Fixed MTP to work with TWRP

arch/x86/kernel/sys_x86_64.c

@@ -0,0 +1,192 @@
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/syscalls.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/smp.h>
+#include <linux/sem.h>
+#include <linux/msg.h>
+#include <linux/shm.h>
+#include <linux/stat.h>
+#include <linux/mman.h>
+#include <linux/file.h>
+#include <linux/utsname.h>
+#include <linux/personality.h>
+#include <linux/random.h>
+#include <linux/uaccess.h>
+#include <linux/elf.h>
+
+#include <asm/ia32.h>
+#include <asm/syscalls.h>
+
+/*
+ * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
+ */
+static unsigned long get_align_mask(void)
+{
+	/* handle 32- and 64-bit case with a single conditional */
+	if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32())))
+		return 0;
+
+	if (!(current->flags & PF_RANDOMIZE))
+		return 0;
+
+	return va_align.mask;
+}
+
+unsigned long align_vdso_addr(unsigned long addr)
+{
+	unsigned long align_mask = get_align_mask();
+	return (addr + align_mask) & ~align_mask;
+}
+
+static int __init control_va_addr_alignment(char *str)
+{
+	/* guard against enabling this on other CPU families */
+	if (va_align.flags < 0)
+		return 1;
+
+	if (*str == 0)
+		return 1;
+
+	if (*str == '=')
+		str++;
+
+	if (!strcmp(str, "32"))
+		va_align.flags = ALIGN_VA_32;
+	else if (!strcmp(str, "64"))
+		va_align.flags = ALIGN_VA_64;
+	else if (!strcmp(str, "off"))
+		va_align.flags = 0;
+	else if (!strcmp(str, "on"))
+		va_align.flags = ALIGN_VA_32 | ALIGN_VA_64;
+	else
+		return 0;
+
+	return 1;
+}
+__setup("align_va_addr", control_va_addr_alignment);
+
+SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
+		unsigned long, prot, unsigned long, flags,
+		unsigned long, fd, unsigned long, off)
+{
+	long error;
+	error = -EINVAL;
+	if (off & ~PAGE_MASK)
+		goto out;
+
+	error = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
+out:
+	return error;
+}
+
+static void find_start_end(unsigned long flags, unsigned long *begin,
+			   unsigned long *end)
+{
+	if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) {
+		unsigned long new_begin;
+		/* This is usually used needed to map code in small
+		   model, so it needs to be in the first 31bit. Limit
+		   it to that.  This means we need to move the
+		   unmapped base down for this case. This can give
+		   conflicts with the heap, but we assume that glibc
+		   malloc knows how to fall back to mmap. Give it 1GB
+		   of playground for now. -AK */
+		*begin = 0x40000000;
+		*end = 0x80000000;
+		if (current->flags & PF_RANDOMIZE) {
+			new_begin = randomize_range(*begin, *begin + 0x02000000, 0);
+			if (new_begin)
+				*begin = new_begin;
+		}
+	} else {
+		*begin = current->mm->mmap_legacy_base;
+		*end = TASK_SIZE;
+	}
+}
+
+unsigned long
+arch_get_unmapped_area(struct file *filp, unsigned long addr,
+		unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	struct vm_unmapped_area_info info;
+	unsigned long begin, end;
+
+	if (flags & MAP_FIXED)
+		return addr;
+
+	find_start_end(flags, &begin, &end);
+
+	if (len > end)
+		return -ENOMEM;
+
+	if (addr) {
+		addr = PAGE_ALIGN(addr);
+		vma = find_vma(mm, addr);
+		if (end - len >= addr &&
+		    (!vma || addr + len <= vma->vm_start))
+			return addr;
+	}
+
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = begin;
+	info.high_limit = end;
+	info.align_mask = filp ? get_align_mask() : 0;
+	info.align_offset = pgoff << PAGE_SHIFT;
+	return vm_unmapped_area(&info);
+}
+
+unsigned long
+arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
+			  const unsigned long len, const unsigned long pgoff,
+			  const unsigned long flags)
+{
+	struct vm_area_struct *vma;
+	struct mm_struct *mm = current->mm;
+	unsigned long addr = addr0;
+	struct vm_unmapped_area_info info;
+
+	/* requested length too big for entire address space */
+	if (len > TASK_SIZE)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED)
+		return addr;
+
+	/* for MAP_32BIT mappings we force the legacy mmap base */
+	if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT))
+		goto bottomup;
+
+	/* requesting a specific address */
+	if (addr) {
+		addr = PAGE_ALIGN(addr);
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr &&
+				(!vma || addr + len <= vma->vm_start))
+			return addr;
+	}
+
+	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+	info.length = len;
+	info.low_limit = PAGE_SIZE;
+	info.high_limit = mm->mmap_base;
+	info.align_mask = filp ? get_align_mask() : 0;
+	info.align_offset = pgoff << PAGE_SHIFT;
+	addr = vm_unmapped_area(&info);
+	if (!(addr & ~PAGE_MASK))
+		return addr;
+	VM_BUG_ON(addr != -ENOMEM);
+
+bottomup:
+	/*
+	 * A failed mmap() very likely causes application failure,
+	 * so fall back to the bottom-up function here. This scenario
+	 * can happen with large stack limits and large mmap()
+	 * allocations.
+	 */
+	return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
+}