arm: armv7: save boot arguments

Save boot arguments r[0-3] into an array for handover of bloblist from
previous boot stage.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index 69e281b086af5b43334559b3557e416b4c17b327..7730a16e5126d59afea1ab1542c929a656ee72a4 100644 (file)
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -152,9 +152,38 @@ ENDPROC(c_runtime_cpu_setup)
  *
  *************************************************************************/
 WEAK(save_boot_params)
+#if (IS_ENABLED(CONFIG_BLOBLIST))
+       /* Calculate the PC-relative address of saved_args */
+       adr     r12, saved_args_offset
+       ldr     r13, saved_args_offset
+       add     r12, r12, r13
+
+       /*
+        * Intentionally swapping r0 with r2 in order to simplify the C
+        * function we use later.
+        */
+       str     r2, [r12]
+       str     r1, [r12, #4]
+       str     r0, [r12, #8]
+       str     r3, [r12, #12]
+#endif
        b       save_boot_params_ret            @ back to my caller
 ENDPROC(save_boot_params)
 
+#if (IS_ENABLED(CONFIG_BLOBLIST))
+saved_args_offset:
+       .long   saved_args - .  /* offset from current code to save_args */
+
+       .section .data
+       .align 2
+       .global saved_args
+saved_args:
+       .rept 4
+       .word 0
+       .endr
+END(saved_args)
+#endif
+
 #ifdef CONFIG_ARMV7_LPAE
 WEAK(switch_to_hypervisor)
        b       switch_to_hypervisor_ret