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x86/boot/compressed: Pull global variable reference into startup32_load_idt()

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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@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221122161017.2426828-11-ardb@kernel.org
This commit is contained in:
Ard Biesheuvel 2022-11-22 17:10:10 +01:00 committed by Borislav Petkov
parent 6aac80a8da
commit d73a257f7f
1 changed files with 8 additions and 12 deletions
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20
arch/x86/boot/compressed/head_64.S
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@ -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