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| author | Alexey Dobriyan <adobriyan@gmail.com> | 2023-04-15 20:37:29 +0300 |
|---|---|---|
| committer | Jonathan Corbet <corbet@lwn.net> | 2023-04-20 17:53:38 -0600 |
| commit | 5c2c34a49be8fa534379c64579671feea52432b9 (patch) | |
| tree | b6f032031ad2d620043c1ca0be82bfb3a89e6348 | |
| parent | 4de3790a6313dd6596ba7d0391ade94a21ee10b5 (diff) | |
ELF: document some de-facto PT_* ABI quirks
Turns out rules about PT_INTERP, PT_GNU_STACK and PT_GNU_PROPERTY
program headers are slightly different.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: https://lore.kernel.org/r/88d3f1bb-f4e0-4c40-9304-3843513a1262@p183
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
| -rw-r--r-- | Documentation/userspace-api/ELF.rst | 34 | ||||
| -rw-r--r-- | Documentation/userspace-api/index.rst | 1 |
2 files changed, 35 insertions, 0 deletions
diff --git a/Documentation/userspace-api/ELF.rst b/Documentation/userspace-api/ELF.rst new file mode 100644 index 000000000000..ac8aeacd458d --- /dev/null +++ b/Documentation/userspace-api/ELF.rst @@ -0,0 +1,34 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================= +Linux-specific ELF idiosyncrasies +================================= + +Definitions +=========== + +"First" program header is the one with the smallest offset in the file: +e_phoff. + +"Last" program header is the one with the biggest offset in the file: +e_phoff + (e_phnum - 1) * sizeof(Elf_Phdr). + +PT_INTERP +========= + +First PT_INTERP program header is used to locate the filename of ELF +interpreter. Other PT_INTERP headers are ignored (since Linux 2.4.11). + +PT_GNU_STACK +============ + +Last PT_GNU_STACK program header defines userspace stack executability +(since Linux 2.6.6). Other PT_GNU_STACK headers are ignored. + +PT_GNU_PROPERTY +=============== + +ELF interpreter's last PT_GNU_PROPERTY program header is used (since +Linux 5.8). If interpreter doesn't have one, then the last PT_GNU_PROPERTY +program header of an executable is used. Other PT_GNU_PROPERTY headers +are ignored. diff --git a/Documentation/userspace-api/index.rst b/Documentation/userspace-api/index.rst index f16337bdb852..72a65db0c498 100644 --- a/Documentation/userspace-api/index.rst +++ b/Documentation/userspace-api/index.rst @@ -23,6 +23,7 @@ place where this information is gathered. spec_ctrl accelerators/ocxl ebpf/index + ELF ioctl/index iommu iommufd |