forked from Minki/linux
4c5e242d3e
ACPI firmware advertises PCI host bridge resources via PNP0A03 _CRS
methods. Some BIOSes include non-window address space in _CRS, and if we
allocate that non-window space for PCI devices, they don't work.
4dc2287c18 ("x86: avoid E820 regions when allocating address space")
works around this issue by clipping out any regions mentioned in the E820
table in the allocate_resource() path, but the implementation has a couple
issues:
- The clipping is done for *all* allocations, not just those for PCI
address space, and
- The clipping is done at each allocation instead of being done once when
setting up the host bridge windows.
Rework the implementation so we only clip PCI host bridge windows, and we
do it once when setting them up.
Example output changes:
BIOS-e820: [mem 0x00000000b0000000-0x00000000c00fffff] reserved
+ acpi PNP0A08:00: clipped [mem 0xc0000000-0xfebfffff window] to [mem 0xc0100000-0xfebfffff window] for e820 entry [mem 0xb0000000-0xc00fffff]
- pci_bus 0000:00: root bus resource [mem 0xc0000000-0xfebfffff window]
+ pci_bus 0000:00: root bus resource [mem 0xc0100000-0xfebfffff window]
Link: https://lore.kernel.org/r/20220304035110.988712-3-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
61 lines
1.5 KiB
C
61 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/dev_printk.h>
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#include <linux/ioport.h>
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#include <asm/e820/api.h>
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static void resource_clip(struct resource *res, resource_size_t start,
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resource_size_t end)
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{
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resource_size_t low = 0, high = 0;
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if (res->end < start || res->start > end)
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return; /* no conflict */
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if (res->start < start)
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low = start - res->start;
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if (res->end > end)
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high = res->end - end;
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/* Keep the area above or below the conflict, whichever is larger */
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if (low > high)
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res->end = start - 1;
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else
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res->start = end + 1;
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}
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void remove_e820_regions(struct device *dev, struct resource *avail)
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{
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int i;
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struct e820_entry *entry;
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u64 e820_start, e820_end;
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struct resource orig = *avail;
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if (!(avail->flags & IORESOURCE_MEM))
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return;
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for (i = 0; i < e820_table->nr_entries; i++) {
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entry = &e820_table->entries[i];
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e820_start = entry->addr;
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e820_end = entry->addr + entry->size - 1;
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resource_clip(avail, e820_start, e820_end);
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if (orig.start != avail->start || orig.end != avail->end) {
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dev_info(dev, "clipped %pR to %pR for e820 entry [mem %#010Lx-%#010Lx]\n",
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&orig, avail, e820_start, e820_end);
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orig = *avail;
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}
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}
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}
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void arch_remove_reservations(struct resource *avail)
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{
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/*
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* Trim out BIOS area (high 2MB) and E820 regions. We do not remove
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* the low 1MB unconditionally, as this area is needed for some ISA
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* cards requiring a memory range, e.g. the i82365 PCMCIA controller.
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*/
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if (avail->flags & IORESOURCE_MEM)
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resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
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}
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