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PANIC on TIM7 IRQ in timer example on armv6-m without FRAME_POINTERS
Summary
I get consistent crashes while testing apps/examples/timer with disabled CONFIG_FRAME_POINTERS. With them enabled, it works, but .text consumes +4.5KiB flash.
Impact
armv6-m thumb MCUs using basic timer peripherals.
Testing
stm32f072b-disco with custom config, Milandr mdr32f1qi with custom config.
Details
After porting basic timer functionality from stm32f0l0g0 onto mdr32, I tried to launch some userspace demos. It worked from time to time. It crashed when I tried to reduce consumed flash space. I even enabled tmrinfo debug prints, but they didn't help much in case of crashes -- though they showed successfull signal passing when everything worked.
I think I found a single Kconfig option that breaks it: CONFIG_FRAME_POINTERS=n. It changes CFLAGS from -fno-omit-frame-pointers -fno-optimize-sibling-calls to -fomit-frame-pointers and saves space. I couldn't get anything else to break at runtime.
Stackdumps/backtraces, defconfigs and workdir patches will follow. I used release/10.3 branch.
stm32f072-disco:btimer defconfig diff with stm32f072-disco:nsh defconfig: I enabled POSIX_TIMERS, PTHREAD, BUILTIN, EXAMPLES_TIMER, STM32F0L0G0_TIM7, TIMER, TIMER_ARCH.
Board timer initialization:
diff --git a/boards/arm/stm32f0l0g0/stm32f072-discovery/src/stm32_bringup.c b/boards/arm/stm32f0l0g0/stm32f072-discovery/src/stm32_bringup.c
index f52f9d545..fb9981ba4 100644
--- a/boards/arm/stm32f0l0g0/stm32f072-discovery/src/stm32_bringup.c
+++ b/boards/arm/stm32f0l0g0/stm32f072-discovery/src/stm32_bringup.c
@@ -30,6 +30,11 @@
#include <syslog.h>
+#ifdef CONFIG_TIMER
+#include <nuttx/irq.h>
+#include "stm32_tim.h"
+#endif
+
#include "stm32f072-discovery.h"
#ifdef CONFIG_EXAMPLES_MODBUS
@@ -80,6 +85,17 @@ int stm32_bringup(void)
}
#endif
+#if defined(CONFIG_TIMER)
+ /* Initialize the timer, at this moment it's only Basic timers 6,7 */
+
+ #if defined(CONFIG_STM32F0L0G0_TIM6)
+ ret = stm32_timer_initialize("/dev/timer6", 6);
+ #endif
+ #if defined(CONFIG_STM32F0L0G0_TIM7)
+ ret = stm32_timer_initialize("/dev/timer7", 7);
+ #endif
+#endif
+
UNUSED(ret);
return OK;
}
Hardware header aborting the build:
diff --git a/arch/arm/src/stm32f0l0g0/hardware/stm32_tim.h b/arch/arm/src/stm32f0l0g0/hardware/stm32_tim.h [170/593]
index ceb057d57..8d69c3024 100644
--- a/arch/arm/src/stm32f0l0g0/hardware/stm32_tim.h
+++ b/arch/arm/src/stm32f0l0g0/hardware/stm32_tim.h
@@ -26,7 +26,7 @@
****************************************************************************/
#if defined(CONFIG_STM32F0L0G0_STM32F0) || defined(CONFIG_STM32F0L0G0_STM32L0)
-#error "Timer definitions should be validated for target before use"
+#warning "Timer definitions should be validated for target before use"
#endif
/* TODO Missing TIM2 definitions available on STM32G0x1 */
@@ -1101,7 +1101,9 @@
#define BTIM_CR1_URS (1 << 2) /* Bit 2: Update Request Source */
#define BTIM_CR1_OPM (1 << 3) /* Bit 3: One Pulse Mode */
#define BTIM_CR1_ARPE (1 << 7) /* Bit 7: Auto-Reload Preload enable */
+#if defined(CONFIG_STM32F0L0G0_STM32G0)
#define BTIM_CR1_UIFREMAP (1 << 11) /* Bit 11: UIF status bit remapping */
+#endif
/* Control register 2 */
@@ -1126,6 +1128,8 @@
/* Counter register */
+#if defined(CONFIG_STM32F0L0G0_STM32G0)
#define BTIM_CNT_UIFCPY (1 << 31) /* Bit 31: UIF copy */
+#endif
#endif /* __ARCH_ARM_SRC_STM32F0L0G0_HARDWARE_STM32_TIM_H */
Basic timers work fine, and I don't need the rest yet.
