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ff2632d7 |
| 17-May-2024 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'powerpc-6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Enable BPF Kernel Functions (kfuncs) in the powerpc BPF JIT.
Merge tag 'powerpc-6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Enable BPF Kernel Functions (kfuncs) in the powerpc BPF JIT.
- Allow per-process DEXCR (Dynamic Execution Control Register) settings via prctl, notably NPHIE which controls hashst/hashchk for ROP protection.
- Install powerpc selftests in sub-directories. Note this changes the way run_kselftest.sh needs to be invoked for powerpc selftests.
- Change fadump (Firmware Assisted Dump) to better handle memory add/remove.
- Add support for passing additional parameters to the fadump kernel.
- Add support for updating the kdump image on CPU/memory add/remove events.
- Other small features, cleanups and fixes.
Thanks to Andrew Donnellan, Andy Shevchenko, Aneesh Kumar K.V, Arnd Bergmann, Benjamin Gray, Bjorn Helgaas, Christian Zigotzky, Christophe Jaillet, Christophe Leroy, Colin Ian King, Cédric Le Goater, Dr. David Alan Gilbert, Erhard Furtner, Frank Li, GUO Zihua, Ganesh Goudar, Geoff Levand, Ghanshyam Agrawal, Greg Kurz, Hari Bathini, Joel Stanley, Justin Stitt, Kunwu Chan, Li Yang, Lidong Zhong, Madhavan Srinivasan, Mahesh Salgaonkar, Masahiro Yamada, Matthias Schiffer, Naresh Kamboju, Nathan Chancellor, Nathan Lynch, Naveen N Rao, Nicholas Miehlbradt, Ran Wang, Randy Dunlap, Ritesh Harjani, Sachin Sant, Shirisha Ganta, Shrikanth Hegde, Sourabh Jain, Stephen Rothwell, sundar, Thorsten Blum, Vaibhav Jain, Xiaowei Bao, Yang Li, and Zhao Chenhui.
* tag 'powerpc-6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (85 commits) powerpc/fadump: Fix section mismatch warning powerpc/85xx: fix compile error without CONFIG_CRASH_DUMP powerpc/fadump: update documentation about bootargs_append powerpc/fadump: pass additional parameters when fadump is active powerpc/fadump: setup additional parameters for dump capture kernel powerpc/pseries/fadump: add support for multiple boot memory regions selftests/powerpc/dexcr: Fix spelling mistake "predicition" -> "prediction" KVM: PPC: Book3S HV nestedv2: Fix an error handling path in gs_msg_ops_kvmhv_nestedv2_config_fill_info() KVM: PPC: Fix documentation for ppc mmu caps KVM: PPC: code cleanup for kvmppc_book3s_irqprio_deliver KVM: PPC: Book3S HV nestedv2: Cancel pending DEC exception powerpc/xmon: Check cpu id in commands "c#", "dp#" and "dx#" powerpc/code-patching: Use dedicated memory routines for patching powerpc/code-patching: Test patch_instructions() during boot powerpc64/kasan: Pass virtual addresses to kasan_init_phys_region() powerpc: rename SPRN_HID2 define to SPRN_HID2_750FX powerpc: Fix typos powerpc/eeh: Fix spelling of the word "auxillary" and update comment macintosh/ams: Fix unused variable warning powerpc/Makefile: Remove bits related to the previous use of -mcmodel=large ...
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#
e789d449 |
| 13-May-2024 |
Michael Ellerman <mpe@ellerman.id.au> |
Merge branch 'topic/kdump-hotplug' into next
Merge our topic branch containing kdump hotplug changes, more detail from the original cover letter:
Commit 247262756121 ("crash: add generic infrastruc
Merge branch 'topic/kdump-hotplug' into next
Merge our topic branch containing kdump hotplug changes, more detail from the original cover letter:
Commit 247262756121 ("crash: add generic infrastructure for crash hotplug support") added a generic infrastructure that allows architectures to selectively update the kdump image component during CPU or memory add/remove events within the kernel itself.
