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Diffstat (limited to 'arch/x86/kernel/sys_x86_64.c')
-rw-r--r--arch/x86/kernel/sys_x86_64.c78
1 files changed, 75 insertions, 3 deletions
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index ff14a5044ce6..051489082d59 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -14,10 +14,73 @@
#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.
+ *
+ * @flags denotes the allocation direction - bottomup or topdown -
+ * or vDSO; see call sites below.
+ */
+unsigned long align_addr(unsigned long addr, struct file *filp,
+ enum align_flags flags)
+{
+ unsigned long tmp_addr;
+
+ /* handle 32- and 64-bit case with a single conditional */
+ if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32())))
+ return addr;
+
+ if (!(current->flags & PF_RANDOMIZE))
+ return addr;
+
+ if (!((flags & ALIGN_VDSO) || filp))
+ return addr;
+
+ tmp_addr = addr;
+
+ /*
+ * We need an address which is <= than the original
+ * one only when in topdown direction.
+ */
+ if (!(flags & ALIGN_TOPDOWN))
+ tmp_addr += va_align.mask;
+
+ tmp_addr &= ~va_align.mask;
+
+ return tmp_addr;
+}
+
+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)
@@ -92,6 +155,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
start_addr = addr;
full_search:
+
+ addr = align_addr(addr, filp, 0);
+
for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
/* At this point: (!vma || addr < vma->vm_end). */
if (end - len < addr) {
@@ -117,6 +183,7 @@ full_search:
mm->cached_hole_size = vma->vm_start - addr;
addr = vma->vm_end;
+ addr = align_addr(addr, filp, 0);
}
}
@@ -161,10 +228,13 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
/* make sure it can fit in the remaining address space */
if (addr > len) {
- vma = find_vma(mm, addr-len);
- if (!vma || addr <= vma->vm_start)
+ unsigned long tmp_addr = align_addr(addr - len, filp,
+ ALIGN_TOPDOWN);
+
+ vma = find_vma(mm, tmp_addr);
+ if (!vma || tmp_addr + len <= vma->vm_start)
/* remember the address as a hint for next time */
- return mm->free_area_cache = addr-len;
+ return mm->free_area_cache = tmp_addr;
}
if (mm->mmap_base < len)
@@ -173,6 +243,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
addr = mm->mmap_base-len;
do {
+ addr = align_addr(addr, filp, ALIGN_TOPDOWN);
+
/*
* Lookup failure means no vma is above this address,
* else if new region fits below vma->vm_start,