diff options
Diffstat (limited to 'gitlab/issues_text/target_arm/host_missing/accel_missing/1421')
| -rw-r--r-- | gitlab/issues_text/target_arm/host_missing/accel_missing/1421 | 19 |
1 files changed, 0 insertions, 19 deletions
diff --git a/gitlab/issues_text/target_arm/host_missing/accel_missing/1421 b/gitlab/issues_text/target_arm/host_missing/accel_missing/1421 deleted file mode 100644 index 3cbdc1e4d..000000000 --- a/gitlab/issues_text/target_arm/host_missing/accel_missing/1421 +++ /dev/null @@ -1,19 +0,0 @@ -GDB memory reads fail on Cortex-M33 -Description of problem: -GDB fails to read memory from the guest. There appear to be at least two problems: - -1. In `arm_cpu_get_phys_page_attrs_debug`, `arm_is_secure(env)` returns false, because the implementation doesn't seem to know about Armv7-M or Armv8-M secure states. However, `arm_mmu_idx(env)` does know how to check `env->v7m.secure`, so it returns `ARMMMUIdx_MSPriv` (the S stands for secure). The mismatch between an apparently non-secure access to a secure MMU seems to cause the read to fail laster. -2. With the MPU enabled (not the case in this repro, but I can provide one), `cpu_memory_rw_debug` computes `page = addr & TARGET_PAGE_MASK`, and uses the page to compute permissions. However, TARGET_PAGE_MASK is based on 4K pages on this platform, but the MPU granularity is 32 bytes. So the wrong page is used for checking. -Steps to reproduce: -``` -# Sorry for the large clone. It's mostly unused files in CMSIS. -git clone --recursive -b qemu-repro-1 https://github.com/dreiss/mpu_experiments -cd mpu_experiments -git checkout origin/qemu-repro-1 -cmake -S . -B build -DBOARD=qemu-mps2-an505 -DAPP=mpu_stacktrace -DCMAKE_BUILD_TYPE=Debug -cmake --build build -/path/to/qemu-system-arm -machine mps2-an505 -nographic -kernel build/kernel.elf -s -S -d int -# Open a separate terminal and cd into mpu_experiments -gdb build/kernel.elf -ex 'target remote :1234' -ex 'break base_case' -ex continue -ex backtrace -ex quit -# Note the memory read failures in the backtrace. -``` |