arch: riscv: implement frame-pointer based stack unwinding

[ycsin]

Influenced heavily by the RISCV64 stack unwinding implementation in the Linux kernel.

zephyr/tests/arch/common/stack_unwind/src/main.c

Lines 15 to 39 in 14149b1

	static void func2(int a)
	{
	printf("%d: %s\n", a, __func__);
	if (a >= 5) {
	k_oops();
	}
	func1(a + 1);
	}
	static void func1(int a)
	{
	printf("%d: %s\n", a, __func__);
	func2(a + 1);
	}
	int main(void)
	{
	printf("Hello World! %s\n", CONFIG_BOARD);
	func1(1);
	return 0;
	}

$ west build -b qemu_riscv64 -p auto -t run zephyr/tests/arch/common/stack_unwind/
...
-- west build: running target run
[1/103] Preparing syscall dependency handling

[3/103] Generating include/generated/version.h
-- Zephyr version: 3.6.99 (/Users/ycsin/zephyrproject/zephyr), build: v3.6.0-2575-g14149b1de14d
[102/103] Linking C executable zephyr/zephyr.elf
Memory region         Used Size  Region Size  %age Used
             RAM:       52260 B       256 MB      0.02%
        IDT_LIST:          0 GB         2 KB      0.00%
Generating files from /Users/ycsin/zephyrproject/build/zephyr/zephyr.elf for board: qemu_riscv64
[102/103] To exit from QEMU enter: 'CTRL+a, x'[QEMU] CPU: riscv64
*** Booting Zephyr OS build v3.6.0-2575-g14149b1de14d ***
Hello World! qemu_riscv64
1: func1
2: func2
3: func1
4: func2
5: func1
6: func2
E:      a0: 0000000000000003    t0: 0000000000000000
E:      a1: 0000000080008d1f    t1: 000000000000004c
E:      a2: 000000000000000a    t2: 0000000000000053
E:      a3: 000000008000a210    t3: 000000000000002a
E:      a4: 000000008000a210    t4: 000000000000002e
E:      a5: 0000000000000004    t5: 000000000000007f
E:      a6: 0000000000000068    t6: 0000000000000010
E:      a7: 000000000000006a
E:      ra: 00000000800003f8
E:    mepc: 0000000080000406
E: mstatus: 0000000a00021880
E: 
E: call trace:
E:       0: fp: 000000008000cac0   ra: 0000000080000442
E:       1: fp: 000000008000cae0   ra: 000000008000040e
E:       2: fp: 000000008000cb00   ra: 0000000080000442
E:       3: fp: 000000008000cb20   ra: 000000008000040e
E:       4: fp: 000000008000cb40   ra: 0000000080000442
E:       5: fp: 000000008000cb60   ra: 000000008000046e
E:       6: fp: 000000008000cb70   ra: 0000000080002382
E:       7: fp: 000000008000cb80   ra: 00000000800007fe
E: >>> ZEPHYR FATAL ERROR 3: Kernel oops on CPU 0
E: Current thread: 0x8000a210 (main)
E: Halting system
qemu-system-riscv64: terminating on signal 2 from pid 2110 (<unknown process>)
ninja: build stopped: interrupted by user.
$ ../zephyr-sdk-0.16.5-1/riscv64-zephyr-elf/bin/riscv64-zephyr-elf-addr2line -a 0000000080000442 -e build/zephyr/zephyr.elf
0x0000000080000442
/Users/ycsin/zephyrproject/zephyr/tests/arch/common/stack_unwind/src/main.c:30
$ ../zephyr-sdk-0.16.5-1/riscv64-zephyr-elf/bin/riscv64-zephyr-elf-addr2line -a 000000008000040e -e build/zephyr/zephyr.elf
0x000000008000040e
/Users/ycsin/zephyrproject/zephyr/tests/arch/common/stack_unwind/src/main.c:24
$ ../zephyr-sdk-0.16.5-1/riscv64-zephyr-elf/bin/riscv64-zephyr-elf-addr2line -a 000000008000046e -e build/zephyr/zephyr.elf
0x000000008000046e
/Users/ycsin/zephyrproject/zephyr/tests/arch/common/stack_unwind/src/main.c:39
$ ../zephyr-sdk-0.16.5-1/riscv64-zephyr-elf/bin/riscv64-zephyr-elf-addr2line -a 0000000080002382 -e build/zephyr/zephyr.elf
0x0000000080002382
/Users/ycsin/zephyrproject/zephyr/kernel/include/kthread.h:176
$ ../zephyr-sdk-0.16.5-1/riscv64-zephyr-elf/bin/riscv64-zephyr-elf-addr2line -a 00000000800007fe -e build/zephyr/zephyr.elf
0x00000000800007fe
/Users/ycsin/zephyrproject/zephyr/include/zephyr/kernel.h:593

[cfriedt]

@ycsin - LGTM - I wonder if it's possible to add a check to a new or existing testsuite.

[ycsin]

@ycsin - LGTM - I wonder if it's possible to add a check to a new or existing testsuite.

Maybe in https://github.com/zephyrproject-rtos/zephyr/tree/main/tests/kernel/fatal/exception ? I'll try.

[con-pax]

Hey @ycsin,

This looks really cool. I am away now, but I can give this a try out next week?

stale

[ycsin]

Rebased and the changes to esp32c3 is now being worked out in #71363 instead, CI is expected to fail in this PR on esp32c3 builds until #71388 is merged

[ycsin]

Rebased on top of #71388, CI is green now.

ping @con-pax @cfriedt @carlocaione @fkokosinski @uLipe

[nashif]

would be nice to make this a generic arch kconfig (CONFIG_FRAME_POINTER), we now have two architectures doing this

[nashif]

ditto