3 files changed, 16 insertions, 9 deletions

diff --git a/firmware/target/arm/imx233/app.lds b/firmware/target/arm/imx233/app.lds
index b378f9ea16..335aa4fcc3 100644
--- a/firmware/target/arm/imx233/app.lds
+++ b/firmware/target/arm/imx233/app.lds
@@ -39,7 +39,7 @@ SECTIONS
     {
         _dramcopystart = .;
     } > DRAM
-        
+
     .text :
     {
         *(.text*)
@@ -47,6 +47,8 @@ SECTIONS
         *(.rodata*)
     } > DRAM
 
+    _dramtextend = .;
+
     .itext :
     {
         _iramstart = .; // always 0
@@ -77,12 +79,17 @@ SECTIONS
 
     _initcopy = LOADADDR(.init);
 
+    /* crt0 needs a temporary stack which does not overlap with init and itext
+     * and is in physical memory: put it *after* init and itext. A small one suffices */
+    crt0_tmpstack_phys = _dramcopyend + 0x200 - CACHED_DRAM_ADDR + UNCACHED_DRAM_ADDR;
+
     .dramcopyend (NOLOAD) :
     {
         _dramcopyend = .;
     } > DRAM
 
-    .stack (NOLOAD) :
+    /* the stack overlaps the init and itext region, to reclaim space */
+    .stack _dramtextend (NOLOAD) :
     {
         *(.stack)
         stackbegin = .;
@@ -90,9 +97,6 @@ SECTIONS
         stackend = .;
     } > DRAM
 
-    /* physical address of the stack */
-    stackend_phys = stackend - CACHED_DRAM_ADDR + UNCACHED_DRAM_ADDR;
-
     /* treat .bss and .ncbss as a single section */
     .bss (NOLOAD) :
     {
diff --git a/firmware/target/arm/imx233/boot.lds b/firmware/target/arm/imx233/boot.lds
index 68472d129c..ca455b47ca 100644
--- a/firmware/target/arm/imx233/boot.lds
+++ b/firmware/target/arm/imx233/boot.lds
@@ -74,7 +74,7 @@ SECTIONS
     } > DRAM
 
     /* physical address of the stack */
-    stackend_phys = stackend - CACHED_DRAM_ADDR + UNCACHED_DRAM_ADDR;
+    crt0_tmpstack_phys = stackend - CACHED_DRAM_ADDR + UNCACHED_DRAM_ADDR;
 
     /* treat .bss and .ncbss as a single section */
     .bss (NOLOAD) :
diff --git a/firmware/target/arm/imx233/crt0.S b/firmware/target/arm/imx233/crt0.S
index 0a71da5d08..5e1720c7c9 100644
--- a/firmware/target/arm/imx233/crt0.S
+++ b/firmware/target/arm/imx233/crt0.S
@@ -56,9 +56,12 @@ start:
     bic     r0, r1
     mcr     p15, 0, r0, c1, c0, 0
 
-    /* To call the C code we need a stack, since the stack is in virtual memory
-     * use the stack's physical address */
-    ldr     sp, =stackend_phys
+    /* To call the C code we need a stack, since the loader's stack might be
+     * in virtual memory, we need a physical address for the stack. Furthermore,
+     * we cannot use the main firmware stack yet because it overlaps with the
+     * init code which will be moved later. We rely on the linker to provide
+     * a safe, temporary stack */
+    ldr     sp, =crt0_tmpstack_phys
 
     /* Enable MMU */
     bl      memory_init