arch: arm: swap_helper: adapt assembly code for Cortex-M Baseline
In this commit we implement the assembly functions in swap_helper.S, namely - z_arm_pendsv() - z_arm_svc() for ARMv6-M and ARMv8-M Baseline architecture. We "inline" the implementation for Baseline, along with the Mainline (ARMv7-M) implementation, i.e. we rework only what is required to build for Baseline Cortex-M. Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>
This commit is contained in:
Ioannis Glaropoulos
Kumar Gala
parent
b689700326
commit
2d6bb624d6
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@ -198,6 +198,34 @@ out_fp_endif:
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cpsie i
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_thread_irq_disabled:
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#if defined(CONFIG_ARM_MPU)
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/* Re-program dynamic memory map */
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push {r2,lr}
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mov r0, r2
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bl z_arm_configure_dynamic_mpu_regions
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pop {r2,r3}
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mov lr, r3
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#endif
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#ifdef CONFIG_USERSPACE
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/* restore mode */
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ldr r3, =_thread_offset_to_mode
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adds r3, r2, r3
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ldr r0, [r3]
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mrs r3, CONTROL
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movs.n r1, #1
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bics r3, r1
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orrs r3, r0
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msr CONTROL, r3
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/* ISB is not strictly necessary here (stack pointer is not being
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* touched), but it's recommended to avoid executing pre-fetched
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* instructions with the previous privilege.
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*/
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isb
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#endif
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ldr r4, =_thread_offset_to_callee_saved
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adds r0, r2, r4
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@ -342,65 +370,8 @@ _thread_irq_disabled:
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*/
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bx lr
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
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/**
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*
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* @brief Service call handler
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*
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* The service call (svc) is used in the following occasions:
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* - IRQ offloading
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* - Kernel run-time exceptions
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*
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* @return N/A
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*/
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SECTION_FUNC(TEXT, z_arm_svc)
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/* Use EXC_RETURN state to find out if stack frame is on the
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* MSP or PSP
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*/
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ldr r0, =0x4
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mov r1, lr
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tst r1, r0
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beq _stack_frame_msp
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mrs r0, PSP
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bne _stack_frame_endif
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_stack_frame_msp:
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mrs r0, MSP
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_stack_frame_endif:
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/* Figure out what SVC call number was invoked */
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ldr r1, [r0, #24] /* grab address of PC from stack frame */
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/* SVC is a two-byte instruction, point to it and read encoding */
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subs r1, r1, #2
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ldrb r1, [r1, #0]
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/*
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* grab service call number:
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* 1: irq_offload (if configured)
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* 2: kernel panic or oops (software generated fatal exception)
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* Planned implementation of system calls for memory protection will
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* expand this case.
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*/
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cmp r1, #2
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beq _oops
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#if defined(CONFIG_IRQ_OFFLOAD)
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push {r0, lr}
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bl z_irq_do_offload /* call C routine which executes the offload */
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pop {r0, r1}
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mov lr, r1
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#endif /* CONFIG_IRQ_OFFLOAD */
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/* exception return is done in z_arm_int_exit() */
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b z_arm_int_exit
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_oops:
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push {r0, lr}
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bl z_do_kernel_oops
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pop {r0, pc}
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#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE) || \
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defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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/**
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*
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@ -417,10 +388,22 @@ SECTION_FUNC(TEXT, z_arm_svc)
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/* Use EXC_RETURN state to find out if stack frame is on the
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* MSP or PSP
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*/
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
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movs r0, #0x4
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mov r1, lr
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tst r1, r0
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beq _stack_frame_msp
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mrs r0, PSP
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bne _stack_frame_endif
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_stack_frame_msp:
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mrs r0, MSP
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_stack_frame_endif:
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#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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tst lr, #0x4 /* did we come from thread mode ? */
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ite eq /* if zero (equal), came from handler mode */
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mrseq r0, MSP /* handler mode, stack frame is on MSP */
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mrsne r0, PSP /* thread mode, stack frame is on PSP */
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#endif
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/* Figure out what SVC call number was invoked */
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@ -429,7 +412,12 @@ SECTION_FUNC(TEXT, z_arm_svc)
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/* SVC is a two-byte instruction, point to it and read the
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* SVC number (lower byte of SCV instruction)
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*/
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
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subs r1, r1, #2
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ldrb r1, [r1]
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#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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ldrb r1, [r1, #-2]
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#endif
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/*
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* grab service call number:
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@ -448,7 +436,12 @@ SECTION_FUNC(TEXT, z_arm_svc)
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* check that we are privileged before invoking other SVCs
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* oops if we are unprivileged
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*/
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
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movs r3, #0x1
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tst r2, r3
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#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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tst r2, #0x1
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#endif
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bne _oops
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#endif /* CONFIG_USERSPACE */
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@ -459,7 +452,12 @@ SECTION_FUNC(TEXT, z_arm_svc)
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#if defined(CONFIG_IRQ_OFFLOAD)
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push {r0, lr}
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bl z_irq_do_offload /* call C routine which executes the offload */
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
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pop {r0, r3}
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mov lr, r3
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#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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pop {r0, lr}
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#endif
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/* exception return is done in z_arm_int_exit() */
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b z_arm_int_exit
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@ -493,13 +491,28 @@ _oops:
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* r8 - saved link register
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*/
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_do_syscall:
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
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movs r3, #24
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ldr r1, [r0, r3] /* grab address of PC from stack frame */
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mov r8, r1
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#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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ldr r8, [r0, #24] /* grab address of PC from stack frame */
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#endif
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ldr r1, =z_arm_do_syscall
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
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str r1, [r0, r3] /* overwrite the PC to point to z_arm_do_syscall */
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#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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str r1, [r0, #24] /* overwrite the PC to point to z_arm_do_syscall */
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#endif
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
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ldr r3, =K_SYSCALL_LIMIT
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cmp r6, r3
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#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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/* validate syscall limit */
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ldr ip, =K_SYSCALL_LIMIT
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cmp r6, ip
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#endif
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blt valid_syscall_id
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/* bad syscall id. Set arg1 to bad id and set call_id to SYSCALL_BAD */
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@ -511,6 +524,20 @@ _do_syscall:
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valid_syscall_id:
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ldr r0, =_kernel
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ldr r0, [r0, #_kernel_offset_to_current]
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#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
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mov ip, r2
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ldr r1, =_thread_offset_to_mode
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ldr r3, [r0, r1]
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movs r2, #1
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bics r3, r2
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/* Store (privileged) mode in thread's mode state variable */
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str r3, [r0, r1]
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mov r2, ip
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dsb
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/* set mode to privileged, r2 still contains value from CONTROL */
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movs r3, #1
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bics r2, r3
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#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
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ldr r1, [r0, #_thread_offset_to_mode]
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bic r1, #1
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/* Store (privileged) mode in thread's mode state variable */
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@ -518,6 +545,7 @@ valid_syscall_id:
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dsb
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/* set mode to privileged, r2 still contains value from CONTROL */
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bic r2, #1
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#endif
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msr CONTROL, r2
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/* ISB is not strictly necessary here (stack pointer is not being
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