From: Benjamin Gray <bgray@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Benjamin Gray <bgray@linux.ibm.com>
Subject: [PATCH v1 2/9] powerpc/dexcr: Track the DEXCR per-process
Date: Wed, 17 Apr 2024 21:23:18 +1000 [thread overview]
Message-ID: <20240417112325.728010-3-bgray@linux.ibm.com> (raw)
In-Reply-To: <20240417112325.728010-1-bgray@linux.ibm.com>
Add capability to make the DEXCR act as a per-process SPR.
We do not yet have an interface for changing the values per task. We
also expect the kernel to use a single DEXCR value across all tasks
while in privileged state, so there is no need to synchronize after
changing it (the userspace aspects will synchronize upon returning to
userspace).
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
---
arch/powerpc/include/asm/processor.h | 1 +
arch/powerpc/kernel/process.c | 10 ++++++++++
arch/powerpc/kernel/ptrace/ptrace-view.c | 7 +------
3 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index b2c51d337e60..882e31296ea6 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -260,6 +260,7 @@ struct thread_struct {
unsigned long sier2;
unsigned long sier3;
unsigned long hashkeyr;
+ unsigned long dexcr;
#endif
};
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9452a54d356c..d482c3fd81d7 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1185,6 +1185,9 @@ static inline void save_sprs(struct thread_struct *t)
if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE))
t->hashkeyr = mfspr(SPRN_HASHKEYR);
+
+ if (cpu_has_feature(CPU_FTR_ARCH_31))
+ t->dexcr = mfspr(SPRN_DEXCR);
#endif
}
@@ -1267,6 +1270,10 @@ static inline void restore_sprs(struct thread_struct *old_thread,
if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE) &&
old_thread->hashkeyr != new_thread->hashkeyr)
mtspr(SPRN_HASHKEYR, new_thread->hashkeyr);
+
+ if (cpu_has_feature(CPU_FTR_ARCH_31) &&
+ old_thread->dexcr != new_thread->dexcr)
+ mtspr(SPRN_DEXCR, new_thread->dexcr);
#endif
}
@@ -1878,6 +1885,9 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
#ifdef CONFIG_PPC_BOOK3S_64
if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE))
p->thread.hashkeyr = current->thread.hashkeyr;
+
+ if (cpu_has_feature(CPU_FTR_ARCH_31))
+ p->thread.dexcr = mfspr(SPRN_DEXCR);
#endif
return 0;
}
diff --git a/arch/powerpc/kernel/ptrace/ptrace-view.c b/arch/powerpc/kernel/ptrace/ptrace-view.c
index 584cf5c3df50..c1819e0a6684 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-view.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-view.c
@@ -469,12 +469,7 @@ static int dexcr_get(struct task_struct *target, const struct user_regset *regse
if (!cpu_has_feature(CPU_FTR_ARCH_31))
return -ENODEV;
- /*
- * The DEXCR is currently static across all CPUs, so we don't
- * store the target's value anywhere, but the static value
- * will also be correct.
- */
- membuf_store(&to, (u64)lower_32_bits(DEXCR_INIT));
+ membuf_store(&to, (u64)lower_32_bits(target->thread.dexcr));
/*
* Technically the HDEXCR is per-cpu, but a hypervisor can't reasonably
--
2.44.0
next prev parent reply other threads:[~2024-04-17 11:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-17 11:23 [PATCH v1 0/9] Add dynamic DEXCR support Benjamin Gray
2024-04-17 11:23 ` [PATCH v1 1/9] selftests/powerpc/dexcr: Add -no-pie to hashchk tests Benjamin Gray
2024-05-07 7:44 ` Andrew Donnellan
2024-04-17 11:23 ` Benjamin Gray [this message]
2024-04-17 11:23 ` [PATCH v1 3/9] powerpc/dexcr: Reset DEXCR value across exec Benjamin Gray
2024-04-17 11:23 ` [PATCH v1 4/9] powerpc/dexcr: Add DEXCR prctl interface Benjamin Gray
2024-04-17 11:23 ` [PATCH v1 5/9] selftests/powerpc/dexcr: Add DEXCR prctl interface test Benjamin Gray
2024-04-17 11:23 ` [PATCH v1 6/9] selftests/powerpc/dexcr: Attempt to enable NPHIE in hashchk selftest Benjamin Gray
2024-04-17 11:23 ` [PATCH v1 7/9] selftests/powerpc/dexcr: Add DEXCR config details to lsdexcr Benjamin Gray
2024-04-17 11:23 ` [PATCH v1 8/9] selftests/powerpc/dexcr: Add chdexcr utility Benjamin Gray
2024-04-17 11:23 ` [PATCH v1 9/9] Documentation: Document PowerPC kernel dynamic DEXCR interface Benjamin Gray
2024-05-08 13:39 ` [PATCH v1 0/9] Add dynamic DEXCR support Michael Ellerman
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=20240417112325.728010-3-bgray@linux.ibm.com \
--to=bgray@linux.ibm.com \
--cc=linuxppc-dev@lists.ozlabs.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: link
Be 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 NNTP newsgroup(s).