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torvaldstorvalds
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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
2 parents b167fdf + eae6d58 commit 22a39c3

19 files changed

Lines changed: 59 additions & 163 deletions

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‎Documentation/staging/static-keys.rst‎

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@@ -201,9 +201,6 @@ static_key->entry field makes use of the two least significant bits.
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* ``void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type)``,
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see: arch/x86/kernel/jump_label.c
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* ``__init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type)``,
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see: arch/x86/kernel/jump_label.c
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* ``struct jump_entry``,
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see: arch/x86/include/asm/jump_label.h
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‎arch/arc/kernel/jump_label.c‎

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@@ -96,19 +96,6 @@ void arch_jump_label_transform(struct jump_entry *entry,
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flush_icache_range(entry->code, entry->code + JUMP_LABEL_NOP_SIZE);
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}
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void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type)
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{
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/*
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* We use only one NOP type (1x, 4 byte) in arch_static_branch, so
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* there's no need to patch an identical NOP over the top of it here.
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* The generic code calls 'arch_jump_label_transform' if the NOP needs
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* to be replaced by a branch, so 'arch_jump_label_transform_static' is
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* never called with type other than JUMP_LABEL_NOP.
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*/
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BUG_ON(type != JUMP_LABEL_NOP);
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}
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#ifdef CONFIG_ARC_DBG_JUMP_LABEL
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#define SELFTEST_MSG "ARC: instruction generation self-test: "
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‎arch/arm/kernel/jump_label.c‎

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@@ -27,9 +27,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
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{
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__arch_jump_label_transform(entry, type, false);
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}
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void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type)
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{
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__arch_jump_label_transform(entry, type, true);
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}

‎arch/arm64/kernel/jump_label.c‎

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@@ -26,14 +26,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
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aarch64_insn_patch_text_nosync(addr, insn);
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}
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void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type)
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{
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/*
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* We use the architected A64 NOP in arch_static_branch, so there's no
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* need to patch an identical A64 NOP over the top of it here. The core
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* will call arch_jump_label_transform from a module notifier if the
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* NOP needs to be replaced by a branch.
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*/
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}

‎arch/mips/include/asm/jump_label.h‎

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@@ -8,6 +8,8 @@
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#ifndef _ASM_MIPS_JUMP_LABEL_H
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#define _ASM_MIPS_JUMP_LABEL_H
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#define arch_jump_label_transform_static arch_jump_label_transform
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#ifndef __ASSEMBLY__
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#include <linux/types.h>

‎arch/mips/kernel/jump_label.c‎

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@@ -88,3 +88,22 @@ void arch_jump_label_transform(struct jump_entry *e,
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mutex_unlock(&text_mutex);
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}
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#ifdef CONFIG_MODULES
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void jump_label_apply_nops(struct module *mod)
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{
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struct jump_entry *iter_start = mod->jump_entries;
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struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
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struct jump_entry *iter;
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/* if the module doesn't have jump label entries, just return */
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if (iter_start == iter_stop)
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return;
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for (iter = iter_start; iter < iter_stop; iter++) {
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/* Only write NOPs for arch_branch_static(). */
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if (jump_label_init_type(iter) == JUMP_LABEL_NOP)
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arch_jump_label_transform(iter, JUMP_LABEL_NOP);
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}
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}
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#endif

‎arch/mips/kernel/module.c‎

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@@ -21,6 +21,7 @@
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#include <linux/spinlock.h>
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#include <linux/jump_label.h>
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extern void jump_label_apply_nops(struct module *mod);
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struct mips_hi16 {
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struct mips_hi16 *next;
@@ -428,8 +429,8 @@ int module_finalize(const Elf_Ehdr *hdr,
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const Elf_Shdr *s;
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char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
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/* Make jump label nops. */
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jump_label_apply_nops(me);
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if (IS_ENABLED(CONFIG_JUMP_LABEL))
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jump_label_apply_nops(me);
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INIT_LIST_HEAD(&me->arch.dbe_list);
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for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {

‎arch/parisc/kernel/jump_label.c‎

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@@ -42,14 +42,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
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patch_text(addr, insn);
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}
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void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type)
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{
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/*
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* We use the architected NOP in arch_static_branch, so there's no
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* need to patch an identical NOP over the top of it here. The core
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* will call arch_jump_label_transform from a module notifier if the
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* NOP needs to be replaced by a branch.
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*/
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}

‎arch/riscv/kernel/jump_label.c‎

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@@ -39,15 +39,3 @@ void arch_jump_label_transform(struct jump_entry *entry,
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patch_text_nosync(addr, &insn, sizeof(insn));
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mutex_unlock(&text_mutex);
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}
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void arch_jump_label_transform_static(struct jump_entry *entry,
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enum jump_label_type type)
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{
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/*
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* We use the same instructions in the arch_static_branch and
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* arch_static_branch_jump inline functions, so there's no
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* need to patch them up here.
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* The core will call arch_jump_label_transform when those
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* instructions need to be replaced.
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*/
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}

‎arch/s390/include/asm/jump_label.h‎

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@@ -10,7 +10,6 @@
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#include <linux/stringify.h>
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#define JUMP_LABEL_NOP_SIZE 6
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#define JUMP_LABEL_NOP_OFFSET 2
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#ifdef CONFIG_CC_IS_CLANG
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#define JUMP_LABEL_STATIC_KEY_CONSTRAINT "i"
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#endif
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/*
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* We use a brcl 0,2 instruction for jump labels at compile time so it
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* We use a brcl 0,<offset> instruction for jump labels so it
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* can be easily distinguished from a hotpatch generated instruction.
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*/
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static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
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{
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asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"
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asm_volatile_goto("0: brcl 0,%l[label]\n"
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".pushsection __jump_table,\"aw\"\n"
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".balign 8\n"
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".long 0b-.,%l[label]-.\n"

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