in device_firmware/freertos_kernel/portable/ARMv8M/non_secure/portable/GCC/ARM_CM23/portasm.c [242:417]
void PendSV_Handler( void ) /* __attribute__ (( naked )) PRIVILEGED_FUNCTION */
{
__asm volatile
(
" .syntax unified \n"
" .extern SecureContext_SaveContext \n"
" .extern SecureContext_LoadContext \n"
" \n"
" mrs r1, psp \n" /* Read PSP in r1. */
" ldr r2, xSecureContextConst \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */
" ldr r0, [r2] \n" /* Read xSecureContext - Value of xSecureContext must be in r0 as it is used as a parameter later. */
" \n"
" cbz r0, save_ns_context \n" /* No secure context to save. */
" push {r0-r2, r14} \n"
" bl SecureContext_SaveContext \n"
" pop {r0-r3} \n" /* LR is now in r3. */
" mov lr, r3 \n" /* LR = r3. */
" lsls r2, r3, #25 \n" /* r2 = r3 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
" bpl save_ns_context \n" /* bpl - branch if positive or zero. If r2 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
" ldr r3, pxCurrentTCBConst \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r2, [r3] \n" /* Read pxCurrentTCB. */
#if( configENABLE_MPU == 1 )
" subs r1, r1, #16 \n" /* Make space for xSecureContext, PSPLIM, CONTROL and LR on the stack. */
" str r1, [r2] \n" /* Save the new top of stack in TCB. */
" mrs r2, psplim \n" /* r2 = PSPLIM. */
" mrs r3, control \n" /* r3 = CONTROL. */
" mov r4, lr \n" /* r4 = LR/EXC_RETURN. */
" stmia r1!, {r0, r2-r4} \n" /* Store xSecureContext, PSPLIM, CONTROL and LR on the stack. */
#else /* configENABLE_MPU */
" subs r1, r1, #12 \n" /* Make space for xSecureContext, PSPLIM and LR on the stack. */
" str r1, [r2] \n" /* Save the new top of stack in TCB. */
" mrs r2, psplim \n" /* r2 = PSPLIM. */
" mov r3, lr \n" /* r3 = LR/EXC_RETURN. */
" stmia r1!, {r0, r2-r3} \n" /* Store xSecureContext, PSPLIM and LR on the stack. */
#endif /* configENABLE_MPU */
" b select_next_task \n"
" \n"
" save_ns_context: \n"
" ldr r3, pxCurrentTCBConst \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r2, [r3] \n" /* Read pxCurrentTCB. */
#if( configENABLE_MPU == 1 )
" subs r1, r1, #48 \n" /* Make space for xSecureContext, PSPLIM, CONTROL, LR and the remaining registers on the stack. */
" str r1, [r2] \n" /* Save the new top of stack in TCB. */
" adds r1, r1, #16 \n" /* r1 = r1 + 16. */
" stmia r1!, {r4-r7} \n" /* Store the low registers that are not saved automatically. */
" mov r4, r8 \n" /* r4 = r8. */
" mov r5, r9 \n" /* r5 = r9. */
" mov r6, r10 \n" /* r6 = r10. */
" mov r7, r11 \n" /* r7 = r11. */
" stmia r1!, {r4-r7} \n" /* Store the high registers that are not saved automatically. */
" mrs r2, psplim \n" /* r2 = PSPLIM. */
" mrs r3, control \n" /* r3 = CONTROL. */
" mov r4, lr \n" /* r4 = LR/EXC_RETURN. */
" subs r1, r1, #48 \n" /* r1 = r1 - 48. */
" stmia r1!, {r0, r2-r4} \n" /* Store xSecureContext, PSPLIM, CONTROL and LR on the stack. */
#else /* configENABLE_MPU */
" subs r1, r1, #44 \n" /* Make space for xSecureContext, PSPLIM, LR and the remaining registers on the stack. */
