Commit d73a257f authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Borislav Petkov
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x86/boot/compressed: Pull global variable reference into startup32_load_idt() 



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: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221122161017.2426828-11-ardb@kernel.org
parent 6aac80a8

arch/x86/boot/compressed/head_64.S

+8 −12
Original line number Diff line number Diff line
@@ -728,16 +728,11 @@ SYM_DATA_END_LABEL(boot32_idt, SYM_L_GLOBAL, boot32_idt_end) 
 *

 * %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
@@ -745,7 +740,7 @@ 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
@@ -753,15 +748,16 @@ 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