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A comment on Linux Syscall Support. Parent comment

Re:Linux Syscall Support by LegionMammal978 on Thursday November 07, 2024 @09:19AM (#42076841)
> On the other hand all of that comes back to bone you if you’re trying to benefit from vDSO without going through a libc.

At least the vDSO functions really don't need much in the way of stack space: generally there's nothing much there but clock_gettime() and gettimeofday(), which just read some values from the vvar area.

The bigger pain, of course, is actually looking up the symbols in the vDSO, which takes at least a minimal ELF parser.

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Re:Linux Syscall Support by t-8ch on Thursday November 07, 2024 @10:03AM (#42077231)
The kernel also provides a minimal vdso elf parser:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...

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Re:Linux Syscall Support by masklinn on Thursday November 07, 2024 @10:04AM (#42077239)
> At least the vDSO functions really don't need much in the way of stack space: generally there's nothing much there but clock_gettime() and gettimeofday(), which just read some values from the vvar area.

And yet that’s exactly one of the things Go fucked up in the past: https://marcan.st/2017/12/debugging-an-evil-go-runtime-bug/

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