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-rw-r--r--arch/arm/kernel/insn.c62
1 files changed, 62 insertions, 0 deletions
diff --git a/arch/arm/kernel/insn.c b/arch/arm/kernel/insn.c
new file mode 100644
index 0000000..b760340
--- /dev/null
+++ b/arch/arm/kernel/insn.c
@@ -0,0 +1,62 @@
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <asm/opcodes.h>
+
+static unsigned long
+__arm_gen_branch_thumb2(unsigned long pc, unsigned long addr, bool link)
+{
+ unsigned long s, j1, j2, i1, i2, imm10, imm11;
+ unsigned long first, second;
+ long offset;
+
+ offset = (long)addr - (long)(pc + 4);
+ if (offset < -16777216 || offset > 16777214) {
+ WARN_ON_ONCE(1);
+ return 0;
+ }
+
+ s = (offset >> 24) & 0x1;
+ i1 = (offset >> 23) & 0x1;
+ i2 = (offset >> 22) & 0x1;
+ imm10 = (offset >> 12) & 0x3ff;
+ imm11 = (offset >> 1) & 0x7ff;
+
+ j1 = (!i1) ^ s;
+ j2 = (!i2) ^ s;
+
+ first = 0xf000 | (s << 10) | imm10;
+ second = 0x9000 | (j1 << 13) | (j2 << 11) | imm11;
+ if (link)
+ second |= 1 << 14;
+
+ return __opcode_thumb32_compose(first, second);
+}
+
+static unsigned long
+__arm_gen_branch_arm(unsigned long pc, unsigned long addr, bool link)
+{
+ unsigned long opcode = 0xea000000;
+ long offset;
+
+ if (link)
+ opcode |= 1 << 24;
+
+ offset = (long)addr - (long)(pc + 8);
+ if (unlikely(offset < -33554432 || offset > 33554428)) {
+ WARN_ON_ONCE(1);
+ return 0;
+ }
+
+ offset = (offset >> 2) & 0x00ffffff;
+
+ return opcode | offset;
+}
+
+unsigned long
+__arm_gen_branch(unsigned long pc, unsigned long addr, bool link)
+{
+ if (IS_ENABLED(CONFIG_THUMB2_KERNEL))
+ return __arm_gen_branch_thumb2(pc, addr, link);
+ else
+ return __arm_gen_branch_arm(pc, addr, link);
+}