Commit 9fbcc076 authored by Qing Zhang's avatar Qing Zhang Committed by Huacai Chen
Browse files

LoongArch: Simplify the processing of jumping new kernel for KASLR 



Modified relocate_kernel() doesn't return new kernel's entry point but
the random_offset. In this way we share the start_kernel() processing
with the normal kernel, which avoids calling 'jr a0' directly and allows
some other operations (e.g, kasan_early_init) before start_kernel() when
KASLR (CONFIG_RANDOMIZE_BASE) is turned on.

Signed-off-by: default avatarQing Zhang <zhangqing@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent fb6d5c1d

arch/loongarch/include/asm/setup.h

+1 −1
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ extern long __la_abs_end; 
extern long __rela_dyn_begin;

extern long __rela_dyn_end;



extern void * __init relocate_kernel(void);

extern unsigned long __init relocate_kernel(void);



#endif

arch/loongarch/kernel/head.S

+6 −5
Original line number Diff line number Diff line
@@ -95,13 +95,14 @@ SYM_CODE_START(kernel_entry) # kernel entry point 
	PTR_LI		sp, (_THREAD_SIZE - PT_SIZE)

	PTR_ADD		sp, sp, tp

	set_saved_sp	sp, t0, t1

#endif



	/* relocate_kernel() returns the new kernel entry point */

	jr		a0

	ASM_BUG()

	/* Jump to the new kernel: new_pc = current_pc + random_offset */

	pcaddi		t0, 0

	add.d		t0, t0, a0

	jirl		zero, t0, 0xc

#endif /* CONFIG_RANDOMIZE_BASE */



#endif

#endif /* CONFIG_RELOCATABLE */



	bl		start_kernel

	ASM_BUG()

arch/loongarch/kernel/relocate.c

+2 −6
Original line number Diff line number Diff line
@@ -157,12 +157,11 @@ static inline void __init update_reloc_offset(unsigned long *addr, long random_o 
	*new_addr = (unsigned long)reloc_offset;

}



void * __init relocate_kernel(void)

unsigned long __init relocate_kernel(void)

{

	unsigned long kernel_length;

	unsigned long random_offset = 0;

	void *location_new = _text; /* Default to original kernel start */

	void *kernel_entry = start_kernel; /* Default to original kernel entry point */

	char *cmdline = early_ioremap(fw_arg1, COMMAND_LINE_SIZE); /* Boot command line is passed in fw_arg1 */



	strscpy(boot_command_line, cmdline, COMMAND_LINE_SIZE);
@@ -190,9 +189,6 @@ void * __init relocate_kernel(void) 


		reloc_offset += random_offset;



		/* Return the new kernel's entry point */

		kernel_entry = RELOCATED_KASLR(start_kernel);



		/* The current thread is now within the relocated kernel */

		__current_thread_info = RELOCATED_KASLR(__current_thread_info);
@@ -204,7 +200,7 @@ void * __init relocate_kernel(void) 


	relocate_absolute(random_offset);



	return kernel_entry;

	return random_offset;

}



/*