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Message-ID: <20250806020520.570988-3-chenmiao.ku@gmail.com>
Date: Wed, 6 Aug 2025 02:05:04 +0000
From: ChenMiao <chenmiao.ku@...il.com>
To: Linux Kernel <linux-kernel@...r.kernel.org>
Cc: Linux OpenRISC <linux-openrisc@...r.kernel.org>,
chenmiao <chenmiao.ku@...il.com>,
Jonathan Corbet <corbet@....net>,
Jonas Bonn <jonas@...thpole.se>,
Stefan Kristiansson <stefan.kristiansson@...nalahti.fi>,
Stafford Horne <shorne@...il.com>,
Peter Zijlstra <peterz@...radead.org>,
Josh Poimboeuf <jpoimboe@...nel.org>,
Jason Baron <jbaron@...mai.com>,
Steven Rostedt <rostedt@...dmis.org>,
Ard Biesheuvel <ardb@...nel.org>,
Masahiro Yamada <masahiroy@...nel.org>,
Sahil Siddiq <sahilcdq0@...il.com>,
Nicolas Schier <nicolas.schier@...ux.dev>,
Johannes Berg <johannes@...solutions.net>,
linux-doc@...r.kernel.org
Subject: [PATCH v2 2/2] openrisc: Add jump label support
From: chenmiao <chenmiao.ku@...il.com>
Implemented the full functionality of jump_label, of course,
with text patching supported by just one API.
By the way, add new macro OPENRISC_INSN_NOP in insn-def.h to use.
- V2: using the patch_insn_write(void *addr, u32 insn) not the
const void *insn.
Link: https://lore.kernel.org/openrisc/aJIC8o1WmVHol9RY@antec/T/#t
Signed-off-by: chenmiao <chenmiao.ku@...il.com>
---
.../core/jump-labels/arch-support.txt | 2 +-
arch/openrisc/Kconfig | 2 +
arch/openrisc/configs/or1ksim_defconfig | 19 ++----
arch/openrisc/configs/virt_defconfig | 1 +
arch/openrisc/include/asm/insn-def.h | 3 +
arch/openrisc/include/asm/jump_label.h | 68 +++++++++++++++++++
arch/openrisc/kernel/Makefile | 1 +
arch/openrisc/kernel/jump_label.c | 53 +++++++++++++++
arch/openrisc/kernel/setup.c | 2 +
9 files changed, 138 insertions(+), 13 deletions(-)
create mode 100644 arch/openrisc/include/asm/jump_label.h
create mode 100644 arch/openrisc/kernel/jump_label.c
diff --git a/Documentation/features/core/jump-labels/arch-support.txt b/Documentation/features/core/jump-labels/arch-support.txt
index ccada815569f..683de7c15058 100644
--- a/Documentation/features/core/jump-labels/arch-support.txt
+++ b/Documentation/features/core/jump-labels/arch-support.txt
@@ -17,7 +17,7 @@
| microblaze: | TODO |
| mips: | ok |
| nios2: | TODO |
- | openrisc: | TODO |
+ | openrisc: | ok |
| parisc: | ok |
| powerpc: | ok |
| riscv: | ok |
diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
index b38fee299bc4..9156635dd264 100644
--- a/arch/openrisc/Kconfig
+++ b/arch/openrisc/Kconfig
@@ -24,6 +24,8 @@ config OPENRISC
select GENERIC_PCI_IOMAP
select GENERIC_IOREMAP
select GENERIC_CPU_DEVICES
+ select HAVE_ARCH_JUMP_LABEL
+ select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_PCI
select HAVE_UID16
select HAVE_PAGE_SIZE_8KB
diff --git a/arch/openrisc/configs/or1ksim_defconfig b/arch/openrisc/configs/or1ksim_defconfig
index 59fe33cefba2..769705ac24d5 100644
