On Sat, May 18, 2019 at 05:58:39AM +0200, Mark Kettenis wrote:
> > Date: Fri, 17 May 2019 17:56:52 -0400
> > From: Patrick Wildt <[email protected]>
> >
> > Hi,
> >
> > claudio@ has a Kaby Lake that exceeds the 128 kB limit, being as big as
> > 190 kB. So, for him the ucode isn't being loaded.
> >
> > On EFI systems we can simply ask EFI to allocate some memory for us.
> > I'm not sure why this file is duplicated 4 times, but it looks like
> > for efiboot this one is currently the file to patch.
> >
> > This diff works for claudio@'s EFI booted system. Since I don't know
> > how much space is available on legacy systems I will not attempt to
> > fix this for the legacy bootloader. Someone that knows more than me
> > about x86 can attempt that.
> >
> > Feedback? ok?
>
> In principle, ye, that is the right approach.
>
> However, until Mike gets us to the point where we no longer care at
> which physical address the kernel was loaded, efiboot will move the
> kernel to a specific physical address after loading it and potentially
> thrash all memory allocated through the EFI interfaces. So there is a
> change that we will overwrite the microcode at that point.
>
> So it might actually be safer to just change the limit to 256k if
> there is a good chance the the memory at the 1MB mark is unlikely to
> be used by anything else.
>
Thanks for pointing this out. Will keep this in mind when we move to
random-PA kernel load.
-ml
> > diff --git a/sys/arch/amd64/stand/efiboot/exec_i386.c
> > b/sys/arch/amd64/stand/efiboot/exec_i386.c
> > index e4b39d6cd0c..ea1d301f1d8 100644
> > --- a/sys/arch/amd64/stand/efiboot/exec_i386.c
> > +++ b/sys/arch/amd64/stand/efiboot/exec_i386.c
> > @@ -46,8 +46,13 @@
> > #include "softraid_amd64.h"
> > #endif
> >
> > +#include <efi.h>
> > +#include <efiapi.h>
> > +#include "eficall.h"
> > #include "efiboot.h"
> >
> > +extern EFI_BOOT_SERVICES *BS;
> > +
> > typedef void (*startfuncp)(int, int, int, int, int, int, int, int)
> > __attribute__ ((noreturn));
> >
> > @@ -165,6 +170,7 @@ run_loadfile(uint64_t *marks, int howto)
> > void
> > ucode_load(void)
> > {
> > + EFI_PHYSICAL_ADDRESS addr;
> > uint32_t model, family, stepping;
> > uint32_t dummy, signature;
> > uint32_t vendor[4];
> > @@ -200,12 +206,12 @@ ucode_load(void)
> > return;
> >
> > buflen = sb.st_size;
> > - if (buflen > 128*1024) {
> > - printf("ucode too large\n");
> > + if (EFI_CALL(BS->AllocatePages, AllocateAnyPages, EfiLoaderData,
> > + EFI_SIZE_TO_PAGES(buflen), &addr) != EFI_SUCCESS) {
> > + printf("cannot allocate memory for ucode\n");
> > return;
> > }
> > -
> > - buf = (char *)(1*1024*1024);
> > + buf = (char *)((paddr_t)addr);
> >
> > if (read(fd, buf, buflen) != buflen) {
> > close(fd);
> >
> >
>
