AArch32: Fix the stack alignment issue
The AArch32 Procedure call Standard mandates that the stack must be aligned
to 8 byte boundary at external interfaces. This patch does the required
changes.
This problem was detected when a crash was encountered in
`psci_print_power_domain_map()` while printing 64 bit values. Aligning
the stack to 8 byte boundary resolved the problem.
Fixes ARM-Software/tf-issues#437
Change-Id: I517bd8203601bb88e9311bd36d477fb7b3efb292
Signed-off-by: Soby Mathew <soby.mathew@arm.com>
diff --git a/bl32/sp_min/aarch32/entrypoint.S b/bl32/sp_min/aarch32/entrypoint.S
index 54f2ced..e2ab923 100644
--- a/bl32/sp_min/aarch32/entrypoint.S
+++ b/bl32/sp_min/aarch32/entrypoint.S
@@ -168,8 +168,11 @@
mov r2, r0 /* handle */
ldcopr r0, SCR
- /* Save SCR in stack */
- push {r0}
+ /*
+ * Save SCR in stack. r1 is pushed to meet the 8 byte
+ * stack alignment requirement.
+ */
+ push {r0, r1}
and r3, r0, #SCR_NS_BIT /* flags */
/* Switch to Secure Mode*/
@@ -191,7 +194,7 @@
/* r0 points to smc context */
/* Restore SCR from stack */
- pop {r1}
+ pop {r1, r2}
stcopr r1, SCR
isb
diff --git a/include/lib/aarch32/smcc_helpers.h b/include/lib/aarch32/smcc_helpers.h
index 5aeca22..4f9d814 100644
--- a/include/lib/aarch32/smcc_helpers.h
+++ b/include/lib/aarch32/smcc_helpers.h
@@ -39,6 +39,7 @@
#define SMC_CTX_GPREG_R2 0x8
#define SMC_CTX_GPREG_R3 0xC
#define SMC_CTX_GPREG_R4 0x10
+#define SMC_CTX_GPREG_R5 0x14
#define SMC_CTX_SP_USR 0x34
#define SMC_CTX_SPSR_MON 0x78
#define SMC_CTX_LR_MON 0x7C
diff --git a/include/lib/aarch32/smcc_macros.S b/include/lib/aarch32/smcc_macros.S
index 4d329f5..b6b7b80 100644
--- a/include/lib/aarch32/smcc_macros.S
+++ b/include/lib/aarch32/smcc_macros.S
@@ -38,22 +38,22 @@
* contains the pointer to the `smc_context_t`.
*/
.macro smcc_save_gp_mode_regs
- push {r0-r3, lr}
+ push {r0-r4, lr}
ldcopr r0, SCR
and r0, r0, #SCR_NS_BIT
bl smc_get_ctx
- /* Save r4 - r12 in the SMC context */
- add r1, r0, #SMC_CTX_GPREG_R4
- stm r1!, {r4-r12}
+ /* Save r5 - r12 in the SMC context */
+ add r1, r0, #SMC_CTX_GPREG_R5
+ stm r1!, {r5-r12}
/*
- * Pop r0 - r3, lr to r4 - r7, lr from stack and then save
+ * Pop r0 - r4, lr to r4 - r8, lr from stack and then save
* it to SMC context.
*/
- pop {r4-r7, lr}
- stm r0, {r4-r7}
+ pop {r4-r8, lr}
+ stm r0, {r4-r8}
/* Save the banked registers including the current SPSR and LR */
mrs r4, sp_usr
diff --git a/lib/cpus/aarch32/cortex_a32.S b/lib/cpus/aarch32/cortex_a32.S
index b51f997..f2b85a3 100644
--- a/lib/cpus/aarch32/cortex_a32.S
+++ b/lib/cpus/aarch32/cortex_a32.S
@@ -72,7 +72,8 @@
* ----------------------------------------------------
*/
func cortex_a32_core_pwr_dwn
- push {lr}
+ /* r12 is pushed to meet the 8 byte stack alignment requirement */
+ push {r12, lr}
/* Assert if cache is enabled */
#if ASM_ASSERTION
@@ -92,7 +93,7 @@
* Come out of intra cluster coherency
* ---------------------------------------------
*/
- pop {lr}
+ pop {r12, lr}
b cortex_a32_disable_smp
endfunc cortex_a32_core_pwr_dwn
@@ -102,7 +103,8 @@
* -------------------------------------------------------
*/
func cortex_a32_cluster_pwr_dwn
- push {lr}
+ /* r12 is pushed to meet the 8 byte stack alignment requirement */
+ push {r12, lr}
/* Assert if cache is enabled */
#if ASM_ASSERTION
@@ -135,7 +137,7 @@
* Come out of intra cluster coherency
* ---------------------------------------------
*/
- pop {lr}
+ pop {r12, lr}
b cortex_a32_disable_smp
endfunc cortex_a32_cluster_pwr_dwn
diff --git a/lib/cpus/aarch32/cpu_helpers.S b/lib/cpus/aarch32/cpu_helpers.S
index 042ffbd..a4dfe5f 100644
--- a/lib/cpus/aarch32/cpu_helpers.S
+++ b/lib/cpus/aarch32/cpu_helpers.S
@@ -76,9 +76,10 @@
*/
.globl prepare_core_pwr_dwn
func prepare_core_pwr_dwn
- push {lr}
+ /* r12 is pushed to meet the 8 byte stack alignment requirement */
+ push {r12, lr}
bl _cpu_data
- pop {lr}
+ pop {r12, lr}
ldr r1, [r0, #CPU_DATA_CPU_OPS_PTR]
#if ASM_ASSERTION
@@ -98,9 +99,10 @@
*/
.globl prepare_cluster_pwr_dwn
func prepare_cluster_pwr_dwn
- push {lr}
+ /* r12 is pushed to meet the 8 byte stack alignment requirement */
+ push {r12, lr}
bl _cpu_data
- pop {lr}
+ pop {r12, lr}
ldr r1, [r0, #CPU_DATA_CPU_OPS_PTR]
#if ASM_ASSERTION
diff --git a/lib/el3_runtime/aarch32/cpu_data.S b/lib/el3_runtime/aarch32/cpu_data.S
index b97911f..2de9029 100644
--- a/lib/el3_runtime/aarch32/cpu_data.S
+++ b/lib/el3_runtime/aarch32/cpu_data.S
@@ -41,9 +41,10 @@
* -----------------------------------------------------------------
*/
func _cpu_data
- push {lr}
+ /* r12 is pushed to meet the 8 byte stack alignment requirement */
+ push {r12, lr}
bl plat_my_core_pos
- pop {lr}
+ pop {r12, lr}
b _cpu_data_by_index
endfunc _cpu_data
diff --git a/lib/psci/aarch32/psci_helpers.S b/lib/psci/aarch32/psci_helpers.S
index 36d5d7d..373c184 100644
--- a/lib/psci/aarch32/psci_helpers.S
+++ b/lib/psci/aarch32/psci_helpers.S
@@ -93,7 +93,8 @@
* -----------------------------------------------------------------------
*/
func psci_do_pwrup_cache_maintenance
- push {lr}
+ /* r12 is pushed to meet the 8 byte stack alignment requirement */
+ push {r12, lr}
/* ---------------------------------------------
* Ensure any inflight stack writes have made it
@@ -123,7 +124,7 @@
stcopr r0, SCTLR
isb
- pop {pc}
+ pop {r12, pc}
endfunc psci_do_pwrup_cache_maintenance
/* ---------------------------------------------
