Refactor alternatives_smp_module* logic to make it available for
holding generic late patching state.
Most of the changes are to pull the module handling logic out
from CONFIG_SMP. In addition now we unconditionally call
alternatives_smp_module_add() and make the decision on patching
for UP or not there.
Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx>
---
arch/x86/include/asm/alternative.h | 13 ++-----
arch/x86/kernel/alternative.c | 55 ++++++++++++++++--------------
2 files changed, 32 insertions(+), 36 deletions(-)
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 13adca37c99a..8235bbb746d9 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -75,24 +75,15 @@ extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
struct module;
-#ifdef CONFIG_SMP
extern void alternatives_smp_module_add(struct module *mod, char *name,
void *locks, void *locks_end,
void *text, void *text_end);
extern void alternatives_smp_module_del(struct module *mod);
-extern void alternatives_enable_smp(void);
extern int alternatives_text_reserved(void *start, void *end);
-extern bool skip_smp_alternatives;
+#ifdef CONFIG_SMP
+extern void alternatives_enable_smp(void);
#else
-static inline void alternatives_smp_module_add(struct module *mod, char *name,
- void *locks, void *locks_end,
- void *text, void *text_end) {}
-static inline void alternatives_smp_module_del(struct module *mod) {}
static inline void alternatives_enable_smp(void) {}
-static inline int alternatives_text_reserved(void *start, void *end)
-{
- return 0;
-}
#endif /* CONFIG_SMP */
#define b_replacement(num) "664"#num
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index fdfda1375f82..32aa1ddf441d 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -470,6 +470,13 @@ static void alternatives_smp_unlock(const s32 *start, const s32 *end,
}
}
+static bool uniproc_patched; /* protected by text_mutex */
+#else /* !CONFIG_SMP */
+#define uniproc_patched false
+static inline void alternatives_smp_unlock(const s32 *start, const s32 *end,
+ u8 *text, u8 *text_end) { }
+#endif /* CONFIG_SMP */
+
struct smp_alt_module {
/* what is this ??? */
struct module *mod;
@@ -486,7 +493,6 @@ struct smp_alt_module {
struct list_head next;
};
static LIST_HEAD(smp_alt_modules);
-static bool uniproc_patched = false; /* protected by text_mutex */
void __init_or_module alternatives_smp_module_add(struct module *mod,
char *name,
@@ -495,23 +501,27 @@ void __init_or_module alternatives_smp_module_add(struct module *mod,
{
struct smp_alt_module *smp;
- mutex_lock(&text_mutex);
+#ifdef CONFIG_SMP
+ /* Patch to UP if other cpus not imminent. */
+ if (!noreplace_smp && (num_present_cpus() == 1 || setup_max_cpus <= 1))
+ uniproc_patched = true;
+#endif
if (!uniproc_patched)
- goto unlock;
+ return;
- if (num_possible_cpus() == 1)
- /* Don't bother remembering, we'll never have to undo it. */
- goto smp_unlock;
+ mutex_lock(&text_mutex);
- smp = kzalloc(sizeof(*smp), GFP_KERNEL);
- if (NULL == smp)
- /* we'll run the (safe but slow) SMP code then ... */
- goto unlock;
+ smp = kzalloc(sizeof(*smp), GFP_KERNEL | __GFP_NOFAIL);
smp->mod = mod;
smp->name = name;
- smp->locks = locks;
- smp->locks_end = locks_end;
+
+ if (num_possible_cpus() != 1 || uniproc_patched) {
+ /* Remember only if we'll need to undo it. */
+ smp->locks = locks;
+ smp->locks_end = locks_end;
+ }
+
smp->text = text;
smp->text_end = text_end;
DPRINTK("locks %p -> %p, text %p -> %p, name %s\n",
@@ -519,9 +529,9 @@ void __init_or_module alternatives_smp_module_add(struct module *mod,
smp->text, smp->text_end, smp->name);
list_add_tail(&smp->next, &smp_alt_modules);
-smp_unlock:
- alternatives_smp_unlock(locks, locks_end, text, text_end);
-unlock:
+
+ if (uniproc_patched)
+ alternatives_smp_unlock(locks, locks_end, text, text_end);
mutex_unlock(&text_mutex);
}
@@ -540,6 +550,7 @@ void __init_or_module alternatives_smp_module_del(struct module *mod)
mutex_unlock(&text_mutex);
}
+#ifdef CONFIG_SMP
void alternatives_enable_smp(void)
{
struct smp_alt_module *mod;
@@ -561,6 +572,7 @@ void alternatives_enable_smp(void)
}
mutex_unlock(&text_mutex);
}
+#endif /* CONFIG_SMP */
/*
* Return 1 if the address range is reserved for SMP-alternatives.
@@ -588,7 +600,6 @@ int alternatives_text_reserved(void *start, void *end)
return 0;
}
-#endif /* CONFIG_SMP */
#ifdef CONFIG_PARAVIRT
void __init_or_module apply_paravirt(struct paravirt_patch_site *start,
@@ -723,21 +734,15 @@ void __init alternative_instructions(void)
apply_alternatives(__alt_instructions, __alt_instructions_end);
-#ifdef CONFIG_SMP
- /* Patch to UP if other cpus not imminent. */
- if (!noreplace_smp && (num_present_cpus() == 1 || setup_max_cpus <= 1)) {
- uniproc_patched = true;
- alternatives_smp_module_add(NULL, "core kernel",
- __smp_locks, __smp_locks_end,
- _text, _etext);
- }
+ alternatives_smp_module_add(NULL, "core kernel",
+ __smp_locks, __smp_locks_end,
+ _text, _etext);
if (!uniproc_patched || num_possible_cpus() == 1) {
free_init_pages("SMP alternatives",
(unsigned long)__smp_locks,
(unsigned long)__smp_locks_end);
}
-#endif
apply_paravirt(__parainstructions, __parainstructions_end);
apply_paravirt(__parainstructions_runtime,
--
2.20.1
