rust: add per-arch HAVE_RUST kernel option

Suggested-by: Russell King (Oracle) <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>

Author: ojeda

arch/Kconfig

@@ -339,6 +339,12 @@ config HAVE_RSEQ
 	  This symbol should be selected by an architecture if it
 	  supports an implementation of restartable sequences.
 
+config HAVE_RUST
+	bool
+	help
+	  This symbol should be selected by an architecture if it
+	  supports Rust.
+
 config HAVE_FUNCTION_ARG_ACCESS_API
 	bool
 	help

arch/arm/Kconfig

@@ -113,6 +113,7 @@ config ARM
 	select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RSEQ
+	select HAVE_RUST if CPU_32v6 || CPU_32v6K
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UID16

arch/arm64/Kconfig

@@ -197,6 +197,7 @@ config ARM64
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select MMU_GATHER_RCU_TABLE_FREE
 	select HAVE_RSEQ
+	select HAVE_RUST
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_KPROBES

arch/powerpc/Kconfig

@@ -232,6 +232,7 @@ config PPC
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
+	select HAVE_RUST			if PPC64 && CPU_LITTLE_ENDIAN
 	select HAVE_SETUP_PER_CPU_AREA		if PPC64
 	select HAVE_SOFTIRQ_ON_OWN_STACK
 	select HAVE_STACKPROTECTOR		if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)

arch/riscv/Kconfig

@@ -98,6 +98,7 @@ config RISCV
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_RUST if 64BIT
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS

arch/x86/Kconfig

@@ -248,6 +248,7 @@ config X86
 	select HAVE_STATIC_CALL_INLINE		if HAVE_STACK_VALIDATION
 	select HAVE_PREEMPT_DYNAMIC
 	select HAVE_RSEQ
+	select HAVE_RUST			if X86_64
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UNSTABLE_SCHED_CLOCK
 	select HAVE_USER_RETURN_NOTIFIER

init/Kconfig

@@ -2055,8 +2055,8 @@ config PROFILING
 
 config RUST
 	bool "Rust support"
+	depends on HAVE_RUST
 	depends on RUST_IS_AVAILABLE
-	depends on ARM64 || CPU_32v6 || CPU_32v6K || (PPC64 && CPU_LITTLE_ENDIAN) || X86_64 || RISCV
 	depends on !MODVERSIONS
 	depends on !GCC_PLUGIN_RANDSTRUCT
 	select CONSTRUCTORS