I also have backported DEBUG_OPT_UNUSED_SECTIONS and ARCH_HAVE_BACKTRACE for arm_backtrace_thumb. There are some autoleds- and pinmapping-related changes in my board/stm32f072-disco directory, I made them because it's not stm32f051-disco board and I wanted to test Modbus slave on a second UART. That works fine.
stm32f072-disco crash log, stackdump and backtrace:
ABCDF
NuttShell (NSH) NuttX-10.3.0
nsh> uname -a
NuttX 10.3.0 098866c45-dirty Jul 15 2022 15:38:41 arm stm32f072-discovery
nsh> free
total used free largest nused nfree
Umem: 12688 6920 5768 5496 45 2
nsh> ps
PID GROUP PRI POLICY TYPE NPX STATE EVENT SIGMASK STACK USED FILLED CPU COMMAND
0 0 0 FIFO Kthread N-- Ready 00000000 000760 000384 50.5% 98.9% Idle Task
2 1 100 RR pthread --- Waiting Semaphore 00000000 001024 000608 59.3% 0.0% mbs_poll 0
3 3 100 RR Task --- Running 00000000 001768 001328 75.1% 2.1% nsh_main
nsh> modbus -s
modbus_main: Protocol stack is running
nsh> modbus -d
nsh> modbus -s
modbus_main: Protocol stack is stopped
nsh> free ps
nsh: free: too many arguments
nsh> free
total used free largest nused nfree
Umem: 12688 5368 7320 4264 39 6
nsh> ps
PID GROUP PRI POLICY TYPE NPX STATE EVENT SIGMASK STACK USED FILLED CPU COMMAND
0 0 0 FIFO Kthread N-- Ready 00000000 000760 000384 50.5% 98.5% Idle Task
3 3 100 RR Task --- Running 00000000 001768 001328 75.1% 2.2% nsh_main
nsh> help
help usage: help [-v] [<cmd>]
? date exec help kill mount sleep usleep
cat df exit hexdump ls printf time xd
cp echo free irqinfo mkdir ps uname
Builtin Apps:
timer sh hello nsh modbus
nsh> ls -l /dev
/dev:
crw-rw-rw- 0 console
crw-rw-rw- 0 null
crw-rw-rw- 0 timer6
crw-rw-rw- 0 timer7
crw-rw-rw- 0 ttyS0
crw-rw-rw- 0 ttyS1
nsh> timer
Open /dev/timer0
ERROR: Failed to open /dev/timer0: 2
nsh> timer -d /dev/timer7
Open /dev/timer7
flags: 00000000 timeout: 1365 timeleft: 65520 nsignals: 0
Set timer interval to 1000000
flags: 00000000 timeout: 999420 timeleft: 65534 nsignals: 0
Attach timer handler
flags: 00000002 timeout: 999420 timeleft: 65501 nsignal[14] arm_hardfault:
Hard Fault:
[14] arm_hardfault: PC: 0x4000140a INSN: 0000
[14] arm_hardfault: IRQ: 3 regs: 0x20002d70
[14] arm_hardfault: PRIMASK: 00000000 IPSR: 00000003
[14] arm_hardfault: PANIC!!! Hard fault
[14] up_assert: Assertion failed at file:armv6-m/arm_hardfault.c line: 124 task: timer
[14] backtrace:
[14] [14] [<0x800f452>] up_backtrace+0xa/0x12c
[14] [14] [<0x800f096>] sched_backtrace+0x20/0x28
[14] [14] [<0x800cd9c>] sched_dumpstack+0x10/0x50
