public inbox for glibc-cvs@sourceware.org help / color / mirror / Atom feed
From: Szabolcs Nagy <nsz@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc] AArch64: Add asymmetric faulting mode for tag violations in mem.tagging tunable Date: Thu, 30 Jun 2022 13:02:24 +0000 (GMT) [thread overview] Message-ID: <20220630130224.2F89B3842AD7@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=e9dd3682963a7038d699430e3ece68045b6caafc commit e9dd3682963a7038d699430e3ece68045b6caafc Author: Tejas Belagod <Tejas.Belagod@arm.com> Date: Mon Jun 27 18:00:50 2022 +0000 AArch64: Add asymmetric faulting mode for tag violations in mem.tagging tunable The new asymmetric mode is available when HWCAP2_MTE3 is set (support is available), bit2 is set in the tunable (user request per application), and the system is configured such that the asymmetric mode is preferred over sync or async (per-cpu system-wide setting). Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> Diff: --- manual/tunables.texi | 3 +++ sysdeps/unix/sysv/linux/aarch64/cpu-features.c | 8 +++++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/manual/tunables.texi b/manual/tunables.texi index 2c076019ae..83cdcdac6d 100644 --- a/manual/tunables.texi +++ b/manual/tunables.texi @@ -602,6 +602,9 @@ Bit 1 enables precise faulting mode for tag violations on systems that support deferred tag violation reporting. This may cause programs to run more slowly. +Bit 2 enables either precise or deferred faulting mode for tag violations +whichever is preferred by the system. + Other bits are currently reserved. @Theglibc{} startup code will automatically enable memory tagging diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c index 41dda8d003..d14c0f4e1f 100644 --- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c +++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c @@ -108,7 +108,13 @@ init_cpu_features (struct cpu_features *cpu_features) TUNABLE_SET (glibc, mem, tagging, cpu_features->mte_state); # endif - if (cpu_features->mte_state & 2) + if (cpu_features->mte_state & 4) + /* Enable choosing system-preferred faulting mode. */ + __prctl (PR_SET_TAGGED_ADDR_CTRL, + (PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_SYNC | PR_MTE_TCF_ASYNC + | MTE_ALLOWED_TAGS), + 0, 0, 0); + else if (cpu_features->mte_state & 2) __prctl (PR_SET_TAGGED_ADDR_CTRL, (PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_SYNC | MTE_ALLOWED_TAGS), 0, 0, 0);
reply other threads:[~2022-06-30 13:02 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20220630130224.2F89B3842AD7@sourceware.org \ --to=nsz@sourceware.org \ --cc=glibc-cvs@sourceware.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).