lwn.git/arch/arm/kernel/machine_kexec.c, branch docs-fixes

kexec: Consolidate machine_kexec_mask_interrupts() implementation

2024-12-11T19:32:34+00:00

Consolidate the machine_kexec_mask_interrupts implementation into a common function located in a new file: kernel/irq/kexec.c. This removes duplicate implementations from architecture-specific files in arch/arm, arch/arm64, arch/powerpc, and arch/riscv, reducing code duplication and improving maintainability. The new implementation retains architecture-specific behavior for CONFIG_GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD, which was previously implemented for ARM64. When enabled (currently for ARM64), it clears the active state of interrupts forwarded to virtual machines (VMs) before handling other interrupt masking operations. Signed-off-by: Eliav Farber Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20241204142003.32859-2-farbere@amazon.com

arch, crash: move arch_crash_save_vmcoreinfo() out to file vmcore_info.c

2024-02-24T01:48:25+00:00

Nathan reported below building error: ===== $ curl -LSso .config https://git.alpinelinux.org/aports/plain/community/linux-edge/config-edge.armv7 $ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- olddefconfig all .. arm-linux-gnueabi-ld: arch/arm/kernel/machine_kexec.o: in function `arch_crash_save_vmcoreinfo': machine_kexec.c:(.text+0x488): undefined reference to `vmcoreinfo_append_str' ==== On architecutres, like arm, s390, ppc, sh, function arch_crash_save_vmcoreinfo() is located in machine_kexec.c and it can only be compiled in when CONFIG_KEXEC_CORE=y. That's not right because arch_crash_save_vmcoreinfo() is used to export arch specific vmcoreinfo. CONFIG_VMCORE_INFO is supposed to control its compiling in. However, CONFIG_VMVCORE_INFO could be independent of CONFIG_KEXEC_CORE, e.g CONFIG_PROC_KCORE=y will select CONFIG_VMVCORE_INFO. Or CONFIG_KEXEC/CONFIG_KEXEC_FILE is set while CONFIG_CRASH_DUMP is not set, it will report linking error. So, on arm, s390, ppc and sh, move arch_crash_save_vmcoreinfo out to a new file vmcore_info.c. Let CONFIG_VMCORE_INFO decide if compiling in arch_crash_save_vmcoreinfo(). [akpm@linux-foundation.org: remove stray newlines at eof] Link: https://lkml.kernel.org/r/20240129135033.157195-3-bhe@redhat.com Signed-off-by: Baoquan He Reported-by: Nathan Chancellor Closes: https://lore.kernel.org/all/20240126045551.GA126645@dev-arch.thelio-3990X/T/#u Cc: Al Viro Cc: Eric W. Biederman Cc: Hari Bathini Cc: Klara Modin Cc: Michael Kelley Cc: Pingfan Liu Cc: Stephen Rothwell Cc: Yang Li Signed-off-by: Andrew Morton

ARM: 9317/1: kexec: Make smp stop calls asynchronous

2023-08-14T11:16:59+00:00

If a panic is triggered by a hrtimer interrupt all online cpus will be notified and set offline. But as highlighted by commit 19dbdcb8039c ("smp: Warn on function calls from softirq context") this call should not be made synchronous with disabled interrupts: softdog: Initiating panic Kernel panic - not syncing: Software Watchdog Timer expired WARNING: CPU: 1 PID: 0 at kernel/smp.c:753 smp_call_function_many_cond unwind_backtrace: show_stack dump_stack_lvl __warn warn_slowpath_fmt smp_call_function_many_cond smp_call_function crash_smp_send_stop.part.0 machine_crash_shutdown __crash_kexec panic softdog_fire __hrtimer_run_queues hrtimer_interrupt Make the smp call for machine_crash_nonpanic_core() asynchronous. Signed-off-by: Mårten Lindahl Signed-off-by: Russell King (Oracle)

