1658385 - add arm64 support to xpcom/build/mach_override.c

Status: REOPENED

(Core :: XPCOM, enhancement)

Description

[Nathan Froyd [:froydnj]]

I really hope some motivated people from upstream have fixed this already.

Comment 1

[Mike Hommey [:glandium]]

(In reply to Nathan Froyd [:froydnj] from comment #0)

I really hope some motivated people from upstream have fixed this already.

No, upstream is essentially dead.
Copy/paste from me on matrix:

it strikes me that mach_override is essentially the same thing as what we use to intercept function calls on windows (mozglue/misc/interceptor), which already has code for arm64. I wonder how much work it would be to make the mozglue thing cross-platform.

Comment 2

[Mike Hommey [:glandium]]

Attachment: Bug 1658385 - Exclude mach_override code on aarch64 builds for now.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c878b0fb16c7
Exclude mach_override code on aarch64 builds for now. r=froydnj

Comment 4

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/c878b0fb16c7

Comment 5

[Mike Hommey [:glandium]]

Forgot to mark leave-open before the merge.

Comment 6

[Nika Layzell [:nika] (ni? for response)]

Switching over to an enhancement.

:glandium, is this something which we should continue tracking? It seems unfortunate to not have the IO interposer on m1 macs (which is what it seems like this might do? I'm unsure)

Comment 7

[Gian-Carlo Pascutto [:gcp]]

I'm unclear if this would still work on modern macOS, regardless of arch: https://stackoverflow.com/questions/51266646/mach-override-function-is-failing-in-mojave-osx-10-14

Comment 8

[Mike Hommey [:glandium]]

(In reply to Gian-Carlo Pascutto [:gcp] from comment #7)

I'm unclear if this would still work on modern macOS, regardless of arch: https://stackoverflow.com/questions/51266646/mach-override-function-is-failing-in-mojave-osx-10-14

Looks like this is talking about a kernel extension, these have different restrictions than userspace.