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authorDavid S. Miller <davem@sunset.davemloft.net>2006-03-02 18:12:27 -0800
committerDavid S. Miller <davem@sunset.davemloft.net>2006-03-20 01:14:14 -0800
commit8bcd17411643beb9a601e032d0cf1016909a81d3 (patch)
treefc71e788df4fada768247fa7c12e983d2f6f1a32 /arch
parent45f791eb0f03e760183d30d3f1f18dc2b8e902fe (diff)
[SPARC64]: Do not allow mapping pages within 4GB of 64-bit VA hole.
The UltraSPARC T1 manual recommends this because the chip could instruction prefetch into the VA hole, and this would also make decoding certain kinds of memory access traps more difficult (because the chip sign extends certain pieces of trap state). Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch')
-rw-r--r--arch/sparc64/kernel/sys_sparc.c90
1 files changed, 68 insertions, 22 deletions
diff --git a/arch/sparc64/kernel/sys_sparc.c b/arch/sparc64/kernel/sys_sparc.c
index 5f8c822a2b4..095db723bb8 100644
--- a/arch/sparc64/kernel/sys_sparc.c
+++ b/arch/sparc64/kernel/sys_sparc.c
@@ -33,14 +33,55 @@
/* #define DEBUG_UNIMP_SYSCALL */
-/* XXX Make this per-binary type, this way we can detect the type of
- * XXX a binary. Every Sparc executable calls this very early on.
- */
asmlinkage unsigned long sys_getpagesize(void)
{
return PAGE_SIZE;
}
+#define VA_EXCLUDE_START (0x0000080000000000UL - (1UL << 32UL))
+#define VA_EXCLUDE_END (0xfffff80000000000UL + (1UL << 32UL))
+
+/* Does addr --> addr+len fall within 4GB of the VA-space hole or
+ * overflow past the end of the 64-bit address space?
+ */
+static inline int invalid_64bit_range(unsigned long addr, unsigned long len)
+{
+ unsigned long va_exclude_start, va_exclude_end;
+
+ va_exclude_start = VA_EXCLUDE_START;
+ va_exclude_end = VA_EXCLUDE_END;
+
+ if (unlikely(len >= va_exclude_start))
+ return 1;
+
+ if (unlikely((addr + len) < addr))
+ return 1;
+
+ if (unlikely((addr >= va_exclude_start && addr < va_exclude_end) ||
+ ((addr + len) >= va_exclude_start &&
+ (addr + len) < va_exclude_end)))
+ return 1;
+
+ return 0;
+}
+
+/* Does start,end straddle the VA-space hole? */
+static inline int straddles_64bit_va_hole(unsigned long start, unsigned long end)
+{
+ unsigned long va_exclude_start, va_exclude_end;
+
+ va_exclude_start = VA_EXCLUDE_START;
+ va_exclude_end = VA_EXCLUDE_END;
+
+ if (likely(start < va_exclude_start && end < va_exclude_start))
+ return 0;
+
+ if (likely(start >= va_exclude_end && end >= va_exclude_end))
+ return 0;
+
+ return 1;
+}
+
#define COLOUR_ALIGN(addr,pgoff) \
((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
(((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
@@ -65,7 +106,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsi
if (test_thread_flag(TIF_32BIT))
task_size = 0xf0000000UL;
- if (len > task_size || len > -PAGE_OFFSET)
+ if (len > task_size || len >= VA_EXCLUDE_START)
return -ENOMEM;
do_color_align = 0;
@@ -100,9 +141,10 @@ full_search:
for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
/* At this point: (!vma || addr < vma->vm_end). */
- if (addr < PAGE_OFFSET && -PAGE_OFFSET - len < addr) {
- addr = PAGE_OFFSET;
- vma = find_vma(mm, PAGE_OFFSET);
+ if (addr < VA_EXCLUDE_START &&
+ (addr + len) >= VA_EXCLUDE_START) {
+ addr = VA_EXCLUDE_END;
+ vma = find_vma(mm, VA_EXCLUDE_END);
}
if (task_size < addr) {
if (start_addr != TASK_UNMAPPED_BASE) {
@@ -174,12 +216,12 @@ unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, u
asmlinkage unsigned long sparc_brk(unsigned long brk)
{
/* People could try to be nasty and use ta 0x6d in 32bit programs */
- if (test_thread_flag(TIF_32BIT) &&
- brk >= 0xf0000000UL)
+ if (test_thread_flag(TIF_32BIT) && brk >= 0xf0000000UL)
return current->mm->brk;
- if ((current->mm->brk & PAGE_OFFSET) != (brk & PAGE_OFFSET))
+ if (unlikely(straddles_64bit_va_hole(current->mm->brk, brk)))
return current->mm->brk;
+
return sys_brk(brk);
}
@@ -340,13 +382,16 @@ asmlinkage unsigned long sys_mmap(unsigned long addr, unsigned long len,
retval = -EINVAL;
if (test_thread_flag(TIF_32BIT)) {
- if (len > 0xf0000000UL ||
- ((flags & MAP_FIXED) && addr > 0xf0000000UL - len))
+ if (len >= 0xf0000000UL)
+ goto out_putf;
+
+ if ((flags & MAP_FIXED) && addr > 0xf0000000UL - len)
goto out_putf;
} else {
- if (len > -PAGE_OFFSET ||
- ((flags & MAP_FIXED) &&
- addr < PAGE_OFFSET && addr + len > -PAGE_OFFSET))
+ if (len >= VA_EXCLUDE_START)
+ goto out_putf;
+
+ if ((flags & MAP_FIXED) && invalid_64bit_range(addr, len))
goto out_putf;
}
@@ -365,9 +410,9 @@ asmlinkage long sys64_munmap(unsigned long addr, size_t len)
{
long ret;
- if (len > -PAGE_OFFSET ||
- (addr < PAGE_OFFSET && addr + len > -PAGE_OFFSET))
+ if (invalid_64bit_range(addr, len))
return -EINVAL;
+
down_write(&current->mm->mmap_sem);
ret = do_munmap(current->mm, addr, len);
up_write(&current->mm->mmap_sem);
@@ -384,18 +429,19 @@ asmlinkage unsigned long sys64_mremap(unsigned long addr,
{
struct vm_area_struct *vma;
unsigned long ret = -EINVAL;
+
if (test_thread_flag(TIF_32BIT))
goto out;
- if (old_len > -PAGE_OFFSET || new_len > -PAGE_OFFSET)
+ if (unlikely(new_len >= VA_EXCLUDE_START))
goto out;
- if (addr < PAGE_OFFSET && addr + old_len > -PAGE_OFFSET)
+ if (unlikely(invalid_64bit_range(addr, old_len)))
goto out;
+
down_write(&current->mm->mmap_sem);
if (flags & MREMAP_FIXED) {
- if (new_addr < PAGE_OFFSET &&
- new_addr + new_len > -PAGE_OFFSET)
+ if (invalid_64bit_range(new_addr, new_len))
goto out_sem;
- } else if (addr < PAGE_OFFSET && addr + new_len > -PAGE_OFFSET) {
+ } else if (invalid_64bit_range(addr, new_len)) {
unsigned long map_flags = 0;
struct file *file = NULL;