1 files changed, 93 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h
new file mode 100644
index 0000000000..5b6efe8abe
--- /dev/null
+++ b/arch/arm64/include/asm/asm-uaccess.h
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_ASM_UACCESS_H
+#define __ASM_ASM_UACCESS_H
+
+#include <asm/alternative-macros.h>
+#include <asm/asm-extable.h>
+#include <asm/assembler.h>
+#include <asm/kernel-pgtable.h>
+#include <asm/mmu.h>
+#include <asm/sysreg.h>
+
+/*
+ * User access enabling/disabling macros.
+ */
+#ifdef CONFIG_ARM64_SW_TTBR0_PAN
+	.macro	__uaccess_ttbr0_disable, tmp1
+	mrs	\tmp1, ttbr1_el1			// swapper_pg_dir
+	bic	\tmp1, \tmp1, #TTBR_ASID_MASK
+	sub	\tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET	// reserved_pg_dir
+	msr	ttbr0_el1, \tmp1			// set reserved TTBR0_EL1
+	add	\tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET
+	msr	ttbr1_el1, \tmp1		// set reserved ASID
+	isb
+	.endm
+
+	.macro	__uaccess_ttbr0_enable, tmp1, tmp2
+	get_current_task \tmp1
+	ldr	\tmp1, [\tmp1, #TSK_TI_TTBR0]	// load saved TTBR0_EL1
+	mrs	\tmp2, ttbr1_el1
+	extr    \tmp2, \tmp2, \tmp1, #48
+	ror     \tmp2, \tmp2, #16
+	msr	ttbr1_el1, \tmp2		// set the active ASID
+	msr	ttbr0_el1, \tmp1		// set the non-PAN TTBR0_EL1
+	isb
+	.endm
+
+	.macro	uaccess_ttbr0_disable, tmp1, tmp2
+alternative_if_not ARM64_HAS_PAN
+	save_and_disable_irq \tmp2		// avoid preemption
+	__uaccess_ttbr0_disable \tmp1
+	restore_irq \tmp2
+alternative_else_nop_endif
+	.endm
+
+	.macro	uaccess_ttbr0_enable, tmp1, tmp2, tmp3
+alternative_if_not ARM64_HAS_PAN
+	save_and_disable_irq \tmp3		// avoid preemption
+	__uaccess_ttbr0_enable \tmp1, \tmp2
+	restore_irq \tmp3
+alternative_else_nop_endif
+	.endm
+#else
+	.macro	uaccess_ttbr0_disable, tmp1, tmp2
+	.endm
+
+	.macro	uaccess_ttbr0_enable, tmp1, tmp2, tmp3
+	.endm
+#endif
+
+#define USER(l, x...)				\
+9999:	x;					\
+	_asm_extable_uaccess	9999b, l
+
+/*
+ * Generate the assembly for LDTR/STTR with exception table entries.
+ * This is complicated as there is no post-increment or pair versions of the
+ * unprivileged instructions, and USER() only works for single instructions.
+ */
+	.macro user_ldp l, reg1, reg2, addr, post_inc
+8888:		ldtr	\reg1, [\addr];
+8889:		ldtr	\reg2, [\addr, #8];
+		add	\addr, \addr, \post_inc;
+
+		_asm_extable_uaccess	8888b, \l;
+		_asm_extable_uaccess	8889b, \l;
+	.endm
+
+	.macro user_stp l, reg1, reg2, addr, post_inc
+8888:		sttr	\reg1, [\addr];
+8889:		sttr	\reg2, [\addr, #8];
+		add	\addr, \addr, \post_inc;
+
+		_asm_extable_uaccess	8888b,\l;
+		_asm_extable_uaccess	8889b,\l;
+	.endm
+
+	.macro user_ldst l, inst, reg, addr, post_inc
+8888:		\inst		\reg, [\addr];
+		add		\addr, \addr, \post_inc;
+
+		_asm_extable_uaccess	8888b, \l;
+	.endm
+#endif