From: "H. Peter Anvin" <hpa@zytor.com>
To: Jiri Kosina <jikos@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Nadav Amit <namit@vmware.com>, Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
the arch/x86 maintainers <x86@kernel.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Masami Hiramatsu <mhiramat@kernel.org>,
Jason Baron <jbaron@akamai.com>,
David Laight <David.Laight@aculab.com>,
Borislav Petkov <bp@alien8.de>, Julia Cartwright <julia@ni.com>,
Jessica Yu <jeyu@kernel.org>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Edward Cree <ecree@solarflare.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>
Subject: Re: [PATCH v3 0/6] Static calls
Date: Mon, 14 Jan 2019 14:54:12 -0800 [thread overview]
Message-ID: <8ca16cca-101d-1d1b-b3da-c9727665fec8@zytor.com> (raw)
In-Reply-To: <9f60be8c-47fb-195b-fdb4-4098f1df3dc2@zytor.com>
I think this sequence ought to work (keep in mind we are already under a
mutex, so the global data is safe even if we are preempted):
set up page table entries
invlpg
set up bp patching global data
cpu = get_cpu()
bp_old_value = atomic_read(bp_write_addr)
do {
atomic_write(&bp_poke_state, 1)
atomic_write(bp_write_addr, 0xcc)
mask <- online_cpu_mask - self
send IPIs
wait for mask = 0
} while (cmpxchg(&bp_poke_state, 1, 2) != 1);
patch sites, remove breakpoints after patching each one
atomic_write(&bp_poke_state, 3);
mask <- online_cpu_mask - self
send IPIs
wait for mask = 0
atomic_write(&bp_poke_state, 0);
tear down patching global data
tear down page table entries
The #BP handler would then look like:
state = cmpxchg(&bp_poke_state, 1, 4);
switch (state) {
case 1:
case 4:
invlpg
cmpxchg(bp_write_addr, 0xcc, bp_old_value)
break;
case 2:
invlpg
complete patch sequence
remove breakpoint
break;
case 3:
/* If we are here, the #BP will go away on its own */
break;
case 0:
/* No patching in progress!!! */
return 0;
}
clear bit in mask
return 1;
The IPI handler:
clear bit in mask
sync_core /* Needed if multiple IPI events are chained */
next prev parent reply other threads:[~2019-01-14 22:55 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-09 22:59 [PATCH v3 0/6] Static calls Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 1/6] compiler.h: Make __ADDRESSABLE() symbol truly unique Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 2/6] static_call: Add basic static call infrastructure Josh Poimboeuf
2019-01-10 14:03 ` Edward Cree
2019-01-10 18:37 ` Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 3/6] x86/static_call: Add out-of-line static call implementation Josh Poimboeuf
2019-01-10 0:16 ` Nadav Amit
2019-01-10 16:28 ` Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 4/6] static_call: Add inline static call infrastructure Josh Poimboeuf
2019-01-09 22:59 ` [PATCH v3 5/6] x86/alternative: Use a single access in text_poke() where possible Josh Poimboeuf
2019-01-10 9:32 ` Nadav Amit
2019-01-10 17:20 ` Josh Poimboeuf
2019-01-10 17:29 ` Nadav Amit
2019-01-10 17:32 ` Steven Rostedt
2019-01-10 17:42 ` Sean Christopherson
2019-01-10 17:57 ` Steven Rostedt
2019-01-10 18:04 ` Sean Christopherson
2019-01-10 18:21 ` Josh Poimboeuf
2019-01-10 18:24 ` Steven Rostedt
2019-01-11 12:10 ` Alexandre Chartre
2019-01-11 15:28 ` Josh Poimboeuf
2019-01-11 16:46 ` Alexandre Chartre
2019-01-11 16:57 ` Josh Poimboeuf
2019-01-11 17:41 ` Jason Baron
2019-01-11 17:54 ` Nadav Amit
2019-01-15 11:10 ` Alexandre Chartre
2019-01-15 16:19 ` Steven Rostedt
2019-01-15 16:45 ` Alexandre Chartre
2019-01-11 0:59 ` hpa
2019-01-11 1:34 ` Sean Christopherson
2019-01-11 8:13 ` hpa
2019-01-09 22:59 ` [PATCH v3 6/6] x86/static_call: Add inline static call implementation for x86-64 Josh Poimboeuf
2019-01-10 1:21 ` [PATCH v3 0/6] Static calls Nadav Amit
2019-01-10 16:44 ` Josh Poimboeuf
2019-01-10 17:32 ` Nadav Amit
2019-01-10 18:18 ` Josh Poimboeuf
2019-01-10 19:45 ` Nadav Amit
2019-01-10 20:32 ` Josh Poimboeuf
2019-01-10 20:48 ` Nadav Amit
2019-01-10 20:57 ` Josh Poimboeuf
2019-01-10 21:47 ` Nadav Amit
2019-01-10 17:31 ` Linus Torvalds
2019-01-10 20:51 ` H. Peter Anvin
2019-01-10 20:30 ` Peter Zijlstra
2019-01-10 20:52 ` Josh Poimboeuf
2019-01-10 23:02 ` Linus Torvalds
2019-01-11 0:56 ` Andy Lutomirski
2019-01-11 1:47 ` Nadav Amit
2019-01-11 15:15 ` Josh Poimboeuf
2019-01-11 15:48 ` Nadav Amit
2019-01-11 16:07 ` Josh Poimboeuf
2019-01-11 17:23 ` Nadav Amit
2019-01-11 19:03 ` Linus Torvalds
2019-01-11 19:17 ` Nadav Amit
2019-01-11 19:23 ` hpa
2019-01-11 19:33 ` Nadav Amit
2019-01-11 19:34 ` Linus Torvalds
2019-01-13 0:34 ` hpa
2019-01-13 0:36 ` hpa
2019-01-11 19:39 ` Jiri Kosina
2019-01-14 2:31 ` H. Peter Anvin
2019-01-14 2:40 ` H. Peter Anvin
2019-01-14 20:11 ` Andy Lutomirski
2019-01-14 22:00 ` H. Peter Anvin
2019-01-14 22:54 ` H. Peter Anvin [this message]
2019-01-15 3:05 ` Andy Lutomirski
2019-01-15 5:01 ` H. Peter Anvin
2019-01-15 5:37 ` H. Peter Anvin
2019-01-14 23:27 ` Andy Lutomirski
2019-01-14 23:51 ` Nadav Amit
2019-01-15 2:28 ` hpa
2019-01-11 20:04 ` Josh Poimboeuf
2019-01-11 20:12 ` Linus Torvalds
2019-01-11 20:31 ` Josh Poimboeuf
2019-01-11 20:46 ` Linus Torvalds
2019-01-11 21:05 ` Andy Lutomirski
2019-01-11 21:10 ` Linus Torvalds
2019-01-11 21:32 ` Josh Poimboeuf
2019-01-14 12:28 ` Peter Zijlstra
2019-01-11 21:22 ` Josh Poimboeuf
2019-01-11 21:23 ` Josh Poimboeuf
2019-01-11 21:25 ` Josh Poimboeuf
2019-01-11 21:36 ` Nadav Amit
2019-01-11 21:41 ` Josh Poimboeuf
2019-01-11 21:55 ` Steven Rostedt
2019-01-11 21:59 ` Nadav Amit
2019-01-11 21:56 ` Nadav Amit
2019-01-12 23:54 ` Andy Lutomirski
2020-02-17 21:10 ` Jann Horn
2020-02-17 21:57 ` Steven Rostedt
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