Add sys/ucontext.h signatures for linux aarch64 glibc #3001

dtolnay · 2022-11-16T07:31:48Z

`getcontext`, `setcontext`, `makecontext`, `swapcontext`

From <sys/ucontext.h>. The specification for these was removed from POSIX.1-2008 in favor of POSIX threads, but glibc continues to ship an implementation for aarch64 just as it does for x86_64.

Libc crate's existing x86_64 binding with the same signatures added in this PR:

libc/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs

Lines 810 to 813 in bbf929d

    
           pub fn getcontext(ucp: *mut ucontext_t) -> ::c_int; 
        
           pub fn setcontext(ucp: *const ucontext_t) -> ::c_int; 
        
           pub fn makecontext(ucp: *mut ucontext_t, func: extern "C" fn(), argc: ::c_int, ...); 
        
           pub fn swapcontext(uocp: *mut ucontext_t, ucp: *const ucontext_t) -> ::c_int;

Glibc implementation:

`iopl`, `ioperm`

From <sys/io.h>. These are functions for accessing x86 I/O ports. ARM has no such I/O ports in the architecture. Linux's man 2 for both functions contains: "This call is mostly for the i386 architecture. On many other architectures it does not exist or will always return an error." Glibc ships one of these "always return an error" implementation of both functions for aarch64.

~~Matching signatures from x86_64:~~

libc/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs

Lines 814 to 815 in bbf929d

    
           pub fn iopl(level: ::c_int) -> ::c_int; 
        
           pub fn ioperm(from: ::c_ulong, num: ::c_ulong, turn_on: ::c_int) -> ::c_int;

~~Glibc implementation:~~

~~https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/arm/ioperm.c~~

The implementation has unsigned int for the argument of iopl but I've used int in the PR to match the Linux docs, which seems more authoritative. Unclear why glibc diverges from this but it doesn't make a difference in the ABI.

rust-highfive · 2022-11-16T07:31:51Z

r? @JohnTitor

(rust-highfive has picked a reviewer for you, use r? to override)

thomcc

Seems fine. Matches declaration in headers, assuming our struct ucontext is right (which this PR doesn't add).

The iopl/ioperm stuff is a bit odd to have but I suppose this allows for following a consistent error handling path rather than cfging it out.

thomcc · 2022-11-16T08:10:07Z

The implementation has unsigned int for the argument of iopl but I've used int in the PR to match the Linux docs, which seems more authoritative

This also matches the way we expose iopl on x86, which is somewhat important.

JohnTitor · 2022-11-16T22:42:59Z

Thanks! @bors r+

bors · 2022-11-16T22:43:01Z

📌 Commit 5d3b73d has been approved by JohnTitor

It is now in the queue for this repository.

bors · 2022-11-16T22:43:09Z

⌛ Testing commit 5d3b73d with merge 5848e85...

Add sys/ucontext.h and sys/io.h signatures for linux aarch64 glibc ### `getcontext`, `setcontext`, `makecontext`, `swapcontext` From \<sys/ucontext.h\>. The specification for these was removed from POSIX.1-2008 in favor of POSIX threads, but glibc continues to ship an implementation for aarch64 just as it does for x86_64. Libc crate's existing x86_64 binding with the same signatures added in this PR: https://github.com/rust-lang/libc/blob/bbf929d2c8355fa19384b3551c5874c866be465f/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs#L810-L813 Glibc implementation: - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/getcontext.S - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/setcontext.S - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/makecontext.c - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/swapcontext.S <br> ### `iopl`, `ioperm` From \<sys/io.h\>. These are functions for accessing x86 I/O ports. ARM has no such I/O ports in the architecture. Linux's `man 2` for both functions contains: _"This call is mostly for the i386 architecture. On many other architectures it does not exist or will always return an error."_ Glibc ships one of these "always return an error" implementation of both functions for aarch64. Matching signatures from x86_64: https://github.com/rust-lang/libc/blob/bbf929d2c8355fa19384b3551c5874c866be465f/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs#L814-L815 Glibc implementation: - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/arm/ioperm.c The implementation has `unsigned int` for the argument of `iopl` but I've used int in the PR to match the Linux docs, which seems more authoritative. Unclear why glibc diverges from this but it doesn't make a difference in the ABI.

