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Diffstat (limited to 'Documentation/ABI/stable/vdso')
| -rw-r--r-- | Documentation/ABI/stable/vdso | 27 |
1 files changed, 0 insertions, 27 deletions
diff --git a/Documentation/ABI/stable/vdso b/Documentation/ABI/stable/vdso deleted file mode 100644 index 8a1cbb59449..00000000000 --- a/Documentation/ABI/stable/vdso +++ /dev/null @@ -1,27 +0,0 @@ -On some architectures, when the kernel loads any userspace program it -maps an ELF DSO into that program's address space. This DSO is called -the vDSO and it often contains useful and highly-optimized alternatives -to real syscalls. - -These functions are called just like ordinary C function according to -your platform's ABI. Call them from a sensible context. (For example, -if you set CS on x86 to something strange, the vDSO functions are -within their rights to crash.) In addition, if you pass a bad -pointer to a vDSO function, you might get SIGSEGV instead of -EFAULT. - -To find the DSO, parse the auxiliary vector passed to the program's -entry point. The AT_SYSINFO_EHDR entry will point to the vDSO. - -The vDSO uses symbol versioning; whenever you request a symbol from the -vDSO, specify the version you are expecting. - -Programs that dynamically link to glibc will use the vDSO automatically. -Otherwise, you can use the reference parser in Documentation/vDSO/parse_vdso.c. - -Unless otherwise noted, the set of symbols with any given version and the -ABI of those symbols is considered stable. It may vary across architectures, -though. - -(As of this writing, this ABI documentation as been confirmed for x86_64. - The maintainers of the other vDSO-using architectures should confirm - that it is correct for their architecture.)
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