[14] [14] [<0x8003c92>] up_assert+0x46/0x234
[14] [14] [<0x8002e94>] _assert+0x2/0xe
[14] [14] [<0x8000c88>] arm_hardfault+0x74/0xa4
[14] [14] [<0x8001162>] irq_dispatch+0x46/0x98
[14] [14] [<0x8000bf6>] arm_doirq+0x22/0x40
[14] [14] [<0x8000860>] exception_common+0x24/0x68
[14] [14] [<0x800447e>] stm32_tim_enableint+0xa/0x10
[14] [14] [<0x8003902>] stm32_start+0x32/0x48
[14] [14] [<0x800c928>] timer_ioctl+0x34/0xb0
[14] [14] [<0x80086ea>] file_vioctl+0x32/0x8c
[14] [14] [<0x8008774>] ioctl+0x1a/0x38
[14] [14] [<0x800ec1e>] timer_main+0x146/0x220
[14] [14] [<0x8002fd8>] nxtask_startup+0x10/0x16
[14] backtrace:
[14] [14] [<0x8001616>] nxtask_start+0x42/0x4c
[14] arm_registerdump: R0: 4000140c R1: 00000000 R2: 00000001 R3: 00000000
[14] arm_registerdump: R4: 00000001 R5: 00000000 R6: 08004429 FP: 20002078
[14] arm_registerdump: R8: 00000000 SB: 00000000 SL: 00000000 R11: 00000000
[14] arm_registerdump: IP: 0000000f SP: 20002db8 LR: 08004483 PC: 4000140c
[14] arm_registerdump: xPSR: 00000000 PRIMASK: 00000000 CONTROL: 00000000
[14] arm_dump_stack: User Stack:
[14] arm_dump_stack: sp: 20002cc8
[14] arm_dump_stack: base: 20002ab8
[14] arm_dump_stack: size: 000003d8
[14] arm_stackdump: 20002cc0: 20002cc8 08003dab 00000000 00000000 4000140c 080033bd 00000000 000003d8
[14] arm_stackdump: 20002ce0: 20002cf8 4000140a 08014019 20002d70 00000003 08002e99 4000140a 08000c8d
[14] arm_stackdump: 20002d00: 00000003 20002d70 00000000 00000001 08000c15 000001dc 00000000 08001165
[14] arm_stackdump: 20002d20: 08004429 00000000 00000003 20002d70 0000001e 00000000 0000001e 00000000
[14] arm_stackdump: 20002d40: 00000000 00000000 20002d70 00000000 20000260 00000003 20002078 08000bfb
[14] arm_stackdump: 20002d60: 00000000 00000000 08004429 08000865 20002db8 00000000 00000001 00000000
[14] arm_stackdump: 20002d80: 08004429 20002078 00000000 00000000 00000000 00000000 4000140c 00000000
[14] arm_stackdump: 20002da0: 00000001 00000000 0000000f 08004483 4000140c 00000000 2000010c 08004483
[14] arm_stackdump: 20002dc0: 2000010c 08003905 00000000 2000010c 00000000 0800c92b 200014e8 00001601
[14] arm_stackdump: 20002de0: 00000000 200014e8 00001601 200020c8 00000000 080086ed 00000001 00000000
[14] arm_stackdump: 20002e00: 20002e30 00001601 00000000 08008779 20002e30 200014e8 00000000 00000003
[14] arm_stackdump: 20002e20: 00000000 20002a90 0800ec23 00001601 00000000 00000001 08001101 00000000
[14] arm_stackdump: 20002e40: dead000e 0800ea6d fffdffff 00000002 7665642f 6d69742f 00377265 08001de9
