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Cortex-M23: Do not use PSPLIM_NS (FreeRTOS#791)
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According to Armv8-M technical reference manual, if the main extension
is not implemented then PSPLIM_NS is RES0. Update the cortex-M23
port to not use the reserved PSPLIM_NS.
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@urutva
urutva authored Sep 28, 2023
1 parent a695b67 commit 9d2571d
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Showing 29 changed files with 833 additions and 145 deletions.
40 changes: 35 additions & 5 deletions portable/ARMv8M/non_secure/port.c
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Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,16 @@
#if ( ( configRUN_FREERTOS_SECURE_ONLY == 1 ) && ( configENABLE_TRUSTZONE == 1 ) )
#error TrustZone needs to be disabled in order to run FreeRTOS on the Secure Side.
#endif

/**
* Cortex-M23 does not have non-secure PSPLIM. We should use PSPLIM on Cortex-M23
* only when FreeRTOS runs on secure side.
*/
#if ( ( portHAS_ARMV8M_MAIN_EXTENSION == 0 ) && ( configRUN_FREERTOS_SECURE_ONLY == 0 ) )
#define portUSE_PSPLIM_REGISTER 0
#else
#define portUSE_PSPLIM_REGISTER 1
#endif
/*-----------------------------------------------------------*/

/**
Expand Down Expand Up @@ -1185,11 +1195,19 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
/* Store the value of the LR and PSPLIM registers before the SVC was raised. We need to
* restore it when we exit from the system call. */
pxMpuSettings->xSystemCallStackInfo.ulLinkRegisterAtSystemCallEntry = pulTaskStack[ portOFFSET_TO_LR ];
__asm volatile ( "mrs %0, psplim" : "=r" ( pxMpuSettings->xSystemCallStackInfo.ulStackLimitRegisterAtSystemCallEntry ) );
#if ( portUSE_PSPLIM_REGISTER == 1 )
{
__asm volatile ( "mrs %0, psplim" : "=r" ( pxMpuSettings->xSystemCallStackInfo.ulStackLimitRegisterAtSystemCallEntry ) );
}
#endif

/* Use the pulSystemCallStack in thread mode. */
__asm volatile ( "msr psp, %0" : : "r" ( pulSystemCallStack ) );
__asm volatile ( "msr psplim, %0" : : "r" ( pxMpuSettings->xSystemCallStackInfo.pulSystemCallStackLimit ) );
#if ( portUSE_PSPLIM_REGISTER == 1 )
{
__asm volatile ( "msr psplim, %0" : : "r" ( pxMpuSettings->xSystemCallStackInfo.pulSystemCallStackLimit ) );
}
#endif

/* Remember the location where we should copy the stack frame when we exit from
* the system call. */
Expand Down Expand Up @@ -1316,11 +1334,19 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
/* Store the value of the LR and PSPLIM registers before the SVC was raised.
* We need to restore it when we exit from the system call. */
pxMpuSettings->xSystemCallStackInfo.ulLinkRegisterAtSystemCallEntry = pulTaskStack[ portOFFSET_TO_LR ];
__asm volatile ( "mrs %0, psplim" : "=r" ( pxMpuSettings->xSystemCallStackInfo.ulStackLimitRegisterAtSystemCallEntry ) );
#if ( portUSE_PSPLIM_REGISTER == 1 )
{
__asm volatile ( "mrs %0, psplim" : "=r" ( pxMpuSettings->xSystemCallStackInfo.ulStackLimitRegisterAtSystemCallEntry ) );
}
#endif

/* Use the pulSystemCallStack in thread mode. */
__asm volatile ( "msr psp, %0" : : "r" ( pulSystemCallStack ) );
__asm volatile ( "msr psplim, %0" : : "r" ( pxMpuSettings->xSystemCallStackInfo.pulSystemCallStackLimit ) );
#if ( portUSE_PSPLIM_REGISTER == 1 )
{
__asm volatile ( "msr psplim, %0" : : "r" ( pxMpuSettings->xSystemCallStackInfo.pulSystemCallStackLimit ) );
}
#endif

