diff options
| author | Diana Craciun <diana.craciun@nxp.com> | 2019-04-22 00:20:34 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-16 19:44:50 +0200 |
| commit | 0454f7b3282bec5d72b6f5c916ac1fe31bd26c67 (patch) | |
| tree | 468c55d1cfa65f918a8476aea8ac5ca322f3fe3a /arch/powerpc/mm | |
| parent | 932e8acaa806376db8ed1f33d8c0159569b935ff (diff) | |
powerpc/fsl: Flush the branch predictor at each kernel entry (64bit)
commit 10c5e83afd4a3f01712d97d3bb1ae34d5b74a185 upstream.
In order to protect against speculation attacks on
indirect branches, the branch predictor is flushed at
kernel entry to protect for the following situations:
- userspace process attacking another userspace process
- userspace process attacking the kernel
Basically when the privillege level change (i.e. the
kernel is entered), the branch predictor state is flushed.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/tlb_low_64e.S | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/mm/tlb_low_64e.S b/arch/powerpc/mm/tlb_low_64e.S index 29d6987c37ba..5486d56da289 100644 --- a/arch/powerpc/mm/tlb_low_64e.S +++ b/arch/powerpc/mm/tlb_low_64e.S @@ -69,6 +69,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) std r15,EX_TLB_R15(r12) std r10,EX_TLB_CR(r12) #ifdef CONFIG_PPC_FSL_BOOK3E +START_BTB_FLUSH_SECTION + mfspr r11, SPRN_SRR1 + andi. r10,r11,MSR_PR + beq 1f + BTB_FLUSH(r10) +1: +END_BTB_FLUSH_SECTION std r7,EX_TLB_R7(r12) #endif TLB_MISS_PROLOG_STATS |