From 058ddee5625ade9e9e011b9ae155ac3b8d4eda3a Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 7 Aug 2008 22:36:59 +0100 Subject: [PATCH] [ARM] Fix SMP booting with non-zero PHYS_OFFSET The existing code tries to get the pmd for the temporary page table by doing: pgd = pgd_alloc(&init_mm); pmd = pmd_offset(pgd, PHYS_OFFSET); Since we have a two level page table, pmd_offset() is a no-op, so this just has a casting effect from a pgd to a pmd - the address argument is unused. So this can't work. Normally, we'd do: pgd = pgd_offset(&init_mm, PHYS_OFFSET); ... pmd = pmd_offset(pgd, PHYS_OFFSET); to get the pmd you want. However, pgd_offset() takes the mm_struct, not the (unattached) pgd we just allocated. So, instead use: pgd = pgd_alloc(&init_mm); pmd = pmd_offset(pgd + pgd_index(PHYS_OFFSET), PHYS_OFFSET); Reported-by: Antti P Miettinen Signed-off-by: Russell King --- arch/arm/kernel/smp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 5a7c09564d1..e9842f6767f 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -100,7 +100,7 @@ int __cpuinit __cpu_up(unsigned int cpu) * a 1:1 mapping for the physical address of the kernel. */ pgd = pgd_alloc(&init_mm); - pmd = pmd_offset(pgd, PHYS_OFFSET); + pmd = pmd_offset(pgd + pgd_index(PHYS_OFFSET), PHYS_OFFSET); *pmd = __pmd((PHYS_OFFSET & PGDIR_MASK) | PMD_TYPE_SECT | PMD_SECT_AP_WRITE); @@ -139,7 +139,7 @@ int __cpuinit __cpu_up(unsigned int cpu) secondary_data.stack = NULL; secondary_data.pgdir = 0; - *pmd_offset(pgd, PHYS_OFFSET) = __pmd(0); + *pmd = __pmd(0); pgd_free(&init_mm, pgd); if (ret) { -- 2.41.1