public inbox for linux-arm-kernel@lists.infradead.org 
 help / color / mirror / Atom feed
From: julien.grall@citrix•com (Julien Grall)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] arm64: Add support for hardware updates of the access and dirty pte bits
Date: Fri, 11 Sep 2015 16:43:47 +0100	[thread overview]
Message-ID: <55F2F6B3.2080108@citrix.com> (raw)
In-Reply-To: <20150910153812.GG22439@arm.com>

Hi Will,

On 10/09/15 16:38, Will Deacon wrote:
> Weird. That doesn't leave a lot of code. Two other things you could try
> are:
> 
>   (1) Put PTE_WRITE back to bit 57

This change doesn't help.

>   (2) Remove the pte_hw_dirty check/set in pte_modify

This one too, if I only drop the check pte_hw_dirty in pte_modify.

But if I disable completely pte_hw_dirty (i.e always return 0 [1]),
I'm able to use without any issue the userspace.

Which means that the problem seems to come from the defition of pte_dirty:

#define pte_dirty(pte)         (pte_sw_dirty(pte) || pte_hw_dirty(pte))

Regards,

[1]
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 6900b2d9..804ec87 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -145,7 +145,8 @@ extern struct page *empty_zero_page;
 #define pte_write(pte)         (!!(pte_val(pte) & PTE_WRITE))
 #define pte_exec(pte)          (!(pte_val(pte) & PTE_UXN))
 
-#ifdef CONFIG_ARM64_HW_AFDBM
+//#ifdef CONFIG_ARM64_HW_AFDBM
+#if 0
 #define pte_hw_dirty(pte)      (!(pte_val(pte) & PTE_RDONLY))
 #else
 #define pte_hw_dirty(pte)      (0)


-- 
Julien Grall

  reply	other threads:[~2015-09-11 15:43 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-10 16:24 [PATCH] arm64: Add support for hardware updates of the access and dirty pte bits Catalin Marinas
2015-09-09 17:21 ` Julien Grall
2015-09-09 18:22   ` Mark Rutland
2015-09-09 18:27     ` Julien Grall
2015-09-10 10:07   ` Catalin Marinas
2015-09-10 10:41     ` Will Deacon
2015-09-10 14:45     ` Julien Grall
2015-09-10 14:54       ` Marc Zyngier
2015-09-10 15:10         ` Julien Grall
2015-09-10 15:21           ` Marc Zyngier
2015-09-10 15:38       ` Will Deacon
2015-09-11 15:43         ` Julien Grall [this message]
2015-09-10 13:01   ` Marc Zyngier
2015-09-10 14:29     ` Julien Grall
2015-09-10 14:49       ` Marc Zyngier
2015-09-10 14:58         ` Julien Grall

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=55F2F6B3.2080108@citrix.com \
    --to=julien.grall@citrix$(echo .)com \
    --cc=linux-arm-kernel@lists$(echo .)infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox