Currently the init_thread_union contains both the stack and the
thread_info of the init thread. The current kernel relocation code makes
use of this such that the C code can update the thread_info in r28, and
then the asm can manipulate that value to find the value for the SP in
the new image.
Once CONFIG_THREAD_INFO_IN_TASK is activated, this will no longer be
possible since the task struct held in r28 will be separate from the
stack.
In preparation for this, change relocate_kernel to just prepare the new
image, and return the applied offset. The assembly code in kernel_entry
can then perform the necessary steps to set up the state for the
relocated image just as it did for the initial image.
Signed-off-by: Matt Redfearn <matt.redfearn@xxxxxxxx>
---
arch/mips/kernel/head.S | 16 ++++++++--------
arch/mips/kernel/relocate.c | 20 ++++++--------------
2 files changed, 14 insertions(+), 22 deletions(-)
diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S
index d1bb506adc10..0fcb3e048ece 100644
--- a/arch/mips/kernel/head.S
+++ b/arch/mips/kernel/head.S
@@ -142,20 +142,20 @@ dtb_found:
/* Copy kernel and apply the relocations */
jal relocate_kernel
- /* Repoint the sp into the new kernel image */
- PTR_LI sp, _THREAD_SIZE - 32 - PT_SIZE
- PTR_ADDU sp, $28
+ /* relocate_kernel returns the offset applied, apply it to ti & sp */
+ PTR_ADDU $28, v0
+ PTR_ADDU sp, v0
+
set_saved_sp sp, t0, t1
- PTR_SUBU sp, 4 * SZREG # init stack pointer
/*
- * relocate_kernel returns the entry point either
- * in the relocated kernel or the original if for
- * some reason relocation failed - jump there now
+ * Find start_kernel in relocated image and jump there
* with instruction hazard barrier because of the
* newly sync'd icache.
*/
- jr.hb v0
+ PTR_LA t0, start_kernel
+ PTR_ADDU t0, v0
+ jr.hb t0
#else
j start_kernel
#endif
diff --git a/arch/mips/kernel/relocate.c b/arch/mips/kernel/relocate.c
index cbf4cc0b0b6c..6c9a8e5c1652 100644
--- a/arch/mips/kernel/relocate.c
+++ b/arch/mips/kernel/relocate.c
@@ -294,15 +294,13 @@ static inline int __init relocation_addr_valid(void *loc_new)
return 1;
}
-void *__init relocate_kernel(void)
+int __init relocate_kernel(void)
{
void *loc_new;
unsigned long kernel_length;
unsigned long bss_length;
long offset = 0;
int res = 1;
- /* Default to original kernel entry point */
- void *kernel_entry = start_kernel;
void *fdt = NULL;
/* Get the command line */
@@ -359,14 +357,14 @@ void *__init relocate_kernel(void)
/* Perform relocations on the new kernel */
res = do_relocations(&_text, loc_new, offset);
if (res < 0)
- goto out;
+ return 0;
/* Sync the caches ready for execution of new kernel */
sync_icache(loc_new, kernel_length);
res = relocate_exception_table(offset);
if (res < 0)
- goto out;
+ return 0;
/*
* The original .bss has already been cleared, and
@@ -390,16 +388,10 @@ void *__init relocate_kernel(void)
* resident in memory and ready to be executed.
*/
if (plat_post_relocation(offset))
- goto out;
-
- /* The current thread is now within the relocated image */
- __current_thread_info = RELOCATED(&init_thread_union);
-
- /* Return the new kernel's entry point */
- kernel_entry = RELOCATED(start_kernel);
+ return 0;
}
-out:
- return kernel_entry;
+
+ return offset;
}
/*
--
2.7.4
