions for memory reserve map ppc64/kexec_file: fix kexec load failure with lack of memory hole arch/powerpc/include/asm/crashdump-ppc64.h | 19 arch/powerpc/include/asm/drmem.h |9 arch/powerpc/include/asm/kexec.h | 29 + arch/powerpc/include/asm/kexec_ranges.h|
