[seL4] SMC in seL4
Hello, I'm porting sel4 to imx6q sabrelite as the trusted OS in trustzone. I initialize the monitor mode directly using the functions "install_monitor_hook()" and “switch_to_mon_mode()”. Is the sp in monitor mode appropriate? After calling smc in SVC mode, it hangs(do nothing in smc_handle()). What's wrong with it? Do you have any ideas? Thank you! Dongxu Ji___ Devel mailing list Devel@sel4.systems https://sel4.systems/lists/listinfo/devel
Re: [seL4] SMC in seL4
Hi Yanyan,
According to your advice，I modified the avail_p_regs[] in hardware.h file
as tk1. 1 MiB starting from 0x37f0 is reserved for monitor mode.
{ /* .start = */ 0x1000, /* .end = */ 0x37f0}
And then
#define MON_PA_START (0x1000 + 0x27f0)
#define MON_PA_SIZE (1 << 20)
#define MON_PA_END (MON_PA_START + MON_PA_SIZE)
#define MON_PA_STACK (MON_PA_END - 0x10)
#define MON_VECTOR_START (MON_PA_START)
set sp:
asm volatile ("cps %0\n\t"
"isb\n"
"mov sp, %1\n\t"
::"I"(MONITOR_MODE),"r"(MON_PA_STACK));
copy monitor mode vector and write into MVBAR:
uint32_t size = arm_monitor_vector_end - arm_monitor_vector;
printf("Copy monitor mode vector from %x to %x size %x \n",
(arm_monitor_vector), MON_VECTOR_START, size);
memcpy((void *)MON_VECTOR_START, (void *)(arm_monitor_vector), size);
asm volatile ("dmb\n isb\n");
asm volatile ("mcr p15, 0, %0, c12, c0, 1"::"r"(MON_VECTOR_START));
I used the arm_monitor_vector provided by the source code in monitor.S and
just didn't perform the operation 'blx r0'. I think the it can jump to
smc_handler and return successfully.
#define VECTOR_BASE 0x37f0
#define STACK_TOP (VECTOR_BASE + (1 << 20) - 0x10)
arm_monitor_vector:
ldr pc, [pc, #28]
ldr pc, [pc, #24]
ldr pc, [pc, #16]
ldr pc, [pc, #16]
ldr pc, [pc, #12]
ldr pc, [pc, #8]
ldr pc, [pc, #4]
ldr pc, [pc, #0]
smc_handler_addr:
.word VECTOR_BASE + (smc_handler - arm_monitor_vector)//0x102c
smc_halt_addr:
.word VECTOR_BASE + (smc_halt - arm_monitor_vector)
smc_stack:
.word STACK_TOP
smc_handler:
/* always have a valid stack */
ldr sp, [pc, #-12]
push {lr}
//blx r0
isb
mrc p15, 0, r5, c1, c1, 0
/* set the NS bit */
orr r5, r5, #1
mcr p15, 0, r5, c1, c1, 0
pop {lr}
isb
movs pc, lr
However, the problem still exists. And I have another question that why set
the sp in monitor mode to sp in SVC mode.
asm volatile ("mov r8, sp\n\t"
"cps %0\n\t"
"isb\n"
"mov sp, r8\n\t"
::"I"(MONITOR_MODE));
Thank you,
Dongxu Ji
于2018年8月28日周二 下午10:10写道：
> Hi Dongxu,
>
>
> As you can see, the arm_monitor_vector uses PC-relative addressing so that
> the code can be moved around in memory. I think ldr pc, =smc_handler
> breaks this. Also, please set the NS bit in SCR to 1 before returning.
>
>
> To reserve a memory region for the monitor-mode code and data, I suggest
> you modify the avail_p_regs[] in
> kernel/include/plat/imx6/plat/machine/hardware.h
> file. See the kernel/include/plat/tk1/plat/machine/hardware.h as an example.
>
>
>
>
> Regards,
>
> Yanyan
>
>
> --
> *From:* Dongxu Ji
> *Sent:* Wednesday, August 29, 2018 12:02 AM
> *To:* devel@sel4.systems; Shen, Yanyan (Data61, Kensington NSW)
> *Subject:* Fwd: [seL4] SMC in seL4
>
> Hi Yanyan,
> 1. It doesn't set the NS bit to 1 in SCR(I just want it to return without
> do anything). The arm_monitor_vector and the smc_handler():
>
> arm_monitor_vector:
> ldr pc, [pc, #28]
> ldr pc, [pc, #24]
> ldr pc, =smc_handler
> ldr pc, [pc, #16]
> ldr pc, [pc, #12]
> ldr pc, [pc, #8]
> ldr pc, [pc, #4]
> ldr pc, [pc, #0]
>
> smc_handler:
> movs pc, lr
>
> 2. I didn't do any extra work other than the boot log:
>
> ..
