kernel/linux.git/arch/s390/lib, branch linux-5.9.y

s390: fix irq state tracing

2020-12-16T09:58:34+00:00

[ Upstream commit b1cae1f84a0f609a34ebcaa087fbecef32f69882 ] With commit 58c644ba512c ("sched/idle: Fix arch_cpu_idle() vs tracing") common code calls arch_cpu_idle() with a lockdep state that tells irqs are on. This doesn't work very well for s390: psw_idle() will enable interrupts to wait for an interrupt. As soon as an interrupt occurs the interrupt handler will verify if the old context was psw_idle(). If that is the case the interrupt enablement bits in the old program status word will be cleared. A subsequent test in both the external as well as the io interrupt handler checks if in the old context interrupts were enabled. Due to the above patching of the old program status word it is assumed the old context had interrupts disabled, and therefore a call to TRACE_IRQS_OFF (aka trace_hardirqs_off_caller) is skipped. Which in turn makes lockdep incorrectly "think" that interrupts are enabled within the interrupt handler. Fix this by unconditionally calling TRACE_IRQS_OFF when entering interrupt handlers. Also call unconditionally TRACE_IRQS_ON when leaving interrupts handlers. This leaves the special psw_idle() case, which now returns with interrupts disabled, but has an "irqs on" lockdep state. So callers of psw_idle() must adjust the state on their own, if required. This is currently only __udelay_disabled(). Fixes: 58c644ba512c ("sched/idle: Fix arch_cpu_idle() vs tracing") Acked-by: Peter Zijlstra (Intel) Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin

s390/test_unwind: fix possible memleak in test_unwind()

2020-08-11T16:16:16+00:00

test_unwind() misses to call kfree(bt) in an error path. Add the missed function call to fix it. Fixes: 0610154650f1 ("s390/test_unwind: print verbose unwinding results") Reported-by: Hulk Robot Signed-off-by: Wang Hai Acked-by: Ilya Leoshkevich Signed-off-by: Heiko Carstens

Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2020-08-08T04:14:30+00:00

Pull misc vfs updates from Al Viro: "No common topic whatsoever in those, sorry" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: define inode flags using bit numbers iov_iter: Move unnecessary inclusion of crypto/hash.h dlmfs: clean up dlmfs_file_{read,write}() a bit

s390: enable HAVE_FUNCTION_ERROR_INJECTION

2020-07-27T08:33:28+00:00

This kernel feature is required for enabling BPF_KPROBE_OVERRIDE. Define override_function_with_return() and regs_set_return_value() functions, and fix compile errors in syscall_wrapper.h. Signed-off-by: Ilya Leoshkevich Signed-off-by: Heiko Carstens

iov_iter: Move unnecessary inclusion of crypto/hash.h

2020-06-30T13:34:23+00:00

The header file linux/uio.h includes crypto/hash.h which pulls in most of the Crypto API. Since linux/uio.h is used throughout the kernel this means that every tiny bit of change to the Crypto API causes the entire kernel to get rebuilt. This patch fixes this by moving it into lib/iov_iter.c instead where it is actually used. This patch also fixes the ifdef to use CRYPTO_HASH instead of just CRYPTO which does not guarantee the existence of ahash. Unfortunately a number of drivers were relying on linux/uio.h to provide access to linux/slab.h. This patch adds inclusions of linux/slab.h as detected by build failures. Also skbuff.h was relying on this to provide a declaration for ahash_request. This patch adds a forward declaration instead. Signed-off-by: Herbert Xu Signed-off-by: Al Viro

Merge tag 's390-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2020-06-08T19:05:31+00:00

Pull s390 updates from Vasily Gorbik: - Add support for multi-function devices in pci code. - Enable PF-VF linking for architectures using the pdev->no_vf_scan flag (currently just s390). - Add reipl from NVMe support. - Get rid of critical section cleanup in entry.S. - Refactor PNSO CHSC (perform network subchannel operation) in cio and qeth. - QDIO interrupts and error handling fixes and improvements, more refactoring changes. - Align ioremap() with generic code. - Accept requests without the prefetch bit set in vfio-ccw. - Enable path handling via two new regions in vfio-ccw. - Other small fixes and improvements all over the code. * tag 's390-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (52 commits) vfio-ccw: make vfio_ccw_regops variables declarations static vfio-ccw: Add trace for CRW event vfio-ccw: Wire up the CRW irq and CRW region vfio-ccw: Introduce a new CRW region vfio-ccw: Refactor IRQ handlers vfio-ccw: Introduce a new schib region vfio-ccw: Refactor the unregister of the async regions vfio-ccw: Register a chp_event callback for vfio-ccw vfio-ccw: Introduce new helper functions to free/destroy regions vfio-ccw: document possible errors vfio-ccw: Enable transparent CCW IPL from DASD s390/pci: Log new handle in clp_disable_fh() s390/cio, s390/qeth: cleanup PNSO CHSC s390/qdio: remove q->first_to_kick s390/qdio: fix up qdio_start_irq() kerneldoc s390: remove critical section cleanup from entry.S s390: add machine check SIGP s390/pci: ioremap() align with generic code s390/ap: introduce new ap function ap_get_qdev() Documentation/s390: Update / remove developerWorks web links ...

