Messages in this thread | | | Subject | Re: [PATCH 3/3] MIPS: cpu-probe: Vulnerabilities for Loongson cores | From | Jiaxun Yang <> | Date | Fri, 1 Jan 2021 00:09:35 +0800 |
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在 2020/12/31 23:43, WANG Xuerui 写道: > Hi Jiaxun, > > On 12/30/20 11:23 AM, Jiaxun Yang wrote: >> Loongson64C is known to be vulnerable to meltdown according to >> PoC from Rui Wang <r@hev.cc>. >> >> Loongson64G defended these side-channel attack by silicon. > "Loongson64G mitigated it in hardware"? >> >> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com> >> --- >> arch/mips/kernel/cpu-probe.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c >> index 2460783dbdb1..24b21f51353c 100644 >> --- a/arch/mips/kernel/cpu-probe.c >> +++ b/arch/mips/kernel/cpu-probe.c >> @@ -2092,6 +2092,8 @@ static inline void cpu_probe_loongson(struct >> cpuinfo_mips *c, unsigned int cpu) >> c->ases |= (MIPS_ASE_LOONGSON_MMI | MIPS_ASE_LOONGSON_CAM | >> MIPS_ASE_LOONGSON_EXT | MIPS_ASE_LOONGSON_EXT2); >> c->ases &= ~MIPS_ASE_VZ; /* VZ of Loongson-3A2000/3000 is >> incomplete */ >> + c->vulnerabilities |= MIPS_VULNBL_MELTDOWN; >> + c->vulnerable |= MIPS_VULNBL_MELTDOWN; >> break; >> case PRID_IMP_LOONGSON_64G: >> c->cputype = CPU_LOONGSON64; >> @@ -2100,6 +2102,8 @@ static inline void cpu_probe_loongson(struct >> cpuinfo_mips *c, unsigned int cpu) >> set_isa(c, MIPS_CPU_ISA_M64R2); >> decode_cpucfg(c); >> c->writecombine = _CACHE_UNCACHED_ACCELERATED; >> + c->vulnerabilities |= MIPS_VULNBL_MELTDOWN | >> + MIPS_VULNBL_SPECTRE_V1 | MIPS_VULNBL_SPECTRE_V2; > > Of course you forgot to set the "mitigated" mask... Oh wait.
Hi Xuerui,
Actually it belongs to not affected category as there is no action to take in kernel.
> > It seems the "mitigated" mask in the 1st patch is never used, so > either code there or here must be amended.
Yes, it's just a place holder for future kernel mitigations~ Or I should leave it until we find out these mitigations?
Thanks.
- Jiaxun
> >> break; >> default: >> panic("Unknown Loongson Processor ID!");
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