> ELF-loader started on CPU: ARM Ltd. Cortex-A9 r2p10
>
> paddr=[2000..203fbfff]
>
> ELF-loading image 'kernel'
>
> paddr=[1000..10026fff]
>
> vaddr=[e000..e0026fff]
>
> virt_entry=e000
>
> ELF-loading image 'sel4test-driver'
>
> paddr=[10027000..10500fff]
>
> vaddr=[8000..4e1fff]
>
> virt_entry=25a6c
>
> Enabling MMU and paging
>
> Jumping to kernel-image entry point...
>
> 3. The initialization operations in platform_init.c:
> set sp:
> #define MONITOR_MODE(0x16)
> #define MON_VECTOR_START(0x1100)
> #define VECTOR_BASE 0x1100
> #define STACK_TOP (VECTOR_BASE + (1 << 12) - 0x10)
>
> asm volatile ( "mrs r1, cpsr\n\t"
> "cps %0\n\t"
> "isb\n"
> "mov sp, %1\n\t"
> "msr cpsr, r1\n\t"
> ::"I"(MONITOR_MODE),"r"(STACK_TOP));
>
> copy monitor mode vector to MON_VECTOR_START and write into MVBAR:
> uint32_t size = arm_monitor_vector_end - arm_monitor_vector;
Re: [seL4] SMC in seL4
Hi Dongxu,
As you can see, the arm_monitor_vector uses PC-relative addressing so that the
code can be moved around in memory. I think ldr pc, =smc_handler breaks this.
Also, please set the NS bit in SCR to 1 before returning.
To reserve a memory region for the monitor-mode code and data, I suggest you
modify the avail_p_regs[] in kernel/include/plat/imx6/plat/machine/hardware.h
file. See the kernel/include/plat/tk1/plat/machine/hardware.h as an example.
Regards,
Yanyan
From: Dongxu Ji
Sent: Wednesday, August 29, 2018 12:02 AM
To: devel@sel4.systems; Shen, Yanyan (Data61, Kensington NSW)
Subject: Fwd: [seL4] SMC in seL4
Hi Yanyan,
1. It doesn't set the NS bit to 1 in SCR(I just want it to return without do
anything). The arm_monitor_vector and the smc_handler():
arm_monitor_vector:
ldr pc, [pc, #28]
ldr pc, [pc, #24]
ldr pc, =smc_handler
ldr pc, [pc, #16]
ldr pc, [pc, #12]
ldr pc, [pc, #8]
ldr pc, [pc, #4]
ldr pc, [pc, #0]
smc_handler:
movs pc, lr
2. I didn't do any extra work other than the boot log:
..
ELF-loader started on CPU: ARM Ltd. Cortex-A9 r2p10
paddr=[2000..203fbfff]
ELF-loading image 'kernel'
paddr=[1000..10026fff]
vaddr=[e000..e0026fff]
virt_entry=e000
ELF-loading image 'sel4test-driver'
paddr=[10027000..10500fff]
vaddr=[8000..4e1fff]
virt_entry=25a6c
Enabling MMU and paging
Jumping to kernel-image entry point...
3. The initialization operations in platform_init.c:
set sp:
#define MONITOR_MODE(0x16)
#define MON_VECTOR_START(0x1100)
#define VECTOR_BASE 0x1100
#define STACK_TOP (VECTOR_BASE + (1 << 12) - 0x10)
asm volatile ( "mrs r1, cpsr\n\t"
"cps %0\n\t"
"isb\n"
"mov sp, %1\n\t"
"msr cpsr, r1\n\t"
::"I"(MONITOR_MODE),"r"(STACK_TOP));
copy monitor mode vector to MON_VECTOR_START and write into MVBAR:
uint32_t size = arm_monitor_vector_end - arm_monitor_vector;
printf("Copy monitor mode vector from %x to %x size %x\n",
(arm_monitor_vector), MON_VECTOR_START, size);
memcpy((void *)MON_VECTOR_START, (void *)(arm_monitor_vector), size);
asm volatile ("dmb\n isb\n");
asm volatile ("mcr p15, 0, %0, c12, c0, 1"::"r"(MON_VECTOR_START));
I enter into SVC mode by software interrupt and call the function smc():
asm (".arch_extension sec\n");
asm volatile ("stmfdsp!, {r3-r11, lr}\n\t"
"dsb\n"
"smc #0\n"
"ldmfdsp!, {r3-r11, pc}");
and then the problem arises.
