6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ard Biesheuvel <ardb@xxxxxxxxxx> commit d73a257f7f86871c3aac24dc20538e3983096647 upstream. In preparation for moving startup32_load_idt() out of head_64.S and turning it into an ordinary function using the ordinary 32-bit calling convention, pull the global variable reference to boot32_idt up into startup32_load_idt() so that startup32_set_idt_entry() does not need to discover its own runtime physical address, which will no longer be correlated with startup_32 once this code is moved into .text. While at it, give startup32_set_idt_entry() static linkage. Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lore.kernel.org/r/20221122161017.2426828-11-ardb@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/boot/compressed/head_64.S | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -744,16 +744,11 @@ SYM_DATA_END_LABEL(boot32_idt, SYM_L_GLO * * %eax: Handler address * %edx: Vector number - * - * Physical offset is expected in %ebp + * %ecx: IDT address */ -SYM_FUNC_START(startup32_set_idt_entry) - push %ebx - - /* IDT entry address to %ebx */ - leal rva(boot32_idt)(%ebp), %ebx - shl $3, %edx - addl %edx, %ebx +SYM_FUNC_START_LOCAL(startup32_set_idt_entry) + /* IDT entry address to %ecx */ + leal (%ecx, %edx, 8), %ecx /* Build IDT entry, lower 4 bytes */ movl %eax, %edx @@ -761,7 +756,7 @@ SYM_FUNC_START(startup32_set_idt_entry) orl $(__KERNEL32_CS << 16), %edx # Target code segment selector /* Store lower 4 bytes to IDT */ - movl %edx, (%ebx) + movl %edx, (%ecx) /* Build IDT entry, upper 4 bytes */ movl %eax, %edx @@ -769,15 +764,16 @@ SYM_FUNC_START(startup32_set_idt_entry) orl $0x00008e00, %edx # Present, Type 32-bit Interrupt Gate /* Store upper 4 bytes to IDT */ - movl %edx, 4(%ebx) + movl %edx, 4(%ecx) - pop %ebx RET SYM_FUNC_END(startup32_set_idt_entry) #endif SYM_FUNC_START(startup32_load_idt) #ifdef CONFIG_AMD_MEM_ENCRYPT + leal rva(boot32_idt)(%ebp), %ecx + /* #VC handler */ leal rva(startup32_vc_handler)(%ebp), %eax movl $X86_TRAP_VC, %edx