/* Remember the location where we should copy the stack frame when we exit from
* the system call. */
Expand Down Expand Up @@ -1415,7 +1441,11 @@ void vPortSVCHandler_C( uint32_t * pulCallerStackAddress ) /* PRIVILEGED_FUNCTIO
/* Restore the LR and PSPLIM to what they were at the time of
* system call entry. */
pulTaskStack[ portOFFSET_TO_LR ] = pxMpuSettings->xSystemCallStackInfo.ulLinkRegisterAtSystemCallEntry;
__asm volatile ( "msr psplim, %0" : : "r" ( pxMpuSettings->xSystemCallStackInfo.ulStackLimitRegisterAtSystemCallEntry ) );
#if ( portUSE_PSPLIM_REGISTER == 1 )
{
__asm volatile ( "msr psplim, %0" : : "r" ( pxMpuSettings->xSystemCallStackInfo.ulStackLimitRegisterAtSystemCallEntry ) );
}
#endif

/* If the hardware used padding to force the stack pointer
* to be double word aligned, set the stacked xPSR bit[9],
Expand Down
10 changes: 3 additions & 7 deletions portable/ARMv8M/non_secure/portable/GCC/ARM_CM23/portasm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -109,7 +109,6 @@
" ldmia r2!, {r0, r3-r6} \n" /* r0 = xSecureContext, r3 = original PSP, r4 = PSPLIM, r5 = CONTROL, r6 = LR. */
" subs r2, #20 \n"
" msr psp, r3 \n"
" msr psplim, r4 \n"
" msr control, r5 \n"
" mov lr, r6 \n"
" ldr r4, xSecureContextConst2 \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */
Expand Down Expand Up @@ -160,7 +159,6 @@
" ldm r0!, {r1-r3} \n" /* Read from stack - r1 = xSecureContext, r2 = PSPLIM and r3 = EXC_RETURN. */
" ldr r4, xSecureContextConst2 \n"
" str r1, [r4] \n" /* Set xSecureContext to this task's value for the same. */
" msr psplim, r2 \n" /* Set this task's PSPLIM value. */
" movs r1, #2 \n" /* r1 = 2. */
" msr CONTROL, r1 \n" /* Switch to use PSP in the thread mode. */
" adds r0, #32 \n" /* Discard everything up to r0. */
Expand Down Expand Up @@ -324,7 +322,7 @@ void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __att
" \n"
" save_special_regs: \n"
" mrs r3, psp \n" /* r3 = PSP. */
" mrs r4, psplim \n" /* r4 = PSPLIM. */
" movs r4, #0 \n" /* r4 = 0. 0 is stored in the PSPLIM slot. */
" mrs r5, control \n" /* r5 = CONTROL. */
" mov r6, lr \n" /* r6 = LR. */
" stmia r2!, {r0, r3-r6} \n" /* Store xSecureContext, original PSP (after hardware has saved context), PSPLIM, CONTROL and LR. */
Expand Down Expand Up @@ -392,7 +390,6 @@ void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __att
" ldmia r2!, {r0, r3-r6} \n" /* r0 = xSecureContext, r3 = original PSP, r4 = PSPLIM, r5 = CONTROL, r6 = LR. */
" subs r2, #20 \n"
" msr psp, r3 \n"
" msr psplim, r4 \n"
" msr control, r5 \n"
" mov lr, r6 \n"
" ldr r4, xSecureContextConst \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */
Expand Down Expand Up @@ -467,7 +464,7 @@ void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __att
" ldr r1, [r3] \n" /* Read pxCurrentTCB. */
" subs r2, r2, #12 \n" /* Make space for xSecureContext, PSPLIM and LR on the stack. */
" str r2, [r1] \n" /* Save the new top of stack in TCB. */
" mrs r1, psplim \n" /* r1 = PSPLIM. */
" movs r1, #0 \n" /* r1 = 0. 0 is stored in the PSPLIM slot. */
" mov r3, lr \n" /* r3 = LR/EXC_RETURN. */
" stmia r2!, {r0, r1, r3} \n" /* Store xSecureContext, PSPLIM and LR on the stack. */
" b select_next_task \n"
Expand All @@ -477,7 +474,7 @@ void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __att
" ldr r1, [r3] \n" /* Read pxCurrentTCB. */
" subs r2, r2, #44 \n" /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */
" str r2, [r1] \n" /* Save the new top of stack in TCB. */
" mrs r1, psplim \n" /* r1 = PSPLIM. */
" movs r1, #0 \n" /* r1 = 0. 0 is stored in the PSPLIM slot. */
" mov r3, lr \n" /* r3 = LR/EXC_RETURN. */
" stmia r2!, {r0, r1, r3-r7} \n" /* Store xSecureContext, PSPLIM, LR and the low registers that are not saved automatically. */
" mov r4, r8 \n" /* r4 = r8. */
Expand All @@ -496,7 +493,6 @@ void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __att
" ldr r2, [r1] \n" /* The first item in pxCurrentTCB is the task top of stack. r2 now points to the top of stack. */
