News: 0001496121

  ARM Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life (Terry Pratchett, Jingo)

Linux 6.12 Patches Neoverse-N3 & Microsoft Azure Cobalt 100 For Speculative SSBS

([Arm] 3 Hours Ago Plus Neoverse-A715)


We are not done yet seeing new Arm cores still impacted by the [1]Speculative Store Bypass handling errata. Merged to Linux 6.12 on Friday was adding the speculative SSBS workaround for the Cortex-A715, Neoverse-N3, and Microsoft Azure Cobalt 100 cores.

Over the past few months we have seen [2]more Arm CPU cores needing the speculative SBBS workaround . The issue deals with MSR writes to the SSBS (Speculative Store Bypass Safe) special purpose register not affecting subsequent speculative instructions. This issue when unmitigated can lead to speculative store bypassing for a period of time.

The workaround within the Linux kernel adds a speculation barrier after MSR writes to the SSBS register. A variety of Cortex and Neoverse cores to date have needed this workaround while the list has grown longer as of Friday. The Cortex-A715, Neoverse-N3, and Microsoft Azure Cobalt 100 are the latest where this workaround/mitigation is being applied.

This went into effect via [3]this merge to Linux 6.12 Git on Friday and will be found in Sunday's Linux 6.12-rc2 kernel.



[1] https://www.phoronix.com/search/Speculative+Store+Bypass

[2] https://www.phoronix.com/news/Arm-SSBS-Linux-More-CPUs

[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ac308609567d31fe44be80ab757a5ddf062362ef


phoronix

The Blue Screen Of Advocacy

The Federal Bureau of Investigation & Privacy Violations has issued a
national advisory warning computer stores to be on the lookout for the
"Bluescreen Bandits". These extreme Linux zealots go from store to store
and from computer to computer typing in "C:\CON\CON" and causing the demo
machines to crash and display the Blue Screen Of Death.

Efforts to apprehend the bandits have so far been unsuccessful. The
outlaws were caught on tape at a CompUSSR location in Southern California,
but in an ironic twist, the surveillance system bluescreened just before
the penguinistas came into clear view.

"We don't have many clues. It's not clear whether a small group is behind
the bluescreen vandalism, or whether hundreds or even thousands of geek
zealots are involved," said the manager of a Capacitor City store.

The manager has good reason to be upset. The bluescreen raid was the top
story in the local newspaper and quickly became a hot topic of discussion.
As a result, the local school board halted its controversial plans to
migrate their computers from Macs to PCs.