Merge tag 'locking-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "This was a fairly quiet cycle for the locking subsystem:

   - lockdep: Fix a handful of the more complex lockdep_init_map_*()
     primitives that can lose the lock_type & cause false reports. No
     such mishap was observed in the wild.

   - jump_label improvements: simplify the cross-arch support of initial
     NOP patching by making it arch-specific code (used on MIPS only),
     and remove the s390 initial NOP patching that was superfluous"

* tag 'locking-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Fix lockdep_init_map_*() confusion
  jump_label: make initial NOP patching the special case
  jump_label: mips: move module NOP patching into arch code
  jump_label: s390: avoid pointless initial NOP patching

14 files changed, 31 insertions, 101 deletions

diff --git a/arch/arc/kernel/jump_label.c b/arch/arc/kernel/jump_label.c
index b8600dc325b5..70b74a5d047b 100644
--- a/arch/arc/kernel/jump_label.c
+++ b/arch/arc/kernel/jump_label.c
@@ -96,19 +96,6 @@ void arch_jump_label_transform(struct jump_entry *entry,
 	flush_icache_range(entry->code, entry->code + JUMP_LABEL_NOP_SIZE);
 }
 
-void arch_jump_label_transform_static(struct jump_entry *entry,
-				      enum jump_label_type type)
-{
-	/*
-	 * We use only one NOP type (1x, 4 byte) in arch_static_branch, so
-	 * there's no need to patch an identical NOP over the top of it here.
-	 * The generic code calls 'arch_jump_label_transform' if the NOP needs
-	 * to be replaced by a branch, so 'arch_jump_label_transform_static' is
-	 * never called with type other than JUMP_LABEL_NOP.
-	 */
-	BUG_ON(type != JUMP_LABEL_NOP);
-}
-
 #ifdef CONFIG_ARC_DBG_JUMP_LABEL
 #define SELFTEST_MSG	"ARC: instruction generation self-test: "
 
diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c
index 303b3ab87f7e..eb9c24b6e8e2 100644
--- a/arch/arm/kernel/jump_label.c
+++ b/arch/arm/kernel/jump_label.c
@@ -27,9 +27,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
 {
 	__arch_jump_label_transform(entry, type, false);
 }
-
-void arch_jump_label_transform_static(struct jump_entry *entry,
-				      enum jump_label_type type)
-{
-	__arch_jump_label_transform(entry, type, true);
-}
diff --git a/arch/arm64/kernel/jump_label.c b/arch/arm64/kernel/jump_label.c
index fc98037e1220..faf88ec9c48e 100644
--- a/arch/arm64/kernel/jump_label.c
+++ b/arch/arm64/kernel/jump_label.c
@@ -26,14 +26,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
 
 	aarch64_insn_patch_text_nosync(addr, insn);
 }
-
-void arch_jump_label_transform_static(struct jump_entry *entry,
-				      enum jump_label_type type)
-{
-	/*
-	 * We use the architected A64 NOP in arch_static_branch, so there's no
-	 * need to patch an identical A64 NOP over the top of it here. The core
-	 * will call arch_jump_label_transform from a module notifier if the
-	 * NOP needs to be replaced by a branch.
-	 */
-}
diff --git a/arch/mips/include/asm/jump_label.h b/arch/mips/include/asm/jump_label.h
index 3185fd3220ec..c5c6864e64bc 100644
--- a/arch/mips/include/asm/jump_label.h
+++ b/arch/mips/include/asm/jump_label.h
@@ -8,6 +8,8 @@
 #ifndef _ASM_MIPS_JUMP_LABEL_H
 #define _ASM_MIPS_JUMP_LABEL_H
 
+#define arch_jump_label_transform_static arch_jump_label_transform
+
 #ifndef __ASSEMBLY__
 