This patch series adds crash hotplug handler for PowerPC and enable support to update the kdump image on CPU/Memory add/remove events.
Among the 6 patches in this series, the first two patches make changes to the generic crash hotplug handler to assist PowerPC in adding support for this feature. The last four patches add support for this feature.
The following section outlines the problem addressed by this patch series, along with the current solution, its shortcomings, and the proposed resolution.
Problem: ======== Due to CPU/Memory hotplug or online/offline events the elfcorehdr (which describes the CPUs and memory of the crashed kernel) and FDT (Flattened Device Tree) of kdump image becomes outdated. Consequently, attempting dump collection with an outdated elfcorehdr or FDT can lead to failed or inaccurate dump collection.
Going forward CPU hotplug or online/offline events are referred as CPU/Memory add/remove events.
Existing solution and its shortcoming: ====================================== The current solution to address the above issue involves monitoring the CPU/memory add/remove events in userspace using udev rules and whenever there are changes in CPU and memory resources, the entire kdump image is loaded again. The kdump image includes kernel, initrd, elfcorehdr, FDT, purgatory. Given that only elfcorehdr and FDT get outdated due to CPU/Memory add/remove events, reloading the entire kdump image is inefficient. More importantly, kdump remains inactive for a substantial amount of time until the kdump reload completes.
Proposed solution: ================== Instead of initiating a full kdump image reload from userspace on CPU/Memory hotplug and online/offline events, the proposed solution aims to update only the necessary kdump image component within the kernel itself.
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Revision tags: v6.9, v6.9-rc7, v6.9-rc6, v6.9-rc5, v6.9-rc4, v6.9-rc3, v6.9-rc2 |
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#
79365026 |
| 26-Mar-2024 |
Sourabh Jain <sourabhjain@linux.ibm.com> |
crash: add a new kexec flag for hotplug support
Commit a72bbec70da2 ("crash: hotplug support for kexec_load()") introduced a new kexec flag, `KEXEC_UPDATE_ELFCOREHDR`. Kexec tool uses this flag to i
crash: add a new kexec flag for hotplug support
Commit a72bbec70da2 ("crash: hotplug support for kexec_load()") introduced a new kexec flag, `KEXEC_UPDATE_ELFCOREHDR`. Kexec tool uses this flag to indicate to the kernel that it is safe to modify the elfcorehdr of the kdump image loaded using the kexec_load system call.
However, it is possible that architectures may need to update kexec segments other then elfcorehdr. For example, FDT (Flatten Device Tree) on PowerPC. Introducing a new kexec flag for every new kexec segment may not be a good solution. Hence, a generic kexec flag bit, `KEXEC_CRASH_HOTPLUG_SUPPORT`, is introduced to share the CPU/Memory hotplug support intent between the kexec tool and the kernel for the kexec_load system call.
Now we have two kexec flags that enables crash hotplug support for kexec_load system call. First is KEXEC_UPDATE_ELFCOREHDR (only used in x86), and second is KEXEC_CRASH_HOTPLUG_SUPPORT (for all architectures).
To simplify the process of finding and reporting the crash hotplug support the following changes are introduced.
1. Define arch specific function to process the kexec flags and determine crash hotplug support
2. Rename the @update_elfcorehdr member of struct kimage to @hotplug_support and populate it for both kexec_load and kexec_file_load syscalls, because architecture can update more than one kexec segment
3. Let generic function crash_check_hotplug_support report hotplug support for loaded kdump image based on value of @hotplug_support
To bring the x86 crash hotplug support in line with the above points, the following changes have been made:
- Introduce the arch_crash_hotplug_support function to process kexec flags and determine crash hotplug support
- Remove the arch_crash_hotplug_[cpu|memory]_support functions
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> Acked-by: Baoquan He <bhe@redhat.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20240326055413.186534-3-sourabhjain@linux.ibm.com
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Revision tags: v6.9-rc1, v6.8, v6.8-rc7 |
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#
06d07429 |
| 29-Feb-2024 |
Jani Nikula <jani.nikula@intel.com> |
Merge drm/drm-next into drm-intel-next
Sync to get the drm_printer changes to drm-intel-next.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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Revision tags: v6.8-rc6, v6.8-rc5 |
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#
41c177cf |
| 11-Feb-2024 |
Rob Clark <robdclark@chromium.org> |
Merge tag 'drm-misc-next-2024-02-08' into msm-next
Merge the drm-misc tree to uprev MSM CI.
