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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/um/kernel/skas/uaccess.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/um/kernel/skas/uaccess.c')
-rw-r--r--arch/um/kernel/skas/uaccess.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c
new file mode 100644
index 000000000..aaee96f07
--- /dev/null
+++ b/arch/um/kernel/skas/uaccess.c
@@ -0,0 +1,366 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#include <linux/err.h>
+#include <linux/highmem.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <asm/current.h>
+#include <asm/page.h>
+#include <kern_util.h>
+#include <asm/futex.h>
+#include <os.h>
+
+pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+
+ if (mm == NULL)
+ return NULL;
+
+ pgd = pgd_offset(mm, addr);
+ if (!pgd_present(*pgd))
+ return NULL;
+
+ p4d = p4d_offset(pgd, addr);
+ if (!p4d_present(*p4d))
+ return NULL;
+
+ pud = pud_offset(p4d, addr);
+ if (!pud_present(*pud))
+ return NULL;
+
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd))
+ return NULL;
+
+ return pte_offset_kernel(pmd, addr);
+}
+
+static pte_t *maybe_map(unsigned long virt, int is_write)
+{
+ pte_t *pte = virt_to_pte(current->mm, virt);
+ int err, dummy_code;
+
+ if ((pte == NULL) || !pte_present(*pte) ||
+ (is_write && !pte_write(*pte))) {
+ err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
+ if (err)
+ return NULL;
+ pte = virt_to_pte(current->mm, virt);
+ }
+ if (!pte_present(*pte))
+ pte = NULL;
+
+ return pte;
+}
+
+static int do_op_one_page(unsigned long addr, int len, int is_write,
+ int (*op)(unsigned long addr, int len, void *arg), void *arg)
+{
+ struct page *page;
+ pte_t *pte;
+ int n;
+
+ pte = maybe_map(addr, is_write);
+ if (pte == NULL)
+ return -1;
+
+ page = pte_page(*pte);
+#ifdef CONFIG_64BIT
+ pagefault_disable();
+ addr = (unsigned long) page_address(page) +
+ (addr & ~PAGE_MASK);
+#else
+ addr = (unsigned long) kmap_atomic(page) +
+ (addr & ~PAGE_MASK);
+#endif
+ n = (*op)(addr, len, arg);
+
+#ifdef CONFIG_64BIT
+ pagefault_enable();
+#else
+ kunmap_atomic((void *)addr);
+#endif
+
+ return n;
+}
+
+static long buffer_op(unsigned long addr, int len, int is_write,
+ int (*op)(unsigned long, int, void *), void *arg)
+{
+ long size, remain, n;
+
+ size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
+ remain = len;
+
+ n = do_op_one_page(addr, size, is_write, op, arg);
+ if (n != 0) {
+ remain = (n < 0 ? remain : 0);
+ goto out;
+ }
+
+ addr += size;
+ remain -= size;
+ if (remain == 0)
+ goto out;
+
+ while (addr < ((addr + remain) & PAGE_MASK)) {
+ n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
+ if (n != 0) {
+ remain = (n < 0 ? remain : 0);
+ goto out;
+ }
+
+ addr += PAGE_SIZE;
+ remain -= PAGE_SIZE;
+ }
+ if (remain == 0)
+ goto out;
+
+ n = do_op_one_page(addr, remain, is_write, op, arg);
+ if (n != 0) {
+ remain = (n < 0 ? remain : 0);
+ goto out;
+ }
+
+ return 0;
+ out:
+ return remain;
+}
+
+static int copy_chunk_from_user(unsigned long from, int len, void *arg)
+{
+ unsigned long *to_ptr = arg, to = *to_ptr;
+
+ memcpy((void *) to, (void *) from, len);
+ *to_ptr += len;
+ return 0;
+}
+
+unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+ return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
+}
+EXPORT_SYMBOL(raw_copy_from_user);
+
+static int copy_chunk_to_user(unsigned long to, int len, void *arg)
+{
+ unsigned long *from_ptr = arg, from = *from_ptr;
+
+ memcpy((void *) to, (void *) from, len);
+ *from_ptr += len;
+ return 0;
+}
+
+unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+ return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
+}
+EXPORT_SYMBOL(raw_copy_to_user);
+
+static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
+{
+ char **to_ptr = arg, *to = *to_ptr;
+ int n;
+
+ strncpy(to, (void *) from, len);
+ n = strnlen(to, len);
+ *to_ptr += n;
+
+ if (n < len)
+ return 1;
+ return 0;
+}
+
+long strncpy_from_user(char *dst, const char __user *src, long count)
+{
+ long n;
+ char *ptr = dst;
+
+ if (!access_ok(src, 1))
+ return -EFAULT;
+ n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
+ &ptr);
+ if (n != 0)
+ return -EFAULT;
+ return strnlen(dst, count);
+}
+EXPORT_SYMBOL(strncpy_from_user);
+
+static int clear_chunk(unsigned long addr, int len, void *unused)
+{
+ memset((void *) addr, 0, len);
+ return 0;
+}
+
+unsigned long __clear_user(void __user *mem, unsigned long len)
+{
+ return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
+}
+EXPORT_SYMBOL(__clear_user);
+
+static int strnlen_chunk(unsigned long str, int len, void *arg)
+{
+ int *len_ptr = arg, n;
+
+ n = strnlen((void *) str, len);
+ *len_ptr += n;
+
+ if (n < len)
+ return 1;
+ return 0;
+}
+
+long strnlen_user(const char __user *str, long len)
+{
+ int count = 0, n;
+
+ if (!access_ok(str, 1))
+ return -EFAULT;
+ n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
+ if (n == 0)
+ return count + 1;
+ return 0;
+}
+EXPORT_SYMBOL(strnlen_user);
+
+/**
+ * arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant
+ * argument and comparison of the previous
+ * futex value with another constant.
+ *
+ * @encoded_op: encoded operation to execute
+ * @uaddr: pointer to user space address
+ *
+ * Return:
+ * 0 - On success
+ * -EFAULT - User access resulted in a page fault
+ * -EAGAIN - Atomic operation was unable to complete due to contention
+ * -ENOSYS - Operation not supported
+ */
+
+int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr)
+{
+ int oldval, ret;
+ struct page *page;
+ unsigned long addr = (unsigned long) uaddr;
+ pte_t *pte;
+
+ ret = -EFAULT;
+ if (!access_ok(uaddr, sizeof(*uaddr)))
+ return -EFAULT;
+ preempt_disable();
+ pte = maybe_map(addr, 1);
+ if (pte == NULL)
+ goto out_inuser;
+
+ page = pte_page(*pte);
+#ifdef CONFIG_64BIT
+ pagefault_disable();
+ addr = (unsigned long) page_address(page) +
+ (((unsigned long) addr) & ~PAGE_MASK);
+#else
+ addr = (unsigned long) kmap_atomic(page) +
+ ((unsigned long) addr & ~PAGE_MASK);
+#endif
+ uaddr = (u32 *) addr;
+ oldval = *uaddr;
+
+ ret = 0;
+
+ switch (op) {
+ case FUTEX_OP_SET:
+ *uaddr = oparg;
+ break;
+ case FUTEX_OP_ADD:
+ *uaddr += oparg;
+ break;
+ case FUTEX_OP_OR:
+ *uaddr |= oparg;
+ break;
+ case FUTEX_OP_ANDN:
+ *uaddr &= ~oparg;
+ break;
+ case FUTEX_OP_XOR:
+ *uaddr ^= oparg;
+ break;
+ default:
+ ret = -ENOSYS;
+ }
+#ifdef CONFIG_64BIT
+ pagefault_enable();
+#else
+ kunmap_atomic((void *)addr);
+#endif
+
+out_inuser:
+ preempt_enable();
+
+ if (ret == 0)
+ *oval = oldval;
+
+ return ret;
+}
+EXPORT_SYMBOL(arch_futex_atomic_op_inuser);
+
+/**
+ * futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
+ * uaddr with newval if the current value is
+ * oldval.
+ * @uval: pointer to store content of @uaddr
+ * @uaddr: pointer to user space address
+ * @oldval: old value
+ * @newval: new value to store to @uaddr
+ *
+ * Return:
+ * 0 - On success
+ * -EFAULT - User access resulted in a page fault
+ * -EAGAIN - Atomic operation was unable to complete due to contention
+ */
+
+int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+ u32 oldval, u32 newval)
+{
+ struct page *page;
+ pte_t *pte;
+ int ret = -EFAULT;
+
+ if (!access_ok(uaddr, sizeof(*uaddr)))
+ return -EFAULT;
+
+ preempt_disable();
+ pte = maybe_map((unsigned long) uaddr, 1);
+ if (pte == NULL)
+ goto out_inatomic;
+
+ page = pte_page(*pte);
+#ifdef CONFIG_64BIT
+ pagefault_disable();
+ uaddr = page_address(page) + (((unsigned long) uaddr) & ~PAGE_MASK);
+#else
+ uaddr = kmap_atomic(page) + ((unsigned long) uaddr & ~PAGE_MASK);
+#endif
+
+ *uval = *uaddr;
+
+ ret = cmpxchg(uaddr, oldval, newval);
+
+#ifdef CONFIG_64BIT
+ pagefault_enable();
+#else
+ kunmap_atomic(uaddr);
+#endif
+ ret = 0;
+
+out_inatomic:
+ preempt_enable();
+ return ret;
+}
+EXPORT_SYMBOL(futex_atomic_cmpxchg_inatomic);