 #include <linux/types.h>
diff --git a/arch/mips/kernel/jump_label.c b/arch/mips/kernel/jump_label.c
index 662c8db9f45b..71a882c8c6eb 100644
--- a/arch/mips/kernel/jump_label.c
+++ b/arch/mips/kernel/jump_label.c
@@ -88,3 +88,22 @@ void arch_jump_label_transform(struct jump_entry *e,
 
 	mutex_unlock(&text_mutex);
 }
+
+#ifdef CONFIG_MODULES
+void jump_label_apply_nops(struct module *mod)
+{
+	struct jump_entry *iter_start = mod->jump_entries;
+	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
+	struct jump_entry *iter;
+
+	/* if the module doesn't have jump label entries, just return */
+	if (iter_start == iter_stop)
+		return;
+
+	for (iter = iter_start; iter < iter_stop; iter++) {
+		/* Only write NOPs for arch_branch_static(). */
+		if (jump_label_init_type(iter) == JUMP_LABEL_NOP)
+			arch_jump_label_transform(iter, JUMP_LABEL_NOP);
+	}
+}
+#endif
diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
index 14f46d17500a..0c936cbf20c5 100644
--- a/arch/mips/kernel/module.c
+++ b/arch/mips/kernel/module.c
@@ -21,6 +21,7 @@
 #include <linux/spinlock.h>
 #include <linux/jump_label.h>
 
+extern void jump_label_apply_nops(struct module *mod);
 
 struct mips_hi16 {
 	struct mips_hi16 *next;
@@ -428,8 +429,8 @@ int module_finalize(const Elf_Ehdr *hdr,
 	const Elf_Shdr *s;
 	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 
-	/* Make jump label nops. */
-	jump_label_apply_nops(me);
+	if (IS_ENABLED(CONFIG_JUMP_LABEL))
+		jump_label_apply_nops(me);
 
 	INIT_LIST_HEAD(&me->arch.dbe_list);
 	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
diff --git a/arch/parisc/kernel/jump_label.c b/arch/parisc/kernel/jump_label.c
index d2f3cb12e282..e253b134500d 100644
--- a/arch/parisc/kernel/jump_label.c
+++ b/arch/parisc/kernel/jump_label.c
@@ -42,14 +42,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
 
 	patch_text(addr, insn);
 }
-
-void arch_jump_label_transform_static(struct jump_entry *entry,
-				      enum jump_label_type type)
-{
-	/*
-	 * We use the architected NOP in arch_static_branch, so there's no
-	 * need to patch an identical NOP over the top of it here. The core
-	 * will call arch_jump_label_transform from a module notifier if the
-	 * NOP needs to be replaced by a branch.
-	 */
-}
diff --git a/arch/riscv/kernel/jump_label.c b/arch/riscv/kernel/jump_label.c
index 20e09056d141..e6694759dbd0 100644
--- a/arch/riscv/kernel/jump_label.c
+++ b/arch/riscv/kernel/jump_label.c
@@ -39,15 +39,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
 	patch_text_nosync(addr, &insn, sizeof(insn));
 	mutex_unlock(&text_mutex);
 }
-
-void arch_jump_label_transform_static(struct jump_entry *entry,
-				      enum jump_label_type type)
-{
-	/*
-	 * We use the same instructions in the arch_static_branch and
-	 * arch_static_branch_jump inline functions, so there's no
-	 * need to patch them up here.
-	 * The core will call arch_jump_label_transform  when those
-	 * instructions need to be replaced.
-	 */
-}
diff --git a/arch/s390/include/asm/jump_label.h b/arch/s390/include/asm/jump_label.h
index 916cfcb36d8a..895f774bbcc5 100644
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -10,7 +10,6 @@
 #include <linux/stringify.h>
 
 #define JUMP_LABEL_NOP_SIZE 6
-#define JUMP_LABEL_NOP_OFFSET 2
 
 #ifdef CONFIG_CC_IS_CLANG
 #define JUMP_LABEL_STATIC_KEY_CONSTRAINT "i"
@@ -21,12 +20,12 @@
 #endif
 
 /*
- * We use a brcl 0,2 instruction for jump labels at compile time so it
+ * We use a brcl 0,<offset> instruction for jump labels so it
  * can be easily distinguished from a hotpatch generated instruction.
  */
 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
 {
-	asm_volatile_goto("0:	brcl	0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"
+	asm_volatile_goto("0:	brcl 0,%l[label]\n"
 			  ".pushsection __jump_table,\"aw\"\n"
 			  ".balign	8\n"
 			  ".long	0b-.,%l[label]-.\n"
diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c
index 6bec000c6c1c..e808bb8bc0da 100644
--- a/arch/s390/kernel/jump_label.c
+++ b/arch/s390/kernel/jump_label.c
@@ -44,14 +44,8 @@ static void jump_label_bug(struct jump_entry *entry, struct insn *expected,
 	panic("Corrupted kernel text");
 }
 