Signed-off-by: Rob Clark <robdclark@chromium.org>
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Revision tags: v6.8-rc4, v6.8-rc3 |
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#
4db102dc |
| 29-Jan-2024 |
Maxime Ripard <mripard@kernel.org> |
Merge drm/drm-next into drm-misc-next
Kickstart 6.9 development cycle.
Signed-off-by: Maxime Ripard <mripard@kernel.org>
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Revision tags: v6.8-rc2 |
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#
be3382ec |
| 23-Jan-2024 |
Lucas De Marchi <lucas.demarchi@intel.com> |
Merge drm/drm-next into drm-xe-next
Sync to v6.8-rc1.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
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#
03c11eb3 |
| 14-Feb-2024 |
Ingo Molnar <mingo@kernel.org> |
Merge tag 'v6.8-rc4' into x86/percpu, to resolve conflicts and refresh the branch
Conflicts: arch/x86/include/asm/percpu.h arch/x86/include/asm/text-patching.h
Signed-off-by: Ingo Molnar <mingo@k
Merge tag 'v6.8-rc4' into x86/percpu, to resolve conflicts and refresh the branch
Conflicts: arch/x86/include/asm/percpu.h arch/x86/include/asm/text-patching.h
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
42ac0be1 |
| 26-Jan-2024 |
Ingo Molnar <mingo@kernel.org> |
Merge branch 'linus' into x86/mm, to refresh the branch and pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
cf79f291 |
| 22-Jan-2024 |
Maxime Ripard <mripard@kernel.org> |
Merge v6.8-rc1 into drm-misc-fixes
Let's kickstart the 6.8 fix cycle.
Signed-off-by: Maxime Ripard <mripard@kernel.org>
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Revision tags: v6.8-rc1, v6.7, v6.7-rc8, v6.7-rc7, v6.7-rc6, v6.7-rc5, v6.7-rc4, v6.7-rc3, v6.7-rc2, v6.7-rc1, v6.6 |
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#
a1c613ae |
| 24-Oct-2023 |
Tvrtko Ursulin <tvrtko.ursulin@intel.com> |
Merge drm/drm-next into drm-intel-gt-next
Work that needs to land in drm-intel-gt-next depends on two patches only present in drm-intel-next, absence of which is causing a merge conflict:
3b918f4
Merge drm/drm-next into drm-intel-gt-next
Work that needs to land in drm-intel-gt-next depends on two patches only present in drm-intel-next, absence of which is causing a merge conflict:
3b918f4f0c8b ("drm/i915/pxp: Optimize GET_PARAM:PXP_STATUS") ac765b7018f6 ("drm/i915/pxp/mtl: intel_pxp_init_hw needs runtime-pm inside pm-complete")
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
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#
9f2a6352 |
| 09-Jan-2024 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'mm-nonmm-stable-2024-01-09-10-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton: "Quite a lot of kexec work this time around. Many singl
Merge tag 'mm-nonmm-stable-2024-01-09-10-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton: "Quite a lot of kexec work this time around. Many singleton patches in many places. The notable patch series are:
- nilfs2 folio conversion from Matthew Wilcox in 'nilfs2: Folio conversions for file paths'.
- Additional nilfs2 folio conversion from Ryusuke Konishi in 'nilfs2: Folio conversions for directory paths'.
- IA64 remnant removal in Heiko Carstens's 'Remove unused code after IA-64 removal'.
