LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Stephen Boyd <sboyd@codeaurora.org>, Will Deacon <will.deacon@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: Fix SMP_ON_UP for non ARM ltd. implementations
Date: Sun, 30 Jan 2011 12:20:27 +0000	[thread overview]
Message-ID: <20110130122027.GA22677@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1296083052-20034-1-git-send-email-sboyd@codeaurora.org>

On Wed, Jan 26, 2011 at 03:04:12PM -0800, Stephen Boyd wrote:
> @@ -393,20 +393,25 @@ ENDPROC(__turn_mmu_on)
>  #ifdef CONFIG_SMP_ON_UP
>  __fixup_smp:
>  	mov	r4, #0x00070000
> -	orr	r3, r4, #0xff000000	@ mask 0xff070000
> -	orr	r4, r4, #0x41000000	@ val 0x41070000
> -	and	r0, r9, r3
> -	teq	r0, r4			@ ARM CPU and ARMv6/v7?
> +	and	r0, r9, r4
> +	teq	r0, r4			@ ARMv6/v7?
>  	bne	__fixup_smp_on_up	@ no, assume UP
>  
> +	orr	r3, r4, #0xff000000	@ mask 0xff070000
>  	orr	r3, r3, #0x0000ff00
>  	orr	r3, r3, #0x000000f0	@ mask 0xff07fff0
> +	orr	r4, r4, #0x41000000	@ val 0x41070000
>  	orr	r4, r4, #0x0000b000
>  	orr	r4, r4, #0x00000020	@ val 0x4107b020
>  	and	r0, r9, r3
>  	teq	r0, r4			@ ARM 11MPCore?
>  	moveq	pc, lr			@ yes, assume SMP
>  
> +	mov	r4, #0x00070000
> +	and	r0, r9, #0x000f0000
> +	teq	r0, r4			@ ARMv6?
> +	beq	__fixup_smp_on_up	@ yes, assume UP
> +

Wouldn't it be better to check for CPUID presence first, then ARM11MPcore,
and lastly preserve of MPIDR-flagged extensions?

Will - can you check whether the below is correct?

 arch/arm/kernel/head.S |   17 +++++++----------
 1 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 17a97b5..f6b31c4 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -390,19 +390,16 @@ ENDPROC(__turn_mmu_on)
 
 #ifdef CONFIG_SMP_ON_UP
 __fixup_smp:
-	mov	r4, #0x00070000
-	orr	r3, r4, #0xff000000	@ mask 0xff070000
-	orr	r4, r4, #0x41000000	@ val 0x41070000
-	and	r0, r9, r3
-	teq	r0, r4			@ ARM CPU and ARMv6/v7?
+	and	r3, r9, #0x000f0000	@ architecture version
+	teq	r3, #0x000f00000	@ CPU ID supported?
 	bne	__fixup_smp_on_up	@ no, assume UP
 
-	orr	r3, r3, #0x0000ff00
-	orr	r3, r3, #0x000000f0	@ mask 0xff07fff0
+	bic	r3, r9, #0x00ff0000
+	bic	r3, r3, #0x0000000f	@ mask 0xff00fff0
+	mov	r4, #0x41000000
 	orr	r4, r4, #0x0000b000
-	orr	r4, r4, #0x00000020	@ val 0x4107b020
-	and	r0, r9, r3
-	teq	r0, r4			@ ARM 11MPCore?
+	orr	r4, r4, #0x00000020	@ val 0x4100b020
+	teq	r3, r4			@ ARM 11MPCore?
 	moveq	pc, lr			@ yes, assume SMP
 
 	mrc	p15, 0, r0, c0, c0, 5	@ read MPIDR

  reply	other threads:[~2011-01-30 12:20 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-26 23:04 Stephen Boyd
2011-01-30 12:20 ` Russell King - ARM Linux [this message]
2011-01-30 16:27   ` Will Deacon
2011-01-30 16:40     ` Russell King - ARM Linux
2011-01-31 21:33       ` Stephen Boyd

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=20110130122027.GA22677@n2100.arm.linux.org.uk \
    --to=linux@arm.linux.org.uk \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sboyd@codeaurora.org \
    --cc=will.deacon@arm.com \
    --subject='Re: [PATCH] ARM: Fix SMP_ON_UP for non ARM ltd. implementations' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).