diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/Kconfig | 36 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 2 |
2 files changed, 34 insertions, 4 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 601691f1570f..d544abd14c01 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1278,11 +1278,41 @@ config HAVE_STATIC_CALL_INLINE config HAVE_PREEMPT_DYNAMIC bool + +config HAVE_PREEMPT_DYNAMIC_CALL + bool depends on HAVE_STATIC_CALL + select HAVE_PREEMPT_DYNAMIC + help + An architecture should select this if it can handle the preemption + model being selected at boot time using static calls. + + Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a + preemption function will be patched directly. + + Where an architecture does not select HAVE_STATIC_CALL_INLINE, any + call to a preemption function will go through a trampoline, and the + trampoline will be patched. + + It is strongly advised to support inline static call to avoid any + overhead. + +config HAVE_PREEMPT_DYNAMIC_KEY + bool + depends on HAVE_ARCH_JUMP_LABEL && CC_HAS_ASM_GOTO + select HAVE_PREEMPT_DYNAMIC help - Select this if the architecture support boot time preempt setting - on top of static calls. It is strongly advised to support inline - static call to avoid any overhead. + An architecture should select this if it can handle the preemption + model being selected at boot time using static keys. + + Each preemption function will be given an early return based on a + static key. This should have slightly lower overhead than non-inline + static calls, as this effectively inlines each trampoline into the + start of its callee. This may avoid redundant work, and may + integrate better with CFI schemes. + + This will have greater overhead than using inline static calls as + the call to the preemption function cannot be entirely elided. config ARCH_WANT_LD_ORPHAN_WARN bool diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index ebe8fc76949a..f13cfdfb30ce 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -245,7 +245,7 @@ config X86 select HAVE_STACK_VALIDATION if X86_64 select HAVE_STATIC_CALL select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION - select HAVE_PREEMPT_DYNAMIC + select HAVE_PREEMPT_DYNAMIC_CALL select HAVE_RSEQ select HAVE_SYSCALL_TRACEPOINTS select HAVE_UNSTABLE_SCHED_CLOCK |