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Fix up hijacking on arm32 (preserve async continuation register) - #123057

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Fix up hijacking on arm32 (preserve async continuation register)#123057
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Flag r2 (see async calling convention) during GC as it might contain an async continuation.

Contributes to #122492.

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Pull request overview

This PR fixes hijacking on ARM32 by preserving the r2 register, which may contain an async continuation object reference. This aligns ARM32 behavior with AMD64 (which preserves rcx) and ARM64 (which preserves x2).

Key Changes:

  • Added PTFF_SAVE_R2 flag definition to enable saving/restoring r2 in transition frames
  • Modified PUSH_PROBE_FRAME/POP_PROBE_FRAME macros to save and restore r2
  • Updated FixupHijackedCallstack to preserve r0, r1, and r2 during hijack fixup
  • Adjusted stack offset calculations to account for the additional saved register

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

FileDescription
src/coreclr/nativeaot/Runtime/unix/unixasmmacrosarm.incAdds PTFF_SAVE_R2 constant (0x00000800) and clarifying comment about matching PInvokeTransitionFrameFlags enum
src/coreclr/nativeaot/Runtime/arm/GcProbe.SUpdates GC probe frame macros to save/restore r2, adjusts stack offset calculation from 144 to 154, and modifies hijack handling to preserve r2 containing async continuation

