fix(aarch64): auto-skip brk instructions in user space#17
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yoinspiration wants to merge 11 commits intoarceos-org:devfrom
Open
fix(aarch64): auto-skip brk instructions in user space#17yoinspiration wants to merge 11 commits intoarceos-org:devfrom
yoinspiration wants to merge 11 commits intoarceos-org:devfrom
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Handle BreakpointLowerEL exceptions by automatically skipping the brk instruction (4 bytes) when the process is not being debugged. This matches Linux behavior where brk instructions are silently ignored for processes without a debugger attached. The implementation skips the instruction by incrementing elr by 4 bytes and recursively calling run() to continue execution immediately.
…owerEL Use Brk64 exception type which is the correct ESR_EL1::EC value for breakpoint exceptions in user space, matching the implementation in trap.rs for kernel space breakpoint handling.
…andling Enable interrupts before recursively calling run() to ensure proper interrupt state management when continuing execution after skipping the brk instruction.
Add debug output to print exception class (EC) values to help diagnose why breakpoint exceptions might not be matching the Brk64 case.
Change debug! to warn! for exception logging to ensure we can see the output with warn log level, helping diagnose the actual exception class value when breakpoint exceptions occur.
Check both Brk64 (0x3C) and BreakpointLowerEL (0x08) exception class values directly instead of relying only on enum matching, to ensure we catch breakpoint exceptions from user space brk instructions.
Handle breakpoint exceptions in user space by automatically skipping the breakpoint instruction when the process is not being debugged. This matches Linux behavior where breakpoint instructions are silently ignored for processes without a debugger attached. Changes: - aarch64: Handle both Brk64 (0x3C) and BreakpointLowerEL (0x08) exceptions, skip 4 bytes, and fix ExceptionInfo::kind() to correctly identify breakpoint exceptions from lower exception level - riscv: Handle Breakpoint exception, skip 2 bytes - loongarch64: Handle Breakpoint exception, skip 4 bytes - x86_64: Handle Breakpoint exception (INT3), skip 1 byte All architectures now recursively call run() after skipping the instruction to continue execution immediately.
…gging Add warn-level logging to diagnose why breakpoint exceptions are not being handled correctly. These logs will show: - All synchronous exceptions with EC, ISS, and ELR values - When a breakpoint exception is detected and handled - When exceptions don't match expected patterns This is temporary debugging code to identify the actual EC values being triggered by brk instructions.
Remove check for BreakpointLowerEL (0x08) as the correct exception type for user space brk instructions is Brk64 (0x3C), not BreakpointLowerEL. Also remove debug logging that was added for troubleshooting. The fix ensures that brk instructions in user space are automatically skipped (by incrementing elr by 4 bytes) and execution continues immediately, matching Linux behavior where brk instructions are silently ignored when no debugger is attached.
Handle BreakpointLowerEL exceptions by automatically skipping the brk instruction (4 bytes) when the process is not being debugged. This matches Linux behavior where brk instructions are silently ignored for processes without a debugger attached. - Handle Brk64 (EC=0x3C) exceptions in UserContext::run() - Handle TrappedMsrMrs (EC=0x18) exceptions that may be triggered by brk - Skip instruction by incrementing elr by 4 bytes and recursively calling run() - Update ExceptionInfo::kind() to recognize TrappedMsrMrs as Breakpoint Also fix function pointer cast warnings in init.rs files for all architectures: - aarch64/init.rs: exception_vector_base - riscv/init.rs: trap_vector_base - loongarch64/init.rs: exception_entry_base and handle_tlb_refill All casts now use 'as *const () as usize' pattern as recommended by the compiler.
This was referenced Dec 21, 2025
Closed
Replace recursive self.run() calls with loop-based implementation to avoid potential stack overflow when handling consecutive breakpoint exceptions. This change applies to all architectures: - aarch64: Brk64 and TrappedMsrMrs exceptions - x86_64: BREAKPOINT_VECTOR - loongarch64: Breakpoint exception - riscv: Breakpoint exception The new implementation uses a loop with continue statement instead of recursive calls, maintaining the same behavior of silently skipping breakpoint instructions when the process is not being debugged.
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Handle breakpoint exceptions (Brk64 and TrappedMsrMrs) by automatically skipping
the brk instruction (4 bytes) when the process is not being debugged. This matches
Linux behavior where brk instructions are silently ignored for processes without
a debugger attached.
Changes:
Also fixes function pointer cast warnings in init.rs files across all architectures
by using the recommended 'as *const () as usize' pattern.