Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 448 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
new file mode 100644
index 000000000..385a189f7
--- /dev/null
+++ b/arch/arm64/include/asm/uaccess.h
@@ -0,0 +1,448 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Based on arch/arm/include/asm/uaccess.h
+ *
+ * Copyright (C) 2012 ARM Ltd.
+ */
+#ifndef __ASM_UACCESS_H
+#define __ASM_UACCESS_H
+
+#include <asm/alternative.h>
+#include <asm/kernel-pgtable.h>
+#include <asm/sysreg.h>
+
+/*
+ * User space memory access functions
+ */
+#include <linux/bitops.h>
+#include <linux/kasan-checks.h>
+#include <linux/string.h>
+
+#include <asm/cpufeature.h>
+#include <asm/mmu.h>
+#include <asm/ptrace.h>
+#include <asm/memory.h>
+#include <asm/extable.h>
+
+#define get_fs()	(current_thread_info()->addr_limit)
+
+static inline void set_fs(mm_segment_t fs)
+{
+	current_thread_info()->addr_limit = fs;
+
+	/*
+	 * Prevent a mispredicted conditional call to set_fs from forwarding
+	 * the wrong address limit to access_ok under speculation.
+	 */
+	spec_bar();
+
+	/* On user-mode return, check fs is correct */
+	set_thread_flag(TIF_FSCHECK);
+
+	/*
+	 * Enable/disable UAO so that copy_to_user() etc can access
+	 * kernel memory with the unprivileged instructions.
+	 */
+	if (IS_ENABLED(CONFIG_ARM64_UAO) && fs == KERNEL_DS)
+		asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO));
+	else
+		asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO,
+				CONFIG_ARM64_UAO));
+}
+
+#define uaccess_kernel()	(get_fs() == KERNEL_DS)
+
+/*
+ * Test whether a block of memory is a valid user space address.
+ * Returns 1 if the range is valid, 0 otherwise.
+ *
+ * This is equivalent to the following test:
+ * (u65)addr + (u65)size <= (u65)current->addr_limit + 1
+ */
+static inline unsigned long __range_ok(const void __user *addr, unsigned long size)
+{
+	unsigned long ret, limit = current_thread_info()->addr_limit;
+
+	/*
+	 * Asynchronous I/O running in a kernel thread does not have the
+	 * TIF_TAGGED_ADDR flag of the process owning the mm, so always untag
+	 * the user address before checking.
+	 */
+	if (IS_ENABLED(CONFIG_ARM64_TAGGED_ADDR_ABI) &&
+	    (current->flags & PF_KTHREAD || test_thread_flag(TIF_TAGGED_ADDR)))
+		addr = untagged_addr(addr);
+
+	__chk_user_ptr(addr);
+	asm volatile(
+	// A + B <= C + 1 for all A,B,C, in four easy steps:
+	// 1: X = A + B; X' = X % 2^64
+	"	adds	%0, %3, %2\n"
+	// 2: Set C = 0 if X > 2^64, to guarantee X' > C in step 4
+	"	csel	%1, xzr, %1, hi\n"
+	// 3: Set X' = ~0 if X >= 2^64. For X == 2^64, this decrements X'
+	//    to compensate for the carry flag being set in step 4. For
+	//    X > 2^64, X' merely has to remain nonzero, which it does.
+	"	csinv	%0, %0, xzr, cc\n"
+	// 4: For X < 2^64, this gives us X' - C - 1 <= 0, where the -1
+	//    comes from the carry in being clear. Otherwise, we are
+	//    testing X' - C == 0, subject to the previous adjustments.
+	"	sbcs	xzr, %0, %1\n"
+	"	cset	%0, ls\n"
+	: "=&r" (ret), "+r" (limit) : "Ir" (size), "0" (addr) : "cc");
+
+	return ret;
+}
+
+#define access_ok(addr, size)	__range_ok(addr, size)
+#define user_addr_max			get_fs
+
+#define _ASM_EXTABLE(from, to)						\
+	"	.pushsection	__ex_table, \"a\"\n"			\
+	"	.align		3\n"					\
+	"	.long		(" #from " - .), (" #to " - .)\n"	\
+	"	.popsection\n"
+
+/*
+ * User access enabling/disabling.