Comment threadsrc/coreclr/nativeaot/Runtime/arm/GcProbe.S Outdated
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Revert "Fix up hijacking on arm32 (preserve async continuation regist…
a029187
…er)" (#123474)
Outerloop runs are consistently crashing on ARM32 and this PR is in the
commit range when it started. Validating a theory.
Reverts #123057
eduardo-vp added a commit to eduardo-vp/runtime that referenced this pull request Jan 23, 2026
@eduardo-vpEduardo Velarde@jkotas
Fix up hijacking on arm32 (preserve async continuation register) (dot…
7c8f53c
…net#123057)
Flag r2 (see [async calling
convention](https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/clr-abi.md#returning-continuation))
during GC as it might contain an async continuation.
Contributes to dotnet#122492.
---------
Co-authored-by: Eduardo Velarde <evelardepola@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
@eduardo-vpeduardo-vp mentioned this pull request Jan 23, 2026
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Fix up hijacking on arm32 (preserve async continuation register) by eduardo-vp · Pull Request #123057 · dotnet/runtime · GitHub
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Fix up hijacking on arm32 (preserve async continuation register) - #123057
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Flag r2 (see async calling convention) during GC as it might contain an async continuation.
Contributes to #122492.
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Pull request overview
This PR fixes hijacking on ARM32 by preserving the r2 register, which may contain an async continuation object reference. This aligns ARM32 behavior with AMD64 (which preserves rcx) and ARM64 (which preserves x2).
Key Changes:
  • Added PTFF_SAVE_R2 flag definition to enable saving/restoring r2 in transition frames
  • Modified PUSH_PROBE_FRAME/POP_PROBE_FRAME macros to save and restore r2
  • Updated FixupHijackedCallstack to preserve r0, r1, and r2 during hijack fixup
  • Adjusted stack offset calculations to account for the additional saved register
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/coreclr/nativeaot/Runtime/unix/unixasmmacrosarm.incAdds PTFF_SAVE_R2 constant (0x00000800) and clarifying comment about matching PInvokeTransitionFrameFlags enum
src/coreclr/nativeaot/Runtime/arm/GcProbe.SUpdates GC probe frame macros to save/restore r2, adjusts stack offset calculation from 144 to 154, and modifies hijack handling to preserve r2 containing async continuation
Comment threadsrc/coreclr/nativeaot/Runtime/arm/GcProbe.S
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Revert "Fix up hijacking on arm32 (preserve async continuation regist…
a029187
…er)" (#123474)
Outerloop runs are consistently crashing on ARM32 and this PR is in the
commit range when it started. Validating a theory.
Reverts #123057
eduardo-vp added a commit
to eduardo-vp/runtime
that referenced
this pull request
Jan 23, 2026
@eduardo-vpEduardo Velarde@jkotas
Fix up hijacking on arm32 (preserve async continuation register) (dot…
7c8f53c
…net#123057)
Flag r2 (see [async calling
convention](https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/clr-abi.md#returning-continuation))
during GC as it might contain an async continuation.
Contributes to dotnet#122492.
---------
Co-authored-by: Eduardo Velarde <evelardepola@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
@eduardo-vpeduardo-vp
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Fix up hijacking on arm32 (preserve async continuation register) by eduardo-vp · Pull Request #123057 · dotnet/runtime · GitHub
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Fix up hijacking on arm32 (preserve async continuation register) - #123057
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Flag r2 (see async calling convention) during GC as it might contain an async continuation.
Contributes to #122492.
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review requested due to automatic review settings
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Pull request overview
This PR fixes hijacking on ARM32 by preserving the r2 register, which may contain an async continuation object reference. This aligns ARM32 behavior with AMD64 (which preserves rcx) and ARM64 (which preserves x2).
Key Changes:
  • Added PTFF_SAVE_R2 flag definition to enable saving/restoring r2 in transition frames
  • Modified PUSH_PROBE_FRAME/POP_PROBE_FRAME macros to save and restore r2
  • Updated FixupHijackedCallstack to preserve r0, r1, and r2 during hijack fixup
  • Adjusted stack offset calculations to account for the additional saved register
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/coreclr/nativeaot/Runtime/unix/unixasmmacrosarm.incAdds PTFF_SAVE_R2 constant (0x00000800) and clarifying comment about matching PInvokeTransitionFrameFlags enum
src/coreclr/nativeaot/Runtime/arm/GcProbe.SUpdates GC probe frame macros to save/restore r2, adjusts stack offset calculation from 144 to 154, and modifies hijack handling to preserve r2 containing async continuation
Comment threadsrc/coreclr/nativeaot/Runtime/arm/GcProbe.S
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Revert "Fix up hijacking on arm32 (preserve async continuation regist…
a029187
…er)" (#123474)
Outerloop runs are consistently crashing on ARM32 and this PR is in the
commit range when it started. Validating a theory.
Reverts #123057
eduardo-vp added a commit
to eduardo-vp/runtime
that referenced
this pull request
Jan 23, 2026
@eduardo-vpEduardo Velarde@jkotas
Fix up hijacking on arm32 (preserve async continuation register) (dot…
7c8f53c
…net#123057)
Flag r2 (see [async calling
convention](https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/clr-abi.md#returning-continuation))
during GC as it might contain an async continuation.
Contributes to dotnet#122492.
---------
Co-authored-by: Eduardo Velarde <evelardepola@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
@eduardo-vpeduardo-vp
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Fix up hijacking on arm32 (preserve async continuation register) by eduardo-vp · Pull Request #123057 · dotnet/runtime · GitHub
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Flag r2 (see async calling convention) during GC as it might contain an async continuation.
Contributes to #122492.
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Pull request overview
This PR fixes hijacking on ARM32 by preserving the r2 register, which may contain an async continuation object reference. This aligns ARM32 behavior with AMD64 (which preserves rcx) and ARM64 (which preserves x2).
Key Changes:
  • Added PTFF_SAVE_R2 flag definition to enable saving/restoring r2 in transition frames
  • Modified PUSH_PROBE_FRAME/POP_PROBE_FRAME macros to save and restore r2
