On 06/01/21 at 10:53am, Mike Rapoport wrote: > From: Mike Rapoport <rppt@xxxxxxxxxxxxx> ...... > diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c > index 7850111008a8..b15ebfe40a73 100644 > --- a/arch/x86/platform/efi/quirks.c > +++ b/arch/x86/platform/efi/quirks.c > @@ -450,6 +450,18 @@ void __init efi_free_boot_services(void) > size -= rm_size; > } Thanks for taking care of the low-1M excluding in efi_free_boot_services(), Mike. You might want to remove the old real mode excluding code either since it's been covered by your new code. diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index b15ebfe40a73..be814f2089ff 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -409,7 +409,6 @@ void __init efi_free_boot_services(void) for_each_efi_memory_desc(md) { unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; - size_t rm_size; if (md->type != EFI_BOOT_SERVICES_CODE && md->type != EFI_BOOT_SERVICES_DATA) { @@ -430,26 +429,6 @@ void __init efi_free_boot_services(void) */ efi_unmap_pages(md); - /* - * Nasty quirk: if all sub-1MB memory is used for boot - * services, we can get here without having allocated the - * real mode trampoline. It's too late to hand boot services - * memory back to the memblock allocator, so instead - * try to manually allocate the trampoline if needed. - * - * I've seen this on a Dell XPS 13 9350 with firmware - * 1.4.4 with SGX enabled booting Linux via Fedora 24's - * grub2-efi on a hard disk. (And no, I don't know why - * this happened, but Linux should still try to boot rather - * panicking early.) - */ - rm_size = real_mode_size_needed(); - if (rm_size && (start + rm_size) < (1<<20) && size >= rm_size) { - set_real_mode_mem(start); - start += rm_size; - size -= rm_size; - } - /* * Don't free memory under 1M for two reasons: * - BIOS might clobber it > > + /* > + * Don't free memory under 1M for two reasons: > + * - BIOS might clobber it > + * - Crash kernel needs it to be reserved > + */ > + if (start + size < SZ_1M) > + continue; > + if (start < SZ_1M) { > + size -= (SZ_1M - start); > + start = SZ_1M; > + } > + > memblock_free_late(start, size); > } > > diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c > index 2e1c1bec0f9e..8ea285aca827 100644 > --- a/arch/x86/realmode/init.c > +++ b/arch/x86/realmode/init.c > @@ -29,14 +29,16 @@ void __init reserve_real_mode(void) > > /* Has to be under 1M so we can execute real-mode AP code. */ > mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE); > - if (!mem) { > + if (!mem) > pr_info("No sub-1M memory is available for the trampoline\n"); > - return; > - } > + else > + set_real_mode_mem(mem); > > - memblock_reserve(mem, size); > - set_real_mode_mem(mem); > - crash_reserve_low_1M(); > + /* > + * Unconditionally reserve the entire fisrt 1M, see comment in > + * setup_arch() > + */ > + memblock_reserve(0, SZ_1M); > } > > static void sme_sev_setup_real_mode(struct trampoline_header *th) > -- > 2.28.0 >