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2022-12-13T23:22:14+00:00

Pull ARM updates from Russell King: - update unwinder to cope with module PLTs - enable UBSAN on ARM - improve kernel fault message - update UEFI runtime page tables dump - avoid clang's __aeabi_uldivmod generated in NWFPE code - disable FIQs on CPU shutdown paths - update XOR register usage - a number of build updates (using .arch, thread pointer, removal of lazy evaluation in Makefile) - conversion of stacktrace code to stackwalk - findbit assembly updates - hwcap feature updates for ARMv8 CPUs - instruction dump updates for big-endian platforms - support for function error injection * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (31 commits) ARM: 9279/1: support function error injection ARM: 9277/1: Make the dumped instructions are consistent with the disassembled ones ARM: 9276/1: Refactor dump_instr() ARM: 9275/1: Drop '-mthumb' from AFLAGS_ISA ARM: 9274/1: Add hwcap for Speculative Store Bypassing Safe ARM: 9273/1: Add hwcap for Speculation Barrier(SB) ARM: 9272/1: vfp: Add hwcap for FEAT_AA32I8MM ARM: 9271/1: vfp: Add hwcap for FEAT_AA32BF16 ARM: 9270/1: vfp: Add hwcap for FEAT_FHM ARM: 9269/1: vfp: Add hwcap for FEAT_DotProd ARM: 9268/1: vfp: Add hwcap FPHP and ASIMDHP for FEAT_FP16 ARM: 9267/1: Define Armv8 registers in AArch32 state ARM: findbit: add unwinder information ARM: findbit: operate by words ARM: findbit: convert to macros ARM: findbit: provide more efficient ARMv7 implementation ARM: findbit: document ARMv5 bit offset calculation ARM: 9259/1: stacktrace: Convert stacktrace to generic ARCH_STACKWALK ARM: 9258/1: stacktrace: Make stack walk callback consistent with generic code ARM: 9265/1: pass -march= only to compiler ...

ARM: kexec: make machine_crash_nonpanic_core() static

2022-11-18T21:55:07+00:00

This symbol is not used outside of the file, so mark it static. Fixes the following warning: arch/arm/kernel/machine_kexec.c:76:6: warning: symbol 'machine_crash_nonpanic_core' was not declared. Should it be static? Link: https://lkml.kernel.org/r/20220929042936.22012-5-bhe@redhat.com Signed-off-by: Chen Lifu Signed-off-by: Baoquan He Acked-by: Baoquan He Cc: "Eric W . Biederman" Cc: Petr Mladek Cc: Russell King Cc: Benjamin Herrenschmidt Cc: Jianglei Nie Cc: Li Chen Cc: Michael Ellerman Cc: Paul Mackerras Cc: ye xingchen Cc: Zeal Robot Signed-off-by: Andrew Morton

ARM: 9257/1: Disable FIQs (but not IRQs) on CPUs shutdown paths

2022-11-07T14:19:02+00:00

Currently the regular CPU shutdown path for ARM disables IRQs/FIQs in the secondary CPUs - smp_send_stop() calls ipi_cpu_stop(), which is responsible for that. IRQs are architecturally masked when we take an interrupt, but FIQs are high priority than IRQs, hence they aren't masked. With that said, it makes sense to disable FIQs here, but there's no need for (re-)disabling IRQs. More than that: there is an alternative path for disabling CPUs, in the form of function crash_smp_send_stop(), which is used for kexec/panic path. This function relies on a SMP call that also triggers a busy-wait loop [at machine_crash_nonpanic_core()], but without disabling FIQs. This might lead to odd scenarios, like early interrupts in the boot of kexec'd kernel or even interrupts in secondary "disabled" CPUs while the main one still works in the panic path and assumes all secondary CPUs are (really!) off. So, let's disable FIQs in both paths and *not* disable IRQs a second time, since they are already masked in both paths by the architecture. This way, we keep both CPU quiesce paths consistent and safe. Cc: Marc Zyngier Cc: Michael Kelley Signed-off-by: Guilherme G. Piccoli Signed-off-by: Russell King (Oracle)

ARM: 9060/1: kexec: Remove unused kexec_reinit callback

2021-03-09T10:25:35+00:00

The last (only?) user of this was removed in commit ba364fc752da ("ARM: Kirkwood: Remove mach-kirkwood"), back in v3.17. Link: https://lore.kernel.org/r/20210210235243.398810-1-joel@jms.id.au Signed-off-by: Joel Stanley Reviewed-by: Arnd Bergmann Signed-off-by: Russell King