bors · 2022-11-16T23:03:23Z

💔 Test failed - checks-actions

dtolnay · 2022-11-18T07:42:50Z

/checkout/target/aarch64-unknown-linux-gnu/debug/build/libc-test-5a973a03a651b470/out/main.c: In function '__test_fn_iopl':
/checkout/target/aarch64-unknown-linux-gnu/debug/build/libc-test-5a973a03a651b470/out/main.c:53524:24: error: 'iopl' undeclared (first use in this function)
53524 |                 return iopl;
      |                        ^~~~
/checkout/target/aarch64-unknown-linux-gnu/debug/build/libc-test-5a973a03a651b470/out/main.c:53524:24: note: each undeclared identifier is reported only once for each function it appears in
/checkout/target/aarch64-unknown-linux-gnu/debug/build/libc-test-5a973a03a651b470/out/main.c: In function '__test_fn_ioperm':
/checkout/target/aarch64-unknown-linux-gnu/debug/build/libc-test-5a973a03a651b470/out/main.c:53529:24: error: 'ioperm' undeclared (first use in this function); did you mean 'ipc_perm'?
53529 |                 return ioperm;
      |                        ^~~~~~
      |                        ipc_perm

I did a bit of digging in glibc, it turns out glibc ships definitions of iopl and ioperm on aarch64 but does not ship a declaration of them in any header. 🤯 I've removed those two from the PR.

JohnTitor · 2022-11-19T05:18:51Z

@bors r+

bors · 2022-11-19T05:18:53Z

📌 Commit 5aec927 has been approved by JohnTitor

It is now in the queue for this repository.

Add sys/ucontext.h signatures for linux aarch64 glibc ### `getcontext`, `setcontext`, `makecontext`, `swapcontext` From \<sys/ucontext.h\>. The specification for these was removed from POSIX.1-2008 in favor of POSIX threads, but glibc continues to ship an implementation for aarch64 just as it does for x86_64. Libc crate's existing x86_64 binding with the same signatures added in this PR: https://github.com/rust-lang/libc/blob/bbf929d2c8355fa19384b3551c5874c866be465f/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs#L810-L813 Glibc implementation: - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/getcontext.S - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/setcontext.S - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/makecontext.c - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/swapcontext.S <br> ### ~~`iopl`, `ioperm`~~ ~~From \<sys/io.h\>. These are functions for accessing x86 I/O ports. ARM has no such I/O ports in the architecture. Linux's `man 2` for both functions contains: _"This call is mostly for the i386 architecture. On many other architectures it does not exist or will always return an error."_ Glibc ships one of these "always return an error" implementation of both functions for aarch64.~~ ~~Matching signatures from x86_64:~~ https://github.com/rust-lang/libc/blob/bbf929d2c8355fa19384b3551c5874c866be465f/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs#L814-L815 ~~Glibc implementation:~~ - ~~https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/arm/ioperm.c~~ ~~The implementation has `unsigned int` for the argument of `iopl` but I've used int in the PR to match the Linux docs, which seems more authoritative. Unclear why glibc diverges from this but it doesn't make a difference in the ABI.~~

bors · 2022-11-19T05:19:04Z

⌛ Testing commit 5aec927 with merge 3a37639...

bors · 2022-11-19T05:51:39Z

💔 Test failed - checks-actions

dtolnay · 2022-11-19T06:00:08Z

Can't tell what failed. 😿

thomcc · 2022-11-19T06:07:36Z

https://github.com/rust-lang/libc/actions/runs/3502179666/jobs/5866446110#step:5:2455 is supposed to print ^PASSED .* tests or ^test result: ok to stdout. https://github.com/rust-lang/libc/blob/master/ci/runtest-android.rs#L41-L47. I'm not sure why this is happening though.