+ */
+#ifdef CONFIG_ARM64_SW_TTBR0_PAN
+static inline void __uaccess_ttbr0_disable(void)
+{
+	unsigned long flags, ttbr;
+
+	local_irq_save(flags);
+	ttbr = read_sysreg(ttbr1_el1);
+	ttbr &= ~TTBR_ASID_MASK;
+	/* reserved_pg_dir placed before swapper_pg_dir */
+	write_sysreg(ttbr - PAGE_SIZE, ttbr0_el1);
+	isb();
+	/* Set reserved ASID */
+	write_sysreg(ttbr, ttbr1_el1);
+	isb();
+	local_irq_restore(flags);
+}
+
+static inline void __uaccess_ttbr0_enable(void)
+{
+	unsigned long flags, ttbr0, ttbr1;
+
+	/*
+	 * Disable interrupts to avoid preemption between reading the 'ttbr0'
+	 * variable and the MSR. A context switch could trigger an ASID
+	 * roll-over and an update of 'ttbr0'.
+	 */
+	local_irq_save(flags);
+	ttbr0 = READ_ONCE(current_thread_info()->ttbr0);
+
+	/* Restore active ASID */
+	ttbr1 = read_sysreg(ttbr1_el1);
+	ttbr1 &= ~TTBR_ASID_MASK;		/* safety measure */
+	ttbr1 |= ttbr0 & TTBR_ASID_MASK;
+	write_sysreg(ttbr1, ttbr1_el1);
+	isb();
+
+	/* Restore user page table */
+	write_sysreg(ttbr0, ttbr0_el1);
+	isb();
+	local_irq_restore(flags);
+}
+
+static inline bool uaccess_ttbr0_disable(void)
+{
+	if (!system_uses_ttbr0_pan())
+		return false;
+	__uaccess_ttbr0_disable();
+	return true;
+}
+
+static inline bool uaccess_ttbr0_enable(void)
+{
+	if (!system_uses_ttbr0_pan())
+		return false;
+	__uaccess_ttbr0_enable();
+	return true;
+}
+#else
+static inline bool uaccess_ttbr0_disable(void)
+{
+	return false;
+}
+
+static inline bool uaccess_ttbr0_enable(void)
+{
+	return false;
+}
+#endif
+
+static inline void __uaccess_disable_hw_pan(void)
+{
+	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN,
+			CONFIG_ARM64_PAN));
+}
+
+static inline void __uaccess_enable_hw_pan(void)
+{
+	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN,
+			CONFIG_ARM64_PAN));
+}
+
+#define __uaccess_disable(alt)						\
+do {									\
+	if (!uaccess_ttbr0_disable())					\
+		asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt,		\
+				CONFIG_ARM64_PAN));			\
+} while (0)
+
+#define __uaccess_enable(alt)						\
+do {									\
+	if (!uaccess_ttbr0_enable())					\
+		asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), alt,		\
+				CONFIG_ARM64_PAN));			\
+} while (0)
+
+static inline void uaccess_disable(void)
+{
+	__uaccess_disable(ARM64_HAS_PAN);
+}
+
+static inline void uaccess_enable(void)
+{
+	__uaccess_enable(ARM64_HAS_PAN);
+}
+
+/*
+ * These functions are no-ops when UAO is present.
+ */
+static inline void uaccess_disable_not_uao(void)
+{
+	__uaccess_disable(ARM64_ALT_PAN_NOT_UAO);
+}
+
+static inline void uaccess_enable_not_uao(void)
+{
+	__uaccess_enable(ARM64_ALT_PAN_NOT_UAO);
+}
+
+/*
+ * Sanitise a uaccess pointer such that it becomes NULL if above the
+ * current addr_limit. In case the pointer is tagged (has the top byte set),
+ * untag the pointer before checking.