--- a/arch/openrisc/configs/or1ksim_defconfig
+++ b/arch/openrisc/configs/or1ksim_defconfig
@@ -3,26 +3,23 @@ CONFIG_LOG_BUF_SHIFT=14
CONFIG_BLK_DEV_INITRD=y
# CONFIG_RD_GZIP is not set
CONFIG_EXPERT=y
-# CONFIG_KALLSYMS is not set
# CONFIG_EPOLL is not set
# CONFIG_TIMERFD is not set
# CONFIG_EVENTFD is not set
# CONFIG_AIO is not set
-# CONFIG_VM_EVENT_COUNTERS is not set
-# CONFIG_COMPAT_BRK is not set
-CONFIG_SLUB=y
-CONFIG_SLUB_TINY=y
-CONFIG_MODULES=y
-# CONFIG_BLOCK is not set
+# CONFIG_KALLSYMS is not set
CONFIG_BUILTIN_DTB_NAME="or1ksim"
CONFIG_HZ_100=y
+CONFIG_JUMP_LABEL=y
+CONFIG_MODULES=y
+# CONFIG_BLOCK is not set
+CONFIG_SLUB_TINY=y
+# CONFIG_COMPAT_BRK is not set
+# CONFIG_VM_EVENT_COUNTERS is not set
CONFIG_NET=y
CONFIG_PACKET=y
CONFIG_UNIX=y
CONFIG_INET=y
-# CONFIG_INET_XFRM_MODE_TRANSPORT is not set
-# CONFIG_INET_XFRM_MODE_TUNNEL is not set
-# CONFIG_INET_XFRM_MODE_BEET is not set
# CONFIG_INET_DIAG is not set
CONFIG_TCP_CONG_ADVANCED=y
# CONFIG_TCP_CONG_BIC is not set
@@ -35,7 +32,6 @@ CONFIG_DEVTMPFS=y
CONFIG_DEVTMPFS_MOUNT=y
# CONFIG_PREVENT_FIRMWARE_BUILD is not set
# CONFIG_FW_LOADER is not set
-CONFIG_PROC_DEVICETREE=y
CONFIG_NETDEVICES=y
CONFIG_ETHOC=y
CONFIG_MICREL_PHY=y
@@ -53,4 +49,3 @@ CONFIG_SERIAL_OF_PLATFORM=y
# CONFIG_DNOTIFY is not set
CONFIG_TMPFS=y
CONFIG_NFS_FS=y
-# CONFIG_ENABLE_MUST_CHECK is not set
diff --git a/arch/openrisc/configs/virt_defconfig b/arch/openrisc/configs/virt_defconfig
index c1b69166c500..4a80c5794877 100644
--- a/arch/openrisc/configs/virt_defconfig
+++ b/arch/openrisc/configs/virt_defconfig
@@ -12,6 +12,7 @@ CONFIG_NR_CPUS=8
CONFIG_SMP=y
CONFIG_HZ_100=y
# CONFIG_OPENRISC_NO_SPR_SR_DSX is not set
+CONFIG_JUMP_LABEL=y
# CONFIG_COMPAT_BRK is not set
CONFIG_NET=y
CONFIG_PACKET=y
diff --git a/arch/openrisc/include/asm/insn-def.h b/arch/openrisc/include/asm/insn-def.h
index dc8d16db1579..2ccdbb37c27c 100644
--- a/arch/openrisc/include/asm/insn-def.h
+++ b/arch/openrisc/include/asm/insn-def.h
@@ -9,4 +9,7 @@
/* or1k instructions are always 32 bits. */
#define OPENRISC_INSN_SIZE 4
+/* or1k nop instruction code */
+#define OPENRISC_INSN_NOP 0x15000000U
+
#endif /* __ASM_INSN_DEF_H */
diff --git a/arch/openrisc/include/asm/jump_label.h b/arch/openrisc/include/asm/jump_label.h
new file mode 100644
index 000000000000..03afca9c3a1f
--- /dev/null
+++ b/arch/openrisc/include/asm/jump_label.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2025 Chen Miao
+ *
+ * Based on arch/arm/include/asm/jump_label.h
+ */
+#ifndef __ASM_JUMP_LABEL_H
+#define __ASM_JUMP_LABEL_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <asm/insn-def.h>
+
+#define HAVE_JUMP_LABEL_BATCH
+
+#define JUMP_LABEL_NOP_SIZE OPENRISC_INSN_SIZE
+
+/*
+ * should aligned 4
+ * for jump_label relative
+ * entry.code = nop.addr - . -> return false
+ * entry.target = l_yes - . -> return true
+ * entry.key = key - .
