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Allocate a user stack to run code in.

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--HG--
branch : dtrg-videocore
This commit is contained in:
David Given 2013-05-22 18:25:30 +01:00
parent cdce394b6c
commit b5e5df4a63
1 changed files with 22 additions and 11 deletions
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33
plat/rpi/boot.s
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@ -16,6 +16,12 @@
.sect .text .sect .text
#define gp r15 #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: begtext:
! Set up system registers. ! Set up system registers.
@ -24,27 +30,28 @@ begtext:
st sp, .returnsp st sp, .returnsp
st lr, .returnlr st lr, .returnlr
! The GPU kernel code will load parameters into r0-r5. Save them ! Wipe the bss. (I'm a little suprised that __m_a_i_n doesn't do this.)
! so that the user code can access them.
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 r0, gp ! pointer
sub r1, gp ! pointer sub r1, gp ! pointer
sub r2, gp ! pointer sub r2, gp ! pointer
sub r3, gp ! pointer sub r3, gp ! pointer
! r4-r5 are not pointers and don't need adjusting ! r4-r5 are not pointers and don't need adjusting
push r0-r5 push r0-r5
sub r0, sp, gp sub r0, sp, gp
st r0, _gpu_parameters 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. ! Push standard parameters onto the stack and go.
mov r0, #0 mov r0, #0
@ -89,3 +96,7 @@ __exit:
.define _gpu_parameters .define _gpu_parameters
.comm _gpu_parameters, 4 .comm _gpu_parameters, 4
! User stack.
.comm .stack, STACKSIZE