It doesn't look like it's caused by this PR, but it also doesn't seem to be failing in other PRs.

thomcc · 2022-11-19T07:58:20Z

Should be fixed by #3005

JohnTitor · 2022-11-19T09:16:31Z

Sorry for the inconvenience! @bors retry

bors · 2022-11-19T09:16:39Z

⌛ Testing commit 5aec927 with merge 0f31121...

Add sys/ucontext.h signatures for linux aarch64 glibc ### `getcontext`, `setcontext`, `makecontext`, `swapcontext` From \<sys/ucontext.h\>. The specification for these was removed from POSIX.1-2008 in favor of POSIX threads, but glibc continues to ship an implementation for aarch64 just as it does for x86_64. Libc crate's existing x86_64 binding with the same signatures added in this PR: https://github.com/rust-lang/libc/blob/bbf929d2c8355fa19384b3551c5874c866be465f/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs#L810-L813 Glibc implementation: - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/getcontext.S - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/setcontext.S - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/makecontext.c - https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/aarch64/swapcontext.S <br> ### ~~`iopl`, `ioperm`~~ ~~From \<sys/io.h\>. These are functions for accessing x86 I/O ports. ARM has no such I/O ports in the architecture. Linux's `man 2` for both functions contains: _"This call is mostly for the i386 architecture. On many other architectures it does not exist or will always return an error."_ Glibc ships one of these "always return an error" implementation of both functions for aarch64.~~ ~~Matching signatures from x86_64:~~ https://github.com/rust-lang/libc/blob/bbf929d2c8355fa19384b3551c5874c866be465f/src/unix/linux_like/linux/gnu/b64/x86_64/mod.rs#L814-L815 ~~Glibc implementation:~~ - ~~https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/arm/ioperm.c~~ ~~The implementation has `unsigned int` for the argument of `iopl` but I've used int in the PR to match the Linux docs, which seems more authoritative. Unclear why glibc diverges from this but it doesn't make a difference in the ABI.~~

bors · 2022-11-19T10:13:11Z

💔 Test failed - checks-actions

JohnTitor · 2022-11-20T03:27:27Z

CI for 1.13 fails because it (ucontext_t precisely) needs libc_align. Could you declare them on align.rs? (We could remove this cfg after setting MSRV to a more recent version but for now let's follow the current policy.)

dtolnay · 2022-11-20T03:50:12Z

👍 Moved to align.rs so that they're properly conditional on libc_align.

JohnTitor · 2022-11-20T04:16:21Z

Thanks! @bors r+

bors · 2022-11-20T04:16:23Z

📌 Commit fd32da6 has been approved by JohnTitor

It is now in the queue for this repository.

bors · 2022-11-20T04:34:28Z

⌛ Testing commit fd32da6 with merge 25aacfd...

bors · 2022-11-20T05:37:30Z

☀️ Test successful - checks-actions, checks-cirrus-freebsd-12, checks-cirrus-freebsd-13, checks-cirrus-freebsd-14
Approved by: JohnTitor
Pushing 25aacfd to master...

rust-highfive assigned JohnTitor Nov 16, 2022

rust-highfive added the S-waiting-on-review label Nov 16, 2022

thomcc approved these changes Nov 16, 2022

View reviewed changes

JohnTitor approved these changes Nov 16, 2022

View reviewed changes

bors added S-waiting-on-bors and removed S-waiting-on-review labels Nov 16, 2022

bors added S-waiting-on-review and removed S-waiting-on-bors labels Nov 16, 2022

dtolnay marked this pull request as draft November 17, 2022 04:59

dtolnay force-pushed the aarch64 branch from 5d3b73d to 5aec927 Compare November 18, 2022 07:39

dtolnay marked this pull request as ready for review November 18, 2022 07:42

dtolnay changed the title ~~Add sys/ucontext.h and sys/io.h signatures for linux aarch64 glibc~~ Add sys/ucontext.h signatures for linux aarch64 glibc Nov 18, 2022

