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    Subject[PATCH 9/9] jump label: Add MIPS support.
    From: David Daney <ddaney@caviumnetworks.com>

    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).

    Cc: Jason Baron <jbaron@redhat.com>
    Acked-by: Ralf Baechle <ralf@linux-mips.org>
    Signed-off-by: David Daney <ddaney@caviumnetworks.com>
    LKML-Reference: <1286218615-24011-3-git-send-email-ddaney@caviumnetworks.com>
    Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
    ---
    arch/mips/Kconfig | 1 +
    arch/mips/include/asm/jump_label.h | 48 ++++++++++++++++++++++++++++++++++
    arch/mips/kernel/Makefile | 3 +-
    arch/mips/kernel/jump_label.c | 50 ++++++++++++++++++++++++++++++++++++
    arch/mips/kernel/module.c | 5 +++
    5 files changed, 106 insertions(+), 1 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 5526faa..9429df3 100644
    --- a/arch/mips/Kconfig
    +++ b/arch/mips/Kconfig
    @@ -12,6 +12,7 @@ config MIPS
    select HAVE_FUNCTION_GRAPH_TRACER
    select HAVE_KPROBES
    select HAVE_KRETPROBES
    + select HAVE_ARCH_JUMP_LABEL
    select RTC_LIB if !MACH_LOONGSON
    select GENERIC_ATOMIC64 if !64BIT

    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 06f8482..db4feb9 100644
    --- a/arch/mips/kernel/Makefile
    +++ b/arch/mips/kernel/Makefile
    @@ -6,7 +6,8 @@ extra-y := head.o init_task.o vmlinux.lds

    obj-y += cpu-probe.o branch.o entry.o genex.o irq.o process.o \
    ptrace.o reset.o setup.o signal.o syscall.o \
    - time.o topology.o traps.o unaligned.o watch.o vdso.o
    + time.o topology.o traps.o unaligned.o watch.o vdso.o \
    + jump_label.o

    ifdef CONFIG_FUNCTION_TRACER
    CFLAGS_REMOVE_ftrace.o = -pg
    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)
    --
    1.7.1



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