search for: current_stack_point

....com> wrote: > One of the issues the LLVMLinux project is having is with the use of > named registers in the Linux kernel code. The kernel uses something like > this in order to assign a C variable name to a register (one for each > kernel arch). > > register unsigned long current_stack_pointer asm("esp"); > > clang doesn't allow this kind of thing which required a patch which less > efficient: > > #define current_stack_pointer ({ \ > unsigned long esp; \ > asm("mov %%esp, %0" : "=r"(esp)); \ > esp; \ > })...

One of the issues the LLVMLinux project is having is with the use of named registers in the Linux kernel code. The kernel uses something like this in order to assign a C variable name to a register (one for each kernel arch). register unsigned long current_stack_pointer asm("esp"); clang doesn't allow this kind of thing which required a patch which less efficient: #define current_stack_pointer ({ \ unsigned long esp; \ asm("mov %%esp, %0" : "=r"(esp)); \ esp; \ }) This works for both gcc and clang, but of...

...ne of the issues the LLVMLinux project is having is with the use of >>  named registers in the Linux kernel code. The kernel uses something like >>  this in order to assign a C variable name to a register (one for each >>  kernel arch). >> >>     register unsigned long current_stack_pointer asm("esp"); >> >>  clang doesn't allow this kind of thing which required a patch which less >>  efficient: >> >>  #define current_stack_pointer ({ \ >>        unsigned long esp; \ >>        asm("mov %%esp, %0" : "=r"(esp)...

...t; One of the issues the LLVMLinux project is having is with the use of >> named registers in the Linux kernel code. The kernel uses something like >> this in order to assign a C variable name to a register (one for each >> kernel arch). >> >> register unsigned long current_stack_pointer asm("esp"); >> >> clang doesn't allow this kind of thing which required a patch which less >> efficient: >> >> #define current_stack_pointer ({ \ >> unsigned long esp; \ >> asm("mov %%esp, %0" : "=r"(esp)); \...

...t is having is with the use of >>>> named registers in the Linux kernel code. The kernel uses something like >>>> this in order to assign a C variable name to a register (one for each >>>> kernel arch). >>>> >>>> register unsigned long current_stack_pointer asm("esp"); >>>> >>>> clang doesn't allow this kind of thing which required a patch which less >>>> efficient: >>>> >>>> #define current_stack_pointer ({ \ >>>> unsigned long esp; \ >>>>...

...LLVMLinux project is having is with the use of >>> named registers in the Linux kernel code. The kernel uses something like >>> this in order to assign a C variable name to a register (one for each >>> kernel arch). >>> >>> register unsigned long current_stack_pointer asm("esp"); >>> >>> clang doesn't allow this kind of thing which required a patch which less >>> efficient: >>> >>> #define current_stack_pointer ({ \ >>> unsigned long esp; \ >>> asm("mov %%esp, %0...

...the LLVMLinux project is having is with the use of >>> named registers in the Linux kernel code. The kernel uses something like >>> this in order to assign a C variable name to a register (one for each >>> kernel arch). >>> >>> register unsigned long current_stack_pointer asm("esp"); >>> >>> clang doesn't allow this kind of thing which required a patch which less >>> efficient: >>> >>> #define current_stack_pointer ({ \ >>> unsigned long esp; \ >>> asm("mov %%esp, %0&quot...

...gt;>> named registers in the Linux kernel code. The kernel uses >>>>> something like >>>>> this in order to assign a C variable name to a register (one for each >>>>> kernel arch). >>>>> >>>>> register unsigned long current_stack_pointer asm("esp"); >>>>> >>>>> clang doesn't allow this kind of thing which required a patch >>>>> which less >>>>> efficient: >>>>> >>>>> #define current_stack_pointer ({ \ >>>>>...

Folks, So, I think we kind of agree that some named registers could be implemented, and that it should be an intrinsic that passes the name of the register down. This C code: register unsigned long current_stack_pointer asm("sp"); unsigned long get_stack_pointer_addr() { return current_stack_pointer; } void set_stack_pointer_addr(unsigned long addr) { current_stack_pointer = addr; } Would become something like: define i32 @get_stack_pointer_addr() nounwind { entry: %0 = call i32 @llvm.read_regi...

...ct is having is with the use of >>>> named registers in the Linux kernel code. The kernel uses something like >>>> this in order to assign a C variable name to a register (one for each >>>> kernel arch). >>>> >>>> register unsigned long current_stack_pointer asm("esp"); >>>> >>>> clang doesn't allow this kind of thing which required a patch which less >>>> efficient: >>>> >>>> #define current_stack_pointer ({ \ >>>> unsigned long esp; \ >>>>...

This series removes some no longer needed stuff from paravirt infrastructure and puts large quantities of paravirt ops under a new config option PARAVIRT_XXL which is selected by XEN_PV only. A pvops kernel without XEN_PV being configured is about 2.5% smaller with this series applied. tip commit 5800dc5c19f34e6e03b5adab1282535cb102fafd ("x86/paravirt: Fix spectre-v2 mitigations for

This series removes some no longer needed stuff from paravirt infrastructure and puts large quantities of paravirt ops under a new config option PARAVIRT_XXL which is selected by XEN_PV only. A pvops kernel without XEN_PV being configured is about 2.5% smaller with this series applied. tip commit 5800dc5c19f34e6e03b5adab1282535cb102fafd ("x86/paravirt: Fix spectre-v2 mitigations for