arch/loongarch/kernel/relocate_kernel.S

Source file repositories/reference/linux-study-clean/arch/loongarch/kernel/relocate_kernel.S

File Facts

System
Linux kernel
Corpus path
arch/loongarch/kernel/relocate_kernel.S
Extension
.S
Size
2445 bytes
Lines
113
Domain
Architecture Layer
Bucket
arch/loongarch
Inferred role
Architecture Layer: arch/loongarch
Status
atlas-only

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/kexec.h>

#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/regdef.h>
#include <asm/loongarch.h>
#include <asm/stackframe.h>
#include <asm/addrspace.h>

SYM_CODE_START(relocate_new_kernel)
	UNWIND_HINT_UNDEFINED
	/*
	 * a0: EFI boot flag for the new kernel
	 * a1: Command line pointer for the new kernel
	 * a2: System table pointer for the new kernel
	 * a3: Start address to jump to after relocation
	 * a4: Pointer to the current indirection page entry
	 */
	move		s0, a4

	/*
	 * In case of a kdump/crash kernel, the indirection page is not
	 * populated as the kernel is directly copied to a reserved location
	 */
	beqz		s0, done

process_entry:
	PTR_L		s1, s0, 0
	PTR_ADDI	s0, s0, SZREG

	/* destination page */
	andi		s2, s1, IND_DESTINATION
	beqz		s2, 1f
	li.w		t0, ~0x1
	and		s3, s1, t0	/* store destination addr in s3 */
	b		process_entry

1:
	/* indirection page, update s0	*/
	andi		s2, s1, IND_INDIRECTION
	beqz		s2, 1f
	li.w		t0, ~0x2
	and		s0, s1, t0
	b		process_entry

1:
	/* done page */
	andi		s2, s1, IND_DONE
	beqz		s2, 1f
	b		done

1:
	/* source page */
	andi		s2, s1, IND_SOURCE
	beqz		s2, process_entry
	li.w		t0, ~0x8
	and		s1, s1, t0
	li.w		s5, (1 << _PAGE_SHIFT) / SZREG

copy_word:
	/* copy page word by word */
	REG_L		s4, s1, 0
	REG_S		s4, s3, 0
	PTR_ADDI	s3, s3, SZREG
	PTR_ADDI	s1, s1, SZREG
	LONG_ADDI	s5, s5, -1
	beqz		s5, process_entry
	b		copy_word

done:

Annotation

Implementation Notes