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From: Yang on 18 Mar 2010 13:40
in handling an interrupt, kernel first saves all the register contents , in
the SAVE_ALL macro, in the last part of this macro,� it adjusts the
data segment selectors for kernel mode.

in kernel 2.4, the __KERNEL_DS segment is loaded into %ds and %es, at line
98 of:

http://lxr.linux.no/#linux-old+v2.4.31/arch/i386/kernel/entry.S


but in kernel 2.6, __USER_DS segment is loaded into %ds and %es, at line
227 of :
http://lxr.linux.no/#linux+v2.6.33/arch/x86/kernel/entry_32.S


I understand that on x86, all the data segment selector contents are
basically the same, but semantically it's better to use the KERNEL_DS
because we are working in kernel mode?



Thanks!
Yang
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Prev: [tip:perf/core] x86, perf: Use apic_write unconditionally
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