kernel.git/arch/powerpc/kernel/fadump.c, branch linux-5.10.y

powerpc/fadump: reset dump area size if fadump memory reserve fails

2023-09-19T10:20:15Z

[ Upstream commit d1eb75e0dfed80d2d85b664e28a39f65b290ab55 ] In case fadump_reserve_mem() fails to reserve memory, the reserve_dump_area_size variable will retain the reserve area size. This will lead to /sys/kernel/fadump/mem_reserved node displaying an incorrect memory reserved by fadump. To fix this problem, reserve dump area size variable is set to 0 if fadump failed to reserve memory. Fixes: 8255da95e545 ("powerpc/fadump: release all the memory above boot memory size") Signed-off-by: Sourabh Jain Acked-by: Mahesh Salgaonkar Signed-off-by: Michael Ellerman Link: https://msgid.link/20230704050715.203581-1-sourabhjain@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/fadump: fix PT_LOAD segment for boot memory area

2022-06-09T08:21:15Z

[ Upstream commit 15eb77f873255cf9f4d703b63cfbd23c46579654 ] Boot memory area is setup as separate PT_LOAD segment in the vmcore as it is moved by f/w, on crash, to a destination address provided by the kernel. Having separate PT_LOAD segment helps in handling the different physical address and offset for boot memory area in the vmcore. Commit ced1bf52f477 ("powerpc/fadump: merge adjacent memory ranges to reduce PT_LOAD segements") inadvertly broke this pre-condition for cases where some of the first kernel memory is available adjacent to boot memory area. This scenario is rare but possible when memory for fadump could not be reserved adjacent to boot memory area owing to memory hole or such. Reading memory from a vmcore exported in such scenario provides incorrect data. Fix it by ensuring no other region is folded into boot memory area. Fixes: ced1bf52f477 ("powerpc/fadump: merge adjacent memory ranges to reduce PT_LOAD segements") Signed-off-by: Hari Bathini Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220406093839.206608-2-hbathini@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/fadump: Fix inaccurate CPU state info in vmcore generated with panic

2022-01-27T09:54:23Z

[ Upstream commit 06e629c25daa519be620a8c17359ae8fc7a2e903 ] In panic path, fadump is triggered via a panic notifier function. Before calling panic notifier functions, smp_send_stop() gets called, which stops all CPUs except the panic'ing CPU. Commit 8389b37dffdc ("powerpc: stop_this_cpu: remove the cpu from the online map.") and again commit bab26238bbd4 ("powerpc: Offline CPU in stop_this_cpu()") started marking CPUs as offline while stopping them. So, if a kernel has either of the above commits, vmcore captured with fadump via panic path would not process register data for all CPUs except the panic'ing CPU. Sample output of crash-utility with such vmcore: # crash vmlinux vmcore ... KERNEL: vmlinux DUMPFILE: vmcore [PARTIAL DUMP] CPUS: 1 DATE: Wed Nov 10 09:56:34 EST 2021 UPTIME: 00:00:42 LOAD AVERAGE: 2.27, 0.69, 0.24 TASKS: 183 NODENAME: XXXXXXXXX RELEASE: 5.15.0+ VERSION: #974 SMP Wed Nov 10 04:18:19 CST 2021 MACHINE: ppc64le (2500 Mhz) MEMORY: 8 GB PANIC: "Kernel panic - not syncing: sysrq triggered crash" PID: 3394 COMMAND: "bash" TASK: c0000000150a5f80 [THREAD_INFO: c0000000150a5f80] CPU: 1 STATE: TASK_RUNNING (PANIC) crash> p -x __cpu_online_mask __cpu_online_mask = $1 = { bits = {0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0} } crash> crash> crash> p -x __cpu_active_mask __cpu_active_mask = $2 = { bits = {0xff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0} } crash> While this has been the case since fadump was introduced, the issue was not identified for two probable reasons: - In general, the bulk of the vmcores analyzed were from crash due to exception. - The above did change since commit 8341f2f222d7 ("sysrq: Use panic() to force a crash") started using panic() instead of deferencing NULL pointer to force a kernel crash. But then commit de6e5d38417e ("powerpc: smp_send_stop do not offline stopped CPUs") stopped marking CPUs as offline till kernel commit bab26238bbd4 ("powerpc: Offline CPU in stop_this_cpu()") reverted that change. To ensure post processing register data of all other CPUs happens as intended, let panic() function take the crash friendly path (read crash_smp_send_stop()) with the help of crash_kexec_post_notifiers option. Also, as register data for all CPUs is captured by f/w, skip IPI callbacks here for fadump, to avoid any complications in finding the right backtraces. Signed-off-by: Hari Bathini Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211207103719.91117-2-hbathini@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/fadump: Mark fadump_calculate_reserve_size as __init

