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[PATCH] i386: PARAVIRT: Remove CONFIG_DEBUG_PARAVIRT

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Remove CONFIG_DEBUG_PARAVIRT.  When inlining code, this option
attempts to trash registers in the patch-site's "clobber" field, on
the grounds that this should find bugs with incorrect clobbers.
Unfortunately, the clobber field really means "registers modified by
this patch site", which includes return values.

Because of this, this option has outlived its usefulness, so remove
it.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Jeremy Fitzhardinge 2007-05-02 19:27:13 +02:00 committed by Andi Kleen
parent 4cdf6bc247
commit 7f63c41c6c
2 changed files with 1 additions and 23 deletions
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10
arch/i386/Kconfig.debug
View file

@ -85,14 +85,4 @@ config DOUBLEFAULT
option saves about 4k and might cause you much additional grey
hair.
config DEBUG_PARAVIRT
bool "Enable some paravirtualization debugging"
default n
depends on PARAVIRT && DEBUG_KERNEL
help
Currently deliberately clobbers regs which are allowed to be
clobbered in inlined paravirt hooks, even in native mode.
If turning this off solves a problem, then DISABLE_INTERRUPTS() or
ENABLE_INTERRUPTS() is lying about what registers can be clobbered.
endmenu

14
arch/i386/kernel/alternative.c
View file

@ -334,19 +334,7 @@ void apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end)
used = paravirt_ops.patch(p->instrtype, p->clobbers, p->instr,
p->len);
#ifdef CONFIG_DEBUG_PARAVIRT
{
int i;
/* Deliberately clobber regs using "not %reg" to find bugs. */
for (i = 0; i < 3; i++) {
if (p->len - used >= 2 && (p->clobbers & (1 << i))) {
memcpy(p->instr + used, "\xf7\xd0", 2);
p->instr[used+1] |= i;
used += 2;
}
}
}
#endif
/* Pad the rest with nops */
nop_out(p->instr + used, p->len - used);
}