Pull x86 apic updates from Thomas Gleixner:
"This update provides:
- Cleanup of the IDT management including the removal of the extra
tracing IDT. A first step to cleanup the vector management code.
- The removal of the paravirt op adjust_exception_frame. This is a
XEN specific issue, but merged through this branch to avoid nasty
merge collisions
- Prevent dmesg spam about the TSC DEADLINE bug, when the CPU has
disabled the TSC DEADLINE timer in CPUID.
- Adjust a debug message in the ioapic code to print out the
information correctly"
* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
x86/idt: Fix the X86_TRAP_BP gate
x86/xen: Get rid of paravirt op adjust_exception_frame
x86/eisa: Add missing include
x86/idt: Remove superfluous ALIGNment
x86/apic: Silence "FW_BUG TSC_DEADLINE disabled due to Errata" on CPUs without the feature
x86/idt: Remove the tracing IDT leftovers
x86/idt: Hide set_intr_gate()
x86/idt: Simplify alloc_intr_gate()
x86/idt: Deinline setup functions
x86/idt: Remove unused functions/inlines
x86/idt: Move interrupt gate initialization to IDT code
x86/idt: Move APIC gate initialization to tables
x86/idt: Move regular trap init to tables
x86/idt: Move IST stack based traps to table init
x86/idt: Move debug stack init to table based
x86/idt: Switch early trap init to IDT tables
x86/idt: Prepare for table based init
x86/idt: Move early IDT setup out of 32-bit asm
x86/idt: Move early IDT handler setup to IDT code
x86/idt: Consolidate IDT invalidation
...
Pull x86 asm updates from Ingo Molnar:
- Introduce the ORC unwinder, which can be enabled via
CONFIG_ORC_UNWINDER=y.
The ORC unwinder is a lightweight, Linux kernel specific debuginfo
implementation, which aims to be DWARF done right for unwinding.
Objtool is used to generate the ORC unwinder tables during build, so
the data format is flexible and kernel internal: there's no
dependency on debuginfo created by an external toolchain.
The ORC unwinder is almost two orders of magnitude faster than the
(out of tree) DWARF unwinder - which is important for perf call graph
profiling. It is also significantly simpler and is coded defensively:
there has not been a single ORC related kernel crash so far, even
with early versions. (knock on wood!)
But the main advantage is that enabling the ORC unwinder allows
CONFIG_FRAME_POINTERS to be turned off - which speeds up the kernel
measurably:
With frame pointers disabled, GCC does not have to add frame pointer
instrumentation code to every function in the kernel. The kernel's
.text size decreases by about 3.2%, resulting in better cache
utilization and fewer instructions executed, resulting in a broad
kernel-wide speedup. Average speedup of system calls should be
roughly in the 1-3% range - measurements by Mel Gorman [1] have shown
a speedup of 5-10% for some function execution intense workloads.
The main cost of the unwinder is that the unwinder data has to be
stored in RAM: the memory cost is 2-4MB of RAM, depending on kernel
config - which is a modest cost on modern x86 systems.
Given how young the ORC unwinder code is it's not enabled by default
- but given the performance advantages the plan is to eventually make
it the default unwinder on x86.
See Documentation/x86/orc-unwinder.txt for more details.
- Remove lguest support: its intended role was that of a temporary
proof of concept for virtualization, plus its removal will enable the
reduction (removal) of the paravirt API as well, so Rusty agreed to
its removal. (Juergen Gross)
- Clean up and fix FSGS related functionality (Andy Lutomirski)
- Clean up IO access APIs (Andy Shevchenko)
- Enhance the symbol namespace (Jiri Slaby)
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
objtool: Handle GCC stack pointer adjustment bug
x86/entry/64: Use ENTRY() instead of ALIGN+GLOBAL for stub32_clone()
x86/fpu/math-emu: Add ENDPROC to functions
x86/boot/64: Extract efi_pe_entry() from startup_64()
x86/boot/32: Extract efi_pe_entry() from startup_32()
x86/lguest: Remove lguest support
x86/paravirt/xen: Remove xen_patch()
objtool: Fix objtool fallthrough detection with function padding
x86/xen/64: Fix the reported SS and CS in SYSCALL
objtool: Track DRAP separately from callee-saved registers
objtool: Fix validate_branch() return codes
x86: Clarify/fix no-op barriers for text_poke_bp()
x86/switch_to/64: Rewrite FS/GS switching yet again to fix AMD CPUs
selftests/x86/fsgsbase: Test selectors 1, 2, and 3
x86/fsgsbase/64: Report FSBASE and GSBASE correctly in core dumps
x86/fsgsbase/64: Fully initialize FS and GS state in start_thread_common
x86/asm: Fix UNWIND_HINT_REGS macro for older binutils
x86/asm/32: Fix regs_get_register() on segment registers
x86/xen/64: Rearrange the SYSCALL entries
x86/asm/32: Remove a bunch of '& 0xffff' from pt_regs segment reads
...
