kernel.git/arch/um/include/asm, branch linux-4.19.y

um: Fix the -Wmissing-prototypes warning for __switch_mm

2024-06-16T11:23:35Z

[ Upstream commit 2cbade17b18c0f0fd9963f26c9fc9b057eb1cb3a ] The __switch_mm function is defined in the user code, and is called by the kernel code. It should be declared in a shared header. Fixes: 4dc706c2f292 ("um: take um_mmu.h to asm/mmu.h, clean asm/mmu_context.h a bit") Signed-off-by: Tiwei Bie Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

um/cpu: Switch to arch_cpu_finalize_init()

2023-08-08T17:49:18Z

commit 9349b5cd0908f8afe95529fc7a8cbb1417df9b0c upstream check_bugs() is about to be phased out. Switch over to the new arch_cpu_finalize_init() implementation. No functional change. Signed-off-by: Thomas Gleixner Acked-by: Richard Weinberger Link: https://lore.kernel.org/r/20230613224545.493148694@linutronix.de Signed-off-by: Daniel Sneddon Signed-off-by: Greg Kroah-Hartman

um: use fallback for random_get_entropy() instead of zero

2022-06-25T09:49:10Z

commit 9f13fb0cd11ed2327abff69f6501a2c124c88b5a upstream. In the event that random_get_entropy() can't access a cycle counter or similar, falling back to returning 0 is really not the best we can do. Instead, at least calling random_get_entropy_fallback() would be preferable, because that always needs to return _something_, even falling back to jiffies eventually. It's not as though random_get_entropy_fallback() is super high precision or guaranteed to be entropic, but basically anything that's not zero all the time is better than returning zero all the time. This is accomplished by just including the asm-generic code like on other architectures, which means we can get rid of the empty stub function here. Cc: Thomas Gleixner Cc: Arnd Bergmann Cc: Richard Weinberger Cc: Anton Ivanov Acked-by: Johannes Berg Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

hugetlbfs: flush TLBs correctly after huge_pmd_unshare

2021-12-01T08:27:43Z

commit a4a118f2eead1d6c49e00765de89878288d4b890 upstream. When __unmap_hugepage_range() calls to huge_pmd_unshare() succeed, a TLB flush is missing. This TLB flush must be performed before releasing the i_mmap_rwsem, in order to prevent an unshared PMDs page from being released and reused before the TLB flush took place. Arguably, a comprehensive solution would use mmu_gather interface to batch the TLB flushes and the PMDs page release, however it is not an easy solution: (1) try_to_unmap_one() and try_to_migrate_one() also call huge_pmd_unshare() and they cannot use the mmu_gather interface; and (2) deferring the release of the page reference for the PMDs page until after i_mmap_rwsem is dropeed can confuse huge_pmd_unshare() into thinking PMDs are shared when they are not. Fix __unmap_hugepage_range() by adding the missing TLB flush, and forcing a flush when unshare is successful. Fixes: 24669e58477e ("hugetlb: use mmu_gather instead of a temporary linked list for accumulating pages)" # 3.6 Signed-off-by: Nadav Amit Reviewed-by: Mike Kravetz Cc: Aneesh Kumar K.V Cc: KAMEZAWA Hiroyuki Cc: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

um: Fix off by one error in IRQ enumeration

2020-01-27T13:51:13Z

[ Upstream commit 09ccf0364ca3e94aba4093707ef433ea8014e2a4 ] Fix an off-by-one in IRQ enumeration Fixes: 49da7e64f33e ("High Performance UML Vector Network Driver") Reported by: Dana Johnson Signed-off-by: Anton Ivanov Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

