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Diffstat (limited to 'results/classifier/mode-deepseek-r1:32b/reasoning/system/1428657')
| -rw-r--r-- | results/classifier/mode-deepseek-r1:32b/reasoning/system/1428657 | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/results/classifier/mode-deepseek-r1:32b/reasoning/system/1428657 b/results/classifier/mode-deepseek-r1:32b/reasoning/system/1428657 new file mode 100644 index 000000000..9841a2a5e --- /dev/null +++ b/results/classifier/mode-deepseek-r1:32b/reasoning/system/1428657 @@ -0,0 +1,22 @@ +<think> +Okay, so I'm trying to figure out whether this QEMU bug report is user-mode related or system-mode related. Let me start by understanding the problem described. + +The issue occurs when running a FreeRTOS demo on QEMU using the arm-none-eabi-gcc compiler. The user observed that after returning from an SVC (Service Call) handler, QEMU doesn't ignore the lowest bit of the program counter (PC), leading to incorrect instruction execution. + +Looking at the GDB trace, the PC is 0xc648 when it hits the IntDefaultHandler. But the stack in PSP shows a return address that should be 0x00003b49, but QEMU seems to execute from there instead of ignoring the lowest bit and taking 0x00003b48. + +The SVC handler changes the PSP (Process Stack Pointer) and sets up the new stack with a return address. According to ARM documentation, when returning from an exception like SVC, the processor should ignore the least significant bit (LSB) of the return address. So if the address is odd, it should be treated as even by masking out the LSB. + +In this case, QEMU isn't doing that; it's executing the instruction at 0x3b49 instead of 0x3b48, which leads to incorrect behavior. The user suggests that this is a bug in QEMU. + +Now, considering whether this is user-mode or system-mode related: + +- User-mode issues typically involve application-level problems where software isn't handling something correctly. +- System-mode issues are more about the environment, like hardware emulation (QEMU), device drivers, or OS behavior. + +Since the problem arises from how QEMU handles the return address after an exception, which involves the CPU's state and exception handling mechanisms, this seems to be a system-level issue. It's related to how QEMU emulates the ARM processor's exception return logic, specifically not masking the PC correctly when returning from SVC mode. + +Therefore, this bug report is about QEMU's system-mode emulation. +</think> + +system \ No newline at end of file |