similar to: Patch: use .pushsection/.popsection

I'm implementing a more efficient version of the Xen iret paravirt_op, so that it can use the real iret instruction where possible. I really need to get access to per-cpu variables, so I can set the event mask state in the vcpu_info structure, but unfortunately at the point where INTERRUPT_RETURN is used in entry.S, the usermode %fs has already been restored. How would you feel if we changed

I'm implementing a more efficient version of the Xen iret paravirt_op, so that it can use the real iret instruction where possible. I really need to get access to per-cpu variables, so I can set the event mask state in the vcpu_info structure, but unfortunately at the point where INTERRUPT_RETURN is used in entry.S, the usermode %fs has already been restored. How would you feel if we changed

.entry.text is a code area which is used for interrupt/syscall entries, and there are many sensitive codes. Thus, it is better to prohibit probing on all of such codes instead of a part of that. Since some symbols are already registered on kprobe blacklist, this also removes them from the blacklist. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt at hitachi.com> Cc: Thomas Gleixner

From: David Vrabel <david.vrabel@citrix.com> In 32 bit guests, if a userspace process has %eax == -ERESTARTSYS (-512) or -ERESTARTNOINTR (-513) when it is interrupted by an event /and/ the process has a pending signal then %eip (and %eax) are corrupted when returning to the main process after handling the signal. The application may then crash with SIGSEGV or a SIGILL or it may have subtly

The ALTERNATIVE() and ALTERNATIVE_2() macros are GNU assembler macros, which makes them quite inflexible for future changes. Convert them to preprocessor macros. Signed-off-by: Josh Poimboeuf <jpoimboe at redhat.com> --- arch/x86/entry/entry_32.S | 12 +++--- arch/x86/entry/entry_64.S | 10 ++--- arch/x86/entry/entry_64_compat.S | 8 ++--

Illustration of how VMI inlines are used to greatly limit the impact of code change in low level assembler code. Spinlocks, system calls, and the fault handling paths are affected by adding some padding bytes to convert the native instructions into a hook point for the hypervisor to insert shim code. These changes are sufficient to glue the Linux low level entry points to hypervisor event

Illustration of how VMI inlines are used to greatly limit the impact of code change in low level assembler code. Spinlocks, system calls, and the fault handling paths are affected by adding some padding bytes to convert the native instructions into a hook point for the hypervisor to insert shim code. These changes are sufficient to glue the Linux low level entry points to hypervisor event

Revert the following 9 commits: [1] 5bdcd510c2ac ("x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs") This was partially reverted because it made good cleanups irrespective of the inlining issue; the error message is still unneeded, and the conversion to STATIC_BRANCH_{NOP,JUMP} should be kept. [2] d5a581d84ae6 ("x86/cpufeature:

Revert the following commits: - 5bdcd510c2ac9efaf55c4cbd8d46421d8e2320cd ("x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs") - d5a581d84ae6b8a4a740464b80d8d9cf1e7947b2 ("x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs") - 0474d5d9d2f7f3b11262f7bf87d0e7314ead9200. ("x86/extable: Macrofy inline assembly

Revert the following commits: - 5bdcd510c2ac9efaf55c4cbd8d46421d8e2320cd ("x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs") - d5a581d84ae6b8a4a740464b80d8d9cf1e7947b2 ("x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs") - 0474d5d9d2f7f3b11262f7bf87d0e7314ead9200. ("x86/extable: Macrofy inline assembly

With CONFIG_PARAVIRT, the kernel .text is littered with a bunch of calls to pv_irq_ops function pointers, like: callq *0xffffffff81e3a400 (pv_irq_ops.save_fl) In non-Xen paravirt environments -- including native, KVM, Hyper-V, and VMware -- the above code gets patched by native_patch() to look like this instead: pushfq pop %rax nopl 0x0(%rax,%rax,1) So in most scenarios,

On Tue, 2017-04-04 at 16:26 +0000, Chandler Carruth via llvm-dev wrote: > On Tue, Apr 4, 2017 at 6:07 AM Yatsina, Marina via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Asm goto feature was introduces to GCC in order to optimize the > > support for tracepoints in Linux kernel (it can be used for other > > things that do nop patching). > >   > > GCC

I implemented sysenter for 32-on-64, since it seemed straightforward enough. It mostly works, but every now and again I get vcpus just hanging in blocked state, as if events are being lost or ignored. Its very similar to the symptoms that other people have reported against the pvops kernel, which I have not managed to reproduce. Perhaps using sysenter is exacerbating an existing bug...

On Wed, 2018-02-07 at 06:20 +0000, Chandler Carruth wrote: > I've landed the patch in r324449. > > Before we merge this into two different Clang release branches and > almost immediately release one of them, I would really like someone > to confirm that this patch works well with the Linux kernel. David, > if you're up for that, it would be great. Alternatively, Guenter

plain text document attachment (xx-paravirt-irqs.patch) Interrupt updates for paravirt ops. Signed-off-by: Steven Rostedt srostedt@redhat.com Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Index: clean-start/arch/x86_64/ia32/ia32entry.S =================================================================== --- clean-start.orig/arch/x86_64/ia32/ia32entry.S +++

plain text document attachment (xx-paravirt-irqs.patch) Interrupt updates for paravirt ops. Signed-off-by: Steven Rostedt srostedt@redhat.com Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Index: clean-start/arch/x86_64/ia32/ia32entry.S =================================================================== --- clean-start.orig/arch/x86_64/ia32/ia32entry.S +++

There are a bunch of issues with defining elf notes using assembler macros, as described here: http://marc.theaimsgroup.com/?l=linux-kernel&m=115633393226158&w=2 Therefore I replaced it with a pre-processor macro. This is a new patch, it should fit into the series anywhere after the -mm patch. It's been submitted to Andrew M so hopefully it'll get picked up for next -mm.

This reverts commit 494b5168f2de009eb80f198f668da374295098dd. The in-kernel workarounds will be replaced with GCC's new "asm inline" syntax. Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com> --- arch/x86/include/asm/paravirt_types.h | 56 ++++++++++++++++++----------------- arch/x86/kernel/macros.S | 1 - 2 files changed, 29 insertions(+), 28

Make paravirt_types.h more understandable: - Use more consistent and logical naming - Simplify interfaces - Put related macros together - Improve whitespace Signed-off-by: Josh Poimboeuf <jpoimboe at redhat.com> --- arch/x86/include/asm/paravirt_types.h | 104 ++++++++++++++++++---------------- 1 file changed, 54 insertions(+), 50 deletions(-) diff --git

Hello all, Here's a new version of the paravirt_ops x86_64 patch. With this message, I'm sending an incremental patch. The complete patches can be found , from now on, at http://et.redhat.com/~gcosta/paravirt_ops/ The main aim of this new update, is to fix a critical bug, namely, Rusty's name. However, I took the opportunity to write some new less important pieces of code,