um: Silence lockdep complaint about mmap_sem

2019-07-31T05:27:04Z

[ Upstream commit 80bf6ceaf9310b3f61934c69b382d4912deee049 ] When we get into activate_mm(), lockdep complains that we're doing something strange: WARNING: possible circular locking dependency detected 5.1.0-10252-gb00152307319-dirty #121 Not tainted ------------------------------------------------------ inside.sh/366 is trying to acquire lock: (____ptrval____) (&(&p->alloc_lock)->rlock){+.+.}, at: flush_old_exec+0x703/0x8d7 but task is already holding lock: (____ptrval____) (&mm->mmap_sem){++++}, at: flush_old_exec+0x6c5/0x8d7 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mm->mmap_sem){++++}: [...] __lock_acquire+0x12ab/0x139f lock_acquire+0x155/0x18e down_write+0x3f/0x98 flush_old_exec+0x748/0x8d7 load_elf_binary+0x2ca/0xddb [...] -> #0 (&(&p->alloc_lock)->rlock){+.+.}: [...] __lock_acquire+0x12ab/0x139f lock_acquire+0x155/0x18e _raw_spin_lock+0x30/0x83 flush_old_exec+0x703/0x8d7 load_elf_binary+0x2ca/0xddb [...] other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem); lock(&(&p->alloc_lock)->rlock); lock(&mm->mmap_sem); lock(&(&p->alloc_lock)->rlock); *** DEADLOCK *** 2 locks held by inside.sh/366: #0: (____ptrval____) (&sig->cred_guard_mutex){+.+.}, at: __do_execve_file+0x12d/0x869 #1: (____ptrval____) (&mm->mmap_sem){++++}, at: flush_old_exec+0x6c5/0x8d7 stack backtrace: CPU: 0 PID: 366 Comm: inside.sh Not tainted 5.1.0-10252-gb00152307319-dirty #121 Stack: [...] Call Trace: [<600420de>] show_stack+0x13b/0x155 [<6048906b>] dump_stack+0x2a/0x2c [<6009ae64>] print_circular_bug+0x332/0x343 [<6009c5c6>] check_prev_add+0x669/0xdad [<600a06b4>] __lock_acquire+0x12ab/0x139f [<6009f3d0>] lock_acquire+0x155/0x18e [<604a07e0>] _raw_spin_lock+0x30/0x83 [<60151e6a>] flush_old_exec+0x703/0x8d7 [<601a8eb8>] load_elf_binary+0x2ca/0xddb [...] I think it's because in exec_mmap() we have down_read(&old_mm->mmap_sem); ... task_lock(tsk); ... activate_mm(active_mm, mm); (which does down_write(&mm->mmap_sem)) I'm not really sure why lockdep throws in the whole knowledge about the task lock, but it seems that old_mm and mm shouldn't ever be the same (and it doesn't deadlock) so tell lockdep that they're different. Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

um: Avoid marking pages with "changed protection"

2019-02-12T18:47:17Z

[ Upstream commit 8892d8545f2d0342b9c550defbfb165db237044b ] Changing protection is a very high cost operation in UML because in addition to an extra syscall it also interrupts mmap merge sequences generated by the tlb. While the condition is not particularly common it is worth avoiding. Signed-off-by: Anton Ivanov Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

Merge branch 'for-linus-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

2018-06-15T21:50:51Z

Pull uml updates from Richard Weinberger: "Minor updates for UML: - fixes for our new vector network driver by Anton - initcall cleanup by Alexander - We have a new mailinglist, sourceforge.net sucks" * 'for-linus-4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: um: Fix raw interface options um: Fix initialization of vector queues um: remove uml initcalls um: Update mailing list address

um: remove uml initcalls

2018-06-10T20:49:14Z

__uml_initcall() is not used and .uml.initcall.init section is empty: $ grep -r '__uml_initcall(' arch/um/include/shared/init.h:#define __uml_initcall(fn) \ $ readelf -s ../umobj/linux | grep __uml_initcall 23214: 00000000603b75d8 0 NOTYPE GLOBAL DEFAULT 32 __uml_initcall_start 25337: 00000000603b75d8 0 NOTYPE GLOBAL DEFAULT 32 __uml_initcall_end So it is unnecessary. Signed-off-by: Alexander Pateenok Signed-off-by: Richard Weinberger

time: Add an asm-generic/compat.h file

2018-04-19T11:28:51Z

We have a couple of files that try to include asm/compat.h on architectures where this is available. Those should generally use the higher-level linux/compat.h file, but that in turn fails to include asm/compat.h when CONFIG_COMPAT is disabled, unless we can provide that header on all architectures. This adds the asm/compat.h for all remaining architectures to simplify the dependencies. Architectures that are getting removed in linux-4.17 are not changed here, to avoid needless conflicts with the removal patches. Those architectures are broken by this patch, but we have already shown that they have no users. Signed-off-by: Arnd Bergmann