[14] arm_stackdump: 20002e60: 0800ead9 00000003 20002a90 08002fdb 200013a8 0800ead9 00000000 0800161b
[14] arm_showtasks: PID PRI USED STACK FILLED CPU COMMAND
[14] arm_dump_task: 0 0 384 760 50.5% 98.2% Idle Task
[14] arm_dump_task: 14 100 888 984 90.2%! 1.7% timer
[14] arm_dump_task: 3 100 1328 1768 75.1% 0.0% nsh_main
[14] backtrace:
[14] [ 0] [<0x800387e>] up_idle+0x2/0x4
[14] [ 0] [<0x800103c>] nx_start+0xfc/0x140
[14] [ 0] [<0x8001034>] nx_start+0xf4/0x140
[14] [ 0] [<0x8000130>] __start+0x70/0x88
[14] backtrace:
[14] [14] [<0x800f452>] up_backtrace+0xa/0x12c
[14] [14] [<0x800f096>] sched_backtrace+0x20/0x28
[14] [14] [<0x800cd9c>] sched_dumpstack+0x10/0x50
[14] [14] [<0x8003b82>] arm_dump_backtrace+0x6/0xc
[14] [14] [<0x800bb7c>] nxsched_foreach+0x2c/0x3c
[14] [14] [<0x8003dc0>] up_assert+0x174/0x234
[14] [14] [<0x8002e94>] _assert+0x2/0xe
[14] [14] [<0x8000c88>] arm_hardfault+0x74/0xa4
[14] [14] [<0x8001162>] irq_dispatch+0x46/0x98
[14] [14] [<0x8000bf6>] arm_doirq+0x22/0x40
[14] [14] [<0x8000860>] exception_common+0x24/0x68
[14] [14] [<0x800447e>] stm32_tim_enableint+0xa/0x10
[14] [14] [<0x8003902>] stm32_start+0x32/0x48
[14] [14] [<0x800c928>] timer_ioctl+0x34/0xb0
[14] [14] [<0x80086ea>] file_vioctl+0x32/0x8c
[14] [14] [<0x8008774>] ioctl+0x1a/0x38
[14] backtrace:
[14] [14] [<0x800ec1e>] timer_main+0x146/0x220
[14] [14] [<0x8002fd8>] nxtask_startup+0x10/0x16
[14] [14] [<0x8001616>] nxtask_start+0x42/0x4c
[14] backtrace:
[14] [ 3] [<0x8004220>] arm_switchcontext+0xc/0x10
[14] [ 3] [<0x8003ee0>] up_block_task+0x60/0x70
[14] [ 3] [<0x8003edc>] up_block_task+0x5c/0x70
[14] [ 3] [<0x800bd12>] nxsem_wait+0x3e/0x5c
[14] [ 3] [<0x800bc6c>] nx_waitpid+0x74/0x80
[14] [ 3] [<0x800bc7a>] waitpid+0x2/0x1a
[14] [ 3] [<0x8007c98>] nsh_builtin+0x50/0xdc
[14] [ 3] [<0x8005edc>] nsh_parse_command+0x14c/0x394
[14] [ 3] [<0x8008d72>] file_write+0x1a/0x28
[14] [ 3] [<0x8008da8>] write+0x2/0x1a
[14] [ 3] [<0x8005a5e>] readline_putc+0x10/0x2a
[14] [ 3] [<0x8006148>] nsh_parse+0x24/0x78
[14] [ 3] [<0x80059b4>] nsh_session+0x84/0x108
[14] [ 3] [<0x80056ba>] nsh_consolemain+0x14/0x22
[14] [ 3] [<0x8004958>] nsh_main+0x28/0x44
[14] [ 3] [<0x8002fd8>] nxtask_startup+0x10/0x16
[14] backtrace:
[14] [ 3] [<0x8004220>] arm_switchcontext+0xc/0x10
Notice it tries to jump into peripheral region ($pc=0x4000140a), that's TIM7 0x40001400-0x400017ff. Same for TIM6 -- $pc=0x4000100a, peripheral region is 0x40001000-0x400013ff.
