Add basic support for ELF thread local storage segments #96
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@vinaychandra Could you try whether this change works for you? |
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Ah, it seems like I understood something wrong. I will create a new version. |
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With the new version, I can now successfully read the TLS template info for a small example: #[thread_local]
pub static mut DATA: u64 = 0;
#[thread_local]
pub static BSS: u64 = 0;
fn kernel_main(boot_info: &'static BootInfo) -> ! {
println!("Hello World{}", "!");
println!("TLS INFO: {:x?}", boot_info.tls_template());
// this panics because we did not set up the fs register yet
println!("DATA: {}, BSS: {}", unsafe { DATA }, BSS);
}The result is the following:
I get the same values with |
vinaychandra
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Feb 19, 2020
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Published as version 0.8.8 |
phil-opp
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This reports the thread local storage segment of the kernel (if present) in the boot information. This should make it possible to use the unstable
#[thread_local]attribute. Since the TLS template overlaps with parts of a LOAD segment, no additional mapping needs to be done.Note that the TLS template should not be used directly. Instead, the kernel should create a copy the TLS template for each thread and then set up the
fsregister accordingly. See https://uclibc.org/docs/tls.pdf for more information.This code only works for a single TLS segment. If more than one TLS segment are present in the executable, the bootloader errors. We can of course lift this restriction if this becomes a problem in practice.
Fixes #95