When running as Xen pv-guest the exception frame on the stack contains
%r11 and %rcx additional to the other data pushed by the processor.
Instead of having a paravirt op being called for each exception type
prepend the Xen specific code to each exception entry. When running as
Xen pv-guest just use the exception entry with prepended instructions,
otherwise use the entry without the Xen specific code.
[ tglx: Merged through tip to avoid ugly merge conflict ]
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: boris.ostrovsky@oracle.com
Cc: luto@amacapital.net
Link: http://lkml.kernel.org/r/20170831174249.26853-1-jg@pfupf.net
We are using the same vector for nested/non-nested posted
interrupts delivery, this may cause interrupts latency in
L1 since we can't kick the L2 vcpu out of vmx-nonroot mode.
This patch introduces a new vector which is only for nested
posted interrupts to solve the problems above.
Signed-off-by: Wincy Van <fanwenyi0529@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Petr Mladek reported the following warning when loading the livepatch
sample module:
WARNING: CPU: 1 PID: 3699 at arch/x86/kernel/stacktrace.c:132 save_stack_trace_tsk_reliable+0x133/0x1a0
...
Call Trace:
__schedule+0x273/0x820
schedule+0x36/0x80
kthreadd+0x305/0x310
? kthread_create_on_cpu+0x80/0x80
? icmp_echo.part.32+0x50/0x50
ret_from_fork+0x2c/0x40
That warning means the end of the stack is no longer recognized as such
for newly forked tasks. The problem was introduced with the following
commit:
ff3f7e2475 ("x86/entry: Fix the end of the stack for newly forked tasks")
... which was completely misguided. It only partially fixed the
reported issue, and it introduced another bug in the process. None of
the other entry code saves the frame pointer before calling into C code,
so it doesn't make sense for ret_from_fork to do so either.
Contrary to what I originally thought, the original issue wasn't related
to newly forked tasks. It was actually related to ftrace. When entry
code calls into a function which then calls into an ftrace handler, the
stack frame looks different than normal.
The original issue will be fixed in the unwinder, in a subsequent patch.
Reported-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: live-patching@vger.kernel.org
Fixes: ff3f7e2475 ("x86/entry: Fix the end of the stack for newly forked tasks")
Link: http://lkml.kernel.org/r/f350760f7e82f0750c8d1dd093456eb212751caa.1495553739.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 mm updates from Ingo Molnar:
"The main x86 MM changes in this cycle were:
- continued native kernel PCID support preparation patches to the TLB
flushing code (Andy Lutomirski)
- various fixes related to 32-bit compat syscall returning address
over 4Gb in applications, launched from 64-bit binaries - motivated
by C/R frameworks such as Virtuozzo. (Dmitry Safonov)
- continued Intel 5-level paging enablement: in particular the
conversion of x86 GUP to the generic GUP code. (Kirill A. Shutemov)
- x86/mpx ABI corner case fixes/enhancements (Joerg Roedel)
- ... plus misc updates, fixes and cleanups"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (62 commits)
mm, zone_device: Replace {get, put}_zone_device_page() with a single reference to fix pmem crash
x86/mm: Fix flush_tlb_page() on Xen
x86/mm: Make flush_tlb_mm_range() more predictable
x86/mm: Remove flush_tlb() and flush_tlb_current_task()
x86/vm86/32: Switch to flush_tlb_mm_range() in mark_screen_rdonly()
x86/mm/64: Fix crash in remove_pagetable()
Revert "x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation"
x86/boot/e820: Remove a redundant self assignment
x86/mm: Fix dump pagetables for 4 levels of page tables
x86/mpx, selftests: Only check bounds-vs-shadow when we keep shadow
x86/mpx: Correctly report do_mpx_bt_fault() failures to user-space
Revert "x86/mm/numa: Remove numa_nodemask_from_meminfo()"
x86/espfix: Add support for 5-level paging
x86/kasan: Extend KASAN to support 5-level paging
x86/mm: Add basic defines/helpers for CONFIG_X86_5LEVEL=y
x86/paravirt: Add 5-level support to the paravirt code
x86/mm: Define virtual memory map for 5-level paging
x86/asm: Remove __VIRTUAL_MASK_SHIFT==47 assert
x86/boot: Detect 5-level paging support
x86/mm/numa: Remove numa_nodemask_from_meminfo()
...