- Arnd Bergmann has enabled the -Wmissing-prototypes warning everywhere in 'Treewide: enable -Wmissing-prototypes'. This had some followup fixes:
- Nathan Chancellor has cleaned up the hexagon build in the series 'hexagon: Fix up instances of -Wmissing-prototypes'.
- Nathan also addressed some s390 warnings in 's390: A couple of fixes for -Wmissing-prototypes'.
- Arnd Bergmann addresses the same warnings for MIPS in his series 'mips: address -Wmissing-prototypes warnings'.
- Baoquan He has made kexec_file operate in a top-down-fitting manner similar to kexec_load in the series 'kexec_file: Load kernel at top of system RAM if required'
- Baoquan He has also added the self-explanatory 'kexec_file: print out debugging message if required'.
- Some checkstack maintenance work from Tiezhu Yang in the series 'Modify some code about checkstack'.
- Douglas Anderson has disentangled the watchdog code's logging when multiple reports are occurring simultaneously. The series is 'watchdog: Better handling of concurrent lockups'.
- Yuntao Wang has contributed some maintenance work on the crash code in 'crash: Some cleanups and fixes'"
* tag 'mm-nonmm-stable-2024-01-09-10-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (157 commits) crash_core: fix and simplify the logic of crash_exclude_mem_range() x86/crash: use SZ_1M macro instead of hardcoded value x86/crash: remove the unused image parameter from prepare_elf_headers() kdump: remove redundant DEFAULT_CRASH_KERNEL_LOW_SIZE scripts/decode_stacktrace.sh: strip unexpected CR from lines watchdog: if panicking and we dumped everything, don't re-enable dumping watchdog/hardlockup: use printk_cpu_sync_get_irqsave() to serialize reporting watchdog/softlockup: use printk_cpu_sync_get_irqsave() to serialize reporting watchdog/hardlockup: adopt softlockup logic avoiding double-dumps kexec_core: fix the assignment to kimage->control_page x86/kexec: fix incorrect end address passed to kernel_ident_mapping_init() lib/trace_readwrite.c:: replace asm-generic/io with linux/io nilfs2: cpfile: fix some kernel-doc warnings stacktrace: fix kernel-doc typo scripts/checkstack.pl: fix no space expression between sp and offset x86/kexec: fix incorrect argument passed to kexec_dprintk() x86/kexec: use pr_err() instead of kexec_dprintk() when an error occurs nilfs2: add missing set_freezable() for freezable kthread kernel: relay: remove relay_file_splice_read dead code, doesn't work docs: submit-checklist: remove all of "make namespacecheck" ...
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#
cbc2fe9d |
| 13-Dec-2023 |
Baoquan He <bhe@redhat.com> |
kexec_file: add kexec_file flag to control debug printing
Patch series "kexec_file: print out debugging message if required", v4.
Currently, specifying '-d' on kexec command will print a lot of deb
kexec_file: add kexec_file flag to control debug printing
Patch series "kexec_file: print out debugging message if required", v4.
Currently, specifying '-d' on kexec command will print a lot of debugging informationabout kexec/kdump loading with kexec_load interface.
However, kexec_file_load prints nothing even though '-d' is specified. It's very inconvenient to debug or analyze the kexec/kdump loading when something wrong happened with kexec/kdump itself or develper want to check the kexec/kdump loading.
In this patchset, a kexec_file flag is KEXEC_FILE_DEBUG added and checked in code. If it's passed in, debugging message of kexec_file code will be printed out and can be seen from console and dmesg. Otherwise, the debugging message is printed like beofre when pr_debug() is taken.
Note: **** ===== 1) The code in kexec-tools utility also need be changed to support passing KEXEC_FILE_DEBUG to kernel when 'kexec -s -d' is specified. The patch link is here: ========= [PATCH] kexec_file: add kexec_file flag to support debug printing http://lists.infradead.org/pipermail/kexec/2023-November/028505.html
2) s390 also has kexec_file code, while I am not sure what debugging information is necessary. So leave it to s390 developer.
