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Fix misdescription about conforming bit

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Conforming bit is bit 42 in segment descriptor, not 43.

Signed-off-by: Yiyang Chen <cyyzero@qq.com>
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Yiyang Chen 2025-07-27 13:07:02 +00:00
parent 2eefbdfed9
commit 3ca30549a0
1 changed files with 1 additions and 1 deletions
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Booting/linux-bootstrap-2.md
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@ -127,7 +127,7 @@ As we can see the first bit(bit 43) is `0` for a _data_ segment and `1` for a _c
* if E(bit 42) is 0, expand up, otherwise, expand down. Read more [here](http://www.sudleyplace.com/dpmione/expanddown.html). * if E(bit 42) is 0, expand up, otherwise, expand down. Read more [here](http://www.sudleyplace.com/dpmione/expanddown.html).
* if W(bit 41)(for Data Segments) is 1, write access is allowed, and if it is 0, the segment is read-only. Note that read access is always allowed on data segments. * if W(bit 41)(for Data Segments) is 1, write access is allowed, and if it is 0, the segment is read-only. Note that read access is always allowed on data segments.
* A(bit 40) controls whether the segment can be accessed by the processor or not. * A(bit 40) controls whether the segment can be accessed by the processor or not.
* C(bit 43) is the conforming bit(for code selectors). If C is 1, the segment code can be executed from a lower level privilege (e.g. user) level. If C is 0, it can only be executed from the same privilege level. * C(bit 42) is the conforming bit(for code selectors). If C is 1, the segment code can be executed from a lower level privilege (e.g. user) level. If C is 0, it can only be executed from the same privilege level.
* R(bit 41) controls read access to code segments; when it is 1, the segment can be read from. Write access is never granted for code segments. * R(bit 41) controls read access to code segments; when it is 1, the segment can be read from. Write access is never granted for code segments.
4. DPL[2-bits] (Descriptor Privilege Level) comprises the bits 45-46. It defines the privilege level of the segment. It can be 0-3 where 0 is the most privileged level. 4. DPL[2-bits] (Descriptor Privilege Level) comprises the bits 45-46. It defines the privilege level of the segment. It can be 0-3 where 0 is the most privileged level.