Target injection safe method for inlining large call tables

A system comprising:

• a memory containing one or more user processes, and an operating system kernel having a memory code region that has a different mapping for each user process;
• and
• one or more CPUs coupled to the memory, the one or more CPUs running the operating system kernel and the one or more user processes;
• wherein the operating system kernel is configured to:
• record frequencies of calls in a frequency table;
• update a search trampoline to cache, as direct calls, calls of the call table that are most frequently made according to the recorded calls in the frequency table;
• receive a request to perform one of the calls in the call table;
• perform a search of the search trampoline to determine whether or not the requested call is cached in the search trampoline;
• if the requested call is cached in the search trampoline, perform the requested call that is cached in the search trampoline;
• and
• if the requested call is not cached in the search trampoline, perform the requested call by accessing the call via the call table.

A non-transitory computer-readable medium comprising instructions executable in a computer system, wherein the instructions when executed in the computer system cause the computer system to carry out a method of redirecting an indirect call in a call table to a direct call, the method comprising:

• recording frequencies of calls in a frequency table;
• updating a search trampoline to cache, as direct calls, calls of the call table that are most frequently made according to the recorded calls in the frequency table;
• receiving a request to perform one of the calls in the call table;
• performing a search of the search trampoline to determine whether or not the requested call is cached in the search trampoline;
• if the requested call is cached in the search trampoline, performing the requested call that is cached in the search trampoline;
• and
• if the requested call is not cached in the search trampoline, performing the requested call by accessing the call via the call table.