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From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
	GCC Patches <gcc-patches@gcc.gnu.org>,
	Richard Sandiford <Richard.Sandiford@arm.com>
Subject: Re: [PATCH] libgcc: Fix uninitialized RA signing on AArch64 [PR107678]
Date: Tue, 6 Dec 2022 11:58:22 +0000	[thread overview]
Message-ID: <PAWPR08MB898214F3635227E79D9721FC831B9@PAWPR08MB8982.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <Y48eaYBn+2fHFOpu@arm.com>

Hi,

> i don't think how[*RA_STATE] can ever be set to REG_SAVED_OFFSET,
> this pseudo reg is not spilled to the stack, it is reset to 0 in
> each frame and then toggled within a frame.

It's is just a state, we can use any state we want since it is a pseudo reg.
These registers are global and shared across all functions in an unwind,
so their state or value isn't reset for each frame. So if we want to reset
it in each frame then using a virtual register to hold per-function data
seems like a bad design. I'm surprised nobody has ever tested it...

Cheers,
Wilco

  reply	other threads:[~2022-12-06 11:58 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-01 16:55 Wilco Dijkstra
2022-12-05 19:04 ` Richard Sandiford
2022-12-06 10:50   ` Szabolcs Nagy
2022-12-06 11:58     ` Wilco Dijkstra [this message]
2022-12-06 21:33       ` Szabolcs Nagy
2023-01-03 17:27   ` Wilco Dijkstra
2023-01-05 14:57     ` Szabolcs Nagy
2023-01-10 16:33       ` Wilco Dijkstra
2023-01-10 18:12         ` Jakub Jelinek
2023-01-11 11:33           ` Martin Liška
2023-01-11 11:59             ` Wilco Dijkstra
2023-01-12 10:49               ` Jakub Jelinek
2023-01-12 12:05                 ` Richard Sandiford
2023-01-12 12:08                   ` Richard Sandiford
2023-01-12 12:28                   ` Jakub Jelinek
2023-01-12 14:39                     ` Jakub Jelinek
2023-01-12 15:22                       ` Richard Sandiford
2023-01-12 15:34                         ` Jakub Jelinek
2023-01-12 15:40                           ` Richard Sandiford
2023-01-12 18:57         ` Jakub Jelinek
2023-01-16 13:04           ` Martin Liška
2023-01-17 19:49             ` Wilco Dijkstra
2023-01-17 20:43               ` Richard Sandiford
2023-01-18 12:49                 ` Wilco Dijkstra

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