+ */
+#define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr)
+static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
+{
+	void __user *safe_ptr;
+
+	asm volatile(
+	"	bics	xzr, %3, %2\n"
+	"	csel	%0, %1, xzr, eq\n"
+	: "=&r" (safe_ptr)
+	: "r" (ptr), "r" (current_thread_info()->addr_limit),
+	  "r" (untagged_addr(ptr))
+	: "cc");
+
+	csdb();
+	return safe_ptr;
+}
+
+/*
+ * The "__xxx" versions of the user access functions do not verify the address
+ * space - it must have been done previously with a separate "access_ok()"
+ * call.
+ *
+ * The "__xxx_error" versions set the third argument to -EFAULT if an error
+ * occurs, and leave it unchanged on success.
+ */
+#define __get_user_asm(instr, alt_instr, reg, x, addr, err, feature)	\
+	asm volatile(							\
+	"1:"ALTERNATIVE(instr "     " reg "1, [%2]\n",			\
+			alt_instr " " reg "1, [%2]\n", feature)		\
+	"2:\n"								\
+	"	.section .fixup, \"ax\"\n"				\
+	"	.align	2\n"						\
+	"3:	mov	%w0, %3\n"					\
+	"	mov	%1, #0\n"					\
+	"	b	2b\n"						\
+	"	.previous\n"						\
+	_ASM_EXTABLE(1b, 3b)						\
+	: "+r" (err), "=&r" (x)						\
+	: "r" (addr), "i" (-EFAULT))
+
+#define __raw_get_user(x, ptr, err)					\
+do {									\
+	unsigned long __gu_val;						\
+	__chk_user_ptr(ptr);						\
+	uaccess_enable_not_uao();					\
+	switch (sizeof(*(ptr))) {					\
+	case 1:								\
+		__get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr),  \
+			       (err), ARM64_HAS_UAO);			\
+		break;							\
+	case 2:								\
+		__get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr),  \
+			       (err), ARM64_HAS_UAO);			\
+		break;							\
+	case 4:								\
+		__get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr),	\
+			       (err), ARM64_HAS_UAO);			\
+		break;							\
+	case 8:								\
+		__get_user_asm("ldr", "ldtr", "%x",  __gu_val, (ptr),	\
+			       (err), ARM64_HAS_UAO);			\
+		break;							\
+	default:							\
+		BUILD_BUG();						\
+	}								\
+	uaccess_disable_not_uao();					\
+	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
+} while (0)
+
+#define __get_user_error(x, ptr, err)					\
+do {									\
+	__typeof__(*(ptr)) __user *__p = (ptr);				\
+	might_fault();							\
+	if (access_ok(__p, sizeof(*__p))) {				\
+		__p = uaccess_mask_ptr(__p);				\
+		__raw_get_user((x), __p, (err));			\
+	} else {							\
+		(x) = (__force __typeof__(x))0; (err) = -EFAULT;	\
+	}								\
+} while (0)
+
+#define __get_user(x, ptr)						\
+({									\
+	int __gu_err = 0;						\
+	__get_user_error((x), (ptr), __gu_err);				\
+	__gu_err;							\
+})
+
+#define get_user	__get_user
+
+#define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature)	\
+	asm volatile(							\
+	"1:"ALTERNATIVE(instr "     " reg "1, [%2]\n",			\
+			alt_instr " " reg "1, [%2]\n", feature)		\
+	"2:\n"								\
+	"	.section .fixup,\"ax\"\n"				\
+	"	.align	2\n"						\
+	"3:	mov	%w0, %3\n"					\
+	"	b	2b\n"						\
+	"	.previous\n"						\
+	_ASM_EXTABLE(1b, 3b)						\
+	: "+r" (err)							\
+	: "r" (x), "r" (addr), "i" (-EFAULT))
+
+#define __raw_put_user(x, ptr, err)					\
+do {									\
+	__typeof__(*(ptr)) __pu_val = (x);				\
+	__chk_user_ptr(ptr);						\
+	uaccess_enable_not_uao();					\
+	switch (sizeof(*(ptr))) {					\
+	case 1:								\
