Hi Jiaxun,
Overall a nice step towards a more conformant arch/mips! Some nits below
though.
On 12/30/20 11:23 AM, Jiaxun Yang wrote:
Add infrastructure to display CPU vulnerabilities.
As most MIPS CPU vendors are dead today and we can't confirm
vulnerabilities states with them, we'll display vulnerabilities
as "Unknown" by default and override them in cpu-probe.c
Add trailing period.
Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
---
arch/mips/Kconfig | 1 +
arch/mips/include/asm/cpu-info.h | 5 ++++
arch/mips/include/asm/cpu.h | 7 +++++
arch/mips/kernel/Makefile | 2 +-
arch/mips/kernel/vulnbl.c | 46 ++++++++++++++++++++++++++++++++
5 files changed, 60 insertions(+), 1 deletion(-)
create mode 100644 arch/mips/kernel/vulnbl.c
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index ef5b2a177b1b..524053b8f769 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -24,6 +24,7 @@ config MIPS
select GENERIC_CLOCKEVENTS
select GENERIC_CMOS_UPDATE
select GENERIC_CPU_AUTOPROBE
+ select GENERIC_CPU_VULNERABILITIES
select GENERIC_GETTIMEOFDAY
select GENERIC_IOMAP
select GENERIC_IRQ_PROBE
diff --git a/arch/mips/include/asm/cpu-info.h b/arch/mips/include/asm/cpu-info.h
index a600670d00e9..1a964dbfc0a8 100644
--- a/arch/mips/include/asm/cpu-info.h
+++ b/arch/mips/include/asm/cpu-info.h
@@ -106,6 +106,11 @@ struct cpuinfo_mips {
unsigned int guestid_mask;
unsigned int guestid_cache;
+ /* Vulnerabilities */
+ unsigned int vulnerabilities; /* Vulnerabilities states that we known */
+ unsigned int vulnerable; /* Vulnerabilities affated */
+ unsigned int mitigations; /* Mitigations */
Could you make the field names a little clearer? Like "known_mask",
"affected_mask" and "mitigated_mask"?
Also I wonder if removing the first mask is okay, since if a bit is
neither "affected" nor "mitigated" then it must belong to the "unknown"
case.
+
#ifdef CONFIG_CPU_LOONGSON3_CPUCFG_EMULATION
/* CPUCFG data for this CPU, synthesized at probe time.
*
diff --git a/arch/mips/include/asm/cpu.h b/arch/mips/include/asm/cpu.h
index f5b04e8f6061..3414c9f5464e 100644
--- a/arch/mips/include/asm/cpu.h
+++ b/arch/mips/include/asm/cpu.h
@@ -447,4 +447,11 @@ enum cpu_type_enum {
#define MIPS_ASE_LOONGSON_EXT 0x00002000 /* Loongson EXTensions */
#define MIPS_ASE_LOONGSON_EXT2 0x00004000 /* Loongson EXTensions R2 */
+/*
+ * CPU security vulnerabilities
+ */
+#define MIPS_VULNBL_MELTDOWN BIT(0)
+#define MIPS_VULNBL_SPECTRE_V1 BIT(1)
+#define MIPS_VULNBL_SPECTRE_V2 BIT(2)
Looking at the arch/x86 vulnerabilities code, I tend to think that
"VULNBL" is not (rather ugly) shorthand for "vulnerability", but
"vulnerability blacklist" (!), because they have "VULNWL" for apparently
"whitelist". So I suggest writing out "VULNERABILITY" fully for clarity.
+
#endif /* _ASM_CPU_H */
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 13a26d254829..39abc8ead5e0 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -8,7 +8,7 @@ extra-y := head.o vmlinux.lds
obj-y += cmpxchg.o cpu-probe.o branch.o elf.o entry.o genex.o idle.o irq.o \
process.o prom.o ptrace.o reset.o setup.o signal.o \
syscall.o time.o topology.o traps.o unaligned.o watch.o \
- vdso.o cacheinfo.o
+ vdso.o cacheinfo.o vulnbl.o
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_ftrace.o = -pg
diff --git a/arch/mips/kernel/vulnbl.c b/arch/mips/kernel/vulnbl.c
new file mode 100644
index 000000000000..fc73da6214fe
--- /dev/null
+++ b/arch/mips/kernel/vulnbl.c
Same with this filename.
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
+ * MIPS CPU vulnerabilities
+ */
+
+#include <linux/device.h>
+
+#include <asm/cpu-info.h>
+#include <asm/cpu.h>
+
+ssize_t cpu_show_meltdown(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ if (!(boot_cpu_data.vulnerabilities & MIPS_VULNBL_MELTDOWN))
+ return sprintf(buf, "Unknown\n");
+
+ if (!(boot_cpu_data.vulnerable & MIPS_VULNBL_MELTDOWN))
+ return sprintf(buf, "Not affected\n");
+
+ return sprintf(buf, "Affected\n");
Be consistent with other arches and use "Vulnerable"?
+}
+
+ssize_t cpu_show_spectre_v1(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ if (!(boot_cpu_data.vulnerabilities & MIPS_VULNBL_SPECTRE_V1))
+ return sprintf(buf, "Unknown\n");
+
+ if (!(boot_cpu_data.vulnerable & MIPS_VULNBL_SPECTRE_V1))
+ return sprintf(buf, "Not affected\n");
+
+ return sprintf(buf, "Affected\n");
Same as above.
+}
+
+ssize_t cpu_show_spectre_v2(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ if (!(boot_cpu_data.vulnerabilities & MIPS_VULNBL_SPECTRE_V2))
+ return sprintf(buf, "Unknown\n");
+
+ if (!(boot_cpu_data.vulnerable & MIPS_VULNBL_SPECTRE_V2))
+ return sprintf(buf, "Not affected\n");
+
+ return sprintf(buf, "Affected\n");
Same as above.
+}
