Only the region described by PT_LOADs of /proc/vmcore are dumpable/readble
by dumping applications. Previously, on x86/x86_64 only system ram resources
will be injected into PT_LOADs.
So in order to make the entire pmem resource is dumpable/readable, we need
to add pmem region into the PT_LOADs of /proc/vmcore.
Here we introduce a new API walk_pmem_res() to sort out the pmem region. Note
that, unlike other walk_xxx_res() API in resource.c, we walk through
pmem resources without IORESOUCE_BUSY flag.
This is kexec_file_load() specific, for kexec_load(), kexec-tools will have a
similar change.
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Borislav Petkov <bp@xxxxxxxxx>
CC: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CC: "H. Peter Anvin" <hpa@xxxxxxxxx>
CC: Baoquan He <bhe@xxxxxxxxxx>
CC: x86@xxxxxxxxxx
Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
---
arch/x86/kernel/crash.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index cdd92ab43cda..97763ea804c6 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -168,6 +168,17 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
return 0;
}
+/*
+ * This function calls the @func callback against all memory ranges, which
+ * are ranges marked as IORESOURCE_MEM and IORES_DESC_PERSISTENT_MEMORY.
+ */
+static int walk_pmem_res(u64 start, u64 end, void *arg,
+ int (*func)(struct resource *, void *))
+{
+ return walk_iomem_res_desc(IORES_DESC_PERSISTENT_MEMORY, IORESOURCE_MEM,
+ start, end, arg, func);
+}
+
/* Gather all the required information to prepare elf headers for ram regions */
static struct crash_mem *fill_up_crash_elf_data(void)
{
@@ -178,6 +189,7 @@ static struct crash_mem *fill_up_crash_elf_data(void)
if (!nr_ranges)
return NULL;
+ walk_pmem_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
/*
* Exclusion of crash region and/or crashk_low_res may cause
* another range split. So add extra two slots here.
@@ -243,6 +255,7 @@ static int prepare_elf_headers(struct kimage *image, void **addr,
ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
if (ret)
goto out;
+ walk_pmem_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
/* Exclude unwanted mem ranges */
ret = elf_header_exclude_ranges(cmem);
--
2.29.2
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