From: Ramana Radhakrishnan <ramana.radhakrishnan@foss.arm.com>
To: Kugan Vivekanandarajah <kugan.vivekanandarajah@linaro.org>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
James Greenhalgh <james.greenhalgh@arm.com>,
Richard Earnshaw <Richard.Earnshaw@arm.com>
Subject: Re: [AARCH64] Disable pc relative literal load irrespective of TARGET_FIX_ERR_A53_84341
Date: Tue, 27 Jun 2017 08:01:00 -0000 [thread overview]
Message-ID: <752a2d93-0641-134f-33dd-bc550618f7f3@foss.arm.com> (raw)
In-Reply-To: <CAELXzTMS9eHrcQ5SxXq4CuipBX4hgqrcYXapSxnAwanXL0AWqA@mail.gmail.com>
On 27/06/17 02:20, Kugan Vivekanandarajah wrote:
> https://gcc.gnu.org/ml/gcc-patches/2016-03/msg00614.html added this
> workaround to get kernel building with when TARGET_FIX_ERR_A53_843419
> is enabled.
>
> This was added to support building kernel loadable modules. In kernel,
> when CONFIG_ARM64_ERRATUM_843419 is selected, the relocation needed
> for ADRP/LDR (R_AARCH64_ADR_PREL_PG_HI21 and
> R_AARCH64_ADR_PREL_PG_HI21_NC are removed from the kernel to avoid
> loading objects with possibly offending sequence). Thus, it could only
> support pc relative literal loads.
>
> However, the following patch was posted to kernel to add
> -mpc-relative-literal-loads
> http://www.spinics.net/lists/arm-kernel/msg476149.html
>
> -mpc-relative-literal-loads is unconditionally added to the kernel
> build as can be seen from:
> https://github.com/torvalds/linux/blob/master/arch/arm64/Makefile
>
> Therefore this patch removes the hunk so that applications like
> SPECcpu2017's 521/621.wrf can be built (with LTO in this case) without
> -mno-pc-relative-literal-loads
Is that because your compiler has defaulted to
-mpc-relative-literal-loads because it has the workaround enabled by
default ? I'm curious as to why others haven't seen this issue.
regards
Ramana
next prev parent reply other threads:[~2017-06-27 8:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-27 1:20 Kugan Vivekanandarajah
2017-06-27 8:01 ` Ramana Radhakrishnan [this message]
2017-06-28 1:02 ` Kugan Vivekanandarajah
2017-06-28 22:06 ` Ramana Radhakrishnan
2017-07-21 10:12 ` Kugan Vivekanandarajah
2017-08-11 10:34 ` Kugan Vivekanandarajah
2017-08-29 8:32 ` Kugan Vivekanandarajah
2017-08-29 12:02 ` James Greenhalgh
2017-08-30 9:05 ` Kugan Vivekanandarajah
2018-03-07 1:59 ` Kugan Vivekanandarajah
2018-03-07 10:35 ` James Greenhalgh
2017-08-11 13:07 Wilco Dijkstra
2017-08-11 13:08 ` Yvan Roux
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