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Rewrite Linux syscalls generation - #24702

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alexrp merged 3 commits into
ziglang:masterfrom
The-King-of-Toasters:syscall-tables
Aug 15, 2025
Merged

Rewrite Linux syscalls generation#24702
alexrp merged 3 commits into
ziglang:masterfrom
The-King-of-Toasters:syscall-tables

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@The-King-of-Toasters

@The-King-of-ToastersThe-King-of-Toasters commented Aug 5, 2025

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Reloaded version of #21440 post writergate. Original description below:

Changes by Arnd Bergmann have migrated all supported architectures to use a table for their syscall lists. This removes the need of calling a C pre-processor and simplifies the logic dramatically.
The side effect is the number of names changed on targets that use the "generic" table. That list (located under scripts/syscall.tbl) adds the _time64 suffix to syscalls taking a timespec64 on 32-bit targets. Similarly, the _time32 suffix has been removed.

The result is a lot of breakage in our Linux wrappers, which makes me worried that the logic for determining the proper timespec to use was subtly broken all this time. Should be a good chance to finish #4726 - we only have 14 12 years after all...

CC @alexrp if things break.

@alexrpalexrp self-assigned this Aug 5, 2025
rootbeer
rootbeer reviewed Aug 5, 2025
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Comment threadtools/generate_linux_syscalls.zig Outdated
@The-King-of-Toasters

The-King-of-Toasters commented Aug 7, 2025•
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I've modified the tool again to consolidate all the logic into one table and restored the order of the emitted variables for easier diffing. This should fix the x32 syscall abi problems that @rootbeer pointed out.

@The-King-of-Toasters
The-King-of-Toastersforce-pushed the syscall-tables branch 2 times, most recently from 29ee317 to 89a1d94CompareAugust 7, 2025 08:11
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The code all looks great, one more suggestion for the x32 ABI though! Again, not a regression but its soooo close now ...

Comment threadtools/generate_linux_syscalls.zig Outdated
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A couple minor comments after looking this over again. The core of the change looks great, and the code seems much simpler now.

Comment threadtools/generate_linux_syscalls.zig Outdated
Comment threadtools/generate_linux_syscalls.zig Outdated
@The-King-of-Toasters
The-King-of-Toastersforce-pushed the syscall-tables branch 2 times, most recently from f707ada to 7f49b6cCompareAugust 8, 2025 09:31
@alexrp

alexrp commented Aug 9, 2025

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Failures look to be #24754.

@The-King-of-Toasters

The-King-of-Toasters commented Aug 12, 2025

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Fixing the merge conflict, but FYI the CI is all green.

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Something I just noticed while looking at this again. Not something to hold up any merges for.

Comment threadlib/std/os/linux.zig
alexrp
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Comment threadtools/generate_linux_syscalls.zig
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Comment threadtools/generate_linux_syscalls.zig
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Comment threadtools/generate_linux_syscalls.zig
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Comment threadtools/generate_linux_syscalls.zig Outdated
@The-King-of-Toasters
Rewrite generate_linux_syscalls to be completely table based
c5f10a3
Changes by Arnd Bergmann have migrated all supported architectures to
use a table for their syscall lists. This removes the need to use the
C pre-processor and simplifies the logic considerably.
All currently supported architectures have been added, with the ones Zig
doesn't support being commented out. Speaking of; OpenRisc has been
enabled for generation.
@The-King-of-Toasters
Linux: Update syscall list for 6.16
6f60c8e
The generic syscall table has different names for syscalls that take a
timespec64 on 32-bit targets, in that it adds the `_time64` suffix.
Similarly, the `_time32` suffix has been removed.
I'm not sure if the existing logic for determining the proper timespec
struct to use was subtly broken, but it should be a good chance to
finish ziglang#4726 - we only have 12 years after all...
As for the changes since 6.11..6.16:
6.11:
- x86_64 gets `uretprobe`, a syscall to speed up returning BPF probes.
- Hexagon gets `clone3`, but don't be fooled: it just returns ENOSYS.
6.13:
- The `*xattr` family of syscalls have been enhanced with new `*xattrat`
versions, similar to the other file-based `at` calls.
6.15:
- Atomically create a detached mount tree and set mount options on it.
Finally, this commit also adds the syscall numbers for OpenRISC and maps
it to the `or1k` cpu.
@The-King-of-Toasters
Linux: Use time64 syscalls when available
6080f2d
Newer 32-bit Linux targets like 32-bit RISC-V only use the 64-bit
time ABI, with these syscalls having `time64` as their suffix.
This is a stopgap solution in favor of a full audit of `std.os.linux` to
prepare for ziglang#4726.
See also ziglang#21440 for prior art.
@The-King-of-Toasters

The-King-of-Toasters commented Aug 15, 2025

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Any more changes needed or does it lgtm?

@alexrp

alexrp commented Aug 15, 2025

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Looks good, thanks!

@alexrp
alexrp merged commit 47e6528 into ziglang:masterAug 15, 2025
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@alexrp
alexrp self-requested a review August 15, 2025 05:45
@alexrpalexrp removed their assignment Aug 15, 2025
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alexrp removed their request for review August 15, 2025 05:45
@alexrpalexrp mentioned this pull request Oct 29, 2025
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@The-King-of-Toasters@alexrp@rootbeer