s390: remove critical section cleanup from entry.S

2020-05-28T10:21:54+00:00

The current code is rather complex and caused a lot of subtle and hard to debug bugs in the past. Simplify the code by calling the system_call handler with interrupts disabled, save machine state, and re-enable them later. This requires significant changes to the machine check handling code as well. When the machine check interrupt arrived while being in kernel mode the new code will signal pending machine checks with a SIGP external call. When userspace was interrupted, the handler will switch to the kernel stack and directly execute s390_handle_mcck(). Signed-off-by: Sven Schnelle Signed-off-by: Vasily Gorbik

s390/mm: fix page table upgrade vs 2ndary address mode accesses

2020-04-21T13:16:43+00:00

A page table upgrade in a kernel section that uses secondary address mode will mess up the kernel instructions as follows: Consider the following scenario: two threads are sharing memory. On CPU1 thread 1 does e.g. strnlen_user(). That gets to old_fs = enable_sacf_uaccess(); len = strnlen_user_srst(src, size); and " la %2,0(%1)\n" " la %3,0(%0,%1)\n" " slgr %0,%0\n" " sacf 256\n" "0: srst %3,%2\n" in strnlen_user_srst(). At that point we are in secondary space mode, control register 1 points to kernel page table and instruction fetching happens via c1, rather than usual c13. Interrupts are not disabled, for obvious reasons. On CPU2 thread 2 does MAP_FIXED mmap(), forcing the upgrade of page table from 3-level to e.g. 4-level one. We'd allocated new top-level table, set it up and now we hit this: notify = 1; spin_unlock_bh(&mm->page_table_lock); } if (notify) on_each_cpu(__crst_table_upgrade, mm, 0); OK, we need to actually change over to use of new page table and we need that to happen in all threads that are currently running. Which happens to include the thread 1. IPI is delivered and we have static void __crst_table_upgrade(void *arg) { struct mm_struct *mm = arg; if (current->active_mm == mm) set_user_asce(mm); __tlb_flush_local(); } run on CPU1. That does static inline void set_user_asce(struct mm_struct *mm) { S390_lowcore.user_asce = mm->context.asce; OK, user page table address updated... __ctl_load(S390_lowcore.user_asce, 1, 1); ... and control register 1 set to it. clear_cpu_flag(CIF_ASCE_PRIMARY); } IPI is run in home space mode, so it's fine - insns are fetched using c13, which always points to kernel page table. But as soon as we return from the interrupt, previous PSW is restored, putting CPU1 back into secondary space mode, at which point we no longer get the kernel instructions from the kernel mapping. The fix is to only fixup the control registers that are currently in use for user processes during the page table update. We must also disable interrupts in enable_sacf_uaccess to synchronize the cr and thread.mm_segment updates against the on_each-cpu. Fixes: 0aaba41b58bc ("s390: remove all code using the access register mode") Cc: stable@vger.kernel.org # 4.15+ Reported-by: Al Viro Reviewed-by: Gerald Schaefer References: CVE-2020-11884 Signed-off-by: Christian Borntraeger

s390/test_unwind: fix spelling mistake "reqister" -> "register"

2019-12-11T18:53:23+00:00

There is a spelling mistake in a pr_info message. Fix it. Link: https://lkml.kernel.org/r/20191202090215.28766-1-colin.king@canonical.com Signed-off-by: Colin Ian King Signed-off-by: Vasily Gorbik

s390/spinlock: remove confusing comment in arch_spin_lock_wait

2019-12-11T18:53:23+00:00

arch_spin_lock_wait does not take steal time into consideration. Signed-off-by: Vasily Gorbik