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-rw-r--r--arch/x86/Kconfig9
-rw-r--r--arch/x86/mm/init_32.c2
-rw-r--r--arch/x86/mm/init_64.c2
3 files changed, 12 insertions, 1 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 648fca42ae6a..0eb801a75dee 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -112,7 +112,14 @@ config MMU
def_bool y
config ZONE_DMA
- def_bool y
+ bool "DMA memory allocation support" if EXPERT
+ default y
+ help
+ DMA memory allocation support allows devices with less than 32-bit
+ addressing to allocate within the first 16MB of address space.
+ Disable if no such devices will be used.
+
+ If unsure, say Y.
config SBUS
bool
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 2cde0a34bed6..29f7c6d98179 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -678,8 +678,10 @@ static void __init zone_sizes_init(void)
{
unsigned long max_zone_pfns[MAX_NR_ZONES];
memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+#ifdef CONFIG_ZONE_DMA
max_zone_pfns[ZONE_DMA] =
virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
+#endif
max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
#ifdef CONFIG_HIGHMEM
max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 0404bb3a077e..d865c4aeec55 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -616,7 +616,9 @@ void __init paging_init(void)
unsigned long max_zone_pfns[MAX_NR_ZONES];
memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+#ifdef CONFIG_ZONE_DMA
max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
+#endif
max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
max_zone_pfns[ZONE_NORMAL] = max_pfn;
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