When unwinding a task, the end of the stack is always at the same offset
right below the saved pt_regs, regardless of which syscall was used to
enter the kernel. That convention allows the unwinder to verify that a
stack is sane.
However, newly forked tasks don't always follow that convention, as
reported by the following unwinder warning seen by Dave Jones:
WARNING: kernel stack frame pointer at ffffc90001443f30 in kworker/u8:8:30468 has bad value (null)
The warning was due to the following call chain:
(ftrace handler)
call_usermodehelper_exec_async+0x5/0x140
ret_from_fork+0x22/0x30
The problem is that ret_from_fork() doesn't create a stack frame before
calling other functions. Fix that by carefully using the frame pointer
macros.
In addition to conforming to the end of stack convention, this also
makes related stack traces more sensible by making it clear to the user
that ret_from_fork() was involved.
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/8854cdaab980e9700a81e9ebf0d4238e4bbb68ef.1483978430.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With frame pointers, when a task is interrupted, its stack is no longer
completely reliable because the function could have been interrupted
before it had a chance to save the previous frame pointer on the stack.
So the caller of the interrupted function could get skipped by a stack
trace.
This is problematic for live patching, which needs to know whether a
stack trace of a sleeping task can be relied upon. There's currently no
way to detect if a sleeping task was interrupted by a page fault
exception or preemption before it went to sleep.
Another issue is that when dumping the stack of an interrupted task, the
unwinder has no way of knowing where the saved pt_regs registers are, so
it can't print them.
This solves those issues by encoding the pt_regs pointer in the frame
pointer on entry from an interrupt or an exception.
This patch also updates the unwinder to be able to decode it, because
otherwise the unwinder would be broken by this change.
Note that this causes a change in the behavior of the unwinder: each
instance of a pt_regs on the stack is now considered a "frame". So
callers of unwind_get_return_address() will now get an occasional
'regs->ip' address that would have previously been skipped over.
Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/8b9f84a21e39d249049e0547b559ff8da0df0988.1476973742.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull kbuild updates from Michal Marek:
- EXPORT_SYMBOL for asm source by Al Viro.
This does bring a regression, because genksyms no longer generates
checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is
working on a patch to fix this.
Plus, we are talking about functions like strcpy(), which rarely
change prototypes.
- Fixes for PPC fallout of the above by Stephen Rothwell and Nick
Piggin
- fixdep speedup by Alexey Dobriyan.
- preparatory work by Nick Piggin to allow architectures to build with
-ffunction-sections, -fdata-sections and --gc-sections
- CONFIG_THIN_ARCHIVES support by Stephen Rothwell
- fix for filenames with colons in the initramfs source by me.
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits)
initramfs: Escape colons in depfile
ppc: there is no clear_pages to export
powerpc/64: whitelist unresolved modversions CRCs
kbuild: -ffunction-sections fix for archs with conflicting sections
kbuild: add arch specific post-link Makefile
kbuild: allow archs to select link dead code/data elimination
kbuild: allow architectures to use thin archives instead of ld -r
kbuild: Regenerate genksyms lexer
kbuild: genksyms fix for typeof handling
fixdep: faster CONFIG_ search
ia64: move exports to definitions
sparc32: debride memcpy.S a bit
[sparc] unify 32bit and 64bit string.h
sparc: move exports to definitions
ppc: move exports to definitions
arm: move exports to definitions
s390: move exports to definitions
m68k: move exports to definitions
alpha: move exports to actual definitions
x86: move exports to actual definitions
...
