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Date:   Sun, 29 Oct 2023 21:42:41 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Brian Gerst' <>,
        "" <>,
        "" <>
CC:     Ingo Molnar <>,
        Thomas Gleixner <>,
        Borislav Petkov <>,
        "H . Peter Anvin" <>,
        "Peter Zijlstra" <>,
        Uros Bizjak <>
Subject: RE: [PATCH v2 00/11] x86-64: Stack protector and percpu improvements

From: Brian Gerst
> Sent: 26 October 2023 17:01
> Currently, x86-64 uses an unusual percpu layout, where the percpu section
> is linked at absolute address 0.  The reason behind this is that older GCC
> versions placed the stack protector (if enabled) at a fixed offset from the
> GS segment base.  Since the GS segement is also used for percpu variables,
> this forced the current layout.
> GCC since version 8.1 supports a configurable location for the stack
> protector value, which allows removal of the restriction on how the percpu
> section is linked.  This allows the percpu section to be linked
> normally, like most other architectures.  In turn, this allows removal
> of code that was needed to support the zero-based percpu section.

I didn't think the minimum gcc version was anything like 8.1.
I'm using 7.5.0 and I don't think that is the oldest version.


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