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| author |  Dave Young <dyoung@redhat.com>
| 2020-02-12 19:04:24 +0800 |
|---|---|---|
| committer |  Borislav Petkov <bp@suse.de>
| 2020-02-24 11:41:57 +0100 |
| commit | 8efbc518b884e1db2dd6a6fce62d0112ab871dcf (patch) | |
| tree | fdfa275df6b758ce61df52b19460539c7eee4c1b /arch/x86/kernel/e820.c | |
| parent | Linux 5.6-rc3 (diff) | |
| download | linux-8efbc518b884e1db2dd6a6fce62d0112ab871dcf.tar.gz linux-8efbc518b884e1db2dd6a6fce62d0112ab871dcf.tar.bz2 linux-8efbc518b884e1db2dd6a6fce62d0112ab871dcf.zip | |
x86/kexec: Do not reserve EFI setup_data in the kexec e820 table
The e820 table for the kexec kernel unconditionally marks setup_data as
reserved because the second kernel can reuse setup_data passed by the
1st kernel's boot loader, for example SETUP_PCI marked regions like PCI
BIOS, etc.
SETUP_EFI types, however, are used by kexec itself to enable EFI in the
2nd kernel. Thus, it is pointless to add this type of setup_data to the
kexec e820 table as reserved.
IOW, what happens is this:
- 1st physical boot: no SETUP_EFI.
- kexec loads a new kernel and prepares a SETUP_EFI setup_data blob, then
reboots the machine.
- 2nd kernel sees SETUP_EFI, reserves it both in the e820 and in the
kexec e820 table.
- If another kexec load is executed, it prepares a new SETUP_EFI blob and
then reboots the machine into the new kernel.
5. The 3rd kexec-ed kernel has two SETUP_EFI ranges reserved. And so on...
Thus skip SETUP_EFI while reserving setup_data in the e820_table_kexec
table because it is not needed.
[ bp: Heavily massage commit message, shorten line and improve comment. ]
Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200212110424.GA2938@dhcp-128-65.nay.redhat.com
Diffstat (limited to 'arch/x86/kernel/e820.c')
| -rw-r--r-- | arch/x86/kernel/e820.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index c5399e80c59c..c92029651b85 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -999,7 +999,15 @@ void __init e820__reserve_setup_data(void) while (pa_data) { data = early_memremap(pa_data, sizeof(*data)); e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN); - e820__range_update_kexec(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN); + + /* + * SETUP_EFI is supplied by kexec and does not need to be + * reserved. + */ + if (data->type != SETUP_EFI) + e820__range_update_kexec(pa_data, + sizeof(*data) + data->len, + E820_TYPE_RAM, E820_TYPE_RESERVED_KERN); if (data->type == SETUP_INDIRECT && ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) { |