arm: armv8: save boot arguments

Save boot arguments x[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/armv8/start.S b/arch/arm/cpu/armv8/start.S
index 6cc1d26e5e2da2571214610d0fbb65ad9451cb8e..746128026172f495da84c3abf1b1b238ab3ef3f1 100644 (file)
--- a/arch/arm/cpu/armv8/start.S
+++ b/arch/arm/cpu/armv8/start.S
@@ -370,5 +370,28 @@ ENTRY(c_runtime_cpu_setup)
 ENDPROC(c_runtime_cpu_setup)
 
 WEAK(save_boot_params)
+#if (IS_ENABLED(CONFIG_BLOBLIST))
+       /* Calculate the PC-relative address of saved_args */
+       adr     x9, saved_args_offset
+       ldr     w10, saved_args_offset
+       add     x9, x9, w10, sxtw
+
+       stp     x0, x1, [x9]
+       stp     x2, x3, [x9, #16]
+#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
+       .dword 0
+       .endr
+END(saved_args)
+#endif