+ */
+#define JUMP_TABLE_ENTRY(key, label) \
+ ".pushsection __jump_table, \"aw\" \n\t" \
+ ".align 4 \n\t" \
+ ".long 1b - ., " label " - . \n\t" \
+ ".long " key " - . \n\t" \
+ ".popsection \n\t"
+
+#define ARCH_STATIC_BRANCH_ASM(key, label) \
+ ".align 4 \n\t" \
+ "1: l.nop \n\t" \
+ " l.nop \n\t" \
+ JUMP_TABLE_ENTRY(key, label)
+
+static __always_inline bool arch_static_branch(struct static_key *const key,
+ const bool branch)
+{
+ asm goto (ARCH_STATIC_BRANCH_ASM("%0", "%l[l_yes]")
+ ::"i"(&((char *)key)[branch])::l_yes);
+
+ return false;
+l_yes:
+ return true;
+}
+
+#define ARCH_STATIC_BRANCH_JUMP_ASM(key, label) \
+ ".align 4 \n\t" \
+ "1: l.j " label " \n\t" \
+ " l.nop \n\t" \
+ JUMP_TABLE_ENTRY(key, label)
+
+static __always_inline bool
+arch_static_branch_jump(struct static_key *const key, const bool branch)
+{
+ asm goto (ARCH_STATIC_BRANCH_JUMP_ASM("%0", "%l[l_yes]")
+ ::"i"(&((char *)key)[branch])::l_yes);
+
+ return false;
+l_yes:
+ return true;
+}
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_JUMP_LABEL_H */
diff --git a/arch/openrisc/kernel/Makefile b/arch/openrisc/kernel/Makefile
index f0957ce16d6b..19e0eb94f2eb 100644
--- a/arch/openrisc/kernel/Makefile
+++ b/arch/openrisc/kernel/Makefile
@@ -9,6 +9,7 @@ obj-y := head.o setup.o or32_ksyms.o process.o dma.o \
traps.o time.o irq.o entry.o ptrace.o signal.o \
sys_call_table.o unwinder.o cacheinfo.o
+obj-$(CONFIG_JUMP_LABEL) += jump_label.o
obj-$(CONFIG_SMP) += smp.o sync-timer.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_MODULES) += module.o
diff --git a/arch/openrisc/kernel/jump_label.c b/arch/openrisc/kernel/jump_label.c
new file mode 100644
index 000000000000..ce259ba30258
--- /dev/null
+++ b/arch/openrisc/kernel/jump_label.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 Chen Miao
+ *
+ * Based on arch/arm/kernel/jump_label.c
+ */
+#include <linux/jump_label.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <asm/bug.h>
+#include <asm/cacheflush.h>
+#include <asm/text-patching.h>
+
+bool arch_jump_label_transform_queue(struct jump_entry *entry,
+ enum jump_label_type type)
+{
+ void *addr = (void *)jump_entry_code(entry);
+ u32 insn;
+
+ if (type == JUMP_LABEL_JMP) {
+ long offset;
+
+ offset = jump_entry_target(entry) - jump_entry_code(entry);
+ /*
+ * The actual maximum range of the l.j instruction's offset is -134,217,728
+ * ~ 134,217,724 (sign 26-bit imm).
+ * For the original jump range, we need to right-shift N by 2 to obtain the
+ * instruction's offset.
+ */
+ if (unlikely(offset < -134217728 || offset > 134217724)) {
+ WARN_ON_ONCE(true);
+ }
+ /* 26bit imm mask */
+ offset = (offset >> 2) & 0x03ffffff;
+
+ insn = offset;
+ } else {
+ insn = OPENRISC_INSN_NOP;
+ }
+
+ if (early_boot_irqs_disabled) {
+ copy_to_kernel_nofault(addr, &insn, sizeof(insn));
+ } else {
+ patch_insn_write(addr, insn);
+ }
+ return true;
+}
+
+void arch_jump_label_transform_apply(void)
+{
+ // flush
+ kick_all_cpus_sync();
+}
diff --git a/arch/openrisc/kernel/setup.c b/arch/openrisc/kernel/setup.c
index a9fb9cc6779e..000a9cc10e6f 100644
--- a/arch/openrisc/kernel/setup.c
+++ b/arch/openrisc/kernel/setup.c
@@ -249,6 +249,8 @@ void __init setup_arch(char **cmdline_p)
initrd_below_start_ok = 1;
}
#endif
+ /* perform jump_table sorting before paging_init locks down read only memory */
+ jump_label_init();
/* paging_init() sets up the MMU and marks all pages as reserved */
paging_init();
--
2.45.2
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