" \n"
" ldmia r2!, {r0, r1, r4} \n" /* Read from stack - r0 = xSecureContext, r1 = PSPLIM and r4 = LR. */
" msr psplim, r1 \n" /* Restore the PSPLIM register value for the task. */
" mov lr, r4 \n" /* LR = r4. */
" ldr r3, xSecureContextConst \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */
" str r0, [r3] \n" /* Restore the task's xSecureContext. */
Expand Down
28 changes: 22 additions & 6 deletions portable/ARMv8M/non_secure/portable/GCC/ARM_CM23_NTZ/portasm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -109,7 +109,9 @@
" ldmia r1!, {r2-r5} \n" /* r2 = original PSP, r3 = PSPLIM, r4 = CONTROL, r5 = LR. */
" subs r1, #16 \n"
" msr psp, r2 \n"
" msr psplim, r3 \n"
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" msr psplim, r3 \n"
#endif
" msr control, r4 \n"
" mov lr, r5 \n"
" \n"
Expand Down Expand Up @@ -155,7 +157,9 @@
" ldr r0, [r1] \n" /* Read top of stack from TCB - The first item in pxCurrentTCB is the task top of stack. */
" \n"
" ldm r0!, {r1-r2} \n" /* Read from stack - r1 = PSPLIM and r2 = EXC_RETURN. */
" msr psplim, r1 \n" /* Set this task's PSPLIM value. */
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" msr psplim, r1 \n" /* Set this task's PSPLIM value. */
#endif
" movs r1, #2 \n" /* r1 = 2. */
" msr CONTROL, r1 \n" /* Switch to use PSP in the thread mode. */
" adds r0, #32 \n" /* Discard everything up to r0. */
Expand Down Expand Up @@ -302,7 +306,11 @@ void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __att
" \n"
" save_special_regs: \n"
" mrs r2, psp \n" /* r2 = PSP. */
" mrs r3, psplim \n" /* r3 = PSPLIM. */
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" mrs r3, psplim \n" /* r3 = PSPLIM. */
#else
" movs r3, #0 \n" /* r3 = 0. 0 is stored in the PSPLIM slot. */
#endif
" mrs r4, control \n" /* r4 = CONTROL. */
" mov r5, lr \n" /* r5 = LR. */
" stmia r1!, {r2-r5} \n" /* Store original PSP (after hardware has saved context), PSPLIM, CONTROL and LR. */
Expand Down Expand Up @@ -370,7 +378,9 @@ void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __att
" ldmia r1!, {r2-r5} \n" /* r2 = original PSP, r3 = PSPLIM, r4 = CONTROL, r5 = LR. */
" subs r1, #16 \n"
" msr psp, r2 \n"
" msr psplim, r3 \n"
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" msr psplim, r3 \n"
#endif
" msr control, r4 \n"
" mov lr, r5 \n"
" \n"
Expand Down Expand Up @@ -416,7 +426,11 @@ void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __att
" ldr r1, [r2] \n" /* Read pxCurrentTCB. */
" subs r0, r0, #40 \n" /* Make space for PSPLIM, LR and the remaining registers on the stack. */
" str r0, [r1] \n" /* Save the new top of stack in TCB. */
" mrs r2, psplim \n" /* r2 = PSPLIM. */
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" mrs r2, psplim \n" /* r2 = PSPLIM. */
#else
" movs r2, #0 \n" /* r2 = 0. 0 is stored in the PSPLIM slot. */
#endif
" mov r3, lr \n" /* r3 = LR/EXC_RETURN. */
" stmia r0!, {r2-r7} \n" /* Store on the stack - PSPLIM, LR and low registers that are not automatically saved. */
" mov r4, r8 \n" /* r4 = r8. */
Expand All @@ -442,7 +456,9 @@ void vClearInterruptMask( __attribute__( ( unused ) ) uint32_t ulMask ) /* __att
" msr psp, r0 \n" /* Remember the new top of stack for the task. */
" subs r0, r0, #40 \n" /* Move to the starting of the saved context. */
" ldmia r0!, {r2-r7} \n" /* Read from stack - r2 = PSPLIM, r3 = LR and r4-r7 restored. */
" msr psplim, r2 \n" /* Restore the PSPLIM register value for the task. */
#if ( configRUN_FREERTOS_SECURE_ONLY == 1 )
" msr psplim, r2 \n" /* Restore the PSPLIM register value for the task. */
#endif
" bx r3 \n"
" \n"
" .align 4 \n"
Expand Down
11 changes: 4 additions & 7 deletions portable/ARMv8M/non_secure/portable/IAR/ARM_CM23/portasm.s
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@ files (__ICCARM__ is defined by the IAR C compiler but not by the IAR assembler.
#define configUSE_MPU_WRAPPERS_V1 0
#endif


