kernel.git/arch/parisc/kernel/smp.c, branch linux-5.18.y

parisc: Find a new timesync master if current CPU is removed

2022-03-29T19:37:13Z

When CPU hotplugging is enabled, the user may want to remove the current CPU which is providing the timer ticks. If this happens we need to find a new timesync master. Signed-off-by: Helge Deller

parisc: Implement __cpu_die() and __cpu_disable() for CPU hotplugging

2022-03-29T19:37:12Z

Add relevant code to __cpu_die() and __cpu_disable() to finally enable the CPU hotplugging features. Reset the irq count values in smp_callin() to zero before bringing up the CPU. It seems that the firmware may need up to 8 seconds to fully stop a CPU in which no other PDC calls are allowed to be made. Use a timeout __cpu_die() to accommodate for this. Use "chcpu -d 1" to bring CPU1 down, and "chcpu -e 1" to bring it up. Signed-off-by: Helge Deller

parisc: move CPU field back into thread_info

2021-11-04T10:21:47Z

In commit 2214c0e77259 ("parisc: Move thread_info into task struct") PA-RISC gained support for THREAD_INFO_IN_TASK while changes were already underway to keep the CPU field in thread_info rather than move it into task_struct when THREAD_INFO_IN_TASK is enabled. The result is a broken build for all PA-RISC configs that enable SMP. So let's partially revert that commit, and get rid of the ugly hack to get at the offset of task_struct::cpu without having to include linux/sched.h, and put the CPU field back where it was before. Reported-by: Guenter Roeck Fixes: bcf9033e5449 ("sched: move CPU field back into thread_info if THREAD_INFO_IN_TASK=y") Signed-off-by: Ard Biesheuvel Signed-off-by: Helge Deller

parisc/kgdb: add kgdb_roundup() to make kgdb work with idle polling

2021-11-01T06:35:59Z

With idle polling, IPIs are not sent when a CPU idle, but queued and run later from do_idle(). The default kgdb_call_nmi_hook() implementation gets the pointer to struct pt_regs from get_irq_reqs(), which doesn't work in that case because it was not called from the IPI interrupt handler. Fix it by defining our own kgdb_roundup() function which sents an IPI_ENTER_KGDB. When that IPI is received on the target CPU kgdb_nmicallback() is called. Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller

parisc: Move thread_info into task struct

2021-11-01T06:35:59Z

This implements the CONFIG_THREAD_INFO_IN_TASK option. With this change: - before thread_info was part of the stack and located at the beginning of the stack - now the thread_info struct is moved and located inside the task_struct structure - the stack is allocated and handled like the major other platforms - drop the cpu field of thread_info and use instead the one in task_struct Signed-off-by: Helge Deller Signed-off-by: Sven Schnelle

parisc: disable preemption in send_IPI_allbutself()

2021-10-30T21:11:01Z

Otherwise we might not stop all other CPUs. Signed-off-by: Sven Schnelle Signed-off-by: Helge Deller

sched/core: Initialize the idle task with preemption disabled

2021-05-12T11:01:45Z

As pointed out by commit de9b8f5dcbd9 ("sched: Fix crash trying to dequeue/enqueue the idle thread") init_idle() can and will be invoked more than once on the same idle task. At boot time, it is invoked for the boot CPU thread by sched_init(). Then smp_init() creates the threads for all the secondary CPUs and invokes init_idle() on them. As the hotplug machinery brings the secondaries to life, it will issue calls to idle_thread_get(), which itself invokes init_idle() yet again. In this case it's invoked twice more per secondary: at _cpu_up(), and at bringup_cpu(). Given smp_init() already initializes the idle tasks for all *possible* CPUs, no further initialization should be required. Now, removing init_idle() from idle_thread_get() exposes some interesting expectations with regards to the idle task's preempt_count: the secondary startup always issues a preempt_disable(), requiring some reset of the preempt count to 0 between hot-unplug and hotplug, which is currently served by idle_thread_get() -> idle_init(). Given the idle task is supposed to have preemption disabled once and never see it re-enabled, it seems that what we actually want is to initialize its preempt_count to PREEMPT_DISABLED and leave it there. Do that, and remove init_idle() from idle_thread_get(). Secondary startups were patched via coccinelle: @begone@ @@ -preempt_disable(); ... cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); Signed-off-by: Valentin Schneider Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra Link: https://lore.kernel.org/r/20210512094636.2958515-1-valentin.schneider@arm.com

parisc: Avoid external interrupts when IPI finishes

2020-10-15T06:10:37Z

No need to allow external interrupts when the IPI loop is going to finish now. Signed-off-by: Helge Deller

mm: remove unneeded includes of

2020-08-07T18:33:26Z

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

2020-06-09T16:39:13Z

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