x86: Log resource clipping for E820 regions

When remove_e820_regions() clips a resource because an E820 region overlaps
it, log a note in dmesg to add in debugging.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/arch/x86/kernel/resource.c b/arch/x86/kernel/resource.c
index 8ffe684..30d524a 100644 (file)
--- a/arch/x86/kernel/resource.c
+++ b/arch/x86/kernel/resource.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/ioport.h>
+#include <linux/printk.h>
 #include <asm/e820/api.h>
 
 static void resource_clip(struct resource *res, resource_size_t start,
@@ -28,6 +29,7 @@ static void remove_e820_regions(struct resource *avail)
        int i;
        struct e820_entry *entry;
        u64 e820_start, e820_end;
+       struct resource orig = *avail;
 
        for (i = 0; i < e820_table->nr_entries; i++) {
                entry = &e820_table->entries[i];
@@ -35,6 +37,11 @@ static void remove_e820_regions(struct resource *avail)
                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("clipped %pR to %pR for e820 entry [mem %#010Lx-%#010Lx]\n",
+                                &orig, avail, e820_start, e820_end);
+                       orig = *avail;
+               }
        }
 }