kernel/linux.git/arch, branch v4.9.196

hypfs: Fix error number left in struct pointer member

2019-10-07T16:53:18+00:00

[ Upstream commit b54c64f7adeb241423cd46598f458b5486b0375e ] In hypfs_fill_super(), if hypfs_create_update_file() fails, sbi->update_file is left holding an error number. This is passed to hypfs_kill_super() which doesn't check for this. Fix this by not setting sbi->update_value until after we've checked for error. Fixes: 24bbb1faf3f0 ("[PATCH] s390_hypfs filesystem") Signed-off-by: David Howells cc: Martin Schwidefsky cc: Heiko Carstens cc: linux-s390@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Sasha Levin

ARM: 8903/1: ensure that usable memory in bank 0 starts from a PMD-aligned address

2019-10-07T16:53:18+00:00

[ Upstream commit 00d2ec1e6bd82c0538e6dd3e4a4040de93ba4fef ] The calculation of memblock_limit in adjust_lowmem_bounds() assumes that bank 0 starts from a PMD-aligned address. However, the beginning of the first bank may be NOMAP memory and the start of usable memory will be not aligned to PMD boundary. In such case the memblock_limit will be set to the end of the NOMAP region, which will prevent any memblock allocations. Mark the region between the end of the NOMAP area and the next PMD-aligned address as NOMAP as well, so that the usable memory will start at PMD-aligned address. Signed-off-by: Mike Rapoport Signed-off-by: Russell King Signed-off-by: Sasha Levin

ARM: 8898/1: mm: Don't treat faults reported from cache maintenance as writes

2019-10-07T16:53:16+00:00

[ Upstream commit 834020366da9ab3fb87d1eb9a3160eb22dbed63a ] Translation faults arising from cache maintenance instructions are rather unhelpfully reported with an FSR value where the WnR field is set to 1, indicating that the faulting access was a write. Since cache maintenance instructions on 32-bit ARM do not require any particular permissions, this can cause our private 'cacheflush' system call to fail spuriously if a translation fault is generated due to page aging when targetting a read-only VMA. In this situation, we will return -EFAULT to userspace, although this is unfortunately suppressed by the popular '__builtin___clear_cache()' intrinsic provided by GCC, which returns void. Although it's tempting to write this off as a userspace issue, we can actually do a little bit better on CPUs that support LPAE, even if the short-descriptor format is in use. On these CPUs, cache maintenance faults additionally set the CM field in the FSR, which we can use to suppress the write permission checks in the page fault handler and succeed in performing cache maintenance to read-only areas even in the presence of a translation fault. Reported-by: Orion Hodson Signed-off-by: Will Deacon Signed-off-by: Russell King Signed-off-by: Sasha Levin

MIPS: tlbex: Explicitly cast _PAGE_NO_EXEC to a boolean

2019-10-07T16:53:15+00:00

[ Upstream commit c59ae0a1055127dd3828a88e111a0db59b254104 ] clang warns: arch/mips/mm/tlbex.c:634:19: error: use of logical '&&' with constant operand [-Werror,-Wconstant-logical-operand] if (cpu_has_rixi && _PAGE_NO_EXEC) { ^ ~~~~~~~~~~~~~ arch/mips/mm/tlbex.c:634:19: note: use '&' for a bitwise operation if (cpu_has_rixi && _PAGE_NO_EXEC) { ^~ & arch/mips/mm/tlbex.c:634:19: note: remove constant to silence this warning if (cpu_has_rixi && _PAGE_NO_EXEC) { ~^~~~~~~~~~~~~~~~ 1 error generated. Explicitly cast this value to a boolean so that clang understands we intend for this to be a non-zero value. Fixes: 00bf1c691d08 ("MIPS: tlbex: Avoid placing software PTE bits in Entry* PFN fields") Link: https://github.com/ClangBuiltLinux/linux/issues/609 Signed-off-by: Nathan Chancellor Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: James Hogan Cc: Nick Desaulniers Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: clang-built-linux@googlegroups.com Signed-off-by: Sasha Levin

arm64: fix unreachable code issue with cmpxchg

2019-10-07T16:53:14+00:00

[ Upstream commit 920fdab7b3ce98c14c840261e364f490f3679a62 ] On arm64 build with clang, sometimes the __cmpxchg_mb is not inlined when CONFIG_OPTIMIZE_INLINING is set. Clang then fails a compile-time assertion, because it cannot tell at compile time what the size of the argument is: mm/memcontrol.o: In function `__cmpxchg_mb': memcontrol.c:(.text+0x1a4c): undefined reference to `__compiletime_assert_175' memcontrol.c:(.text+0x1a4c): relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol `__compiletime_assert_175' Mark all of the cmpxchg() style functions as __always_inline to ensure that the compiler can see the result. Acked-by: Nick Desaulniers Reported-by: Nathan Chancellor Link: https://github.com/ClangBuiltLinux/linux/issues/648 Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Reviewed-by: Andrew Murray Tested-by: Andrew Murray Signed-off-by: Arnd Bergmann Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

