riscv: Enable generic CPU vulnerabilites support

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@huawei.com>
Link: https://lore.kernel.org/r/20240703022732.2068316-1-ruanjinjie@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 0f3cd7c3a4360529331d8dd0023c11460b957622..4871220061c45c36bd82f73f4e03bc2475e4de00 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -92,6 +92,7 @@ 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