The following commit has been merged into the x86/seves branch of tip: Commit-ID: 0c289ff81c24033777fab23019039f11e1449ba4 Gitweb: https://git.kernel.org/tip/0c289ff81c24033777fab23019039f11e1449ba4 Author: Joerg Roedel <jroedel@xxxxxxx> AuthorDate: Wed, 10 Mar 2021 09:43:20 +01:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Thu, 18 Mar 2021 16:44:43 +01:00 x86/boot/compressed/64: Reload CS in startup_32 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 <jroedel@xxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lkml.kernel.org/r/20210312123824.306-4-joro@xxxxxxxxxx --- 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 e94874f..c59c80c 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
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