Messages in this thread | | | From | Martin Steigerwald <> | Subject | Requirements for retpoline in Linux 4.15 (was: Re: Linux 4.15) | Date | Mon, 29 Jan 2018 10:41:15 +0100 |
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Hi Linus, hi everyone,
Linus Torvalds - 28.01.18, 22:52: > details), and perhaps equally importantly, to actually get the biggest > fix for the indirect branch mitigations, you need not just the kernel > updates, you need to have a compiler with support for the "retpoline" > indirect branch model. > > You can do > > cat /sys/devices/system/cpu/vulnerabilities/spectre_v2 > > and if you don't have a compiler that supports the retpoline > mitigations, you'll get: > > Vulnerable: Minimal generic ASM retpoline > > because only the assembly code (not the C code) will have the > retpoline mitigation. So keep that in mind.
I have:
% cat /proc/version Linux version 4.15.0-tp520-btrfstrim+ ([…]) (gcc version 7.3.0 (Debian 7.3.0-1)) #38 SMP PREEMPT Mon Jan 29 09:38:44 CET 2018
% grep RETPO /boot/config-4.15.0-tp520-btrfstrim+ CONFIG_RETPOLINE=y
% gcc --version | head -1 gcc (Debian 7.3.0-1) 7.3.0
% apt changelog gcc-7 gcc-7 (7.3.0-1) unstable; urgency=medium
* GCC 7.3.0 release. * Ignore bootstrap comparison failures in gcc/d on alpha. Addresses: #888394.
-- Matthias Klose […] Thu, 25 Jan 2018 12:07:10 +0100
Yet:
% grep . /sys/devices/system/cpu/vulnerabilities/* /sys/devices/system/cpu/vulnerabilities/meltdown:Mitigation: PTI /sys/devices/system/cpu/vulnerabilities/spectre_v1:Vulnerable /sys/devices/system/cpu/vulnerabilities/spectre_v2:Vulnerable: Minimal generic ASM retpoline
From what I read gcc 7.3 was supposed to include back ported retpoline patches. What am I missing here?
Thanks, -- Martin
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