Failing to patch because not enough space is available for a call or jump
or because the site clobbers do not allow the target clobbers to fit is
a fatal error; it means the kernel can not be properly virtualized.
In patch_insns, we just keep a warning instead; it may not be fatal, as
they paravirt-ops backend may just be trying to insert a greedy but not
necessary inline function.
Signed-off-by: Zachary Amsden <zach@xxxxxxxxxx>
diff -r fcb59055d2b2 arch/i386/kernel/paravirt.c
--- a/arch/i386/kernel/paravirt.c Thu Apr 19 12:36:06 2007 -0700
+++ b/arch/i386/kernel/paravirt.c Thu Apr 19 15:42:02 2007 -0700
@@ -132,10 +140,8 @@ unsigned paravirt_patch_call(void *targe
unsigned char *call = site;
unsigned long delta = (unsigned long)target - (unsigned long)(call+5);
- if (tgt_clobbers & ~site_clobbers)
- return len; /* target would clobber too much for this site */
- if (len < 5)
- return len; /* call too long for patch site */
+ BUG_ON(tgt_clobbers & ~site_clobbers);
+ BUG_ON(len < 5);
*call++ = 0xe8; /* call */
*(unsigned long *)call = delta;
@@ -148,8 +154,7 @@ unsigned paravirt_patch_jmp(void *target
unsigned char *jmp = site;
unsigned long delta = (unsigned long)target - (unsigned long)(jmp+5);
- if (len < 5)
- return len; /* call too long for patch site */
+ BUG_ON(len < 5);
*jmp++ = 0xe9; /* jmp */
*(unsigned long *)jmp = delta;
@@ -186,7 +191,10 @@ unsigned paravirt_patch_insns(void *site
{
unsigned insn_len = end - start;
- if (insn_len > len || start == NULL)
+ WARN_ON(insn_len > len);
+ BUG_ON(start == NULL);
+
+ if (insn_len > len)
insn_len = len;
else
memcpy(site, start, insn_len);
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