From 73159fdcdb9be3eda61b846864352c29371baeb6 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 5 May 2014 12:19:31 -0700 Subject: [PATCH] x86, mm: Ensure correct alignment of the fixmap The early_ioremap code requires that its buffers not span a PMD boundary. The logic for ensuring that only works if the fixmap is aligned, so assert that it's aligned correctly. To make this work reliably, reserve_top_address needs to be adjusted. Signed-off-by: Andy Lutomirski Link: http://lkml.kernel.org/r/e59a5f4362661f75dd4841fa74e1f2448045e245.1399317206.git.luto@amacapital.net Signed-off-by: H. Peter Anvin --- arch/x86/mm/ioremap.c | 6 ++++++ arch/x86/mm/pgtable.c | 6 +++--- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 597ac155c91c..6ef98c55a899 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -355,6 +355,12 @@ void __init early_ioremap_init(void) { pmd_t *pmd; +#ifdef CONFIG_X86_64 + BUILD_BUG_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1)); +#else + WARN_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1)); +#endif + early_ioremap_setup(); pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)); diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index c96314abd144..5f8bdda1d1ba 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -449,9 +449,9 @@ void __init reserve_top_address(unsigned long reserve) { #ifdef CONFIG_X86_32 BUG_ON(fixmaps_set > 0); - printk(KERN_INFO "Reserving virtual address space above 0x%08x\n", - (int)-reserve); - __FIXADDR_TOP = -reserve - PAGE_SIZE; + __FIXADDR_TOP = round_down(-reserve, 1 << PMD_SHIFT) - PAGE_SIZE; + printk(KERN_INFO "Reserving virtual address space above 0x%08lx (rounded to 0x%08lx)\n", + -reserve, __FIXADDR_TOP + PAGE_SIZE); #endif } -- 2.34.1