On Thu, 9 Feb 2017, Borislav Petkov wrote:
> I can't say that I'm thrilled about the ifdeffery this is adding.
>
> But I can't think of a cleaner approach at a quick glance, though -
> that's generic and arch-specific code intertwined muck. Sad face.
It's trivial enough to do ....
Thanks,
tglx
---
arch/x86/mm/mmap.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -55,6 +55,10 @@ static unsigned long stack_maxrandom_siz
#define MIN_GAP (128*1024*1024UL + stack_maxrandom_size())
#define MAX_GAP (TASK_SIZE/6*5)
+#ifndef CONFIG_COMPAT
+# define mmap_rnd_compat_bits mmap_rnd_bits
+#endif
+
static int mmap_is_legacy(void)
{
if (current->personality & ADDR_COMPAT_LAYOUT)
@@ -66,20 +70,14 @@ static int mmap_is_legacy(void)
return sysctl_legacy_va_layout;
}
-unsigned long arch_mmap_rnd(void)
+static unsigned long arch_rnd(unsigned int rndbits)
{
- unsigned long rnd;
-
- if (mmap_is_ia32())
-#ifdef CONFIG_COMPAT
- rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1);
-#else
- rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
-#endif
- else
- rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1);
+ return (get_random_long() & ((1UL << rndbits) - 1)) << PAGE_SHIFT;
+}
- return rnd << PAGE_SHIFT;
+unsigned long arch_mmap_rnd(void)
+{
+ return arch_rnd(mmap_is_ia32() ? mmap_rnd_compat_bits : mmap_rnd_bits);
}
static unsigned long mmap_base(unsigned long rnd)