Test: **** ==== Testing was done in v1 on x86_64 and arm64. For v4, tested on x86_64 again. And on x86_64, the printed messages look like below: -------------------------------------------------------------- kexec measurement buffer for the loaded kernel at 0x207fffe000. Loaded purgatory at 0x207fff9000 Loaded boot_param, command line and misc at 0x207fff3000 bufsz=0x1180 memsz=0x1180 Loaded 64bit kernel at 0x207c000000 bufsz=0xc88200 memsz=0x3c4a000 Loaded initrd at 0x2079e79000 bufsz=0x2186280 memsz=0x2186280 Final command line is: root=/dev/mapper/fedora_intel--knightslanding--lb--02-root ro rd.lvm.lv=fedora_intel-knightslanding-lb-02/root console=ttyS0,115200N81 crashkernel=256M E820 memmap: 0000000000000000-000000000009a3ff (1) 000000000009a400-000000000009ffff (2) 00000000000e0000-00000000000fffff (2) 0000000000100000-000000006ff83fff (1) 000000006ff84000-000000007ac50fff (2) ...... 000000207fff6150-000000207fff615f (128) 000000207fff6160-000000207fff714f (1) 000000207fff7150-000000207fff715f (128) 000000207fff7160-000000207fff814f (1) 000000207fff8150-000000207fff815f (128) 000000207fff8160-000000207fffffff (1) nr_segments = 5 segment[0]: buf=0x000000004e5ece74 bufsz=0x211 mem=0x207fffe000 memsz=0x1000 segment[1]: buf=0x000000009e871498 bufsz=0x4000 mem=0x207fff9000 memsz=0x5000 segment[2]: buf=0x00000000d879f1fe bufsz=0x1180 mem=0x207fff3000 memsz=0x2000 segment[3]: buf=0x000000001101cd86 bufsz=0xc88200 mem=0x207c000000 memsz=0x3c4a000 segment[4]: buf=0x00000000c6e38ac7 bufsz=0x2186280 mem=0x2079e79000 memsz=0x2187000 kexec_file_load: type:0, start:0x207fff91a0 head:0x109e004002 flags:0x8 ---------------------------------------------------------------------------
This patch (of 7):
When specifying 'kexec -c -d', kexec_load interface will print loading information, e.g the regions where kernel/initrd/purgatory/cmdline are put, the memmap passed to 2nd kernel taken as system RAM ranges, and printing all contents of struct kexec_segment, etc. These are very helpful for analyzing or positioning what's happening when kexec/kdump itself failed. The debugging printing for kexec_load interface is made in user space utility kexec-tools.
Whereas, with kexec_file_load interface, 'kexec -s -d' print nothing. Because kexec_file code is mostly implemented in kernel space, and the debugging printing functionality is missed. It's not convenient when debugging kexec/kdump loading and jumping with kexec_file_load interface.
Now add KEXEC_FILE_DEBUG to kexec_file flag to control the debugging message printing. And add global variable kexec_file_dbg_print and macro kexec_dprintk() to facilitate the printing.
This is a preparation, later kexec_dprintk() will be used to replace the existing pr_debug(). Once 'kexec -s -d' is specified, it will print out kexec/kdump loading information. If '-d' is not specified, it regresses to pr_debug().
Link: https://lkml.kernel.org/r/20231213055747.61826-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20231213055747.61826-2-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Conor Dooley <conor@kernel.org> Cc: Joe Perches <joe@perches.com> Cc: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.6-rc7 |
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#
a940daa5 |
| 17-Oct-2023 |
Thomas Gleixner <tglx@linutronix.de> |
Merge branch 'linus' into smp/core
Pull in upstream to get the fixes so depending changes can be applied.
