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Diffstat (limited to 'results/classifier/deepseek-2/output/peripherals/459')
| -rw-r--r-- | results/classifier/deepseek-2/output/peripherals/459 | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/results/classifier/deepseek-2/output/peripherals/459 b/results/classifier/deepseek-2/output/peripherals/459 new file mode 100644 index 000000000..075351b94 --- /dev/null +++ b/results/classifier/deepseek-2/output/peripherals/459 @@ -0,0 +1,36 @@ + +bcm2835_aux (raspi3) fails when the receive FIFO fills up +Description of problem: +When a bare-metal application on the `raspi3` board reads the `AUX_MU_STAT_REG` MMIO register while the device's buffer is at full receive FIFO capacity (i.e. `s->read_count == BCM2835_AUX_RX_FIFO_LEN`) the assertion `assert(s->read_count < BCM2835_AUX_RX_FIFO_LEN)` fails. + +The assertion in question is currently in line 141 of `hw/char/bcm2835_aux.c`: https://gitlab.com/qemu-project/qemu/-/blob/9c2647f75004c4f7d64c9c0ec55f8c6f0739a8b1/hw/char/bcm2835_aux.c#L141 +but in my current QEMU version, it seems that it was in line 140, but I don't think that has any implication on this error. If the below steps to reproduce are followed, the full output of a normal QEMU (no debugging output or anything) is simply: + +```text +$ echo abcdefgh | qemu-system-aarch64 -M raspi3 -kernel kernel8.elf -serial null -serial stdio +qemu-system-aarch64: /build/qemu-71DV4m/qemu-4.2/hw/char/bcm2835_aux.c:140: bcm2835_aux_read: Assertion `s->read_count < BCM2835_AUX_RX_FIFO_LEN' failed. +Aborted (core dumped) +``` + +Notice, that there is nothing really wrong with the implementation, if for instance an application that uses the `AUX_MU_LSR_REG` instead to check whether input is available, everything works as expected. It really seems that just this assertion is wrong. Also notice that the [BCM2835 manual](https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf) (page 18) explicitly allows values inclusive 8. +Steps to reproduce: +1. write a minimal bare-metal application for aarch64 using below main file +2. compile it with a decent aarch64 compiler, linker script and entry assembly as `kernel8.elf` +3. `echo abcdefgh | qemu-system-aarch64 -M raspi3 -kernel kernel8.elf -serial null -serial stdio` +4. QEMU crashes with the above state assertion error +Additional information: +Minimal bare-metal application (`main.c`): + +```c +#define MMIO_BASE 0x3F000000 +#define AUX_MU_STAT ((volatile unsigned int*)(MMIO_BASE+0x00215064)) + +void main() { + while (1) { + // Just read STAT register to trigger the assertion error + *AUX_MU_STAT; + } +} +``` + +Also see [kernel8.elf.zip](/uploads/b12ae2750d2df1bb8db2701f3145f653/kernel8.elf.zip) for a precompiled version of the above application. |