" str r1, [r2] \n" /* Save the new top of stack in TCB. */
" mrs r2, psplim \n" /* r2 = PSPLIM. */
" mov r3, lr \n" /* r3 = LR/EXC_RETURN. */
" stmia r1!, {r0, r2-r7} \n" /* Store xSecureContext, PSPLIM, LR and the low registers that are not saved automatically. */
" mov r4, r8 \n" /* r4 = r8. */
" mov r5, r9 \n" /* r5 = r9. */
" mov r6, r10 \n" /* r6 = r10. */
" mov r7, r11 \n" /* r7 = r11. */
" stmia r1!, {r4-r7} \n" /* Store the high registers that are not saved automatically. */
#endif /* configENABLE_MPU */
" \n"
" select_next_task: \n"
" cpsid i \n"
" bl vTaskSwitchContext \n"
" cpsie i \n"
" \n"
" ldr r2, pxCurrentTCBConst \n" /* Read the location of pxCurrentTCB i.e. &( pxCurrentTCB ). */
" ldr r3, [r2] \n" /* Read pxCurrentTCB. */
" ldr r1, [r3] \n" /* The first item in pxCurrentTCB is the task top of stack. r1 now points to the top of stack. */
" \n"
#if( configENABLE_MPU == 1 )
" dmb \n" /* Complete outstanding transfers before disabling MPU. */
" ldr r2, xMPUCTRLConst \n" /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */
" ldr r4, [r2] \n" /* Read the value of MPU_CTRL. */
" movs r5, #1 \n" /* r5 = 1. */
" bics r4, r5 \n" /* r4 = r4 & ~r5 i.e. Clear the bit 0 in r4. */
" str r4, [r2] \n" /* Disable MPU. */
" \n"
" adds r3, #4 \n" /* r3 = r3 + 4. r3 now points to MAIR0 in TCB. */
" ldr r4, [r3] \n" /* r4 = *r3 i.e. r4 = MAIR0. */
" ldr r2, xMAIR0Const \n" /* r2 = 0xe000edc0 [Location of MAIR0]. */
" str r4, [r2] \n" /* Program MAIR0. */
" ldr r2, xRNRConst \n" /* r2 = 0xe000ed98 [Location of RNR]. */
" adds r3, #4 \n" /* r3 = r3 + 4. r3 now points to first RBAR in TCB. */
" movs r5, #4 \n" /* r5 = 4. */
" str r5, [r2] \n" /* Program RNR = 4. */
" ldmia r3!, {r6,r7} \n" /* Read first set of RBAR/RLAR from TCB. */
" ldr r4, xRBARConst \n" /* r4 = 0xe000ed9c [Location of RBAR]. */
" stmia r4!, {r6,r7} \n" /* Write first set of RBAR/RLAR registers. */
" movs r5, #5 \n" /* r5 = 5. */
" str r5, [r2] \n" /* Program RNR = 5. */
" ldmia r3!, {r6,r7} \n" /* Read second set of RBAR/RLAR from TCB. */
" ldr r4, xRBARConst \n" /* r4 = 0xe000ed9c [Location of RBAR]. */
" stmia r4!, {r6,r7} \n" /* Write second set of RBAR/RLAR registers. */
" movs r5, #6 \n" /* r5 = 6. */
" str r5, [r2] \n" /* Program RNR = 6. */
" ldmia r3!, {r6,r7} \n" /* Read third set of RBAR/RLAR from TCB. */
" ldr r4, xRBARConst \n" /* r4 = 0xe000ed9c [Location of RBAR]. */
" stmia r4!, {r6,r7} \n" /* Write third set of RBAR/RLAR registers. */
" movs r5, #7 \n" /* r5 = 7. */
" str r5, [r2] \n" /* Program RNR = 7. */
" ldmia r3!, {r6,r7} \n" /* Read fourth set of RBAR/RLAR from TCB. */
" ldr r4, xRBARConst \n" /* r4 = 0xe000ed9c [Location of RBAR]. */
" stmia r4!, {r6,r7} \n" /* Write fourth set of RBAR/RLAR registers. */
" \n"
" ldr r2, xMPUCTRLConst \n" /* r2 = 0xe000ed94 [Location of MPU_CTRL]. */
" ldr r4, [r2] \n" /* Read the value of MPU_CTRL. */
" movs r5, #1 \n" /* r5 = 1. */
" orrs r4, r5 \n" /* r4 = r4 | r5 i.e. Set the bit 0 in r4. */
" str r4, [r2] \n" /* Enable MPU. */
