Allocate a user stack to run code in.

--HG--
branch : dtrg-videocore

diff --git a/plat/rpi/boot.s b/plat/rpi/boot.s
index e190f2a..9e54d32 100644 (file)
--- a/plat/rpi/boot.s
+++ b/plat/rpi/boot.s
@@ -16,6 +16,12 @@
 .sect .text
 
 #define gp r15
+#define STACKSIZE 16*1024
+
+! MAIN ENTRY POINT
+!
+! When running as a kernel, our parameters are passed in in r0-r5, so
+! the startup sequence mustn't disturb these.
 
 begtext:
        ! Set up system registers.
@@ -24,27 +30,28 @@ begtext:
        st sp, .returnsp
        st lr, .returnlr
 
-       ! The GPU kernel code will load parameters into r0-r5. Save them
-       ! so that the user code can access them.
+       ! Wipe the bss. (I'm a little suprised that __m_a_i_n doesn't do this.)
+       
+       lea r6, begbss
+       lea r7, endbss
+       mov r8, #0
+_1:
+       stb r8, (r6)
+       addcmpb.lt r6, #1, r7, _1
+
+       ! Set up the new stack and save the kernel parameters to it.
 
+       lea sp, .stack + STACKSIZE
        sub r0, gp ! pointer
        sub r1, gp ! pointer
        sub r2, gp ! pointer
        sub r3, gp ! pointer
        ! r4-r5 are not pointers and don't need adjusting
        push r0-r5
+
        sub r0, sp, gp
        st r0, _gpu_parameters
 
-       ! Wipe the bss. (I'm a little suprised that __m_a_i_n doesn't do this.)
-       
-       lea r0, begbss
-       lea r1, endbss
-       mov r2, #0
-_1:
-       stb r2, (r0)
-       addcmpb.lt r0, #1, r1, _1
-       
        ! Push standard parameters onto the stack and go.
        
        mov r0, #0
@@ -89,3 +96,7 @@ __exit:
 .define _gpu_parameters
 .comm _gpu_parameters, 4
 
+! User stack.
+
+.comm .stack, STACKSIZE
+