From: "H. Peter Anvin" <hpa@zytor.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: mingo@redhat.com, linux-kernel@vger.kernel.org,
tglx@linutronix.de, hpa@linux.intel.com, rjw@sisk.pl,
linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/setup] x86, setup: "glove box" BIOS calls -- infrastructure
Date: Fri, 10 Apr 2009 10:19:32 -0700 [thread overview]
Message-ID: <49DF7FA4.9070909@zytor.com> (raw)
In-Reply-To: <20090410080444.GC16512@elf.ucw.cz>
Pavel Machek wrote:
>
>> + .code16
>> + .text
>> + .globl intcall
>> + .type intcall, @function
>> +intcall:
>> + /* Self-modify the INT instruction. Ugly, but works. */
>> + cmpb %al, 3f
>> + je 1f
>> + movb %al, 3f
>> + jmp 1f /* Synchronize pipeline */
>> +1:
>
> There are various CPU bugs with self-modifying code, but I guess we
> are not using it heavily enough. Also we are single-threaded so that
> should be ok.
> Pavel
>
This case is extremely straightforward, so I'm not worried about it.
The final JMP is actually not required (there is a LOOP instruction
between the modify and the invocation point) but is there for extra safety.
FWIW, we already do SMC during the transfer to protected mode
(pmjump.S), and hopefully got the issues worked out there.
-hpa
next prev parent reply other threads:[~2009-04-10 17:20 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-09 23:06 [PATCH 0/6] x86, setup: "glove box" BIOS interrupts H. Peter Anvin
2009-04-09 23:12 ` [tip:x86/setup] x86, setup: "glove box" BIOS calls -- infrastructure H. Peter Anvin
2009-04-10 8:04 ` Pavel Machek
2009-04-10 10:39 ` Ingo Molnar
2009-04-10 10:46 ` Pavel Machek
2009-04-10 11:25 ` Ingo Molnar
2009-04-10 11:38 ` Pavel Machek
2009-04-10 11:49 ` Ingo Molnar
2009-04-11 16:13 ` Avi Kivity
2009-04-12 5:21 ` H. Peter Anvin
2009-04-12 14:01 ` Ingo Molnar
2009-04-12 14:39 ` Avi Kivity
2009-04-12 14:59 ` Linus Torvalds
2009-04-12 16:33 ` Ingo Molnar
2009-04-12 18:57 ` Avi Kivity
2009-04-13 4:16 ` Ingo Molnar
2009-04-13 4:24 ` Ingo Molnar
2009-04-13 16:27 ` H. Peter Anvin
2009-04-13 16:57 ` Pavel Machek
2009-04-13 17:00 ` H. Peter Anvin
2009-04-13 18:34 ` Alan Jenkins
2009-04-13 19:08 ` H. Peter Anvin
2009-04-14 0:06 ` Ingo Molnar
2009-04-14 4:42 ` H. Peter Anvin
2009-04-14 9:03 ` Jeremy Fitzhardinge
2009-04-14 15:59 ` H. Peter Anvin
2009-04-13 6:44 ` Avi Kivity
2009-04-12 17:51 ` H. Peter Anvin
2009-04-10 17:17 ` H. Peter Anvin
2009-04-10 17:19 ` H. Peter Anvin [this message]
2009-04-09 23:13 ` [tip:x86/setup] x86, setup: "glove box" BIOS interrupts in the core boot code H. Peter Anvin
2009-04-09 23:13 ` [tip:x86/setup] x86, setup: "glove box" BIOS interrupts in the APM code H. Peter Anvin
2009-04-09 23:13 ` [tip:x86/setup] x86, setup: "glove box" BIOS interrupts in the EDD code H. Peter Anvin
2009-04-09 23:13 ` [tip:x86/setup] x86, setup: "glove box" BIOS interrupts in the MCA code H. Peter Anvin
2009-04-09 23:13 ` [tip:x86/setup] x86, setup: "glove box" BIOS interrupts in the video code H. Peter Anvin
2009-04-10 8:05 ` Pavel Machek
2009-04-10 18:05 ` [PATCH 0/6] x86, setup: "glove box" BIOS interrupts Rafael J. Wysocki
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