Thank you,
Dongxu Ji
mailto:yanyan.s...@data61.csiro.au>> 于2018年8月28日周二
下午8:30写道：
Hi,
The smc_handle() in monitor.S, it does nothing but "movs pc, lr".
Does it set the NS bit to 1 in SCR?
Also, what did you do to ensure that 0x1100 is not used by the kernel?
Could you share the code (if possible) so that I could better understand the
problem.
Regards,
Yanyan
____
From: Devel on behalf of 冀东旭
mailto:jidongxu1...@gmail.com>>
Sent: Tuesday, August 28, 2018 1:02 PM
To: devel@sel4.systems
Subject: [seL4] SMC in seL4
Hello,
I'm porting sel4 to imx6q sabrelite as the trusted OS in trustzone. I
initialize the monitor mode by setting the sp to STACK_TOP and copying
arm_monitor_vector to MON_VECTOR_START according to the functions
"install_monitor_hook()" and "switch_to_mon_mode()" in "platform_init.c".
#define VECTOR_BASE 0x1100(addr is not used by the seL4 kernel)
#define STACK_TOP (VECTOR_BASE + (1 << 12) - 0x10)
#define MON_VECTOR_START0x1100(The VECTOR_BASE is the same as
MON_VECTOR_START)
The smc_handle() in monitor.S, it does nothing but "movs pc, lr". After
calling smc in SVC mode, it hangs without any log. If I comment the "smc #0",
it can return the caller successfully in usr mode.
stmfdsp!, {r3-r11, lr}
dsb
smc #0
ldmfdsp!, {r3-r11, pc}
Is the sp in monitor mode appropriate? Or I need to do something else in
initialization operations? What's wrong with it? Do you have any ideas?
Thank you!
Dongxu Ji
___
Devel mailing list
Devel@sel4.systems
https://sel4.systems/lists/listinfo/devel
Re: [seL4] SMC in seL4
Hi,
The smc_handle() in monitor.S, it does nothing but "movs pc, lr".
Does it set the NS bit to 1 in SCR?
Also, what did you do to ensure that 0x1100 is not used by the kernel?
Could you share the code (if possible) so that I could better understand the
problem.
Regards,
Yanyan
From: Devel on behalf of 冀东旭
Sent: Tuesday, August 28, 2018 1:02 PM
To: devel@sel4.systems
Subject: [seL4] SMC in seL4
Hello,
I'm porting sel4 to imx6q sabrelite as the trusted OS in trustzone. I
initialize the monitor mode by setting the sp to STACK_TOP and copying
arm_monitor_vector to MON_VECTOR_START according to the functions
"install_monitor_hook()" and "switch_to_mon_mode()" in "platform_init.c".
#define VECTOR_BASE 0x1100(addr is not used by the seL4 kernel)
#define STACK_TOP (VECTOR_BASE + (1 << 12) - 0x10)
#define MON_VECTOR_START0x1100(The VECTOR_BASE is the same as
MON_VECTOR_START)
The smc_handle() in monitor.S, it does nothing but "movs pc, lr". After
calling smc in SVC mode, it hangs without any log. If I comment the "smc #0",
it can return the caller successfully in usr mode.
stmfdsp!, {r3-r11, lr}
dsb
smc #0
ldmfdsp!, {r3-r11, pc}
Is the sp in monitor mode appropriate? Or I need to do something else in
initialization operations? What's wrong with it? Do you have any ideas?
Thank you!
Dongxu Ji
___
Devel mailing list
Devel@sel4.systems
https://sel4.systems/lists/listinfo/devel
[seL4] SMC in seL4
Hello,
I'm porting sel4 to imx6q sabrelite as the trusted OS in trustzone. I
initialize the monitor mode by setting the sp to STACK_TOP and
copying arm_monitor_vector to MON_VECTOR_START according to the
functions "install_monitor_hook()" and "switch_to_mon_mode()" in
"platform_init.c".
#define VECTOR_BASE 0x1100(addr is not used by the seL4 kernel)
#define STACK_TOP (VECTOR_BASE + (1 << 12) - 0x10)
#define MON_VECTOR_START0x1100(The VECTOR_BASE is the same as
MON_VECTOR_START)
The smc_handle() in monitor.S, it does nothing but "movs pc, lr".
After calling smc in SVC mode, it hangs without any log. If I comment
the "smc #0", it can return the caller successfully in usr mode.
stmfdsp!, {r3-r11, lr}
dsb
smc #0
ldmfdsp!, {r3-r11, pc}
Is the sp in monitor mode appropriate? Or I need to do something else
in initialization operations? What's wrong with it? Do you have any
ideas?
Thank you!
Dongxu Ji
___
Devel mailing list
Devel@sel4.systems
https://sel4.systems/lists/listinfo/devel
