[PATCH v2 2/7] x86/boot/compressed/64: Reload CS in startup_32
From: Joerg Roedel <joro@8bytes.org>
Date: 2021-03-10 08:45:03
Also in:
lkml, virtualization
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Joerg Roedel <redacted> Exception handling in the startup_32 boot path requires the CS selector to be correctly set up. Reload it from the current GDT. Signed-off-by: Joerg Roedel <redacted> --- arch/x86/boot/compressed/head_64.S | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index e94874f4bbc1..c59c80ca546d 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S@@ -107,9 +107,16 @@ SYM_FUNC_START(startup_32) movl %eax, %gs movl %eax, %ss -/* setup a stack and make sure cpu supports long mode. */ + /* Setup a stack and load CS from current GDT */ leal rva(boot_stack_end)(%ebp), %esp + pushl $__KERNEL32_CS + leal rva(1f)(%ebp), %eax + pushl %eax + lretl +1: + + /* Make sure cpu supports long mode. */ call verify_cpu testl %eax, %eax jnz .Lno_longmode
--
2.30.1