x86-64: Move out cleanup higmap [_brk_end, _end) out of init_memory_mapping()

It is not related to init_memory_mapping(),  and init_memory_mapping() is
getting more bigger.

So make it as seperated function and call it from reserve_brk() and that is
point when _brk_end is concluded.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4D1933E0.7090305@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index fc0fe743f3a1..635185ba4435 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -293,10 +293,32 @@ static void __init init_gbpages(void)
         else
                 direct_gbpages = 0;
 }
+
+static void __init cleanup_highmap_brk_end(void)
+{
+        pud_t *pud;
+        pmd_t *pmd;
+
+        mmu_cr4_features = read_cr4();
+
+        /*
+         * _brk_end cannot change anymore, but it and _end may be
+         * located on different 2M pages. cleanup_highmap(), however,
+         * can only consider _end when it runs, so destroy any
+         * mappings beyond _brk_end here.
+         */
+        pud = pud_offset(pgd_offset_k(_brk_end), _brk_end);
+        pmd = pmd_offset(pud, _brk_end - 1);
+        while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1))
+                pmd_clear(pmd);
+}
 #else
 static inline void init_gbpages(void)
 {
 }
+static inline void cleanup_highmap_brk_end(void)
+{
+}
 #endif
 
 static void __init reserve_brk(void)
@@ -307,6 +329,8 @@ static void __init reserve_brk(void)
         /* Mark brk area as locked down and no longer taking any
            new allocations */
         _brk_start = 0;
+
+        cleanup_highmap_brk_end();
 }
 
 #ifdef CONFIG_BLK_DEV_INITRD