2021-05-14T07:50:30Z

[ Upstream commit fbced1546eaaab57a32e56c974ea8acf10c6abd8 ] If fadump_calculate_reserve_size() is not inlined, there is a modpost warning: WARNING: modpost: vmlinux.o(.text+0x5196c): Section mismatch in reference from the function fadump_calculate_reserve_size() to the function .init.text:parse_crashkernel() The function fadump_calculate_reserve_size() references the function __init parse_crashkernel(). This is often because fadump_calculate_reserve_size lacks a __init annotation or the annotation of parse_crashkernel is wrong. fadump_calculate_reserve_size() calls parse_crashkernel(), which is marked as __init and fadump_calculate_reserve_size() is called from within fadump_reserve_mem(), which is also marked as __init. Mark fadump_calculate_reserve_size() as __init to fix the section mismatch. Additionally, remove the inline keyword as it is not necessary to inline this function; the compiler is still free to do so if it feels it is worthwhile since commit 889b3c1245de ("compiler: remove CONFIG_OPTIMIZE_INLINING entirely"). Fixes: 11550dc0a00b ("powerpc/fadump: reuse crashkernel parameter for fadump memory reservation") Signed-off-by: Nathan Chancellor Signed-off-by: Michael Ellerman Link: https://github.com/ClangBuiltLinux/linux/issues/1300 Link: https://lore.kernel.org/r/20210302195013.2626335-1-nathan@kernel.org Signed-off-by: Sasha Levin

Merge tag 'powerpc-5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2020-10-16T19:21:15Z

