Fix semihosting::exit() on riscv64 QEMU targets. #215
Closed
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
QEMU's handler for REPORT_EXCEPTION (a.k.a. TARGET_SYS_EXIT in QEMU sources) expects two arguments for 64-bit systems, including riscv64. In the event that a second argument is not provided, QEMU takes an error path which does *not* exit the simulation. The net result is that semihosting::debug::exit() hangs on riscv64 qemu simulation. Provide the necessry extra paramater to the syscall so that exit now works properly. Note that the second parameter only affects the simulator exit code if the first parameter is ApplicationExit, and we use ApplicationExit only for successful exit, so we can simply hardcode 0 as second parameter. On the error path we set first parameter to RunTimeErrorUnknown and QEMU properly returns exit code 1 regardless of second parameter.
|
Hold off, I just tested this on riscv32 target and return error codes are broken by this change. Will resubmit. |
|
SYS_EXIT has the different API on 32-bit and 64-bit:
The master branch is correct for 32-bit and this PR is correct for 64-bit. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
QEMU's handler for REPORT_EXCEPTION (a.k.a. TARGET_SYS_EXIT in QEMU sources) expects two arguments for 64-bit systems, including riscv64. In the event that a second argument is not provided, QEMU takes an error path which does not exit the simulation.
The net result is that semihosting::debug::exit() hangs on riscv64 qemu simulation.
Provide the necessry extra paramater to the syscall so that exit now works properly.
Note that the second parameter only affects the simulator exit code if the first parameter is ApplicationExit, and we use ApplicationExit only for successful exit, so we can simply hardcode 0 as second parameter. On the error path we set first parameter to RunTimeErrorUnknown and QEMU properly returns exit code 1 regardless of second parameter.