x86: work around gcc 3.4.x bug

Simon Horman reported that gcc-3.4.x crashes when compiling
pgd_prepopulate_pmd() when PREALLOCATED_PMDS == 0 and CONFIG_DEBUG_INFO
is enabled.

Adding an extra check for PREALLOCATED_PMDS == 0 [which is compiled out
by gcc] seems to avoid the problem.

Reported-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 557b2abceef8..d50302774fe2 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -207,6 +207,9 @@ static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
         unsigned long addr;
         int i;
 
+        if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */
+                return;
+
         pud = pud_offset(pgd, 0);
 
         for (addr = i = 0; i < PREALLOCATED_PMDS;