x86/kernel/head_32.S

1 /* SPDX-License-Identifier: GPL-2.0 */
19 #include <asm/asm-offsets.h>
21 #include <asm/processor-flags.h>
22 #include <asm/msr-index.h>
26 #include <asm/nospec-branch.h>
32 #define pa(X) ((X) - __PAGE_OFFSET)
51  * Worst-case size of the kernel mapping we need to make:
61  * 32-bit kernel entrypoint; only used by the boot CPU.  On entry,
62  * %esi points to the real-mode code as a 32-bit pointer.
77 	movl %eax,%es
81 	leal -__PAGE_OFFSET(%ecx),%esp
95  * Note: %esi still has the pointer to the real-mode data.
132 #define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
133 	movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
142  * Non-boot CPU entry point; entered from trampoline.S
153 	movl %eax,%es
158 	leal -__PAGE_OFFSET(%ecx),%esp
185 	movl $-1,pa(X86_CPUID)		# preset CPUID level
215 	cmpl $(0x8000ffff-0x80000001), %eax
227 	/* Setup EFER (Extended Feature Enable Register) */
238  * Enable paging
253 	cmpl $-1,X86_CPUID
257 	xorl %eax,%eax			# call CPUID with 0 -> return vendor ID
291 	movl $(__USER_DS),%eax		# DS/ES contains default USER segment
293 	movl %eax,%es
324 	.fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
337 	/* The vector number is in pt_regs->gs */
340 	pushl	%fs		/* pt_regs->fs (__fsh varies by model) */
341 	pushl	%es		/* pt_regs->es (__esh varies by model) */
342 	pushl	%ds		/* pt_regs->ds (__dsh varies by model) */
343 	pushl	%eax		/* pt_regs->ax */
344 	pushl	%ebp		/* pt_regs->bp */
345 	pushl	%edi		/* pt_regs->di */
346 	pushl	%esi		/* pt_regs->si */
347 	pushl	%edx		/* pt_regs->dx */
348 	pushl	%ecx		/* pt_regs->cx */
349 	pushl	%ebx		/* pt_regs->bx */
351 	/* Fix up DS and ES */
354 	movl	%ecx, %es
359 	/* Load GS into pt_regs->gs (and maybe clobber __gsh) */
365 	popl	%ebx		/* pt_regs->bx */
366 	popl	%ecx		/* pt_regs->cx */
367 	popl	%edx		/* pt_regs->dx */
368 	popl	%esi		/* pt_regs->si */
369 	popl	%edi		/* pt_regs->di */
370 	popl	%ebp		/* pt_regs->bp */
371 	popl	%eax		/* pt_regs->ax */
372 	popl	%ds		/* pt_regs->ds (always ignores __dsh) */
373 	popl	%es		/* pt_regs->es (always ignores __esh) */
374 	popl	%fs		/* pt_regs->fs (always ignores __fsh) */
375 	popl	%gs		/* pt_regs->gs (always ignores __gsh) */
377 	addl	$4, %esp	/* pop pt_regs->orig_ax */
381 /* This is the default interrupt "handler" :-) */
388 	pushl %es
392 	movl %eax,%es
407 	popl %es
466 	/* Page-aligned for the benefit of paravirt? */
485 	.align PAGE_SIZE		/* needs to be page-sized too */
502  * The SIZEOF_PTREGS gap is a convention which helps the in-kernel unwinder
506 		.long init_thread_union + THREAD_SIZE -
507 		SIZEOF_PTREGS - TOP_OF_KERNEL_STACK_PADDING)
513 #include "../../x86/xen/xen-head.S"
516  * The IDT and GDT 'descriptors' are a strange 48-bit object
518  * like usual segment descriptors - they consist of a 16-bit
519  * segment size, and 32-bit linear address value:
528 	.long boot_gdt - __PAGE_OFFSET
534 	.word GDT_ENTRIES*8-1