From: Hongbo Zhang <hongbo.zh...@nxp.com>

The legacy code saves target PC at stack top, this patch changes it to stack
bottom, because we will save more contents for PSCI v1.0, by this way we don't
need to adjust the stack pointer when more contents are saved.

Signed-off-by: Hongbo Zhang <hongbo.zh...@nxp.com>
Signed-off-by: Wang Dongsheng <dongsheng.w...@nxp.com>
---
 arch/arm/cpu/armv7/psci.S   | 9 +++++----
 arch/arm/include/asm/psci.h | 4 ++++
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
index 3b92f1d..5b235df 100644
--- a/arch/arm/cpu/armv7/psci.S
+++ b/arch/arm/cpu/armv7/psci.S
@@ -259,7 +259,8 @@ ENTRY(psci_cpu_on_common)
 
        mov     r0, r1
        bl      psci_get_cpu_stack_top          @ get stack top of target CPU
-       str     r2, [r0]                        @ store target PC at stack top
+       sub     r5, r0, #PSCI_TARGET_PC_OFFSET
+       str     r2, [r5]                        @ store target PC
        dsb
 
        pop     {pc}
@@ -286,14 +287,13 @@ ENDPROC(psci_cpu_off_common)
 
 @ expects CPU ID in r0 and returns stack top in r0
 ENTRY(psci_get_cpu_stack_top)
-       mov     r5, #0x400                      @ 1kB of stack per CPU
+       mov     r5, #PSCI_PERCPU_STACK_SIZE     @ 1kB of stack per CPU
        mul     r0, r0, r5
 
        ldr     r5, =psci_text_end              @ end of monitor text
        add     r5, r5, #0x2000                 @ Skip two pages
        lsr     r5, r5, #12                     @ Align to start of page
        lsl     r5, r5, #12
-       sub     r5, r5, #4                      @ reserve 1 word for target PC
        sub     r0, r5, r0                      @ here's our stack!
 
        bx      lr
@@ -306,7 +306,8 @@ ENTRY(psci_cpu_entry)
 
        bl      psci_get_cpu_id                 @ CPU ID => r0
        bl      psci_get_cpu_stack_top          @ stack top => r0
-       ldr     r0, [r0]                        @ target PC at stack top
+       sub     r0, r0, #PSCI_TARGET_PC_OFFSET
+       ldr     r0, [r0]                        @ get target PC
        b       _do_nonsec_entry
 ENDPROC(psci_cpu_entry)
 
diff --git a/arch/arm/include/asm/psci.h b/arch/arm/include/asm/psci.h
index 2367ec0..cb08544 100644
--- a/arch/arm/include/asm/psci.h
+++ b/arch/arm/include/asm/psci.h
@@ -63,6 +63,10 @@
 #define ARM_PSCI_1_0_FN_STAT_RESIDENCY         ARM_PSCI_0_2_FN(16)
 #define ARM_PSCI_1_0_FN_STAT_COUNT             ARM_PSCI_0_2_FN(17)
 
+/* size of percpu stack, 1kB */
+#define PSCI_PERCPU_STACK_SIZE         0x400
+#define PSCI_TARGET_PC_OFFSET          (PSCI_PERCPU_STACK_SIZE - 4)
+
 #ifndef __ASSEMBLY__
 int psci_update_dt(void *fdt);
 void psci_board_init(void);
-- 
2.1.4

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