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Revision tags: v6.6-rc6 |
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#
57390019 |
| 11-Oct-2023 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-next into drm-misc-next
Updating drm-misc-next to the state of Linux v6.6-rc2.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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Revision tags: v6.6-rc5 |
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#
de801933 |
| 03-Oct-2023 |
Ingo Molnar <mingo@kernel.org> |
Merge tag 'v6.6-rc4' into perf/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Revision tags: v6.6-rc4, v6.6-rc3 |
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#
6f23fc47 |
| 18-Sep-2023 |
Ingo Molnar <mingo@kernel.org> |
Merge tag 'v6.6-rc2' into locking/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Revision tags: v6.6-rc2 |
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#
a3f9e4bc |
| 15-Sep-2023 |
Jani Nikula <jani.nikula@intel.com> |
Merge drm/drm-next into drm-intel-next
Sync to v6.6-rc1.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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#
c900529f |
| 12-Sep-2023 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-fixes into drm-misc-fixes
Forwarding to v6.6-rc1.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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Revision tags: v6.6-rc1 |
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#
d68b4b6f |
| 29-Aug-2023 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- An extensive rework of kexec and crash Kconfig from
Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- An extensive rework of kexec and crash Kconfig from Eric DeVolder ("refactor Kconfig to consolidate KEXEC and CRASH options")
- kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a couple of macros to args.h")
- gdb feature work from Kuan-Ying Lee ("Add GDB memory helper commands")
- vsprintf inclusion rationalization from Andy Shevchenko ("lib/vsprintf: Rework header inclusions")
- Switch the handling of kdump from a udev scheme to in-kernel handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory hot un/plug")
- Many singleton patches to various parts of the tree
* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits) document while_each_thread(), change first_tid() to use for_each_thread() drivers/char/mem.c: shrink character device's devlist[] array x86/crash: optimize CPU changes crash: change crash_prepare_elf64_headers() to for_each_possible_cpu() crash: hotplug support for kexec_load() x86/crash: add x86 crash hotplug support crash: memory and CPU hotplug sysfs attributes kexec: exclude elfcorehdr from the segment digest crash: add generic infrastructure for crash hotplug support crash: move a few code bits to setup support of crash hotplug kstrtox: consistently use _tolower() kill do_each_thread() nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse scripts/bloat-o-meter: count weak symbol sizes treewide: drop CONFIG_EMBEDDED lockdep: fix static memory detection even more lib/vsprintf: declare no_hash_pointers in sprintf.h lib/vsprintf: split out sprintf() and friends kernel/fork: stop playing lockless games for exe_file replacement adfs: delete unused "union adfs_dirtail" definition ...
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Revision tags: v6.5, v6.5-rc7 |
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#
a72bbec7 |
| 14-Aug-2023 |
Eric DeVolder <eric.devolder@oracle.com> |
crash: hotplug support for kexec_load()
The hotplug support for kexec_load() requires changes to the userspace kexec-tools and a little extra help from the kernel.
Given a kdump capture kernel load
crash: hotplug support for kexec_load()
The hotplug support for kexec_load() requires changes to the userspace kexec-tools and a little extra help from the kernel.
Given a kdump capture kernel loaded via kexec_load(), and a subsequent hotplug event, the crash hotplug handler finds the elfcorehdr and rewrites it to reflect the hotplug change. That is the desired outcome, however, at kernel panic time, the purgatory integrity check fails (because the elfcorehdr changed), and the capture kernel does not boot and no vmcore is generated.
Therefore, the userspace kexec-tools/kexec must indicate to the kernel that the elfcorehdr can be modified (because the kexec excluded the elfcorehdr from the digest, and sized the elfcorehdr memory buffer appropriately).
To facilitate hotplug support with kexec_load(): - a new kexec flag KEXEC_UPATE_ELFCOREHDR indicates that it is safe for the kernel to modify the kexec_load()'d elfcorehdr - the /sys/kernel/crash_elfcorehdr_size node communicates the preferred size of the elfcorehdr memory buffer - The sysfs crash_hotplug nodes (ie. /sys/devices/system/[cpu|memory]/crash_hotplug) dynamically take into account kexec_file_load() vs kexec_load() and KEXEC_UPDATE_ELFCOREHDR. This is critical so that the udev rule processing of crash_hotplug is all that is needed to determine if the userspace unload-then-load of the kdump image is to be skipped, or not. The proposed udev rule change looks like: # The kernel updates the crash elfcorehdr for CPU and memory changes SUBSYSTEM=="cpu", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end" SUBSYSTEM=="memory", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end"
The table below indicates the behavior of kexec_load()'d kdump image updates (with the new udev crash_hotplug rule in place):
Kernel |Kexec -------+-----+---- Old |Old |New | a | a -------+-----+---- New | a | b -------+-----+----
where kexec 'old' and 'new' delineate kexec-tools has the needed modifications for the crash hotplug feature, and kernel 'old' and 'new' delineate the kernel supports this crash hotplug feature.
