diff options
| author | David Woodhouse <dwmw@amazon.co.uk> | 2025-03-26 14:16:03 +0000 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-04-10 12:17:14 +0200 |
| commit | de085ddd493bccb77a3ec1b99ae7466133540f4d (patch) | |
| tree | 1cdb0bfa0be7fa4b284974246bfd6bc6608f8a1e | |
| parent | 7516e7216bdfb9e2fab0a0ca3bd23cb2e61e46ed (diff) | |
x86/kexec: Invalidate GDT/IDT from relocate_kernel() instead of earlier
Reduce the window during which exceptions are unhandled, by leaving the
GDT/IDT in place all the way into the relocate_kernel() function, until
the moment that %cr3 gets replaced.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250326142404.256980-4-dwmw2@infradead.org
| -rw-r--r-- | arch/x86/kernel/machine_kexec_64.c | 10 | ||||
| -rw-r--r-- | arch/x86/kernel/relocate_kernel_64.S | 9 |
2 files changed, 9 insertions, 10 deletions
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index ecb0da54abd1..949c9e4bfad2 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -434,16 +434,10 @@ void __nocfi machine_kexec(struct kimage *image) * with from a table in memory. At no other time is the * descriptor table in memory accessed. * - * I take advantage of this here by force loading the - * segments, before I zap the gdt with an invalid value. + * Take advantage of this here by force loading the segments, + * before the GDT is zapped with an invalid value. */ load_segments(); - /* - * The gdt & idt are now invalid. - * If you want to load them you must set up your own idt & gdt. - */ - native_idt_invalidate(); - native_gdt_invalidate(); /* now call it */ image->start = relocate_kernel_ptr((unsigned long)image->head, diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S index 8808cfca6322..3062cb3efc44 100644 --- a/arch/x86/kernel/relocate_kernel_64.S +++ b/arch/x86/kernel/relocate_kernel_64.S @@ -79,8 +79,13 @@ SYM_CODE_START_NOALIGN(relocate_kernel) pushq %r15 pushf - /* zero out flags, and disable interrupts */ - pushq $0 + /* Invalidate GDT/IDT, zero out flags */ + pushq $0 + pushq $0 + + lidt (%rsp) + lgdt (%rsp) + addq $8, %rsp popfq /* Switch to the identity mapped page tables */ |