When in Rome...
In order not to be left behind, we add jump label support for MIPS.
Tested on 64-bit big endian (Octeon), and 32-bit little endian
(malta/qemu).
Signed-off-by: David Daney <ddaney@xxxxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
---
Now that the core jump label support has been merged, this patch
easily go via Ralf's tree.
The only changes from v2 are Makefile and Kconfig improvements.
arch/mips/Kconfig | 1 +
arch/mips/include/asm/jump_label.h | 48 ++++++++++++++++++++++++++++++++++
arch/mips/kernel/Makefile | 2 +
arch/mips/kernel/jump_label.c | 50 ++++++++++++++++++++++++++++++++++++
arch/mips/kernel/module.c | 5 +++
5 files changed, 106 insertions(+), 0 deletions(-)
create mode 100644 arch/mips/include/asm/jump_label.h
create mode 100644 arch/mips/kernel/jump_label.c
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 7fc6bd1..4419e83 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -21,6 +21,7 @@ config MIPS
select HAVE_DMA_API_DEBUG
select HAVE_GENERIC_HARDIRQS
select GENERIC_IRQ_PROBE
+ select HAVE_ARCH_JUMP_LABEL
menu "Machine selection"
diff --git a/arch/mips/include/asm/jump_label.h b/arch/mips/include/asm/jump_label.h
new file mode 100644
index 0000000..7622ccf
--- /dev/null
+++ b/arch/mips/include/asm/jump_label.h
@@ -0,0 +1,48 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2010 Cavium Networks, Inc.
+ */
+#ifndef _ASM_MIPS_JUMP_LABEL_H
+#define _ASM_MIPS_JUMP_LABEL_H
+
+#include <linux/types.h>
+
+#ifdef __KERNEL__
+
+#define JUMP_LABEL_NOP_SIZE 4
+
+#ifdef CONFIG_64BIT
+#define WORD_INSN ".dword"
+#else
+#define WORD_INSN ".word"
+#endif
+
+#define JUMP_LABEL(key, label) \
+ do { \
+ asm goto("1:\tnop\n\t" \
+ "nop\n\t" \
+ ".pushsection __jump_table, \"a\"\n\t" \
+ WORD_INSN " 1b, %l[" #label "], %0\n\t" \
+ ".popsection\n\t" \
+ : : "i" (key) : : label); \
+ } while (0)
+
+
+#endif /* __KERNEL__ */
+
+#ifdef CONFIG_64BIT
+typedef u64 jump_label_t;
+#else
+typedef u32 jump_label_t;
+#endif
+
+struct jump_entry {
+ jump_label_t code;
+ jump_label_t target;
+ jump_label_t key;
+};
+
+#endif /* _ASM_MIPS_JUMP_LABEL_H */
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 22b2e0e..35ce5a5 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -106,4 +106,6 @@ obj-$(CONFIG_MIPS_CPUFREQ) += cpufreq/
obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o
+obj-$(CONFIG_JUMP_LABEL) += jump_label.o
+
CPPFLAGS_vmlinux.lds := $(KBUILD_CFLAGS)
diff --git a/arch/mips/kernel/jump_label.c b/arch/mips/kernel/jump_label.c
new file mode 100644
index 0000000..52d3c70
--- /dev/null
+++ b/arch/mips/kernel/jump_label.c
@@ -0,0 +1,50 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2010 Cavium Networks, Inc.
+ */
+
+#include <linux/jump_label.h>
+#include <linux/kernel.h>
+#include <linux/memory.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/cpu.h>
+
+#include <asm/cacheflush.h>
+#include <asm/inst.h>
+
+#define J_RANGE_MASK ((1ul << 28) - 1)
+
+void arch_jump_label_transform(struct jump_entry *e,
+ enum jump_label_type type)
+{
+ union mips_instruction insn;
+ union mips_instruction *insn_p =
+ (union mips_instruction *)(unsigned long)e->code;
+
+ /* Jump only works within a 256MB aligned region. */
+ BUG_ON((e->target & ~J_RANGE_MASK) != (e->code & ~J_RANGE_MASK));
+
+ /* Target must have 4 byte alignment. */
+ BUG_ON((e->target & 3) != 0);
+
+ if (type == JUMP_LABEL_ENABLE) {
+ insn.j_format.opcode = j_op;
+ insn.j_format.target = (e->target & J_RANGE_MASK) >> 2;
+ } else {
+ insn.word = 0; /* nop */
+ }
+
+ get_online_cpus();
+ mutex_lock(&text_mutex);
+ *insn_p = insn;
+
+ flush_icache_range((unsigned long)insn_p,
+ (unsigned long)insn_p + sizeof(*insn_p));
+
+ mutex_unlock(&text_mutex);
+ put_online_cpus();
+}
diff --git a/arch/mips/kernel/module.c b/arch/mips/kernel/module.c
index 6f51dda..bb9cde4 100644
--- a/arch/mips/kernel/module.c
+++ b/arch/mips/kernel/module.c
@@ -30,6 +30,8 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spinlock.h>
+#include <linux/jump_label.h>
+
#include <asm/pgtable.h> /* MODULE_START */
struct mips_hi16 {
@@ -390,6 +392,9 @@ 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);
+
INIT_LIST_HEAD(&me->arch.dbe_list);
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)
--
1.7.2.3