+		__put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr),	\
+			       (err), ARM64_HAS_UAO);			\
+		break;							\
+	case 2:								\
+		__put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr),	\
+			       (err), ARM64_HAS_UAO);			\
+		break;							\
+	case 4:								\
+		__put_user_asm("str", "sttr", "%w", __pu_val, (ptr),	\
+			       (err), ARM64_HAS_UAO);			\
+		break;							\
+	case 8:								\
+		__put_user_asm("str", "sttr", "%x", __pu_val, (ptr),	\
+			       (err), ARM64_HAS_UAO);			\
+		break;							\
+	default:							\
+		BUILD_BUG();						\
+	}								\
+	uaccess_disable_not_uao();					\
+} while (0)
+
+#define __put_user_error(x, ptr, err)					\
+do {									\
+	__typeof__(*(ptr)) __user *__p = (ptr);				\
+	might_fault();							\
+	if (access_ok(__p, sizeof(*__p))) {				\
+		__p = uaccess_mask_ptr(__p);				\
+		__raw_put_user((x), __p, (err));			\
+	} else	{							\
+		(err) = -EFAULT;					\
+	}								\
+} while (0)
+
+#define __put_user(x, ptr)						\
+({									\
+	int __pu_err = 0;						\
+	__put_user_error((x), (ptr), __pu_err);				\
+	__pu_err;							\
+})
+
+#define put_user	__put_user
+
+extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
+#define raw_copy_from_user(to, from, n)					\
+({									\
+	unsigned long __acfu_ret;					\
+	uaccess_enable_not_uao();					\
+	__acfu_ret = __arch_copy_from_user((to),			\
+				      __uaccess_mask_ptr(from), (n));	\
+	uaccess_disable_not_uao();					\
+	__acfu_ret;							\
+})
+
+extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
+#define raw_copy_to_user(to, from, n)					\
+({									\
+	unsigned long __actu_ret;					\
+	uaccess_enable_not_uao();					\
+	__actu_ret = __arch_copy_to_user(__uaccess_mask_ptr(to),	\
+				    (from), (n));			\
+	uaccess_disable_not_uao();					\
+	__actu_ret;							\
+})
+
+extern unsigned long __must_check __arch_copy_in_user(void __user *to, const void __user *from, unsigned long n);
+#define raw_copy_in_user(to, from, n)					\
+({									\
+	unsigned long __aciu_ret;					\
+	uaccess_enable_not_uao();					\
+	__aciu_ret = __arch_copy_in_user(__uaccess_mask_ptr(to),	\
+				    __uaccess_mask_ptr(from), (n));	\
+	uaccess_disable_not_uao();					\
+	__aciu_ret;							\
+})
+
+#define INLINE_COPY_TO_USER
+#define INLINE_COPY_FROM_USER
+
+extern unsigned long __must_check __arch_clear_user(void __user *to, unsigned long n);
+static inline unsigned long __must_check __clear_user(void __user *to, unsigned long n)
+{
+	if (access_ok(to, n)) {
+		uaccess_enable_not_uao();
+		n = __arch_clear_user(__uaccess_mask_ptr(to), n);
+		uaccess_disable_not_uao();
+	}
+	return n;
+}
+#define clear_user	__clear_user
+
+extern long strncpy_from_user(char *dest, const char __user *src, long count);
+
+extern __must_check long strnlen_user(const char __user *str, long n);
+
+#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
+struct page;
+void memcpy_page_flushcache(char *to, struct page *page, size_t offset, size_t len);
+extern unsigned long __must_check __copy_user_flushcache(void *to, const void __user *from, unsigned long n);
+
+static inline int __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size)
+{
+	kasan_check_write(dst, size);
+	return __copy_user_flushcache(dst, __uaccess_mask_ptr(src), size);
+}
+#endif
+
+#endif /* __ASM_UACCESS_H */