Commit-ID: 919a02d1280a3845bac70e6b7891ca070f21a60a Gitweb: http://git.kernel.org/tip/919a02d1280a3845bac70e6b7891ca070f21a60a Author: Kirill A. Shutemov <kirill.shute...@linux.intel.com> AuthorDate: Tue, 6 Jun 2017 14:31:24 +0300 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 13 Jun 2017 08:56:53 +0200
x86/boot/efi: Define __KERNEL32_CS GDT on 64-bit configurations We would need to switch temporarily to compatibility mode during booting with 5-level paging enabled. It would require 32-bit code segment descriptor. Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com> Reviewed-by: Matt Fleming <m...@codeblueprint.co.uk> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Andy Lutomirski <l...@amacapital.net> Cc: Andy Lutomirski <l...@kernel.org> Cc: Borislav Petkov <b...@alien8.de> Cc: Brian Gerst <brge...@gmail.com> Cc: Dave Hansen <dave.han...@intel.com> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Josh Poimboeuf <jpoim...@redhat.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: linux-a...@vger.kernel.org Cc: linux...@kvack.org Link: http://lkml.kernel.org/r/20170606113133.22974-6-kirill.shute...@linux.intel.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/boot/compressed/eboot.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index b75c20f..c3e869e 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -1046,8 +1046,29 @@ struct boot_params *efi_main(struct efi_config *c, memset((char *)gdt->address, 0x0, gdt->size); desc = (struct desc_struct *)gdt->address; - /* The first GDT is a dummy and the second is unused. */ - desc += 2; + /* The first GDT is a dummy. */ + desc++; + + if (IS_ENABLED(CONFIG_X86_64)) { + /* __KERNEL32_CS */ + desc->limit0 = 0xffff; + desc->base0 = 0x0000; + desc->base1 = 0x0000; + desc->type = SEG_TYPE_CODE | SEG_TYPE_EXEC_READ; + desc->s = DESC_TYPE_CODE_DATA; + desc->dpl = 0; + desc->p = 1; + desc->limit = 0xf; + desc->avl = 0; + desc->l = 0; + desc->d = SEG_OP_SIZE_32BIT; + desc->g = SEG_GRANULARITY_4KB; + desc->base2 = 0x00; + desc++; + } else { + /* Second entry is unused on 32-bit */ + desc++; + } /* __KERNEL_CS */ desc->limit0 = 0xffff;
