Messages in this thread | | | Date | Wed, 9 Jun 2021 11:54:39 +0300 | From | Mike Rapoport <> | Subject | Re: [PATCH] x86/setup: Document that Windows reserves the first MiB |
| |
On Tue, Jun 08, 2021 at 10:30:46PM +0200, Borislav Petkov wrote: > It does so unconditionally too, on Intel and AMD machines, to work > around BIOS bugs, as confirmed by Microsoft folks (see Link for full > details). > > Reflow the paragraph, while at it. > > Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Thanks for taking care of this!
> Link: https://lkml.kernel.org/r/MWHPR21MB159330952629D36EEDE706B3D7379@MWHPR21MB1593.namprd21.prod.outlook.com > --- > arch/x86/kernel/setup.c | 21 +++++++++++---------- > 1 file changed, 11 insertions(+), 10 deletions(-) > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > index 7638ac6c3d80..85acd22f8022 100644 > --- a/arch/x86/kernel/setup.c > +++ b/arch/x86/kernel/setup.c > @@ -1060,17 +1060,18 @@ void __init setup_arch(char **cmdline_p) > #endif > > /* > - * Find free memory for the real mode trampoline and place it > - * there. > - * If there is not enough free memory under 1M, on EFI-enabled > - * systems there will be additional attempt to reclaim the memory > - * for the real mode trampoline at efi_free_boot_services(). > + * Find free memory for the real mode trampoline and place it there. If > + * there is not enough free memory under 1M, on EFI-enabled systems > + * there will be additional attempt to reclaim the memory for the real > + * mode trampoline at efi_free_boot_services(). > * > - * Unconditionally reserve the entire first 1M of RAM because > - * BIOSes are know to corrupt low memory and several > - * hundred kilobytes are not worth complex detection what memory gets > - * clobbered. Moreover, on machines with SandyBridge graphics or in > - * setups that use crashkernel the entire 1M is reserved anyway. > + * Unconditionally reserve the entire first 1M of RAM because BIOSes > + * are known to corrupt low memory and several hundred kilobytes are not > + * worth complex detection what memory gets clobbered. Windows does the > + * same thing for very similar reasons. > + * > + * Moreover, on machines with SandyBridge graphics or in setups that use > + * crashkernel the entire 1M is reserved anyway. > */ > reserve_real_mode(); > > -- > 2.29.2 > > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette
-- Sincerely yours, Mike.
| |