[RFC PATCH] riscv: Enable generic CPU vulnerabilites support

[Jinjie Ruan]

Currently x86, ARM and ARM64 support generic CPU vulnerabilites, but
RISC-V not, such as:

	# cd /sys/devices/system/cpu/vulnerabilities/
x86:
	# cat spec_store_bypass
		Mitigation: Speculative Store Bypass disabled via prctl and seccomp
	# cat meltdown
		Not affected

ARM64:

	# cat spec_store_bypass
		Mitigation: Speculative Store Bypass disabled via prctl and seccomp
	# cat meltdown
		Mitigation: PTI

RISC-V:

	# cat /sys/devices/system/cpu/vulnerabilities
	# ... No such file or directory

As SiFive RISC-V Core IP offerings are not affected by Meltdown and
Spectre, it can use the default weak function as below:

	# cat spec_store_bypass
		Not affected
	# cat meltdown
		Not affected

Link: https://www.sifive.cn/blog/sifive-statement-on-meltdown-and-spectre

Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
 arch/riscv/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 0525ee2d63c7..3b44e7b51436 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -85,6 +85,7 @@ config RISCV
 	select GENERIC_ATOMIC64 if !64BIT
 	select GENERIC_CLOCKEVENTS_BROADCAST if SMP
 	select GENERIC_CPU_DEVICES
+	select GENERIC_CPU_VULNERABILITIES
 	select GENERIC_EARLY_IOREMAP
 	select GENERIC_ENTRY
 	select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
-- 
2.34.1