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From: Brian Gerst <brgerst@gmail.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Sami Tolvanen <samitolvanen@google.com>,
	alyssa.milburn@linux.intel.com, keescook@chromium.org,
	jpoimboe@kernel.org, joao@overdrivepizza.com,
	tim.c.chen@linux.intel.com, Brian Gerst <brgerst@gmail.com>
Subject: [PATCH 0/2] x86: Rewrite ret_from_fork() in C
Date: Thu, 22 Jun 2023 08:07:48 -0400	[thread overview]
Message-ID: <20230622120750.5549-1-brgerst@gmail.com> (raw)

When kCFI is enabled, special handling is needed for the indirect call
to the kernel thread function.  Handling this in pure assembly is not
simple, so moving it to C is more appropriate.  Instead of moving just
the indirect call to C as Peter Zijlstra has proposed, this patchset
rewrites the whole ret_from_fork() function in C (other than some
necessary asm glue remaning).

Brian Gerst (2):
  x86/32: Remove schedule_tail_wrapper()
  x86: Rewrite ret_from_fork() in C

 arch/x86/entry/entry_32.S        | 54 ++++++++------------------------
 arch/x86/entry/entry_64.S        | 35 ++++++---------------
 arch/x86/include/asm/switch_to.h |  4 ++-
 arch/x86/kernel/process.c        | 22 ++++++++++++-
 4 files changed, 47 insertions(+), 68 deletions(-)

-- 
2.41.0


             reply	other threads:[~2023-06-22 12:08 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-22 12:07 Brian Gerst [this message]
2023-06-22 12:07 ` [PATCH 1/2] x86/32: Remove schedule_tail_wrapper() Brian Gerst
2023-06-22 12:07 ` [PATCH 2/2] x86: Rewrite ret_from_fork() in C Brian Gerst
2023-06-22 13:29   ` Peter Zijlstra
2023-06-22 16:04     ` Brian Gerst
2023-06-22 16:33       ` H. Peter Anvin
2023-06-22 17:33         ` Brian Gerst
2023-06-23 18:12   ` Brian Gerst

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