bors added S-waiting-on-bors and removed S-waiting-on-review labels Nov 19, 2022

bors added S-waiting-on-review and removed S-waiting-on-bors labels Nov 19, 2022

bors added S-waiting-on-bors and removed S-waiting-on-review labels Nov 19, 2022

bors added S-waiting-on-review and removed S-waiting-on-bors labels Nov 19, 2022

Add sys/ucontext.h signatures for linux aarch64 glibc

fd32da6

dtolnay force-pushed the aarch64 branch from 5aec927 to fd32da6 Compare November 20, 2022 03:48

bors added S-waiting-on-bors and removed S-waiting-on-review labels Nov 20, 2022

bors merged commit 25aacfd into rust-lang:master Nov 20, 2022

dtolnay deleted the aarch64 branch November 20, 2022 05:54

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Add sys/ucontext.h signatures for linux aarch64 glibc #3001

Add sys/ucontext.h signatures for linux aarch64 glibc #3001

dtolnay commented Nov 16, 2022 •

edited

rust-highfive commented Nov 16, 2022

thomcc left a comment

thomcc commented Nov 16, 2022

JohnTitor commented Nov 16, 2022

bors commented Nov 16, 2022

bors commented Nov 16, 2022

bors commented Nov 16, 2022

dtolnay commented Nov 18, 2022

JohnTitor commented Nov 19, 2022

bors commented Nov 19, 2022

bors commented Nov 19, 2022

bors commented Nov 19, 2022

dtolnay commented Nov 19, 2022

thomcc commented Nov 19, 2022

thomcc commented Nov 19, 2022

JohnTitor commented Nov 19, 2022

bors commented Nov 19, 2022

bors commented Nov 19, 2022

JohnTitor commented Nov 20, 2022

dtolnay commented Nov 20, 2022

JohnTitor commented Nov 20, 2022

bors commented Nov 20, 2022

bors commented Nov 20, 2022

bors commented Nov 20, 2022

	pub fn getcontext(ucp: *mut ucontext_t) -> ::c_int;
	pub fn setcontext(ucp: *const ucontext_t) -> ::c_int;
	pub fn makecontext(ucp: *mut ucontext_t, func: extern "C" fn(), argc: ::c_int, ...);
	pub fn swapcontext(uocp: mut ucontext_t, ucp: const ucontext_t) -> ::c_int;

	pub fn iopl(level: ::c_int) -> ::c_int;
	pub fn ioperm(from: ::c_ulong, num: ::c_ulong, turn_on: ::c_int) -> ::c_int;

Add sys/ucontext.h signatures for linux aarch64 glibc #3001

Add sys/ucontext.h signatures for linux aarch64 glibc #3001

Conversation

dtolnay commented Nov 16, 2022 • edited

getcontext, setcontext, makecontext, swapcontext

iopl, ioperm

rust-highfive commented Nov 16, 2022

thomcc left a comment

Choose a reason for hiding this comment

thomcc commented Nov 16, 2022

JohnTitor commented Nov 16, 2022

bors commented Nov 16, 2022

bors commented Nov 16, 2022

bors commented Nov 16, 2022

dtolnay commented Nov 18, 2022

JohnTitor commented Nov 19, 2022

bors commented Nov 19, 2022

bors commented Nov 19, 2022

bors commented Nov 19, 2022

dtolnay commented Nov 19, 2022

thomcc commented Nov 19, 2022

thomcc commented Nov 19, 2022

JohnTitor commented Nov 19, 2022

bors commented Nov 19, 2022

bors commented Nov 19, 2022

JohnTitor commented Nov 20, 2022

dtolnay commented Nov 20, 2022

JohnTitor commented Nov 20, 2022

bors commented Nov 20, 2022

bors commented Nov 20, 2022

bors commented Nov 20, 2022

dtolnay commented Nov 16, 2022 •

edited

`getcontext`, `setcontext`, `makecontext`, `swapcontext`

`iopl`, `ioperm`