path: root/arch
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authorRich Felker <>2019-08-02 14:04:45 -0400
committerRich Felker <>2019-08-02 14:04:45 -0400
commit0705fe93566fca735bf0df155f71641df02fc273 (patch)
tree3ee3ba011e9f09ca9f7ca55a557a12f49b9ec5ce /arch
parent006a75a99789f383713e4f47affd7c90e39cc827 (diff)
clock_gettime: add support for 32-bit vdso with 64-bit time_t
this fixes a major upcoming performance regression introduced by commit 72f50245d018af0c31b38dec83c557a4e5dd1ea8, whereby 32-bit archs would lose vdso clock_gettime after switching to 64-bit time_t, unless the kernel supports time64 and provides a time64 version of the vdso function. this would incur not just one but two syscalls: first, the failed time64 syscall, then the fallback time32 one. overflow of the 32-bit result is detected and triggers a revert to syscalls. normally, on a system that's not Y2038-ready, this would still overflow, but if the process has been migrated to a time64-capable kernel or if the kernel has been hot-patched to add time64 syscalls, it may conceivably work.
Diffstat (limited to 'arch')
0 files changed, 0 insertions, 0 deletions