ARM: kexec: fix oops after TLB are invalidated

2021-02-05T10:23:29+00:00

Giancarlo Ferrari reports the following oops while trying to use kexec: Unable to handle kernel paging request at virtual address 80112f38 pgd = fd7ef03e [80112f38] *pgd=0001141e(bad) Internal error: Oops: 80d [#1] PREEMPT SMP ARM ... This is caused by machine_kexec() trying to set the kernel text to be read/write, so it can poke values into the relocation code before copying it - and an interrupt occuring which changes the page tables. The subsequent writes then hit read-only sections that trigger a data abort resulting in the above oops. Fix this by copying the relocation code, and then writing the variables into the destination, thereby avoiding the need to make the kernel text read/write. Reported-by: Giancarlo Ferrari Tested-by: Giancarlo Ferrari Signed-off-by: Russell King

mm: remove unneeded includes of

2020-08-07T18:33:26+00:00

Patch series "mm: cleanup usage of " Most architectures have very similar versions of pXd_alloc_one() and pXd_free_one() for intermediate levels of page table. These patches add generic versions of these functions in and enable use of the generic functions where appropriate. In addition, functions declared and defined in headers are used mostly by core mm and early mm initialization in arch and there is no actual reason to have the included all over the place. The first patch in this series removes unneeded includes of In the end it didn't work out as neatly as I hoped and moving pXd_alloc_track() definitions to would require unnecessary changes to arches that have custom page table allocations, so I've decided to move lib/ioremap.c to mm/ and make pgalloc-track.h local to mm/. This patch (of 8): In most cases header is required only for allocations of page table memory. Most of the .c files that include that header do not use symbols declared in and do not require that header. As for the other header files that used to include , it is possible to move that include into the .c file that actually uses symbols from and drop the include from the header file. The process was somewhat automated using sed -i -E '/[<"]asm\/pgalloc\.h/d' \ $(grep -L -w -f /tmp/xx \ $(git grep -E -l '[<"]asm/pgalloc\.h')) where /tmp/xx contains all the symbols defined in arch/*/include/asm/pgalloc.h. [rppt@linux.ibm.com: fix powerpc warning] Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Reviewed-by: Pekka Enberg Acked-by: Geert Uytterhoeven [m68k] Cc: Abdul Haleem Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Christophe Leroy Cc: Joerg Roedel Cc: Max Filippov Cc: Peter Zijlstra Cc: Satheesh Rajendran Cc: Stafford Horne Cc: Stephen Rothwell Cc: Steven Rostedt Cc: Joerg Roedel Cc: Matthew Wilcox Link: http://lkml.kernel.org/r/20200627143453.31835-1-rppt@kernel.org Link: http://lkml.kernel.org/r/20200627143453.31835-2-rppt@kernel.org Signed-off-by: Linus Torvalds

mm: don't include asm/pgtable.h if linux/mm.h is already included

2020-06-09T16:39:13+00:00

Patch series "mm: consolidate definitions of page table accessors", v2. The low level page table accessors (pXY_index(), pXY_offset()) are duplicated across all architectures and sometimes more than once. For instance, we have 31 definition of pgd_offset() for 25 supported architectures. Most of these definitions are actually identical and typically it boils down to, e.g. static inline unsigned long pmd_index(unsigned long address) { return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); } static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) { return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address); } These definitions can be shared among 90% of the arches provided XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined. For architectures that really need a custom version there is always possibility to override the generic version with the usual ifdefs magic. These patches introduce include/linux/pgtable.h that replaces include/asm-generic/pgtable.h and add the definitions of the page table accessors to the new header. This patch (of 12): The linux/mm.h header includes to allow inlining of the functions involving page table manipulations, e.g. pte_alloc() and pmd_alloc(). So, there is no point to explicitly include in the files that include . The include statements in such cases are remove with a simple loop: for f in $(git grep -l "include ") ; do sed -i -e '/include / d' $f done Signed-off-by: Mike Rapoport Signed-off-by: Andrew Morton Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brian Cain Cc: Catalin Marinas Cc: Chris Zankel Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Greentime Hu Cc: Greg Ungerer Cc: Guan Xuetao Cc: Guo Ren Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ley Foon Tan Cc: Mark Salter Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Mike Rapoport Cc: Nick Hu Cc: Paul Walmsley Cc: Richard Weinberger Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Tony Luck Cc: Vincent Chen Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org Signed-off-by: Linus Torvalds