" dsb \n" /* Force memory writes before continuing. */
#endif /* configENABLE_MPU */
" \n"
#if( configENABLE_MPU == 1 )
" ldmia r1!, {r0, r2-r4} \n" /* Read from stack - r0 = xSecureContext, r2 = PSPLIM, r3 = CONTROL and r4 = LR. */
" msr psplim, r2 \n" /* Restore the PSPLIM register value for the task. */
" msr control, r3 \n" /* Restore the CONTROL register value for the task. */
" mov lr, r4 \n" /* LR = r4. */
" ldr r2, xSecureContextConst \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */
" str r0, [r2] \n" /* Restore the task's xSecureContext. */
" cbz r0, restore_ns_context \n" /* If there is no secure context for the task, restore the non-secure context. */
" push {r1,r4} \n"
" bl SecureContext_LoadContext \n" /* Restore the secure context. */
" pop {r1,r4} \n"
" mov lr, r4 \n" /* LR = r4. */
" lsls r2, r4, #25 \n" /* r2 = r4 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
" bpl restore_ns_context \n" /* bpl - branch if positive or zero. If r2 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
" msr psp, r1 \n" /* Remember the new top of stack for the task. */
" bx lr \n"
#else /* configENABLE_MPU */
" ldmia r1!, {r0, r2-r3} \n" /* Read from stack - r0 = xSecureContext, r2 = PSPLIM and r3 = LR. */
" msr psplim, r2 \n" /* Restore the PSPLIM register value for the task. */
" mov lr, r3 \n" /* LR = r3. */
" ldr r2, xSecureContextConst \n" /* Read the location of xSecureContext i.e. &( xSecureContext ). */
" str r0, [r2] \n" /* Restore the task's xSecureContext. */
" cbz r0, restore_ns_context \n" /* If there is no secure context for the task, restore the non-secure context. */
" push {r1,r3} \n"
" bl SecureContext_LoadContext \n" /* Restore the secure context. */
" pop {r1,r3} \n"
" mov lr, r3 \n" /* LR = r3. */
" lsls r2, r3, #25 \n" /* r2 = r3 << 25. Bit[6] of EXC_RETURN is 1 if secure stack was used, 0 if non-secure stack was used to store stack frame. */
" bpl restore_ns_context \n" /* bpl - branch if positive or zero. If r2 >= 0 ==> Bit[6] in EXC_RETURN is 0 i.e. non-secure stack was used. */
" msr psp, r1 \n" /* Remember the new top of stack for the task. */
" bx lr \n"
#endif /* configENABLE_MPU */
" \n"
" restore_ns_context: \n"
" adds r1, r1, #16 \n" /* Move to the high registers. */
" ldmia r1!, {r4-r7} \n" /* Restore the high registers that are not automatically restored. */
" mov r8, r4 \n" /* r8 = r4. */
" mov r9, r5 \n" /* r9 = r5. */
" mov r10, r6 \n" /* r10 = r6. */
" mov r11, r7 \n" /* r11 = r7. */
" msr psp, r1 \n" /* Remember the new top of stack for the task. */
" subs r1, r1, #32 \n" /* Go back to the low registers. */
" ldmia r1!, {r4-r7} \n" /* Restore the low registers that are not automatically restored. */
" bx lr \n"
" \n"
" .align 4 \n"
"pxCurrentTCBConst: .word pxCurrentTCB \n"
"xSecureContextConst: .word xSecureContext \n"
#if( configENABLE_MPU == 1 )
"xMPUCTRLConst: .word 0xe000ed94 \n"
"xMAIR0Const: .word 0xe000edc0 \n"
"xRNRConst: .word 0xe000ed98 \n"
"xRBARConst: .word 0xe000ed9c \n"
#endif /* configENABLE_MPU */
);
}