Pull powerpc updates from Michael Ellerman: - A series from Nick adding ARCH_WANT_IRQS_OFF_ACTIVATE_MM & selecting it for powerpc, as well as a related fix for sparc. - Remove support for PowerPC 601. - Some fixes for watchpoints & addition of a new ptrace flag for detecting ISA v3.1 (Power10) watchpoint features. - A fix for kernels using 4K pages and the hash MMU on bare metal Power9 systems with > 16TB of RAM, or RAM on the 2nd node. - A basic idle driver for shallow stop states on Power10. - Tweaks to our sched domains code to better inform the scheduler about the hardware topology on Power9/10, where two SMT4 cores can be presented by firmware as an SMT8 core. - A series doing further reworks & cleanups of our EEH code. - Addition of a filter for RTAS (firmware) calls done via sys_rtas(), to prevent root from overwriting kernel memory. - Other smaller features, fixes & cleanups. Thanks to: Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Athira Rajeev, Biwen Li, Cameron Berkenpas, Cédric Le Goater, Christophe Leroy, Christoph Hellwig, Colin Ian King, Daniel Axtens, David Dai, Finn Thain, Frederic Barrat, Gautham R. Shenoy, Greg Kurz, Gustavo Romero, Ira Weiny, Jason Yan, Joel Stanley, Jordan Niethe, Kajol Jain, Konrad Rzeszutek Wilk, Laurent Dufour, Leonardo Bras, Liu Shixin, Luca Ceresoli, Madhavan Srinivasan, Mahesh Salgaonkar, Nathan Lynch, Nicholas Mc Guire, Nicholas Piggin, Nick Desaulniers, Oliver O'Halloran, Pedro Miraglia Franco de Carvalho, Pratik Rajesh Sampat, Qian Cai, Qinglang Miao, Ravi Bangoria, Russell Currey, Satheesh Rajendran, Scott Cheloha, Segher Boessenkool, Srikar Dronamraju, Stan Johnson, Stephen Kitt, Stephen Rothwell, Thiago Jung Bauermann, Tyrel Datwyler, Vaibhav Jain, Vaidyanathan Srinivasan, Vasant Hegde, Wang Wensheng, Wolfram Sang, Yang Yingliang, zhengbin. * tag 'powerpc-5.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (228 commits) Revert "powerpc/pci: unmap legacy INTx interrupts when a PHB is removed" selftests/powerpc: Fix eeh-basic.sh exit codes cpufreq: powernv: Fix frame-size-overflow in powernv_cpufreq_reboot_notifier powerpc/time: Make get_tb() common to PPC32 and PPC64 powerpc/time: Make get_tbl() common to PPC32 and PPC64 powerpc/time: Remove get_tbu() powerpc/time: Avoid using get_tbl() and get_tbu() internally powerpc/time: Make mftb() common to PPC32 and PPC64 powerpc/time: Rename mftbl() to mftb() powerpc/32s: Remove #ifdef CONFIG_PPC_BOOK3S_32 in head_book3s_32.S powerpc/32s: Rename head_32.S to head_book3s_32.S powerpc/32s: Setup the early hash table at all time. powerpc/time: Remove ifdef in get_dec() and set_dec() powerpc: Remove get_tb_or_rtc() powerpc: Remove __USE_RTC() powerpc: Tidy up a bit after removal of PowerPC 601. powerpc: Remove support for PowerPC 601 powerpc: Remove PowerPC 601 powerpc: Drop SYNC_601() ISYNC_601() and SYNC() powerpc: Remove CONFIG_PPC601_SYNC_FIX ...

arch, drivers: replace for_each_membock() with for_each_mem_range()

2020-10-14T01:38:35Z

There are several occurrences of the following pattern: for_each_memblock(memory, reg) { start = __pfn_to_phys(memblock_region_memory_base_pfn(reg); end = __pfn_to_phys(memblock_region_memory_end_pfn(reg)); /* do something with start and end */ } Using for_each_mem_range() iterator is more appropriate in such cases and allows simpler and cleaner code. [akpm@linux-foundation.org: fix arch/arm/mm/pmsa-v7.c build] [rppt@linux.ibm.com: mips: fix cavium-octeon build caused by memblock refactoring] Link: http://lkml.kernel.org/r/20200827124549.GD167163@linux.ibm.com Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Cc: Andy Lutomirski Cc: Baoquan He Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Daniel Axtens Cc: Dave Hansen Cc: Emil Renner Berthing Cc: Hari Bathini Cc: Ingo Molnar Cc: Ingo Molnar Cc: Jonathan Cameron Cc: Marek Szyprowski Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Miguel Ojeda Cc: Palmer Dabbelt Cc: Paul Mackerras Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Russell King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Will Deacon Cc: Yoshinori Sato Link: https://lkml.kernel.org/r/20200818151634.14343-13-rppt@kernel.org Signed-off-by: Linus Torvalds

arch, mm: replace for_each_memblock() with for_each_mem_pfn_range()

