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| author |   Diana Craciun <diana.craciun@nxp.com> | 2018-12-12 16:03:05 +0200 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2018-12-20 22:59:03 +1100 |
| commit | 10c5e83afd4a3f01712d97d3bb1ae34d5b74a185 (patch) | |
| tree | 19f032a9630407a6b0d0bbfe13c44cb4573f57f1 /arch/powerpc/mm/tlb_low_64e.S | |
| parent | powerpc/fsl: Add nospectre_v2 command line argument (diff) | |
| download | linux-dev-10c5e83afd4a3f01712d97d3bb1ae34d5b74a185.tar.xz linux-dev-10c5e83afd4a3f01712d97d3bb1ae34d5b74a185.zip | |
powerpc/fsl: Flush the branch predictor at each kernel entry (64bit)
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>
Diffstat (limited to 'arch/powerpc/mm/tlb_low_64e.S')
| -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 7fd20c52a8ec..9ed90064f542 100644 --- a/arch/powerpc/mm/tlb_low_64e.S +++ b/arch/powerpc/mm/tlb_low_64e.S @@ -70,6 +70,13 @@ 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 |