  • Updated FixupHijackedCallstack to preserve r0, r1, and r2 during hijack fixup
  • Adjusted stack offset calculations to account for the additional saved register
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/coreclr/nativeaot/Runtime/unix/unixasmmacrosarm.incAdds PTFF_SAVE_R2 constant (0x00000800) and clarifying comment about matching PInvokeTransitionFrameFlags enum
src/coreclr/nativeaot/Runtime/arm/GcProbe.SUpdates GC probe frame macros to save/restore r2, adjusts stack offset calculation from 144 to 154, and modifies hijack handling to preserve r2 containing async continuation
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@MichalStrehovsky
Revert "Fix up hijacking on arm32 (preserve async continuation regist…
a029187
…er)" (#123474)
Outerloop runs are consistently crashing on ARM32 and this PR is in the
commit range when it started. Validating a theory.
Reverts #123057
eduardo-vp added a commit
to eduardo-vp/runtime
that referenced
this pull request
Jan 23, 2026
@eduardo-vpEduardo Velarde@jkotas
Fix up hijacking on arm32 (preserve async continuation register) (dot…
7c8f53c
…net#123057)
Flag r2 (see [async calling
convention](https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/clr-abi.md#returning-continuation))
during GC as it might contain an async continuation.
Contributes to dotnet#122492.
---------
Co-authored-by: Eduardo Velarde <evelardepola@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
@eduardo-vpeduardo-vp
mentioned this pull request
Jan 23, 2026
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// Strip utm_, fbclid, gclid, etc. from all links on page
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var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
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return url;
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}
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if (clean !== a.href) a.href = clean;
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});
observer.observe(document.body, { childList: true, subtree: true });
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}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
Fix up hijacking on arm32 (preserve async continuation register) by eduardo-vp · Pull Request #123057 · dotnet/runtime · GitHub
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Fix up hijacking on arm32 (preserve async continuation register) - #123057
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Flag r2 (see async calling convention) during GC as it might contain an async continuation.
Contributes to #122492.
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Pull request overview
This PR fixes hijacking on ARM32 by preserving the r2 register, which may contain an async continuation object reference. This aligns ARM32 behavior with AMD64 (which preserves rcx) and ARM64 (which preserves x2).
Key Changes:
  • Added PTFF_SAVE_R2 flag definition to enable saving/restoring r2 in transition frames
  • Modified PUSH_PROBE_FRAME/POP_PROBE_FRAME macros to save and restore r2
  • Updated FixupHijackedCallstack to preserve r0, r1, and r2 during hijack fixup
  • Adjusted stack offset calculations to account for the additional saved register
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/coreclr/nativeaot/Runtime/unix/unixasmmacrosarm.incAdds PTFF_SAVE_R2 constant (0x00000800) and clarifying comment about matching PInvokeTransitionFrameFlags enum
src/coreclr/nativeaot/Runtime/arm/GcProbe.SUpdates GC probe frame macros to save/restore r2, adjusts stack offset calculation from 144 to 154, and modifies hijack handling to preserve r2 containing async continuation
Comment threadsrc/coreclr/nativeaot/Runtime/arm/GcProbe.S
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Revert "Fix up hijacking on arm32 (preserve async continuation regist…
a029187
…er)" (#123474)
Outerloop runs are consistently crashing on ARM32 and this PR is in the
commit range when it started. Validating a theory.
Reverts #123057
eduardo-vp added a commit
to eduardo-vp/runtime
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Jan 23, 2026
@eduardo-vpEduardo Velarde@jkotas
Fix up hijacking on arm32 (preserve async continuation register) (dot…
7c8f53c
…net#123057)
Flag r2 (see [async calling
convention](https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/clr-abi.md#returning-continuation))
during GC as it might contain an async continuation.
Contributes to dotnet#122492.
---------
Co-authored-by: Eduardo Velarde <evelardepola@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
@eduardo-vpeduardo-vp
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, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
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var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
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Fix up hijacking on arm32 (preserve async continuation register) by eduardo-vp · Pull Request #123057 · dotnet/runtime · GitHub
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Fix up hijacking on arm32 (preserve async continuation register) - #123057
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Fix up hijacking on arm32 (preserve async continuation register)#123057
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Flag r2 (see async calling convention) during GC as it might contain an async continuation.
Contributes to #122492.
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Pull request overview
This PR fixes hijacking on ARM32 by preserving the r2 register, which may contain an async continuation object reference. This aligns ARM32 behavior with AMD64 (which preserves rcx) and ARM64 (which preserves x2).
Key Changes:
  • Added PTFF_SAVE_R2 flag definition to enable saving/restoring r2 in transition frames
  • Modified PUSH_PROBE_FRAME/POP_PROBE_FRAME macros to save and restore r2
  • Updated FixupHijackedCallstack to preserve r0, r1, and r2 during hijack fixup
  • Adjusted stack offset calculations to account for the additional saved register
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/coreclr/nativeaot/Runtime/unix/unixasmmacrosarm.incAdds PTFF_SAVE_R2 constant (0x00000800) and clarifying comment about matching PInvokeTransitionFrameFlags enum
src/coreclr/nativeaot/Runtime/arm/GcProbe.SUpdates GC probe frame macros to save/restore r2, adjusts stack offset calculation from 144 to 154, and modifies hijack handling to preserve r2 containing async continuation
Comment threadsrc/coreclr/nativeaot/Runtime/arm/GcProbe.S
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@MichalStrehovsky
Revert "Fix up hijacking on arm32 (preserve async continuation regist…
a029187
…er)" (#123474)
Outerloop runs are consistently crashing on ARM32 and this PR is in the