Pull low-level x86 updates from Ingo Molnar:
"In this cycle this topic tree has become one of those 'super topics'
that accumulated a lot of changes:
- Add CONFIG_VMAP_STACK=y support to the core kernel and enable it on
x86 - preceded by an array of changes. v4.8 saw preparatory changes
in this area already - this is the rest of the work. Includes the
thread stack caching performance optimization. (Andy Lutomirski)
- switch_to() cleanups and all around enhancements. (Brian Gerst)
- A large number of dumpstack infrastructure enhancements and an
unwinder abstraction. The secret long term plan is safe(r) live
patching plus maybe another attempt at debuginfo based unwinding -
but all these current bits are standalone enhancements in a frame
pointer based debug environment as well. (Josh Poimboeuf)
- More __ro_after_init and const annotations. (Kees Cook)
- Enable KASLR for the vmemmap memory region. (Thomas Garnier)"
[ The virtually mapped stack changes are pretty fundamental, and not
x86-specific per se, even if they are only used on x86 right now. ]
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
x86/asm: Get rid of __read_cr4_safe()
thread_info: Use unsigned long for flags
x86/alternatives: Add stack frame dependency to alternative_call_2()
x86/dumpstack: Fix show_stack() task pointer regression
x86/dumpstack: Remove dump_trace() and related callbacks
x86/dumpstack: Convert show_trace_log_lvl() to use the new unwinder
oprofile/x86: Convert x86_backtrace() to use the new unwinder
x86/stacktrace: Convert save_stack_trace_*() to use the new unwinder
perf/x86: Convert perf_callchain_kernel() to use the new unwinder
x86/unwind: Add new unwind interface and implementations
x86/dumpstack: Remove NULL task pointer convention
fork: Optimize task creation by caching two thread stacks per CPU if CONFIG_VMAP_STACK=y
sched/core: Free the stack early if CONFIG_THREAD_INFO_IN_TASK
lib/syscall: Pin the task stack in collect_syscall()
x86/process: Pin the target stack in get_wchan()
x86/dumpstack: Pin the target stack when dumping it
kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function
sched/core: Add try_get_task_stack() and put_task_stack()
x86/entry/64: Fix a minor comment rebase error
iommu/amd: Don't put completion-wait semaphore on stack
...
This warning:
WARNING: CPU: 0 PID: 3331 at arch/x86/entry/common.c:45 enter_from_user_mode+0x32/0x50
CPU: 0 PID: 3331 Comm: ldt_gdt_64 Not tainted 4.8.0-rc7+ #13
Call Trace:
dump_stack+0x99/0xd0
__warn+0xd1/0xf0
warn_slowpath_null+0x1d/0x20
enter_from_user_mode+0x32/0x50
error_entry+0x6d/0xc0
? general_protection+0x12/0x30
? native_load_gs_index+0xd/0x20
? do_set_thread_area+0x19c/0x1f0
SyS_set_thread_area+0x24/0x30
do_int80_syscall_32+0x7c/0x220
entry_INT80_compat+0x38/0x50
... can be reproduced by running the GS testcase of the ldt_gdt test unit in
the x86 selftests.
do_int80_syscall_32() will call enter_form_user_mode() to convert context
tracking state from user state to kernel state. The load_gs_index() call
can fail with user gsbase, gsbase will be fixed up and proceed if this
happen.
However, enter_from_user_mode() will be called again in the fixed up path
though it is context tracking kernel state currently.
This patch fixes it by just fixing up gsbase and telling lockdep that IRQs
are off once load_gs_index() failed with user gsbase.
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1475197266-3440-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
As EBS does not mean anything reasonable in the context it is used, it
seems like a misspelling for EBX.
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
I was fishing RIP (i.e. RCX) out of pt_regs->cx and RFLAGS (i.e.
R11) out of pt_regs->r11. While it usually worked (pt_regs
started out with CX == IP and R11 == FLAGS), it was very
fragile. In particular, it broke sys_iopl() because sys_iopl()
forgot to mark itself as using ptregs.
Undo that part of the syscall rework. There was no compelling
reason to do it this way. While I'm at it, load RCX and R11
before the other regs to be a little friendlier to the CPU, as
they will be the first of the reloaded registers to be used.
Reported-and-tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 1e423bff95 x86/entry/64: ("Migrate the 64-bit syscall slow path to C")
Link: http://lkml.kernel.org/r/a85f8360c397e48186a9bc3e565ad74307a7b011.1454261517.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
64-bit syscalls currently have an optimization in which they are
called with partial pt_regs. A small handful require full
pt_regs.
In the 32-bit and compat cases, I cleaned this up by forcing
full pt_regs for all syscalls. The performance hit doesn't
really matter as the affected system calls are fundamentally
heavy and this is the 32-bit compat case.
I want to clean up the 64-bit case as well, but I don't want to
hurt fast path performance. To do that, I want to force the
syscalls that use pt_regs onto the slow path. This will enable
us to make slow path syscalls be real ABI-compliant C functions.
Use the new syscall entry qualification machinery for this.
'stub_clone' is now 'stub_clone/ptregs'.
The next patch will eliminate the stubs, and we'll just have
'sys_clone/ptregs'.
As of this patch, two-phase entry tracing is no longer used. It
has served its purpose (namely a huge speedup on some workloads
prior to more general opportunistic SYSRET support), and once
the dust settles I'll send patches to back it out.
The implementation is heavily based on a patch from Brian Gerst:
http://lkml.kernel.org/g/1449666173-15366-1-git-send-email-brgerst@gmail.com
Originally-From: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/b9beda88460bcefec6e7d792bd44eca9b760b0c4.1454022279.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
