On Fri, Jun 16, 2023, at 1:50 AM, Mike Rapoport wrote: > From: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx> > > module_alloc() is used everywhere as a mean to allocate memory for code. > > Beside being semantically wrong, this unnecessarily ties all subsystems > that need to allocate code, such as ftrace, kprobes and BPF to modules > and puts the burden of code allocation to the modules code. > > Several architectures override module_alloc() because of various > constraints where the executable memory can be located and this causes > additional obstacles for improvements of code allocation. > > Start splitting code allocation from modules by introducing > execmem_text_alloc(), execmem_free(), jit_text_alloc(), jit_free() APIs. > > Initially, execmem_text_alloc() and jit_text_alloc() are wrappers for > module_alloc() and execmem_free() and jit_free() are replacements of > module_memfree() to allow updating all call sites to use the new APIs. > > The intention semantics for new allocation APIs: > > * execmem_text_alloc() should be used to allocate memory that must reside > close to the kernel image, like loadable kernel modules and generated > code that is restricted by relative addressing. > > * jit_text_alloc() should be used to allocate memory for generated code > when there are no restrictions for the code placement. For > architectures that require that any code is within certain distance > from the kernel image, jit_text_alloc() will be essentially aliased to > execmem_text_alloc(). > Is there anything in this series to help users do the appropriate synchronization when the actually populate the allocated memory with code? See here, for example: https://lore.kernel.org/linux-fsdevel/cb6533c6-cea0-4f04-95cf-b8240c6ab405@xxxxxxxxxxxxxxxx/T/#u