commit range when it started. Validating a theory.
Reverts #123057
eduardo-vp added a commit
to eduardo-vp/runtime
that referenced
this pull request
Jan 23, 2026
@eduardo-vpEduardo Velarde@jkotas
Fix up hijacking on arm32 (preserve async continuation register) (dot…
7c8f53c
…net#123057)
Flag r2 (see [async calling
convention](https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/clr-abi.md#returning-continuation))
during GC as it might contain an async continuation.
Contributes to dotnet#122492.
---------
Co-authored-by: Eduardo Velarde <evelardepola@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
@eduardo-vpeduardo-vp
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, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
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function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
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(function(){
try {
var __m = "*";
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Fix up hijacking on arm32 (preserve async continuation register) by eduardo-vp · Pull Request #123057 · dotnet/runtime · GitHub
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Fix up hijacking on arm32 (preserve async continuation register) - #123057
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Fix up hijacking on arm32 (preserve async continuation register)#123057
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Flag r2 (see async calling convention) during GC as it might contain an async continuation.
Contributes to #122492.
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Pull request overview
This PR fixes hijacking on ARM32 by preserving the r2 register, which may contain an async continuation object reference. This aligns ARM32 behavior with AMD64 (which preserves rcx) and ARM64 (which preserves x2).
Key Changes:
  • Added PTFF_SAVE_R2 flag definition to enable saving/restoring r2 in transition frames
  • Modified PUSH_PROBE_FRAME/POP_PROBE_FRAME macros to save and restore r2
  • Updated FixupHijackedCallstack to preserve r0, r1, and r2 during hijack fixup
  • Adjusted stack offset calculations to account for the additional saved register
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/coreclr/nativeaot/Runtime/unix/unixasmmacrosarm.incAdds PTFF_SAVE_R2 constant (0x00000800) and clarifying comment about matching PInvokeTransitionFrameFlags enum
src/coreclr/nativeaot/Runtime/arm/GcProbe.SUpdates GC probe frame macros to save/restore r2, adjusts stack offset calculation from 144 to 154, and modifies hijack handling to preserve r2 containing async continuation
Comment threadsrc/coreclr/nativeaot/Runtime/arm/GcProbe.S
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@MichalStrehovsky
Revert "Fix up hijacking on arm32 (preserve async continuation regist…
a029187
…er)" (#123474)
Outerloop runs are consistently crashing on ARM32 and this PR is in the
commit range when it started. Validating a theory.
Reverts #123057
eduardo-vp added a commit
to eduardo-vp/runtime
that referenced
this pull request
Jan 23, 2026
@eduardo-vpEduardo Velarde@jkotas
Fix up hijacking on arm32 (preserve async continuation register) (dot…
7c8f53c
…net#123057)
Flag r2 (see [async calling
convention](https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/clr-abi.md#returning-continuation))
during GC as it might contain an async continuation.
Contributes to dotnet#122492.
---------
Co-authored-by: Eduardo Velarde <evelardepola@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
@eduardo-vpeduardo-vp
mentioned this pull request
Jan 23, 2026
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, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
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filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
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::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
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var style = document.getElementById('universal-dark-mode-style');
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if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
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console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
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Fix up hijacking on arm32 (preserve async continuation register) by eduardo-vp · Pull Request #123057 · dotnet/runtime · GitHub
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Fix up hijacking on arm32 (preserve async continuation register) - #123057
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Flag r2 (see async calling convention) during GC as it might contain an async continuation.
Contributes to #122492.
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review requested due to automatic review settings
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Pull request overview
This PR fixes hijacking on ARM32 by preserving the r2 register, which may contain an async continuation object reference. This aligns ARM32 behavior with AMD64 (which preserves rcx) and ARM64 (which preserves x2).
Key Changes:
  • Added PTFF_SAVE_R2 flag definition to enable saving/restoring r2 in transition frames
  • Modified PUSH_PROBE_FRAME/POP_PROBE_FRAME macros to save and restore r2
  • Updated FixupHijackedCallstack to preserve r0, r1, and r2 during hijack fixup
  • Adjusted stack offset calculations to account for the additional saved register
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
FileDescription
src/coreclr/nativeaot/Runtime/unix/unixasmmacrosarm.incAdds PTFF_SAVE_R2 constant (0x00000800) and clarifying comment about matching PInvokeTransitionFrameFlags enum
src/coreclr/nativeaot/Runtime/arm/GcProbe.SUpdates GC probe frame macros to save/restore r2, adjusts stack offset calculation from 144 to 154, and modifies hijack handling to preserve r2 containing async continuation
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Revert "Fix up hijacking on arm32 (preserve async continuation regist…
a029187
…er)" (#123474)
Outerloop runs are consistently crashing on ARM32 and this PR is in the
commit range when it started. Validating a theory.
Reverts #123057
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@eduardo-vpEduardo Velarde@jkotas
Fix up hijacking on arm32 (preserve async continuation register) (dot…
7c8f53c
…net#123057)
Flag r2 (see [async calling
convention](https://github.com/dotnet/runtime/blob/main/docs/design/coreclr/botr/clr-abi.md#returning-continuation))
during GC as it might contain an async continuation.
Contributes to dotnet#122492.
---------
Co-authored-by: Eduardo Velarde <evelardepola@microsoft.com>
Co-authored-by: Jan Kotas <jkotas@microsoft.com>
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