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-rw-r--r--arch/arm64/include/asm/asm-extable.h126
1 files changed, 126 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h
new file mode 100644
index 000000000..980d1dd8e
--- /dev/null
+++ b/arch/arm64/include/asm/asm-extable.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ASM_ASM_EXTABLE_H
+#define __ASM_ASM_EXTABLE_H
+
+#include <linux/bits.h>
+#include <asm/gpr-num.h>
+
+#define EX_TYPE_NONE 0
+#define EX_TYPE_BPF 1
+#define EX_TYPE_UACCESS_ERR_ZERO 2
+#define EX_TYPE_KACCESS_ERR_ZERO 3
+#define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 4
+
+/* Data fields for EX_TYPE_UACCESS_ERR_ZERO */
+#define EX_DATA_REG_ERR_SHIFT 0
+#define EX_DATA_REG_ERR GENMASK(4, 0)
+#define EX_DATA_REG_ZERO_SHIFT 5
+#define EX_DATA_REG_ZERO GENMASK(9, 5)
+
+/* Data fields for EX_TYPE_LOAD_UNALIGNED_ZEROPAD */
+#define EX_DATA_REG_DATA_SHIFT 0
+#define EX_DATA_REG_DATA GENMASK(4, 0)
+#define EX_DATA_REG_ADDR_SHIFT 5
+#define EX_DATA_REG_ADDR GENMASK(9, 5)
+
+#ifdef __ASSEMBLY__
+
+#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
+ .pushsection __ex_table, "a"; \
+ .align 2; \
+ .long ((insn) - .); \
+ .long ((fixup) - .); \
+ .short (type); \
+ .short (data); \
+ .popsection;
+
+#define EX_DATA_REG(reg, gpr) \
+ (.L__gpr_num_##gpr << EX_DATA_REG_##reg##_SHIFT)
+
+#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero) \
+ __ASM_EXTABLE_RAW(insn, fixup, \
+ EX_TYPE_UACCESS_ERR_ZERO, \
+ ( \
+ EX_DATA_REG(ERR, err) | \
+ EX_DATA_REG(ZERO, zero) \
+ ))
+
+#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \
+ _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
+
+#define _ASM_EXTABLE_UACCESS(insn, fixup) \
+ _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
+
+/*
+ * Create an exception table entry for uaccess `insn`, which will branch to `fixup`
+ * when an unhandled fault is taken.
+ */
+ .macro _asm_extable_uaccess, insn, fixup
+ _ASM_EXTABLE_UACCESS(\insn, \fixup)
+ .endm
+
+/*
+ * Create an exception table entry for `insn` if `fixup` is provided. Otherwise
+ * do nothing.
+ */
+ .macro _cond_uaccess_extable, insn, fixup
+ .ifnc \fixup,
+ _asm_extable_uaccess \insn, \fixup
+ .endif
+ .endm
+
+#else /* __ASSEMBLY__ */
+
+#include <linux/stringify.h>
+
+#define __ASM_EXTABLE_RAW(insn, fixup, type, data) \
+ ".pushsection __ex_table, \"a\"\n" \
+ ".align 2\n" \
+ ".long ((" insn ") - .)\n" \
+ ".long ((" fixup ") - .)\n" \
+ ".short (" type ")\n" \
+ ".short (" data ")\n" \
+ ".popsection\n"
+
+#define EX_DATA_REG(reg, gpr) \
+ "((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"
+
+#define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero) \
+ __DEFINE_ASM_GPR_NUMS \
+ __ASM_EXTABLE_RAW(#insn, #fixup, \
+ __stringify(EX_TYPE_UACCESS_ERR_ZERO), \
+ "(" \
+ EX_DATA_REG(ERR, err) " | " \
+ EX_DATA_REG(ZERO, zero) \
+ ")")
+
+#define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero) \
+ __DEFINE_ASM_GPR_NUMS \
+ __ASM_EXTABLE_RAW(#insn, #fixup, \
+ __stringify(EX_TYPE_KACCESS_ERR_ZERO), \
+ "(" \
+ EX_DATA_REG(ERR, err) " | " \
+ EX_DATA_REG(ZERO, zero) \
+ ")")
+
+#define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \
+ _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
+
+#define _ASM_EXTABLE_UACCESS(insn, fixup) \
+ _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
+
+#define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err) \
+ _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)
+
+#define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr) \
+ __DEFINE_ASM_GPR_NUMS \
+ __ASM_EXTABLE_RAW(#insn, #fixup, \
+ __stringify(EX_TYPE_LOAD_UNALIGNED_ZEROPAD), \
+ "(" \
+ EX_DATA_REG(DATA, data) " | " \
+ EX_DATA_REG(ADDR, addr) \
+ ")")
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_ASM_EXTABLE_H */