|
Elite Member
|
引用:
|
作者deanhu
根據AMD自己發出來的消息，Linux Kernel 4.15的PTI patch已將AMD CPU排除在外。AMD這麼有把握？
|
你可以自己看整個merge的patches
https://github.com/torvalds/linux/c...40663af75f64R99
看起來其實這些寫patches的人根本無法說出AMD一定沒問題
只是單純相信AMD確認沒問題是真的沒問題
不過在PTI patches裡面也提到AMD有另外一個問題
在這裡順便修正
引用:
User space process size. This is the first address outside the user range.
There are a few constraints that determine this:
+ *
On Intel CPUs, if a SYSCALL instruction is at the highest canonical
address, then that syscall will enter the kernel with a
non-canonical return address, and SYSRET will explode dangerously.
We avoid this particular problem by preventing anything executable
from being mapped at the maximum canonical address.
+ *
On AMD CPUs in the Ryzen family, there's a nasty bug in which the
CPUs malfunction if they execute code from the highest canonical page.
They'll speculate right off the end of the canonical space, and
bad things happen. This is worked around in the same way as the
Intel problem.
|
看起來是引發問題的原因 I 跟 A 兩者本質上不同
只是導致的結果同樣可以來利用 |