* Why set ORIG_EAX(%esp) to -1 in arch/i386/kernel/entry.S:error_code?
@ 2006-08-29 19:03 Jeremy Fitzhardinge
2006-08-29 21:55 ` Linus Torvalds
0 siblings, 1 reply; 3+ messages in thread
From: Jeremy Fitzhardinge @ 2006-08-29 19:03 UTC (permalink / raw)
To: Linux Kernel Mailing List, Andi Kleen, Zachary Amsden,
Linus Torvalds, Chuck Ebbert
There doesn't seem much point; nothing seems to use it on the
trap-handling paths. Is it a historical left-over?
J
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Why set ORIG_EAX(%esp) to -1 in arch/i386/kernel/entry.S:error_code?
2006-08-29 19:03 Why set ORIG_EAX(%esp) to -1 in arch/i386/kernel/entry.S:error_code? Jeremy Fitzhardinge
@ 2006-08-29 21:55 ` Linus Torvalds
2006-08-29 22:29 ` Jeremy Fitzhardinge
0 siblings, 1 reply; 3+ messages in thread
From: Linus Torvalds @ 2006-08-29 21:55 UTC (permalink / raw)
To: Jeremy Fitzhardinge
Cc: Linux Kernel Mailing List, Andi Kleen, Zachary Amsden,
Chuck Ebbert
On Tue, 29 Aug 2006, Jeremy Fitzhardinge wrote:
>
> There doesn't seem much point; nothing seems to use it on the trap-handling
> paths. Is it a historical left-over?
No. It's important that ORIG_EAX be set to some value that is _not_ a
valid system call number, so that the system call restart logic (see the
signal handling code) doesn't trigger.
Linus
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Why set ORIG_EAX(%esp) to -1 in arch/i386/kernel/entry.S:error_code?
2006-08-29 21:55 ` Linus Torvalds
@ 2006-08-29 22:29 ` Jeremy Fitzhardinge
0 siblings, 0 replies; 3+ messages in thread
From: Jeremy Fitzhardinge @ 2006-08-29 22:29 UTC (permalink / raw)
To: Linus Torvalds
Cc: Linux Kernel Mailing List, Andi Kleen, Zachary Amsden,
Chuck Ebbert
Linus Torvalds wrote:
> No. It's important that ORIG_EAX be set to some value that is _not_ a
> valid system call number, so that the system call restart logic (see the
> signal handling code) doesn't trigger.
>
Ah, yes, I see. I'll add a comment in my i386-pda patch to entry.S.
J
^ permalink raw reply [flat|nested] 3+ messages in thread
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2006-08-29 19:03 Why set ORIG_EAX(%esp) to -1 in arch/i386/kernel/entry.S:error_code? Jeremy Fitzhardinge
2006-08-29 21:55 ` Linus Torvalds
2006-08-29 22:29 ` Jeremy Fitzhardinge
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