Milandr mdr32f1qi stackdump/backtrace:
nsh> ps
PID GROUP PRI POLICY TYPE NPX STATE EVENT SIGMASK STACK USED FILLED COMMAND
0 0 0 FIFO Kthread N-- Ready 00000000 001000 000368 36.8% Idle Task
1 1 100 RR Task --- Running 00000000 002024 001344 66.4% nsh_main
nsh> free
total used free largest nused nfree
Umem: 43936 7120 36816 32752 48 5
nsh> timer
Open /dev/timer1
flags: 00000000 timeout: 0 timeleft: 0 nsignals: 0
Set timer interval to 100
flags: 00000000 timeout: 100 timeleft: 100 nsignals: 0
Attach timer handler
flags: 00000002 timeout: 100 timeleft: 100 nsignals: 0
Start the timer
flags: 00000003 timeout: 100 timeleft: 93 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 85 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 77 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 69 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 61 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 53 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 45 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 38 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 30 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 22 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 14 nsignals: 0
flags: 00000003 timeout: 100 timeleft: 6 nsignals: 0
arm_hardfault:
Hard Fault:
arm_hardfault: PC: 0 INSN: 12f4
arm_hardfault: IRQ: 3 regs: 0x201038e8
arm_hardfault: PRIMASK: 00000001 IPSR: 00000003
arm_hardfault: PANIC!!! Hard fault
up_assert: Assertion failed at file:armv6-m/arm_hardfault.c line: 124 task: timer
backtrace:
[ 6] [<0x12466>] up_backtrace+0x12c0000000a/0x11
[ 6] [<0x11c8a>] sched_backtrace+0x2a00000020/0x11
[ 6] [<0xdeb8>] sched_dumpstack+0x5000000010/0x10
[ 6] [<0x4a3c>] up_assert+0x21400000040/0x10
[ 6] [<0x349a>] _assert+0xc00000002/0x10
[ 6] [<0xc00>] arm_hardfault+0xa400000074/0xf
[ 6] [<0xf5c>] irq_dispatch+0x480000001c/0xf
[ 6] [<0xb74>] arm_doirq+0x340000001c/0xf
[ 6] [<0x7e8>] exception_common+0x6800000024/0xf
[ 6] [<0xfffffffe>] g_timerops+0xfffe50effffe50ee/0x14
[ 6] [<0x2>] Unknown+0x2/0xd
[ 6] [<0x4c6c>] up_block_task+0x700000005c/0x10
[ 6] [<0xd828>] nxsig_timedwait+0xfc000000a0/0x10
[ 6] [<0xd580>] nxsig_nanosleep+0x800000002c/0x10
[ 6] [<0xd628>] clock_nanosleep+0x5c00000054/0x10
[ 6] [<0xee5a>] usleep+0x380000002a/0x10
backtrace:
[ 6] [<0x10490>] timer_main+0x21c00000164/0x11
[ 6] [<0x3624>] nxtask_startup+0x1600000010/0x10
[ 6] [<0x13aa>] nxtask_start+0x4c00000042/0x10
arm_registerdump: R0: 00000002 R1: 20102a78 R2: 201003cc R3: 20102a78
arm_registerdump: R4: 20100354 R5: 20102a78 R6: 20100444 FP: 00000006
arm_registerdump: R8: 00000000 SB: 00000000 SL: 00000000 R11: 00000000
arm_registerdump: IP: 00000000 SP: 20103930 LR: 00004c71 PC: 00000002
arm_registerdump: xPSR: 20000238 PRIMASK: 00000001 CONTROL: 00000000
arm_dump_stack: User Stack:
arm_dump_stack: sp: 20103878
arm_dump_stack: base: 20103248
arm_dump_stack: size: 000007f0
arm_stackdump: 20103860: 00000001 00000000 00004b45 00017f69 20103878 00004b55 00000001 00000000
arm_stackdump: 20103880: 00000002 000040fd 00000000 000007f0 201038a8 00000000 00017aa8 201038e8
arm_stackdump: 201038a0: 00000003 0000349f 00000000 00000c05 00000003 201038e8 00000000 20100468
arm_stackdump: 201038c0: 20100348 00000003 00000006 00000f5f 00000000 00000b79 00000000 00000000
arm_stackdump: 201038e0: 20100444 000007ed 20103930 00000001 20100354 20102a78 20100444 00000006
