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yaml --- r: 166202 b: refs/heads/master c: 8bbde7a h: refs/heads/master v: v3
git-mirror · Sep 24, 2009 · ea2c006 · ea2c006
1 parent 144799d
commit ea2c006
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Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 738ef42e32fe95553a424c04016b936c9f6c9afb
+refs/heads/master: 8bbde7a7062facf8af35bcc9a64cbafe8f36f3cf
diff --git a/trunk/arch/powerpc/kernel/process.c b/trunk/arch/powerpc/kernel/process.c
@@ -1165,7 +1165,22 @@ static inline unsigned long brk_rnd(void)
 
 unsigned long arch_randomize_brk(struct mm_struct *mm)
 {
-	unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
+	unsigned long base = mm->brk;
+	unsigned long ret;
+
+#ifdef CONFIG_PPC64
+	/*
+	 * If we are using 1TB segments and we are allowed to randomise
+	 * the heap, we can put it above 1TB so it is backed by a 1TB
+	 * segment. Otherwise the heap will be in the bottom 1TB
+	 * which always uses 256MB segments and this may result in a
+	 * performance penalty.
+	 */
+	if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
+		base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
+#endif
+
+	ret = PAGE_ALIGN(base + brk_rnd());
 
 	if (ret < mm->brk)
 		return mm->brk;