powerpc/pseries: correctly track irq state in default idle

2019-10-07T16:53:13+00:00

[ Upstream commit 92c94dfb69e350471473fd3075c74bc68150879e ] prep_irq_for_idle() is intended to be called before entering H_CEDE (and it is used by the pseries cpuidle driver). However the default pseries idle routine does not call it, leading to mismanaged lazy irq state when the cpuidle driver isn't in use. Manifestations of this include: * Dropped IPIs in the time immediately after a cpu comes online (before it has installed the cpuidle handler), making the online operation block indefinitely waiting for the new cpu to respond. * Hitting this WARN_ON in arch_local_irq_restore(): /* * We should already be hard disabled here. We had bugs * where that wasn't the case so let's dbl check it and * warn if we are wrong. Only do that when IRQ tracing * is enabled as mfmsr() can be costly. */ if (WARN_ON_ONCE(mfmsr() & MSR_EE)) __hard_irq_disable(); Call prep_irq_for_idle() from pseries_lpar_idle() and honor its result. Fixes: 363edbe2614a ("powerpc: Default arch idle could cede processor on pseries") Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190910225244.25056-1-nathanl@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/64s/exception: machine check use correct cfar for late handler

2019-10-07T16:53:13+00:00

[ Upstream commit 0b66370c61fcf5fcc1d6901013e110284da6e2bb ] Bare metal machine checks run an "early" handler in real mode before running the main handler which reports the event. The main handler runs exactly as a normal interrupt handler, after the "windup" which sets registers back as they were at interrupt entry. CFAR does not get restored by the windup code, so that will be wrong when the handler is run. Restore the CFAR to the saved value before running the late handler. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190802105709.27696-8-npiggin@gmail.com Signed-off-by: Sasha Levin

powerpc/pseries/mobility: use cond_resched when updating device tree

2019-10-07T16:53:11+00:00

[ Upstream commit ccfb5bd71d3d1228090a8633800ae7cdf42a94ac ] After a partition migration, pseries_devicetree_update() processes changes to the device tree communicated from the platform to Linux. This is a relatively heavyweight operation, with multiple device tree searches, memory allocations, and conversations with partition firmware. There's a few levels of nested loops which are bounded only by decisions made by the platform, outside of Linux's control, and indeed we have seen RCU stalls on large systems while executing this call graph. Use cond_resched() in these loops so that the cpu is yielded when needed. Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190802192926.19277-4-nathanl@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/futex: Fix warning: 'oldval' may be used uninitialized in this function

2019-10-07T16:53:11+00:00

[ Upstream commit 38a0d0cdb46d3f91534e5b9839ec2d67be14c59d ] We see warnings such as: kernel/futex.c: In function 'do_futex': kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] return oldval == cmparg; ^ kernel/futex.c:1651:6: note: 'oldval' was declared here int oldval, ret; ^ This is because arch_futex_atomic_op_inuser() only sets *oval if ret is 0 and GCC doesn't see that it will only use it when ret is 0. Anyway, the non-zero ret path is an error path that won't suffer from setting *oval, and as *oval is a local var in futex_atomic_op_inuser() it will have no impact. Signed-off-by: Christophe Leroy [mpe: reword change log slightly] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/86b72f0c134367b214910b27b9a6dd3321af93bb.1565774657.git.christophe.leroy@c-s.fr Signed-off-by: Sasha Levin

powerpc/rtas: use device model APIs and serialization during LPM

2019-10-07T16:53:11+00:00

[ Upstream commit a6717c01ddc259f6f73364779df058e2c67309f8 ] The LPAR migration implementation and userspace-initiated cpu hotplug can interleave their executions like so: 1. Set cpu 7 offline via sysfs. 2. Begin a partition migration, whose implementation requires the OS to ensure all present cpus are online; cpu 7 is onlined: rtas_ibm_suspend_me -> rtas_online_cpus_mask -> cpu_up This sets cpu 7 online in all respects except for the cpu's corresponding struct device; dev->offline remains true. 3. Set cpu 7 online via sysfs. _cpu_up() determines that cpu 7 is already online and returns success. The driver core (device_online) sets dev->offline = false. 4. The migration completes and restores cpu 7 to offline state: rtas_ibm_suspend_me -> rtas_offline_cpus_mask -> cpu_down This leaves cpu7 in a state where the driver core considers the cpu device online, but in all other respects it is offline and unused. Attempts to online the cpu via sysfs appear to succeed but the driver core actually does not pass the request to the lower-level cpuhp support code. This makes the cpu unusable until the cpu device is manually set offline and then online again via sysfs. Instead of directly calling cpu_up/cpu_down, the migration code should use the higher-level device core APIs to maintain consistent state and serialize operations. Fixes: 120496ac2d2d ("powerpc: Bring all threads online prior to migration/hibernation") Signed-off-by: Nathan Lynch Reviewed-by: Gautham R. Shenoy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190802192926.19277-2-nathanl@linux.ibm.com Signed-off-by: Sasha Levin