arm_stackdump: 20103900: 00000000 00000000 00000000 00000000 00000002 20102a78 201003cc 20102a78
arm_stackdump: 20103920: 00000000 00004c71 00000002 20000238 20100444 00004c71 20102a00 20102a00
arm_stackdump: 20103940: 20102a00 20102a00 20103988 20102a24 00000000 0000d82d 00000000 00000001
arm_stackdump: 20103960: 20102bc4 00000000 20102bc4 201039c8 201039c8 00000000 20100500 0000d585
arm_stackdump: 20103980: 0000079a 00000000 00000000 00000003 0000001c 201039c8 0007a120 00000000
arm_stackdump: 201039a0: 00000000 0000d62d 00000000 00000000 201039c8 00000000 00000000 0007a120
arm_stackdump: 201039c0: 0000001c 0000ee5f 00000000 1dcd6500 201039ac 00000003 00000000 00010495
arm_stackdump: 201039e0: 00001101 00000000 dead0006 000102c1 fffdffff 00000002 7665642f 6d69742f
arm_stackdump: 20103a00: 00317265 00001be1 0001032d 00000001 20103238 00003627 20102a00 0001032d
arm_showtasks: PID PRI USED STACK FILLED COMMAND
arm_dump_task: 0 0 368 1000 36.8% Idle Task
arm_dump_task: 1 100 1344 2024 66.4% nsh_main
arm_dump_task: 6 100 948 2032 46.6% timer
backtrace:
[ 0] [<0xe80>] nx_start+0x140000000fc/0xf
[ 0] [<0xe80>] nx_start+0x140000000fc/0xf
[ 0] [<0xe78>] nx_start+0x140000000f4/0xf
[ 0] [<0x106>] __start+0x6000000046/0xf
backtrace:
[ 1] [<0x4f68>] arm_switchcontext+0x100000000c/0x10
[ 1] [<0x4c70>] up_block_task+0x7000000060/0x10
[ 1] [<0x4c6c>] up_block_task+0x700000005c/0x10
[ 1] [<0x1fc6>] nxsem_wait+0x5c0000003e/0x10
[ 1] [<0xd1b8>] nx_waitpid+0x8000000074/0x10
[ 1] [<0xd1c6>] waitpid+0x1a00000002/0x10
[ 1] [<0x84e0>] nsh_builtin+0xdc00000050/0x10
[ 1] [<0x5198>] nsh_execute+0x1ec00000014/0x10
[ 1] [<0xa60a>] file_write+0x280000001a/0x10
[ 1] [<0xa632>] nx_write+0x260000001a/0x10
[ 1] [<0x5cd4>] nsh_parse_command+0x668000005d4/0x10
[ 1] [<0x8e68>] readline_common+0x404000001a4/0x10
[ 1] [<0x5da2>] nsh_parse+0x940000003a/0x10
[ 1] [<0x9534>] nsh_session+0x118000000e4/0x10
[ 1] [<0x877c>] nsh_consolemain+0x2000000014/0x10
[ 1] [<0x501c>] nsh_main+0x4400000028/0x10
backtrace:
[ 1] [<0x4f68>] arm_switchcontext+0x100000000c/0x10
[ 1] [<0x13aa>] nxtask_start+0x4c00000042/0x10
backtrace:
[ 6] [<0x12466>] up_backtrace+0x12c0000000a/0x11
[ 6] [<0x11c8a>] sched_backtrace+0x2a00000020/0x11
[ 6] [<0xdeb8>] sched_dumpstack+0x5000000010/0x10
[ 6] [<0x4972>] arm_dump_backtrace+0xc00000006/0x10
[ 6] [<0xd0c8>] nxsched_foreach+0x3c0000002c/0x10
[ 6] [<0x4b6a>] up_assert+0x2140000016e/0x10
[ 6] [<0x349a>] _assert+0xc00000002/0x10
[ 6] [<0xc00>] arm_hardfault+0xa400000074/0xf
[ 6] [<0xf5c>] irq_dispatch+0x480000001c/0xf
[ 6] [<0xb74>] arm_doirq+0x340000001c/0xf
[ 6] [<0x7e8>] exception_common+0x6800000024/0xf
[ 6] [<0xfffffffe>] g_timerops+0xfffe50effffe50ee/0x14
[ 6] [<0x2>] Unknown+0x2/0xd
[ 6] [<0x4c6c>] up_block_task+0x700000005c/0x10
[ 6] [<0xd828>] nxsig_timedwait+0xfc000000a0/0x10
[ 6] [<0xd580>] nxsig_nanosleep+0x800000002c/0x10
backtrace:
[ 6] [<0xd628>] clock_nanosleep+0x5c00000054/0x10
[ 6] [<0xee5a>] usleep+0x380000002a/0x10
[ 6] [<0x10490>] timer_main+0x21c00000164/0x11
[ 6] [<0x3624>] nxtask_startup+0x1600000010/0x10
[ 6] [<0x13aa>] nxtask_start+0x4c00000042/0x10
This time, $pc is at 0x0, which is start of Flash. TIMER1 base address on this platform is at 0x40007000, but it doesn't show up. AHB-Lite SRAM at 0x20100000 as main memory, DTCM SRAM at 0x20000000 as OS heap (noexec nodma).
