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Message-Id: <20220730151020.3175975-1-guoren@kernel.org>
Date: Sat, 30 Jul 2022 11:10:20 -0400
From: guoren@...nel.org
To: guoren@...nel.org, arnd@...db.de
Cc: linux-csky@...r.kernel.org, linux-arch@...r.kernel.org,
linux-kernel@...r.kernel.org, Guo Ren <guoren@...ux.alibaba.com>
Subject: [PATCH] csky: Add jump-label implementation
From: Guo Ren <guoren@...ux.alibaba.com>
Add jump-label implementation for static branch
Signed-off-by: Guo Ren <guoren@...ux.alibaba.com>
Signed-off-by: Guo Ren <guoren@...nel.org>
---
arch/csky/Kconfig | 2 ++
arch/csky/include/asm/jump_label.h | 47 ++++++++++++++++++++++++++
arch/csky/kernel/Makefile | 1 +
arch/csky/kernel/jump_label.c | 54 ++++++++++++++++++++++++++++++
4 files changed, 104 insertions(+)
create mode 100644 arch/csky/include/asm/jump_label.h
create mode 100644 arch/csky/kernel/jump_label.c
diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 21d72b078eef..41d7d614f7a2 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -40,6 +40,8 @@ config CSKY
select GX6605S_TIMER if CPU_CK610
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_AUDITSYSCALL
+ select HAVE_ARCH_JUMP_LABEL if !CPU_CK610
+ select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_CONTEXT_TRACKING
diff --git a/arch/csky/include/asm/jump_label.h b/arch/csky/include/asm/jump_label.h
new file mode 100644
index 000000000000..d488ba6084bc
--- /dev/null
+++ b/arch/csky/include/asm/jump_label.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __ASM_CSKY_JUMP_LABEL_H
+#define __ASM_CSKY_JUMP_LABEL_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+
+#define JUMP_LABEL_NOP_SIZE 4
+
+static __always_inline bool arch_static_branch(struct static_key *key,
+ bool branch)
+{
+ asm_volatile_goto(
+ "1: nop32 \n"
+ " .pushsection __jump_table, \"aw\" \n"
+ " .align 2 \n"
+ " .long 1b - ., %l[label] - . \n"
+ " .long %0 - . \n"
+ " .popsection \n"
+ : : "i"(&((char *)key)[branch]) : : label);
+
+ return false;
+label:
+ return true;
+}
+
+static __always_inline bool arch_static_branch_jump(struct static_key *key,
+ bool branch)
+{
+ asm_volatile_goto(
+ "1: bsr32 %l[label] \n"
+ " .pushsection __jump_table, \"aw\" \n"
+ " .align 2 \n"
+ " .long 1b - ., %l[label] - . \n"
+ " .long %0 - . \n"
+ " .popsection \n"
+ : : "i"(&((char *)key)[branch]) : : label);
+
+ return false;
+label:
+ return true;
+}
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_CSKY_JUMP_LABEL_H */
diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile
index 4eb41421ca5b..6f14c924b20d 100644
--- a/arch/csky/kernel/Makefile
+++ b/arch/csky/kernel/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_CSKY_PMU_V1) += perf_event.o
obj-$(CONFIG_PERF_EVENTS) += perf_callchain.o
obj-$(CONFIG_HAVE_PERF_REGS) += perf_regs.o
+obj-$(CONFIG_JUMP_LABEL) += jump_label.o
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE)
diff --git a/arch/csky/kernel/jump_label.c b/arch/csky/kernel/jump_label.c
new file mode 100644
index 000000000000..d0e8b21447e1
--- /dev/null
+++ b/arch/csky/kernel/jump_label.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/jump_label.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+#include <asm/cacheflush.h>
+
+#define NOP32_HI 0xc400
+#define NOP32_LO 0x4820
+#define BSR_LINK 0xe000
+
+void arch_jump_label_transform(struct jump_entry *entry,
+ enum jump_label_type type)
+{
+ unsigned long addr = jump_entry_code(entry);
+ u16 insn[2];
+ int ret = 0;
+
+ if (type == JUMP_LABEL_JMP) {
+ long offset = jump_entry_target(entry) - jump_entry_code(entry);
+
+ if (WARN_ON(offset & 1 || offset < -67108864 || offset >= 67108864))
+ return;
+
+ offset = offset >> 1;
+
+ insn[0] = BSR_LINK |
+ ((uint16_t)((unsigned long) offset >> 16) & 0x3ff);
+ insn[1] = (uint16_t)((unsigned long) offset & 0xffff);
+ } else {
+ insn[0] = NOP32_HI;
+ insn[1] = NOP32_LO;
+ }
+
+ ret = copy_to_kernel_nofault((void *)addr, insn, 4);
+ WARN_ON(ret);
+
+ flush_icache_range(addr, addr + 4);
+}
+
+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.
+ */
+ arch_jump_label_transform(entry, type);
+}
--
2.36.1
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