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linux/arch/x86/kernel/resource.c
Bjorn Helgaas 00904bf64c x86/PCI: Tidy E820 removal messages
These messages:

  clipped [mem size 0x00000000 64bit] to [mem size 0xfffffffffffa0000 64bit] for e820 entry [mem 0x0009f000-0x000fffff]

aren't as useful as they could be because (a) the resource is often
IORESOURCE_UNSET, so we print the size instead of the start/end and (b) we
print the available resource even if it is empty after removing the E820
entry.

Print the available space by hand to avoid the IORESOURCE_UNSET problem and
only if it's non-empty.  No functional change intended.

Link: https://lore.kernel.org/r/20221208190341.1560157-4-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
2022-12-10 10:33:11 -06:00

73 lines
1.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/ioport.h>
#include <linux/printk.h>
#include <asm/e820/api.h>
#include <asm/pci_x86.h>
static void resource_clip(struct resource *res, resource_size_t start,
resource_size_t end)
{
resource_size_t low = 0, high = 0;
if (res->end < start || res->start > end)
return; /* no conflict */
if (res->start < start)
low = start - res->start;
if (res->end > end)
high = res->end - end;
/* Keep the area above or below the conflict, whichever is larger */
if (low > high)
res->end = start - 1;
else
res->start = end + 1;
}
static void remove_e820_regions(struct resource *avail)
{
int i;
struct e820_entry *entry;
u64 e820_start, e820_end;
struct resource orig = *avail;
if (!pci_use_e820)
return;
for (i = 0; i < e820_table->nr_entries; i++) {
entry = &e820_table->entries[i];
e820_start = entry->addr;
e820_end = entry->addr + entry->size - 1;
resource_clip(avail, e820_start, e820_end);
if (orig.start != avail->start || orig.end != avail->end) {
pr_info("resource: avoiding allocation from e820 entry [mem %#010Lx-%#010Lx]\n",
e820_start, e820_end);
if (avail->end > avail->start)
/*
* Use %pa instead of %pR because "avail"
* is typically IORESOURCE_UNSET, so %pR
* shows the size instead of addresses.
*/
pr_info("resource: remaining [mem %pa-%pa] available\n",
&avail->start, &avail->end);
orig = *avail;
}
}
}
void arch_remove_reservations(struct resource *avail)
{
/*
* Trim out BIOS area (high 2MB) and E820 regions. We do not remove
* the low 1MB unconditionally, as this area is needed for some ISA
* cards requiring a memory range, e.g. the i82365 PCMCIA controller.
*/
if (avail->flags & IORESOURCE_MEM) {
resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
remove_e820_regions(avail);
}
}