OS crashes in processing TIMER1 interrupt while trying to do the timer_notify callback to send a 17 signal to timer_main POSIX signal handler and switch tasks in up_block_task, (but g_readytorun.head->xcp.regs is bad? -- investigate). I can catch it with a hardware breakpoint at *0x0 and *0x2.
It's definitely "-fomit-frame-pointers" option and not "-foptimize-sibling-calls" option.
I fiddled with CFLAGS in Toolchain.defs and moved the -fno-optimize-sibling-calls two lines down to the other branch.
-Os -fno-optimize-sibling-calls combination has no effect on this build. Both were introduced in #5082.
-Os includes -fomit-frame-pointers -foptimize-sibling-calls: https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
Maybe there's something happening in assembly which expects thumb r7 = fp?
Thumb unwinder doesn't need it AFAICS.
# Disable FRAME_POINTER: baseline
/t/N/nuttx devel/10.3 ○ λ arm-none-eabi-size nuttx
text data bss dec hex filename
92456 476 3396 96328 17848 nuttx
/t/N/nuttx devel/10.3 ○ λ grep "^08" System.map | wc -l
861
# Enable FRAME_POINTER back: +4.5kB
/t/N/nuttx devel/10.3 ○ λ arm-none-eabi-size nuttx
text data bss dec hex filename
97072 476 3396 100944 18a50 nuttx
/t/N/nuttx devel/10.3 ○ λ grep "^08" System.map | wc -l
861
# Set cflags to -fno-omit-frame-pointer (hybrid); -Os includes -foptimize-sibling-calls
/t/N/nuttx devel/10.3 ○ λ arm-none-eabi-size nuttx
text data bss dec hex filename
97072 476 3396 100944 18a50 nuttx
/t/N/nuttx devel/10.3 ○ λ grep "^08" System.map | wc -l
861
# Set cflags to -fomit-frame-pointer -fno-optimize-sibling-calls (hybrid2)
/t/N/nuttx devel/10.3 ○ λ arm-none-eabi-size nuttx
text data bss dec hex filename
92456 476 3396 96328 17848 nuttx
/t/N/nuttx devel/10.3 ○ λ grep "^08" System.map | wc -l
861
BTW, never heard about Milandr MDR32 before and there is not much info about it on Internet. Are you planing to add support to it on mainline?
@acassis I could verify timers on STM32F429I-disco board sometime next week, though it's armv7e-m. I don't have access to any STM32F1-based boards.
Milandr has a line of MCUs produced since ~2010, see the official manufacturer site https://ic.milandr.ru/products/mikrokontrollery_i_protsessory/ and unofficial wiki http://startmilandr.codepx.ru/doku.php/prog:start (both sites in Russian). Some of them are ARM Cortex-M1 or M3, some RISC-V RV32IMA.
The LDM-Systems company sells evaluation boards https://ldm-systems.ru/catalog/helper?cat=milandr&scat=op
I am not affiliated with them, we're only evaluating their chips for our next network-connected device with all silicon components originating from Russia. I thought about bringing mainline support, but I've been porting NuttX/10.3 for a month now, the only board is only 50% feature-complete, and I still rely on vendor's open-source (?) HAL for a couple of drivers. I will consult with my employer by the end of August 2022 if anything useful comes out of this project.