SPM: Use Main Stack for initialization
On reset, the Main Stack is used by default.
TF-M changes the stack to Processor Stack.
This patch remove the change to PSP in startup.s and:
- Rename the ARM_LIB_STACK to ER_INITIAL_PSP
- Rename the ARM_LIB_STACK_MSP to ARM_LIB_STACK
The renaming is to align the __main function of ARMClang where the
ARM_LIB_STACK is set to the current SP (MSP)
For Library Mode, the stacks are set to back to use PSP before entering
c code to avoid massive corresponding changes.
For FF-M implementations, this patch also:
- Seal the Main Stack before entering c code
- Manually free the Main Stack usage after initialization as the init
function does not return
Change-Id: Ie1b6f2fca1f774c4812a89fa45bb039b16fe5af0
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
Co-authored-by: Summer Qin <summer.qin@arm.com>
diff --git a/secure_fw/spm/include/tfm_arch.h b/secure_fw/spm/include/tfm_arch.h
index 8a96d9f..8eb24b8 100644
--- a/secure_fw/spm/include/tfm_arch.h
+++ b/secure_fw/spm/include/tfm_arch.h
@@ -103,6 +103,13 @@
*/
void tfm_arch_clear_fp_status(void);
+/*
+ * This function is called after SPM has initialized.
+ * It frees the stack used by SPM initialization and do Exception Return.
+ * It does not return.
+ */
+void tfm_arch_free_msp_and_exc_ret(uint32_t exc_return);
+
void tfm_arch_init_context(struct tfm_arch_ctx_t *p_actx,
void *param, uintptr_t pfn,
uintptr_t stk_btm, uintptr_t stk_top);