Modified relocate_kernel is not returned directly new kernel's entry point，
instead, we share start_kernel processing with the normal kernel, which avoids
calling 'jr a0' directly and we can do other operations(eg: kasan_early_init)
before start_kernel when CONFIG_RANDOMIZE_BASE is turned on.
Signed-off-by: Qing Zhang <zhangqing@xxxxxxxxxxx>
---
arch/loongarch/include/asm/setup.h | 2 +-
arch/loongarch/kernel/head.S | 10 +++++-----
arch/loongarch/kernel/relocate.c | 8 ++------
3 files changed, 8 insertions(+), 12 deletions(-)
diff --git a/arch/loongarch/include/asm/setup.h b/arch/loongarch/include/asm/setup.h
index be05c0e706a2..2dca0d1dd90a 100644
--- a/arch/loongarch/include/asm/setup.h
+++ b/arch/loongarch/include/asm/setup.h
@@ -33,7 +33,7 @@ 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
diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S
index aa64b179744f..35c4a78614c3 100644
--- a/arch/loongarch/kernel/head.S
+++ b/arch/loongarch/kernel/head.S
@@ -95,12 +95,12 @@ 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 new kernel: new_pc = current_pc + random_offset */
+ pcaddi t0, 0
+ add.d t0, t0, a0
+ jirl zero, t0, 0xc
+#endif
#endif
bl start_kernel
diff --git a/arch/loongarch/kernel/relocate.c b/arch/loongarch/kernel/relocate.c
index 01f94d1e3edf..6c3eff9af9fb 100644
--- a/arch/loongarch/kernel/relocate.c
+++ b/arch/loongarch/kernel/relocate.c
@@ -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;
}
/*
--
2.20.1
