Hi Dave,
Some nitpicking in changelog:
On 5/03/2024 2:32 pm, Dave Young wrote:
crashkernel reservation failed on a Thinkpad t440s laptop recently,
',' -> '.' to make it as a standalone sentence.
Actually the memblock reservation succeeded, but later insert_resource()
failed.
Test step:
kexec load ->
kexec reboot ->
check the crashkernel memory
dmesg|grep "crashkernel reserved"; saw reserved suceeeded:
"suceeeded" -> "succeeded".
0x00000000d0000000 - 0x00000000da000000
grep Crash /proc/iomem: got nothing
And somehow I found it's not easy to read. :-)
The background story is like below:
Better to have an blank line to make text more breathable.
Currently E820 code reserves setup_data regions for both the current kernel
and the kexec kernel, and it will also insert them into resources list.
"will insert" -> "inserts".
Before the kexec kernel reboot nobody passes the old setup_data, kexec only
^ "reboots" ^ and
passes SETUP_EFI and SETUP_IMA if needed. Thus the old setup data memory
are not used at all. But due to old kernel updated the kexec e820 table
^ is ^ updates
as well so kexec kernel see them as E820_TYPE_RESERVED_KERN regions, later
"so kexec kernel" -> ", the kexec kernel"
"see" -> "sees"
", later" -> ", and later"
the old setup_data regions will be inserted into resources list in kexec
"will be" -> "are"
kernel by e820__reserve_resources().
Note, due to no setup_data passed in for those old regions they are not
^ is
early reserved (by function early_reserve_memory), crashkernel memblock
^ and the
reservation will just regard them as usable memory and it could reserve
"regard" -> "treat"
reserve crashkernel region overlaps with the old setup_data regions.
double "reserve".
"crashkernel region" -> "the crashkernel region"
"overlaps" -> "which overlaps"
Just like the bug I noticed here, kdump insert_resource failed because
e820__reserve_resources added the overlapped chunks in /proc/iomem already.
^ has added
Finally, looking at the code, the old setup_data regions are not used
at all as no setup_data passed in by the kexec boot loader. Although
^ is passed
something like SETUP_PCI etc could be needed, kexec should pass
the info as setup_data so that kexec kernel can take care of them.
This should be taken care of in other separate patches if needed.
Thus drop the useless buggy code here.
Signed-off-by: Dave Young <[email protected]>
---
arch/x86/kernel/e820.c | 16 +---------------
1 file changed, 1 insertion(+), 15 deletions(-)
Index: linux/arch/x86/kernel/e820.c
===================================================================
--- linux.orig/arch/x86/kernel/e820.c
+++ linux/arch/x86/kernel/e820.c
@@ -1015,16 +1015,6 @@ void __init e820__reserve_setup_data(voi
pa_next = data->next;
e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
-
- /*
- * SETUP_EFI and SETUP_IMA are supplied by kexec and do not need
- * to be reserved.
- */
- if (data->type != SETUP_EFI && data->type != SETUP_IMA)
- e820__range_update_kexec(pa_data,
- sizeof(*data) + data->len,
- E820_TYPE_RAM,
E820_TYPE_RESERVED_KERN);
-
if (data->type == SETUP_INDIRECT) {
len += data->len;
early_memunmap(data, sizeof(*data));
@@ -1036,12 +1026,9 @@ void __init e820__reserve_setup_data(voi
indirect = (struct setup_indirect *)data->data;
- if (indirect->type != SETUP_INDIRECT) {
+ if (indirect->type != SETUP_INDIRECT)
e820__range_update(indirect->addr,
indirect->len,
E820_TYPE_RAM,
E820_TYPE_RESERVED_KERN);
- e820__range_update_kexec(indirect->addr,
indirect->len,
- E820_TYPE_RAM,
E820_TYPE_RESERVED_KERN);
- }
}
pa_data = pa_next;
@@ -1049,7 +1036,6 @@ void __init e820__reserve_setup_data(voi
}
e820__update_table(e820_table);
- e820__update_table(e820_table_kexec);
pr_info("extended physical RAM map:\n");
e820__print_table("reserve setup_data");
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