diff options
Diffstat (limited to 'tools/objtool/Documentation/stack-validation.txt')
| -rw-r--r-- | tools/objtool/Documentation/stack-validation.txt | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/tools/objtool/Documentation/stack-validation.txt b/tools/objtool/Documentation/stack-validation.txt index 0542e46c7552..30f38fdc0d56 100644 --- a/tools/objtool/Documentation/stack-validation.txt +++ b/tools/objtool/Documentation/stack-validation.txt @@ -315,13 +315,15 @@ they mean, and suggestions for how to fix them. function tracing inserts additional calls, which is not obvious from the sources). -10. file.o: warning: func()+0x5c: alternative modifies stack - - This means that an alternative includes instructions that modify the - stack. The problem is that there is only one ORC unwind table, this means - that the ORC unwind entries must be valid for each of the alternatives. - The easiest way to enforce this is to ensure alternatives do not contain - any ORC entries, which in turn implies the above constraint. +10. file.o: warning: func()+0x5c: stack layout conflict in alternatives + + This means that in the use of the alternative() or ALTERNATIVE() + macro, the code paths have conflicting modifications to the stack. + The problem is that there is only one ORC unwind table, which means + that the ORC unwind entries must be consistent for all possible + instruction boundaries regardless of which code has been patched. + This limitation can be overcome by massaging the alternatives with + NOPs to shift the stack changes around so they no longer conflict. 11. file.o: warning: unannotated intra-function call |