Messages in this thread | | | Date | Tue, 20 Aug 2019 11:02:10 +0100 | From | Dave Martin <> | Subject | Re: [PATCH v8 22/27] binfmt_elf: Extract .note.gnu.property from an ELF file |
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On Tue, Aug 13, 2019 at 01:52:20PM -0700, Yu-cheng Yu wrote: > An ELF file's .note.gnu.property indicates features the executable file > can support. For example, the property GNU_PROPERTY_X86_FEATURE_1_AND > indicates the file supports GNU_PROPERTY_X86_FEATURE_1_IBT and/or > GNU_PROPERTY_X86_FEATURE_1_SHSTK. > > With this patch, if an arch needs to setup features from ELF properties, > it needs CONFIG_ARCH_USE_GNU_PROPERTY to be set, and specific > arch_parse_property() and arch_setup_property(). > > For example, for X86_64: > > int arch_setup_property(void *ehdr, void *phdr, struct file *f, bool inter) > { > int r; > uint32_t property; > > r = get_gnu_property(ehdr, phdr, f, GNU_PROPERTY_X86_FEATURE_1_AND, > &property); > ... > } > > This patch is derived from code provided by H.J. Lu <hjl.tools@gmail.com>. > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
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For the hell of it, I tried implementing an alternate version [1] that tries to integrate into the existing ELF loader more directly.
This may or may not be a better approach, but tries to solve some issues such as not repeatedly reading and parsing the properties.
Cheers ---Dave
[1] [RFC PATCH 0/2] ELF: Alternate program property parser https://lore.kernel.org/lkml/1566295063-7387-1-git-send-email-Dave.Martin@arm.com/
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