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author | Jeremy Fitzhardinge <jeremy@goop.org> | 2006-12-07 02:14:02 +0100 |
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committer | Andi Kleen <andi@basil.nowhere.org> | 2006-12-07 02:14:02 +0100 |
commit | f95d47caae5302a63d92be9a0292abc90e2a14e1 (patch) | |
tree | cfa963975d104c56aba28df6c941759175ed4b98 /kernel/latency.c | |
parent | [PATCH] i386: Initialize the per-CPU data area (diff) | |
download | linux-f95d47caae5302a63d92be9a0292abc90e2a14e1.tar.xz linux-f95d47caae5302a63d92be9a0292abc90e2a14e1.zip |
[PATCH] i386: Use %gs as the PDA base-segment in the kernel
This patch is the meat of the PDA change. This patch makes several related
changes:
1: Most significantly, %gs is now used in the kernel. This means that on
entry, the old value of %gs is saved away, and it is reloaded with
__KERNEL_PDA.
2: entry.S constructs the stack in the shape of struct pt_regs, and this
is passed around the kernel so that the process's saved register
state can be accessed.
Unfortunately struct pt_regs doesn't currently have space for %gs
(or %fs). This patch extends pt_regs to add space for gs (no space
is allocated for %fs, since it won't be used, and it would just
complicate the code in entry.S to work around the space).
3: Because %gs is now saved on the stack like %ds, %es and the integer
registers, there are a number of places where it no longer needs to
be handled specially; namely context switch, and saving/restoring the
register state in a signal context.
4: And since kernel threads run in kernel space and call normal kernel
code, they need to be created with their %gs == __KERNEL_PDA.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Diffstat (limited to 'kernel/latency.c')
0 files changed, 0 insertions, 0 deletions