EXTERN pxCurrentTCB
EXTERN xSecureContext
EXTERN vTaskSwitchContext
Expand Down Expand Up @@ -167,7 +168,6 @@ vRestoreContextOfFirstTask:
ldmia r2!, {r0, r3-r6} /* r0 = xSecureContext, r3 = original PSP, r4 = PSPLIM, r5 = CONTROL, r6 = LR. */
subs r2, #20
msr psp, r3
msr psplim, r4
msr control, r5
mov lr, r6
ldr r4, =xSecureContext /* Read the location of xSecureContext i.e. &( xSecureContext ). */
Expand Down Expand Up @@ -203,7 +203,6 @@ vRestoreContextOfFirstTask:
ldm r0!, {r1-r3} /* Read from stack - r1 = xSecureContext, r2 = PSPLIM and r3 = EXC_RETURN. */
ldr r4, =xSecureContext
str r1, [r4] /* Set xSecureContext to this task's value for the same. */
msr psplim, r2 /* Set this task's PSPLIM value. */
movs r1, #2 /* r1 = 2. */
msr CONTROL, r1 /* Switch to use PSP in the thread mode. */
adds r0, #32 /* Discard everything up to r0. */
Expand Down Expand Up @@ -279,7 +278,7 @@ PendSV_Handler:

save_special_regs:
mrs r3, psp /* r3 = PSP. */
mrs r4, psplim /* r4 = PSPLIM. */
movs r4, #0 /* r4 = 0. 0 is stored in the PSPLIM slot. */
mrs r5, control /* r5 = CONTROL. */
mov r6, lr /* r6 = LR. */
stmia r2!, {r0, r3-r6} /* Store xSecureContext, original PSP (after hardware has saved context), PSPLIM, CONTROL and LR. */
Expand Down Expand Up @@ -347,7 +346,6 @@ PendSV_Handler:
ldmia r2!, {r0, r3-r6} /* r0 = xSecureContext, r3 = original PSP, r4 = PSPLIM, r5 = CONTROL, r6 = LR. */
subs r2, #20
msr psp, r3
msr psplim, r4
msr control, r5
mov lr, r6
ldr r4, =xSecureContext /* Read the location of xSecureContext i.e. &( xSecureContext ). */
Expand Down Expand Up @@ -406,7 +404,7 @@ PendSV_Handler:

subs r2, r2, #12 /* Make space for xSecureContext, PSPLIM and LR on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
mrs r1, psplim /* r1 = PSPLIM. */
movs r1, #0 /* r1 = 0. 0 is stored in the PSPLIM slot. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
stmia r2!, {r0, r1, r3} /* Store xSecureContext, PSPLIM and LR on the stack. */

Expand All @@ -417,7 +415,7 @@ PendSV_Handler:
ldr r1, [r3] /* Read pxCurrentTCB. */
subs r2, r2, #44 /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */
str r2, [r1] /* Save the new top of stack in TCB. */
mrs r1, psplim /* r1 = PSPLIM. */
movs r1, #0 /* r1 = 0. 0 is stored in the PSPLIM slot. */
mov r3, lr /* r3 = LR/EXC_RETURN. */
stmia r2!, {r0, r1, r3-r7} /* Store xSecureContext, PSPLIM, LR and the low registers that are not saved automatically. */
mov r4, r8 /* r4 = r8. */
Expand All @@ -436,7 +434,6 @@ PendSV_Handler:
ldr r2, [r1] /* The first item in pxCurrentTCB is the task top of stack. r2 now points to the top of stack. */

ldmia r2!, {r0, r1, r4} /* Read from stack - r0 = xSecureContext, r1 = PSPLIM and r4 = LR. */
msr psplim, r1 /* Restore the PSPLIM register value for the task. */
mov lr, r4 /* LR = r4. */
ldr r3, =xSecureContext /* Read the location of xSecureContext i.e. &( xSecureContext ). */
str r0, [r3] /* Restore the task's xSecureContext. */
Expand Down
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