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-rw-r--r--arch/arm64/include/asm/asm-uaccess.h93
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
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+++ b/arch/arm64/include/asm/asm-uaccess.h
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+/* 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