[kernel-hardening] [PATCH v2 06/11] MIPS: Call relocate_kernel if CONFIG_RELOCATABLE=y

Matt Redfearn
2016-03-31T09:05:37Z

If CONFIG_RELOCATABLE is enabled, call relocate_kernel.

This function will return the entry point of the relocated kernel if
copy/relocate is sucessful or the original entry point if not. The stack
pointer must then be pointed into the new image.

Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
---

Changes in v2: None

arch/mips/kernel/head.S | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S
index 4e4cc5b9a771..7dc043349d66 100644
--- a/arch/mips/kernel/head.S
+++ b/arch/mips/kernel/head.S
@@ -132,7 +132,27 @@ not_found:
set_saved_sp sp, t0, t1
PTR_SUBU sp, 4 * SZREG # init stack pointer

+#ifdef CONFIG_RELOCATABLE
+ /* 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
+ 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
+ * with instruction hazard barrier because of the
+ * newly sync'd icache.
+ */
+ jr.hb v0
+#else
j start_kernel
+#endif
END(kernel_entry)

#ifdef CONFIG_SMP
--
2.5.0