Behavior 'a' indicates the unload-then-reload of the entire kdump image. For the kexec 'old' column, the unload-then-reload occurs due to the missing flag KEXEC_UPDATE_ELFCOREHDR. An 'old' kernel (with 'new' kexec) does not present the crash_hotplug sysfs node, which leads to the unload-then-reload of the kdump image.
Behavior 'b' indicates the desired optimized behavior of the kernel directly modifying the elfcorehdr and avoiding the unload-then-reload of the kdump image.
If the udev rule is not updated with crash_hotplug node check, then no matter any combination of kernel or kexec is new or old, the kdump image continues to be unload-then-reload on hotplug changes.
To fully support crash hotplug feature, there needs to be a rollout of kernel, kexec-tools and udev rule changes. However, the order of the rollout of these pieces does not matter; kexec_load()'d kdump images still function for hotplug as-is.
Link: https://lkml.kernel.org/r/20230814214446.6659-7-eric.devolder@oracle.com Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> Suggested-by: Hari Bathini <hbathini@linux.ibm.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Akhil Raj <lf32.dev@gmail.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Young <dyoung@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Mimi Zohar <zohar@linux.ibm.com> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Sean Christopherson <seanjc@google.com> Cc: Sourabh Jain <sourabhjain@linux.ibm.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.5-rc6, v6.5-rc5, v6.5-rc4, v6.5-rc3, v6.5-rc2, v6.5-rc1, v6.4, v6.4-rc7, v6.4-rc6, v6.4-rc5, v6.4-rc4, v6.4-rc3, v6.4-rc2, v6.4-rc1, v6.3, v6.3-rc7, v6.3-rc6, v6.3-rc5, v6.3-rc4, v6.3-rc3, v6.3-rc2, v6.3-rc1, v6.2, v6.2-rc8, v6.2-rc7, v6.2-rc6, v6.2-rc5, v6.2-rc4, v6.2-rc3, v6.2-rc2, v6.2-rc1 |
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4f2c0a4a |
| 14-Dec-2022 |
Nick Terrell <terrelln@fb.com> |
Merge branch 'main' into zstd-linus
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Revision tags: v6.1, v6.1-rc8, v6.1-rc7, v6.1-rc6, v6.1-rc5, v6.1-rc4, v6.1-rc3, v6.1-rc2 |
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14e77332 |
| 22-Oct-2022 |
Nick Terrell <terrelln@fb.com> |
Merge branch 'main' into zstd-next
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Revision tags: v6.1-rc1 |
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97acb6a8 |
| 03-Oct-2022 |
Tvrtko Ursulin <tvrtko.ursulin@intel.com> |
Merge drm/drm-next into drm-intel-gt-next
Daniele needs 84d4333c1e28 ("misc/mei: Add NULL check to component match callback functions") in order to merge the DG2 HuC patches.
Signed-off-by: Tvrtko
Merge drm/drm-next into drm-intel-gt-next
Daniele needs 84d4333c1e28 ("misc/mei: Add NULL check to component match callback functions") in order to merge the DG2 HuC patches.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
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Revision tags: v6.0, v6.0-rc7, v6.0-rc6, v6.0-rc5, v6.0-rc4, v6.0-rc3, v6.0-rc2, v6.0-rc1 |
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44627916 |
| 05-Aug-2022 |
Andreas Gruenbacher <agruenba@redhat.com> |
Merge part of branch 'for-next.instantiate' into for-next
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