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-rw-r--r--arch/mips/kernel/jump_label.c109
1 files changed, 109 insertions, 0 deletions
diff --git a/arch/mips/kernel/jump_label.c b/arch/mips/kernel/jump_label.c
new file mode 100644
index 000000000..f7978d50a
--- /dev/null
+++ b/arch/mips/kernel/jump_label.c
@@ -0,0 +1,109 @@
+/*
+ * 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 parameters for the standard MIPS and the microMIPS jump
+ * instruction encoding respectively:
+ *
+ * - the ISA bit of the target, either 0 or 1 respectively,
+ *
+ * - the amount the jump target address is shifted right to fit in the
+ * immediate field of the machine instruction, either 2 or 1,
+ *
+ * - the mask determining the size of the jump region relative to the
+ * delay-slot instruction, either 256MB or 128MB,
+ *
+ * - the jump target alignment, either 4 or 2 bytes.
+ */
+#define J_ISA_BIT IS_ENABLED(CONFIG_CPU_MICROMIPS)
+#define J_RANGE_SHIFT (2 - J_ISA_BIT)
+#define J_RANGE_MASK ((1ul << (26 + J_RANGE_SHIFT)) - 1)
+#define J_ALIGN_MASK ((1ul << J_RANGE_SHIFT) - 1)
+
+void arch_jump_label_transform(struct jump_entry *e,
+ enum jump_label_type type)
+{
+ union mips_instruction *insn_p;
+ union mips_instruction insn;
+ long offset;
+
+ insn_p = (union mips_instruction *)msk_isa16_mode(e->code);
+
+ /* Target must have the right alignment and ISA must be preserved. */
+ BUG_ON((e->target & J_ALIGN_MASK) != J_ISA_BIT);
+
+ if (type == JUMP_LABEL_JMP) {
+ if (!IS_ENABLED(CONFIG_CPU_MICROMIPS) && MIPS_ISA_REV >= 6) {
+ offset = e->target - ((unsigned long)insn_p + 4);
+ offset >>= 2;
+
+ /*
+ * The branch offset must fit in the instruction's 26
+ * bit field.
+ */
+ WARN_ON((offset >= (long)BIT(25)) ||
+ (offset < -(long)BIT(25)));
+
+ insn.j_format.opcode = bc6_op;
+ insn.j_format.target = offset;
+ } else {
+ /*
+ * Jump only works within an aligned region its delay
+ * slot is in.
+ */
+ WARN_ON((e->target & ~J_RANGE_MASK) !=
+ ((e->code + 4) & ~J_RANGE_MASK));
+
+ insn.j_format.opcode = J_ISA_BIT ? mm_j32_op : j_op;
+ insn.j_format.target = e->target >> J_RANGE_SHIFT;
+ }
+ } else {
+ insn.word = 0; /* nop */
+ }
+
+ mutex_lock(&text_mutex);
+ if (IS_ENABLED(CONFIG_CPU_MICROMIPS)) {
+ insn_p->halfword[0] = insn.word >> 16;
+ insn_p->halfword[1] = insn.word;
+ } else
+ *insn_p = insn;
+
+ flush_icache_range((unsigned long)insn_p,
+ (unsigned long)insn_p + sizeof(*insn_p));
+
+ mutex_unlock(&text_mutex);
+}
+
+#ifdef CONFIG_MODULES
+void jump_label_apply_nops(struct module *mod)
+{
+ struct jump_entry *iter_start = mod->jump_entries;
+ struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
+ struct jump_entry *iter;
+
+ /* if the module doesn't have jump label entries, just return */
+ if (iter_start == iter_stop)
+ return;
+
+ for (iter = iter_start; iter < iter_stop; iter++) {
+ /* Only write NOPs for arch_branch_static(). */
+ if (jump_label_init_type(iter) == JUMP_LABEL_NOP)
+ arch_jump_label_transform(iter, JUMP_LABEL_NOP);
+ }
+}
+#endif