diff options
| author | Linus Torvalds | 2019-11-27 11:25:04 -0800 |
|---|---|---|
| committer | Linus Torvalds | 2019-11-27 11:25:04 -0800 |
| commit | 80eb5fea3c14fb171facb5242a1555b3aafea4d0 (patch) | |
| tree | 08c6840f7d25876ff515dab190a38bfcfecaea88 /arch/powerpc/include/asm | |
| parent | 9a3d7fd275be4559277667228902824165153c80 (diff) | |
| parent | af2e8c68b9c5403f77096969c516f742f5bb29e0 (diff) | |
Merge tag 'powerpc-spectre-rsb' of powerpc-CVE-2019-18660.bundle
Pull powerpc Spectre-RSB fixes from Michael Ellerman:
"We failed to activate the mitigation for Spectre-RSB (Return Stack
Buffer, aka. ret2spec) on context switch, on CPUs prior to Power9
DD2.3.
That allows a process to poison the RSB (called Link Stack on Power
CPUs) and possibly misdirect speculative execution of another process.
If the victim process can be induced to execute a leak gadget then it
may be possible to extract information from the victim via a side
channel.
The fix is to correctly activate the link stack flush mitigation on
all CPUs that have any mitigation of Spectre v2 in userspace enabled.
There's a second commit which adds a link stack flush in the KVM guest
exit path. A leak via that path has not been demonstrated, but we
believe it's at least theoretically possible.
This is the fix for CVE-2019-18660"
* tag 'powerpc-spectre-rsb' of /home/torvalds/Downloads/powerpc-CVE-2019-18660.bundle:
KVM: PPC: Book3S HV: Flush link stack on guest exit to host kernel
powerpc/book3s64: Fix link stack flush on context switch
Diffstat (limited to 'arch/powerpc/include/asm')
| -rw-r--r-- | arch/powerpc/include/asm/asm-prototypes.h | 3 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/security_features.h | 3 |
2 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h index 8561498e653c..d84d1417ddb6 100644 --- a/arch/powerpc/include/asm/asm-prototypes.h +++ b/arch/powerpc/include/asm/asm-prototypes.h @@ -152,9 +152,12 @@ void _kvmppc_save_tm_pr(struct kvm_vcpu *vcpu, u64 guest_msr); /* Patch sites */ extern s32 patch__call_flush_count_cache; extern s32 patch__flush_count_cache_return; +extern s32 patch__flush_link_stack_return; +extern s32 patch__call_kvm_flush_link_stack; extern s32 patch__memset_nocache, patch__memcpy_nocache; extern long flush_count_cache; +extern long kvm_flush_link_stack; #ifdef CONFIG_PPC_TRANSACTIONAL_MEM void kvmppc_save_tm_hv(struct kvm_vcpu *vcpu, u64 msr, bool preserve_nv); diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h index 759597bf0fd8..ccf44c135389 100644 --- a/arch/powerpc/include/asm/security_features.h +++ b/arch/powerpc/include/asm/security_features.h @@ -81,6 +81,9 @@ static inline bool security_ftr_enabled(unsigned long feature) // Software required to flush count cache on context switch #define SEC_FTR_FLUSH_COUNT_CACHE 0x0000000000000400ull +// Software required to flush link stack on context switch +#define SEC_FTR_FLUSH_LINK_STACK 0x0000000000001000ull + // Features enabled by default #define SEC_FTR_DEFAULT \ |