kernel.git/arch/x86/kernel/traps.c, branch linux-4.11.y

x86/debug: Fix the printk() debug output of signal_fault(), do_trap() and do_general_protection()

2017-04-11T07:11:13Z

Since commit: 4bcc595ccd80 "printk: reinstate KERN_CONT for printing" ... the debug output of signal_fault(), do_trap() and do_general_protection() looks garbled, e.g.: traps: conftest[9335] trap invalid opcode ip:400428 sp:7ffeaba1b0d8 error:0 in conftest[400000+1000] (note the unintended line break.) Fix the bug by adding KERN_CONTs. Signed-off-by: Markus Trippelsdorf Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:36Z

We are going to split out of , which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

x86/traps: Get rid of unnecessary preempt_disable/preempt_enable_no_resched

2017-02-04T08:36:59Z

Exception handlers which may run on IST stack call ist_enter() at the start of execution and ist_exit() in the end. ist_enter() disables preemption unconditionally and ist_exit() enables it. So the extra preempt_disable/enable() pairs nested inside the ist_enter/exit() regions are pointless and can be removed. Signed-off-by: Alexander Kuleshov Cc: Tony Luck Cc: Jianyu Zhan Cc: Paul Gortmaker Cc: Andy Lutomirski Cc: Borislav Petkov Link: http://lkml.kernel.org/r/20161128075057.7724-1-kuleshovmail@gmail.com Signed-off-by: Thomas Gleixner

x86/fpu: Handle #NM without FPU emulation as an error

2016-11-01T06:47:54Z

Don't use CR0.TS. Make it an error rather than making nonsensical changes to the FPU state. (The cond_local_irq_enable() appears to have been pointless, too.) Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Quentin Casasnovas Cc: Rik van Riel Cc: Rusty Russell Cc: Thomas Gleixner Cc: kvm list Link: http://lkml.kernel.org/r/f1ee6bf73ed1025fccaab321ba43d0594245f927.1477951965.git.luto@kernel.org Signed-off-by: Ingo Molnar

x86/mm: Improve stack-overflow #PF handling

2016-09-08T06:47:20Z

If we get a page fault indicating kernel stack overflow, invoke handle_stack_overflow(). To prevent us from overflowing the stack again while handling the overflow (because we are likely to have very little stack space left), call handle_stack_overflow() on the double-fault stack. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/6d6cf96b3fb9b4c9aa303817e1dc4de0c7c36487.1472603235.git.luto@kernel.org [ Minor edit. ] Signed-off-by: Ingo Molnar

x86/mm/64: Enable vmapped stacks (CONFIG_HAVE_ARCH_VMAP_STACK=y)

2016-08-24T10:11:42Z

This allows x86_64 kernels to enable vmapped stacks by setting HAVE_ARCH_VMAP_STACK=y - which enables the CONFIG_VMAP_STACK=y high level Kconfig option. There are a couple of interesting bits: First, x86 lazily faults in top-level paging entries for the vmalloc area. This won't work if we get a page fault while trying to access the stack: the CPU will promote it to a double-fault and we'll die. To avoid this problem, probe the new stack when switching stacks and forcibly populate the pgd entry for the stack when switching mms. Second, once we have guard pages around the stack, we'll want to detect and handle stack overflow. I didn't enable it on x86_32. We'd need to rework the double-fault code a bit and I'm concerned about running out of vmalloc virtual addresses under some workloads. This patch, by itself, will behave somewhat erratically when the stack overflows while RSP is still more than a few tens of bytes above the bottom of the stack. Specifically, we'll get #PF and make it to no_context and them oops without reliably triggering a double-fault, and no_context doesn't know about stack overflows. The next patch will improve that case. Thank you to Nadav and Brian for helping me pay enough attention to the SDM to hopefully get this right. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Nadav Amit Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/c88f3e2920b18e6cc621d772a04a62c06869037e.1470907718.git.luto@kernel.org [ Minor edits. ] Signed-off-by: Ingo Molnar

x86/kernel: Audit and remove any unnecessary uses of module.h

2016-07-14T13:06:41Z

Historically a lot of these existed because we did not have a distinction between what was modular code and what was providing support to modules via EXPORT_SYMBOL and friends. That changed when we forked out support for the latter into the export.h file. This means we should be able to reduce the usage of module.h in code that is obj-y Makefile or bool Kconfig. The advantage in doing so is that module.h itself sources about 15 other headers; adding significantly to what we feed cpp, and it can obscure what headers we are effectively using. Since module.h was the source for init.h (for __init) and for export.h (for EXPORT_SYMBOL) we consider each obj-y/bool instance for the presence of either and replace as needed. Build testing revealed some implicit header usage that was fixed up accordingly. Note that some bool/obj-y instances remain since module.h is the header for some exception table entry stuff, and for things like __init_or_module (code that is tossed when MODULES=n). Signed-off-by: Paul Gortmaker Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20160714001901.31603-4-paul.gortmaker@windriver.com Signed-off-by: Ingo Molnar

x86/entry/traps: Don't force in_interrupt() to return true in IST handlers

2016-06-10T11:54:47Z

Forcing in_interrupt() to return true if we're not in a bona fide interrupt confuses the softirq code. This fixes warnings like: NOHZ: local_softirq_pending 282 ... which can happen when running things like selftests/x86. This will change perf's static percpu buffer usage in IST context. I think this is okay, and it's changing the behavior to match historical (pre-4.0) behavior. Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: stable@vger.kernel.org Fixes: 959274753857 ("x86, traps: Track entry into and exit from IST context") Link: http://lkml.kernel.org/r/cdc215f94d118d691d73df35275022331156fb45.1464130360.git.luto@kernel.org Signed-off-by: Ingo Molnar

x86/asm: Stop depending on ptrace.h in alternative.h

2016-04-29T09:56:40Z

alternative.h pulls in ptrace.h, which means that alternatives can't be used in anything referenced from ptrace.h, which is a mess. Break the dependency by pulling text patching helpers into their own header. Signed-off-by: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/99b93b13f2c9eb671f5c98bba4c2cbdc061293a2.1461698311.git.luto@kernel.org Signed-off-by: Ingo Molnar

Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-03-15T17:23:56Z

Pull x86 fpu updates from Ingo Molnar: "The biggest change in terms of impact is the changing of the FPU context switch model to 'eagerfpu' for all CPU types, via: commit 58122bf1d856: "x86/fpu: Default eagerfpu=on on all CPUs" This makes all FPU saves and restores synchronous and makes the FPU code a lot more obvious to read. In the next cycle, if this change is problem free, we'll remove the old lazy FPU restore code altogether. This change flushed out some old bugs, which should all be fixed by now, BYMMV" * 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/fpu: Default eagerfpu=on on all CPUs x86/fpu: Speed up lazy FPU restores slightly x86/fpu: Fold fpu_copy() into fpu__copy() x86/fpu: Fix FNSAVE usage in eagerfpu mode x86/fpu: Fix math emulation in eager fpu mode