The r1 register is modified several times during the cache-ram setup of
the MPC83xx SoCs.
Since this SP modification confuses debuggers, we use a general purpose
register to compute the new stack pointer value, and only set the SP
once after all computations are done.
Signed-off-by: Mario Six <mario....@gdsys.cc>
---
Changes in v2:
Patch added (following a suggestion by Joakim Tjernlund)
---
arch/powerpc/cpu/mpc83xx/start.S | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/cpu/mpc83xx/start.S b/arch/powerpc/cpu/mpc83xx/start.S
index 0001687703..c366f615e7 100644
--- a/arch/powerpc/cpu/mpc83xx/start.S
+++ b/arch/powerpc/cpu/mpc83xx/start.S
@@ -258,14 +258,17 @@ in_flash:
#endif
/* set up the stack pointer in our newly created
- * cache-ram (r1) */
- lis r1, (CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_GBL_DATA_OFFSET)@h
- ori r1, r1, (CONFIG_SYS_INIT_RAM_ADDR +
CONFIG_SYS_GBL_DATA_OFFSET)@l
+ * cache-ram; use r3 to keep the new SP for now to
+ * avoid overiding the SP it uselessly */
+ lis r3, (CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_GBL_DATA_OFFSET)@h
+ ori r3, r3, (CONFIG_SYS_INIT_RAM_ADDR +
CONFIG_SYS_GBL_DATA_OFFSET)@l
li r0, 0 /* Make room for stack frame header and */
- stwu r0, -4(r1) /* clear final stack frame so that */
- stwu r0, -4(r1) /* stack backtraces terminate cleanly */
+ stwu r0, -4(r3) /* clear final stack frame so that */
+ stwu r0, -4(r3) /* stack backtraces terminate cleanly */
+ /* Finally, actually set SP */
+ mr r1, r3
/* let the C-code set up the rest */
/* */
--
2.11.0
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