similar to: Prius Online & Game Guard

Replies inline. At a high level, it feels like we'll eventually need a new instruction to represent the kind of control flow a guard entails (to be clear: we should probably still start with an intrinsic) -- they are fairly well-behaved, i.e. readonly, nounwind etc. as far as the immediate "physical" caller is concerned, but not so as far as its callers's callers are concerned.

On 03/25/2019 12:40 PM, Juergen Gross wrote: > On 25/03/2019 16:57, Waiman Long wrote: >> It was found that passing an invalid cpu number to pv_vcpu_is_preempted() >> might panic the kernel in a VM guest. For example, >> >> [ 2.531077] Oops: 0000 [#1] SMP PTI >> : >> [ 2.532545] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 >> [ 2.533321]

On 03/25/2019 12:40 PM, Juergen Gross wrote: > On 25/03/2019 16:57, Waiman Long wrote: >> It was found that passing an invalid cpu number to pv_vcpu_is_preempted() >> might panic the kernel in a VM guest. For example, >> >> [ 2.531077] Oops: 0000 [#1] SMP PTI >> : >> [ 2.532545] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 >> [ 2.533321]

On Thu, Feb 18, 2016 at 12:48 PM, Eric Christopher <echristo at gmail.com> wrote: > Heh. I like his more, but I see where you're coming from as well - the easy > way (for me at least) to look at the guard is as an implicit branch to a > side exit that restores (or communicates) state back to the interpreter. The By "this" do you mean "explicit conditional branch

It was found that passing an invalid cpu number to pv_vcpu_is_preempted() might panic the kernel in a VM guest. For example, [ 2.531077] Oops: 0000 [#1] SMP PTI : [ 2.532545] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [ 2.533321] RIP: 0010:__raw_callee_save___kvm_vcpu_is_preempted+0x0/0x20 To guard against this kind of kernel panic, check is added to pv_vcpu_is_preempted() to

It was found that passing an invalid cpu number to pv_vcpu_is_preempted() might panic the kernel in a VM guest. For example, [ 2.531077] Oops: 0000 [#1] SMP PTI : [ 2.532545] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [ 2.533321] RIP: 0010:__raw_callee_save___kvm_vcpu_is_preempted+0x0/0x20 To guard against this kind of kernel panic, check is added to pv_vcpu_is_preempted() to

Hi Andy, Thanks for replying, responses inline below: On Fri, Feb 19, 2016 at 11:12 AM, Andrew Trick <atrick at apple.com> wrote: > This clearly doesn't need operand bundles, but using an intrinsic > would permit special code motion semantics. It could be hoisted and > merged with other traps, but the condition could never be widened > beyond the union of the original

Given the following C++ code: ``` // test.cpp struct Foo { int public_foo(); int outside_foo(); [[gnu::always_inline]] int inline_foo() { int x = outside_foo(); if (x % 17) { x += 1; } return x; } [[gnu::noinline]] int inline_bar1() { int x = inline_foo(); if (x % 23) { x += 2; } return x; } [[gnu::noinline]] int inline_bar2() {

Sanjoy gave the long answer, let me give the short one. :) "deopt" argument bundles are used in the middle end, they are lowered into a statepoint, and generate the existing stackmap format. i.e. one builds on the other. On 02/18/2016 11:43 AM, Eric Christopher wrote: > Hi Sanjoy, > > A quick question here. With the bailing to the interpreter support > that you're

Hello developeRs, Apologies in advance for a rather long email, but to describe the problem, I need to step through many details. I have been working on a new dispatching system (futile.paradigm on CRAN) based on functional programming concepts that is an alternative to S3 and S4 dispatching. I use a declarative syntax using guard statements to control the dispatching between function variants. I

While we're talking about this, I'd just mention again that the same issue arises for *normal* functions too, when linked into a shared library: int foo() { return 1; } int bar() { return foo(); } Now, compare: clang -fPIC -O1 -S -o - test.c gcc -fPIC -O1 -S -o - test.c GCC will refuse to inline foo into bar, or use any information about foo in compiling bar, because foo is

> On 2016-Feb-24, at 15:57, Sanjoy Das via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Hi all, > > This is something that came up in the "RFC: Add guard intrinsics to > LLVM" thread; and while I'm not exactly blocked on this, figuring out > a path forward here will be helpful in deciding if we can use the > available_externally linkage type to

----- Original Message ----- > From: "James Y Knight via llvm-dev" <llvm-dev at lists.llvm.org> > To: "Sanjoy Das" <sanjoy at playingwithpointers.com> > Cc: "llvm-dev" <llvm-dev at lists.llvm.org> > Sent: Thursday, February 25, 2016 1:41:43 PM > Subject: Re: [llvm-dev] Possible soundness issue with > available_externally (split

On 2020-04-10, Michael Kruse via llvm-dev wrote: >#ifndef NDEBUG in the LLVM source and assert() are at least somewhat >linked. For instance, consider >https://github.com/llvm/llvm-project/blob/8423a6f36386aabced2a367c0ea53487901d31ca/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp#L2668 > >The #ifndef NDEBUG is used to guard the value that checked in an >assert() later. Only

Hallo Leute :) Ich bin sehr neu in der Linux Branche und sto?e zu anfang direkt an meine grenzen. Wine startet alle meine Windows Programme einwandfrei.. ausser das spiel was ich in meiner freizeit spiele wenn ich mal nicht rausgehe und mal langeweile habe. Das spielt nennt sich Dragonica. Ich benutze Ubuntu 9. Der Patcher startet erfolgroch. nachdem ich das spiel starte.. ?ffnet sich dieses

Full_Name: D Kreil Version: 2.8.1 and 2.9.0 OS: Debian Linux Submission from: (NULL) (141.244.140.179) Group: Accuracy I understand that most floating point numbers are approximated due to their binary storage. On the other hand, I thought that modern math CPUs used guard digits to protect against trivial underflows. Not true? # integers, no problem > 1+1+1==3 [1] TRUE # binary floating

Full_Name: D Kreil Version: 2.8.1 and 2.9.0 OS: Debian Linux Submission from: (NULL) (141.244.140.179) Group: Accuracy I understand that most floating point numbers are approximated due to their binary storage. On the other hand, I thought that modern math CPUs used guard digits to protect against trivial underflows. Not true? # integers, no problem > 1+1+1==3 [1] TRUE # binary floating

Hello Everyone, I want to raise a discussion about @llvm.experimental.guard intrinsic and reasons why we should give up using it. Here is an alternative approach to representation of guards that resolves some of fundamental flaws that the current guards have. Basically, this intrinsic was introduced to model the following situation: we want to check that some condition is true, and if it's

Hi all, This is something that came up in the "RFC: Add guard intrinsics to LLVM" thread; and while I'm not exactly blocked on this, figuring out a path forward here will be helpful in deciding if we can use the available_externally linkage type to expression certain semantic properties guard intrinsics will have. Let's start with an example that shows that we have a problem

On Wed, Feb 24, 2016 at 10:56 PM Hal Finkel <hfinkel at anl.gov> wrote: > ----- Original Message ----- > > From: "Sanjoy Das" <sanjoy at playingwithpointers.com> > > To: "Hal Finkel" <hfinkel at anl.gov> > > Cc: "Chandler Carruth" <chandlerc at google.com>, "llvm-dev" < > llvm-dev at lists.llvm.org>,