From: "Andi Kleen" <[email protected]>
Look for gaps in the e820 memory map to put PCI resources in.
This hopefully fixes problems with the PCI code assigning 32bit BARs MMIO
resources which are >32bit.
Signed-off-by: Andi Kleen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
25-akpm/arch/x86_64/kernel/e820.c | 59 +++++++++++++++++++++++++++++++++++++
25-akpm/arch/x86_64/kernel/setup.c | 12 -------
25-akpm/include/asm-x86_64/e820.h | 1
3 files changed, 61 insertions(+), 11 deletions(-)
diff -puN arch/x86_64/kernel/e820.c~x86_64-port-over-e820-gap-detection-from-i386 arch/x86_64/kernel/e820.c
--- 25/arch/x86_64/kernel/e820.c~x86_64-port-over-e820-gap-detection-from-i386 2005-04-12 03:21:25.287292648 -0700
+++ 25-akpm/arch/x86_64/kernel/e820.c 2005-04-12 03:21:25.293291736 -0700
@@ -511,3 +511,62 @@ void __init parse_memopt(char *p, char *
end_user_pfn >>= PAGE_SHIFT;
}
+unsigned long pci_mem_start = 0xaeedbabe;
+
+/*
+ * 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;
+ unsigned long last;
+ int i;
+ 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;
+
+ /*
+ * Since "last" is at most 4GB, we know we'll
+ * fit in 32 bits if this condition is true
+ */
+ if (last > end) {
+ unsigned long gap = last - end;
+
+ if (gap > gapsize) {
+ gapsize = gap;
+ gapstart = end;
+ found = 1;
+ }
+ }
+ if (start < last)
+ last = start;
+ }
+
+ if (!found) {
+ gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
+ printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit address range\n"
+ KERN_ERR "PCI: Unassigned devices with 32bit resource registers may break!\n");
+ }
+
+ /*
+ * Start allocating dynamic PCI memory a bit into the gap,
+ * aligned up to the nearest megabyte.
+ *
+ * Question: should we try to pad it up a bit (do something
+ * like " + (gapsize >> 3)" in there too?). We now have the
+ * technology.
+ */
+ pci_mem_start = (gapstart + 0xfffff) & ~0xfffff;
+
+ printk(KERN_INFO "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
+ pci_mem_start, gapstart, gapsize);
+}
diff -puN arch/x86_64/kernel/setup.c~x86_64-port-over-e820-gap-detection-from-i386 arch/x86_64/kernel/setup.c
--- 25/arch/x86_64/kernel/setup.c~x86_64-port-over-e820-gap-detection-from-i386 2005-04-12 03:21:25.288292496 -0700
+++ 25-akpm/arch/x86_64/kernel/setup.c 2005-04-12 03:21:25.294291584 -0700
@@ -76,9 +76,6 @@ int __initdata acpi_force = 0;
int acpi_numa __initdata;
-/* For PCI or other memory-mapped resources */
-unsigned long pci_mem_start = 0x10000000;
-
/* Boot loader ID as an integer, for the benefit of proc_dointvec */
int bootloader_type;
@@ -495,7 +492,6 @@ static void __init reserve_ebda_region(v
void __init setup_arch(char **cmdline_p)
{
- unsigned long low_mem_size;
unsigned long kernel_end;
ROOT_DEV = old_decode_dev(ORIG_ROOT_DEV);
@@ -654,13 +650,7 @@ void __init setup_arch(char **cmdline_p)
request_resource(&ioport_resource, &standard_io_resources[i]);
}
- /* Will likely break when you have unassigned resources with more
- than 4GB memory and bridges that don't support more than 4GB.
- Doing it properly would require to use pci_alloc_consistent
- in this case. */
- low_mem_size = ((end_pfn << PAGE_SHIFT) + 0xfffff) & ~0xfffff;
- if (low_mem_size > pci_mem_start)
- pci_mem_start = low_mem_size;
+ e820_setup_gap();
#ifdef CONFIG_GART_IOMMU
iommu_hole_init();
diff -puN include/asm-x86_64/e820.h~x86_64-port-over-e820-gap-detection-from-i386 include/asm-x86_64/e820.h
--- 25/include/asm-x86_64/e820.h~x86_64-port-over-e820-gap-detection-from-i386 2005-04-12 03:21:25.289292344 -0700
+++ 25-akpm/include/asm-x86_64/e820.h 2005-04-12 03:21:25.294291584 -0700
@@ -50,6 +50,7 @@ extern void e820_print_map(char *who);
extern int e820_mapped(unsigned long start, unsigned long end, unsigned type);
extern void e820_bootmem_free(pg_data_t *pgdat, unsigned long start,unsigned long end);
+extern void e820_setup_gap(void);
extern void __init parse_memopt(char *p, char **end);
_
-
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