diff options
| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2006-12-07 02:14:02 +0100 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-12-07 02:14:02 +0100 |
| commit | f95d47caae5302a63d92be9a0292abc90e2a14e1 (patch) | |
| tree | cfa963975d104c56aba28df6c941759175ed4b98 /arch/i386/kernel/signal.c | |
| parent | 62111195800d80c66cdc69063ea3145878c99fbf (diff) | |
[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 'arch/i386/kernel/signal.c')
| -rw-r--r-- | arch/i386/kernel/signal.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c index 43002cfb40c..65d7620eaa0 100644 --- a/arch/i386/kernel/signal.c +++ b/arch/i386/kernel/signal.c @@ -128,7 +128,7 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *peax X86_EFLAGS_TF | X86_EFLAGS_SF | X86_EFLAGS_ZF | \ X86_EFLAGS_AF | X86_EFLAGS_PF | X86_EFLAGS_CF) - GET_SEG(gs); + COPY_SEG(gs); GET_SEG(fs); COPY_SEG(es); COPY_SEG(ds); @@ -244,9 +244,7 @@ setup_sigcontext(struct sigcontext __user *sc, struct _fpstate __user *fpstate, { int tmp, err = 0; - tmp = 0; - savesegment(gs, tmp); - err |= __put_user(tmp, (unsigned int __user *)&sc->gs); + err |= __put_user(regs->xgs, (unsigned int __user *)&sc->gs); savesegment(fs, tmp); err |= __put_user(tmp, (unsigned int __user *)&sc->fs); |