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authorAlok Kataria <akataria@vmware.com>2008-06-24 11:48:30 -0700
committerIngo Molnar <mingo@elte.hu>2008-07-08 13:10:39 +0200
commit3381959da5a00ae8289cfbd28b0b6d228f2d1d46 (patch)
tree6383c6b4cc564f84a07e84fd30622aa661d03c79 /arch/x86/kernel/e820.c
parentc987d12f8455b19b3b057d63bac3de161bd809fc (diff)
x86: cleanup e820_setup_gap(), add e820_search_gap(), v2
This is a preparatory patch for the next patch in series. Moves some code from e820_setup_gap to a new function e820_search_gap. This patch is a part of a bug fix where we walk the ACPI table to calculate a gap for PCI optional devices. v1->v2: Patch on top of tip/master. Fixes a bug introduced in the last patch about the typeof "last". Also the new function e820_search_gap now returns if we found a gap in e820_map. Signed-off-by: Alok N Kataria <akataria@vmware.com> Cc: lenb@kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/e820.c')
-rw-r--r--arch/x86/kernel/e820.c43
1 files changed, 28 insertions, 15 deletions
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 3900ff51bc6..22cfd665224 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -488,26 +488,22 @@ void __init update_e820(void)
}
/*
- * Search for the biggest gap in the low 32 bits of the e820
- * memory space. We pass this space to PCI to assign MMIO resources
- * for hotplug or unconfigured devices in.
- * Hopefully the BIOS let enough space left.
+ * Search for a gap in the e820 memory space from start_addr to 2^32.
*/
-__init void e820_setup_gap(void)
+__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
+ unsigned long start_addr)
{
- unsigned long gapstart, gapsize, round;
- unsigned long long last;
- int i;
+ unsigned long long last = 0x100000000ull;
+ int i = e820.nr_map;
int found = 0;
- last = 0x100000000ull;
- gapstart = 0x10000000;
- gapsize = 0x400000;
- i = e820.nr_map;
while (--i >= 0) {
unsigned long long start = e820.map[i].addr;
unsigned long long end = start + e820.map[i].size;
+ if (end < start_addr)
+ continue;
+
/*
* Since "last" is at most 4GB, we know we'll
* fit in 32 bits if this condition is true
@@ -515,15 +511,32 @@ __init void e820_setup_gap(void)
if (last > end) {
unsigned long gap = last - end;
- if (gap > gapsize) {
- gapsize = gap;
- gapstart = end;
+ if (gap >= *gapsize) {
+ *gapsize = gap;
+ *gapstart = end;
found = 1;
}
}
if (start < last)
last = start;
}
+ return found;
+}
+
+/*
+ * Search for the biggest gap in the low 32 bits of the e820
+ * memory space. We pass this space to PCI to assign MMIO resources
+ * for hotplug or unconfigured devices in.
+ * Hopefully the BIOS let enough space left.
+ */
+__init void e820_setup_gap(void)
+{
+ unsigned long gapstart, gapsize, round;
+ int found;
+
+ gapstart = 0x10000000;
+ gapsize = 0x400000;
+ found = e820_search_gap(&gapstart, &gapsize, 0);
#ifdef CONFIG_X86_64
if (!found) {