Gerd Hoffmann wrote:
[ depending on CONFIG_SMP ]
Okay, thanks. Yes, I agree such would make sense.
Patch below. It simply returns in case the tables are empty and nothing
is do to, thus avoids printing the confusing message.
It does avoid the message but well, that's also _all_ it avoids. Why do
you want to do it this way? If I apply the attached, things compile and
work fine which seems to confirm that, yes, all this smp_alternatives
code is simply dead baggage on !CONFIG_SMP.
Yes, the #ifdef in arch/i386/kernel/module.c is a bit clumsy. Just proof
of concept, might be abstracted out a bit better. It does lose most of
alternatives.c which would seem to be good thing.
Unless I'm missing some points, I believe this code should not be
compiled in for !CONFIG_SMP.
One other point, although probably not a relevant one. Your changes in
module_finalize() potentially change behaviour. It used to be:
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
void *seg;
if (strcmp(".altinstructions", secstrings + s->sh_name))
continue;
seg = (void *)s->sh_addr;
apply_alternatives(seg, seg + s->sh_size);
}
which means that any .altinstructions section would be patched. It's now:
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
...
if (!strcmp(".altinstructions", secstrings + s->sh_name))
alt = s;
...
}
if (alt) {
/* patch .altinstructions */
void *aseg = (void *)alt->sh_addr;
apply_alternatives(aseg, aseg + alt->sh_size);
}
which means that only the last such section would. I suppose there's
only one such section anyway, but not seeing a break in the original
does make me wonder if this was originally done on purpose.
Rene.
Index: local/arch/i386/kernel/alternative.c
===================================================================
--- local.orig/arch/i386/kernel/alternative.c 2006-05-11 20:28:56.000000000 +0200
+++ local/arch/i386/kernel/alternative.c 2006-05-11 20:32:24.000000000 +0200
@@ -118,6 +118,8 @@ void apply_alternatives(struct alt_instr
}
}
+#ifdef CONFIG_SMP
+
static void alternatives_smp_save(struct alt_instr *start, struct alt_instr *end)
{
struct alt_instr *a;
@@ -283,10 +285,13 @@ void alternatives_smp_switch(int smp)
spin_unlock_irqrestore(&smp_alt, flags);
}
+#endif /* CONFIG_SMP */
+
void __init alternative_instructions(void)
{
apply_alternatives(__alt_instructions, __alt_instructions_end);
+#ifdef CONFIG_SMP
/* switch to patch-once-at-boottime-only mode and free the
* tables in case we know the number of CPUs will never ever
* change */
@@ -318,4 +323,5 @@ void __init alternative_instructions(voi
_text, _etext);
alternatives_smp_switch(0);
}
+#endif
}
Index: local/arch/i386/kernel/module.c
===================================================================
--- local.orig/arch/i386/kernel/module.c 2006-05-11 20:28:56.000000000 +0200
+++ local/arch/i386/kernel/module.c 2006-05-11 20:29:00.000000000 +0200
@@ -112,12 +112,14 @@ int module_finalize(const Elf_Ehdr *hdr,
char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
- if (!strcmp(".text", secstrings + s->sh_name))
- text = s;
if (!strcmp(".altinstructions", secstrings + s->sh_name))
alt = s;
+#ifdef CONFIG_SMP
if (!strcmp(".smp_locks", secstrings + s->sh_name))
locks= s;
+ if (!strcmp(".text", secstrings + s->sh_name))
+ text = s;
+#endif
}
if (alt) {
@@ -126,16 +128,20 @@ int module_finalize(const Elf_Ehdr *hdr,
apply_alternatives(aseg, aseg + alt->sh_size);
}
if (locks && text) {
+#ifdef CONFIG_SMP
void *lseg = (void *)locks->sh_addr;
void *tseg = (void *)text->sh_addr;
alternatives_smp_module_add(me, me->name,
lseg, lseg + locks->sh_size,
tseg, tseg + text->sh_size);
+#endif
}
return 0;
}
void module_arch_cleanup(struct module *mod)
{
+#ifdef CONFIG_SMP
alternatives_smp_module_del(mod);
+#endif
}
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