-static struct insn orignop = {
-	.opcode = 0xc004,
-	.offset = JUMP_LABEL_NOP_OFFSET >> 1,
-};
-
 static void jump_label_transform(struct jump_entry *entry,
-				 enum jump_label_type type,
-				 int init)
+				 enum jump_label_type type)
 {
 	void *code = (void *)jump_entry_code(entry);
 	struct insn old, new;
@@ -63,27 +57,22 @@ static void jump_label_transform(struct jump_entry *entry,
 		jump_label_make_branch(entry, &old);
 		jump_label_make_nop(entry, &new);
 	}
-	if (init) {
-		if (memcmp(code, &orignop, sizeof(orignop)))
-			jump_label_bug(entry, &orignop, &new);
-	} else {
-		if (memcmp(code, &old, sizeof(old)))
-			jump_label_bug(entry, &old, &new);
-	}
+	if (memcmp(code, &old, sizeof(old)))
+		jump_label_bug(entry, &old, &new);
 	s390_kernel_write(code, &new, sizeof(new));
 }
 
 void arch_jump_label_transform(struct jump_entry *entry,
 			       enum jump_label_type type)
 {
-	jump_label_transform(entry, type, 0);
+	jump_label_transform(entry, type);
 	text_poke_sync();
 }
 
 bool arch_jump_label_transform_queue(struct jump_entry *entry,
 				     enum jump_label_type type)
 {
-	jump_label_transform(entry, type, 0);
+	jump_label_transform(entry, type);
 	return true;
 }
 
@@ -91,10 +80,3 @@ void arch_jump_label_transform_apply(void)
 {
 	text_poke_sync();
 }
-
-void __init_or_module arch_jump_label_transform_static(struct jump_entry *entry,
-						       enum jump_label_type type)
-{
-	jump_label_transform(entry, type, 1);
-	text_poke_sync();
-}
diff --git a/arch/s390/kernel/module.c b/arch/s390/kernel/module.c
index 26125a9c436d..2d159b32885b 100644
--- a/arch/s390/kernel/module.c
+++ b/arch/s390/kernel/module.c
@@ -548,6 +548,5 @@ int module_finalize(const Elf_Ehdr *hdr,
 #endif /* CONFIG_FUNCTION_TRACER */
 	}
 
-	jump_label_apply_nops(me);
 	return 0;
 }
diff --git a/arch/sparc/kernel/module.c b/arch/sparc/kernel/module.c
index df39580f398d..66c45a2764bc 100644
--- a/arch/sparc/kernel/module.c
+++ b/arch/sparc/kernel/module.c
@@ -208,9 +208,6 @@ int module_finalize(const Elf_Ehdr *hdr,
 		    const Elf_Shdr *sechdrs,
 		    struct module *me)
 {
-	/* make jump label nops */
-	jump_label_apply_nops(me);
-
 	do_patch_sections(hdr, sechdrs);
 
 	/* Cheetah's I-cache is fully coherent.  */
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index 68f091ba8443..f5b8ef02d172 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -146,16 +146,3 @@ void arch_jump_label_transform_apply(void)
 	text_poke_finish();
 	mutex_unlock(&text_mutex);
 }
-
-static enum {
-	JL_STATE_START,
-	JL_STATE_NO_UPDATE,
-	JL_STATE_UPDATE,
-} jlstate __initdata_or_module = JL_STATE_START;
-
-__init_or_module void arch_jump_label_transform_static(struct jump_entry *entry,
-				      enum jump_label_type type)
-{
-	if (jlstate == JL_STATE_UPDATE)
-		jump_label_transform(entry, type, 1);
-}
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 67828d973389..b1abf663417c 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -310,9 +310,6 @@ int module_finalize(const Elf_Ehdr *hdr,
 					    tseg, tseg + text->sh_size);
 	}
 
-	/* make jump label nops */
-	jump_label_apply_nops(me);
-
 	if (orc && orc_ip)
 		unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
 				   (void *)orc->sh_addr, orc->sh_size);