2020-10-14T01:38:35Z

There are several occurrences of the following pattern: for_each_memblock(memory, reg) { start_pfn = memblock_region_memory_base_pfn(reg); end_pfn = memblock_region_memory_end_pfn(reg); /* do something with start_pfn and end_pfn */ } Rather than iterate over all memblock.memory regions and each time query for their start and end PFNs, use for_each_mem_pfn_range() iterator to get simpler and clearer code. Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Reviewed-by: Baoquan He Acked-by: Miguel Ojeda [.clang-format] Cc: Andy Lutomirski Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Daniel Axtens Cc: Dave Hansen Cc: Emil Renner Berthing Cc: Hari Bathini Cc: Ingo Molnar Cc: Ingo Molnar Cc: Jonathan Cameron Cc: Marek Szyprowski Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Palmer Dabbelt Cc: Paul Mackerras Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Russell King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Will Deacon Cc: Yoshinori Sato Link: https://lkml.kernel.org/r/20200818151634.14343-12-rppt@kernel.org Signed-off-by: Linus Torvalds

powerpc/fadump: Remove set but not used variable 'elf'

2020-08-24T15:31:32Z

Fix gcc '-Wunused-but-set-variable' warning: arch/powerpc/kernel/fadump.c: In function fadump_update_elfcore_header: arch/powerpc/kernel/fadump.c:790:17: warning: variable elf set but not used [-Wunused-but-set-variable] It is introduced by commit ebaeb5ae2437 ("fadump: Convert firmware-assisted cpu state dump data into elf notes."), but never used, so remove it. Reported-by: Hulk Robot Signed-off-by: zhengbin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1574144074-142032-2-git-send-email-zhengbin13@huawei.com

powerpc/fadump: Fix build error with CONFIG_PRESERVE_FA_DUMP=y

2020-07-27T07:04:54Z

skiroot_defconfig fails: arch/powerpc/kernel/fadump.c:48:17: error: ‘cpus_in_fadump’ defined but not used 48 | static atomic_t cpus_in_fadump; Fix it by moving the definition into the #ifdef where it's used. Fixes: ba608c4fa12c ("powerpc/fadump: fix race between pstore write and fadump crash trigger") Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200727070341.595634-1-mpe@ellerman.id.au

powerpc/fadump: fix race between pstore write and fadump crash trigger

2020-07-16T03:12:44Z

When we enter into fadump crash path via system reset we fail to update the pstore. On the system reset path we first update the pstore then we go for fadump crash. But the problem here is when all the CPUs try to get the pstore lock to initiate the pstore write, only one CPUs will acquire the lock and proceed with the pstore write. Since it in NMI context CPUs that fail to get lock do not wait for their turn to write to the pstore and simply proceed with the next operation which is fadump crash. One of the CPU who proceeded with fadump crash path triggers the crash and does not wait for the CPU who gets the pstore lock to complete the pstore update. Timeline diagram to depicts the sequence of events that leads to an unsuccessful pstore update when we hit fadump crash path via system reset. 1 2 3 ... n CPU Threads | | | | | | | | Reached to -->|--->|---->| ----------->| system reset | | | | path | | | | | | | | Try to -->|--->|---->|------------>| acquire the | | | | pstore lock | | | | | | | | | | | | Got the -->| +->| | |<-+ pstore lock | | | | | |--> Didn't get the | --------------------------+ lock and moving | | | | ahead on fadump | | | | crash path | | | | Begins the -->| | | | process to | | | |<-- Got the chance to update the | | | | trigger the crash pstore | -> | | ... <- | | | | | | | | | | | | |<-- Triggers the | | | | | | crash | | | | | | ^ | | | | | | | Writing to -->| | | | | | | pstore | | | | | | | | | | ^ |__________________| | | CPU Relax | | | +-----------------------------------------+ | v Race: crash triggered before pstore update completes To avoid this race condition a barrier is added on crash_fadump path, it prevents the CPU to trigger the crash until all the online CPUs completes their task. A barrier is added to make sure all the secondary CPUs hit the crash_fadump function before we initiates the crash. A timeout is kept to ensure the primary CPU (one who initiates the crash) do not wait for secondary CPUs indefinitely. Signed-off-by: Sourabh Jain Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200713052435.183750-1-sourabhjain@linux.ibm.com