From: Nicholas Piggin <npiggin@gmail.com>
To: Christophe LEROY <christophe.leroy@c-s.fr>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
aneesh.kumar@linux.vnet.ibm.com, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC PATCH v3 5/7] powerpc: 'current_set' is now a table of task_struct pointers
Date: Wed, 3 Oct 2018 16:09:11 +1000 [thread overview]
Message-ID: <20181003160911.18fb0c60@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <0336ff43-55ac-067b-23a9-4cb4b2fd38f3@c-s.fr>
On Wed, 3 Oct 2018 08:00:43 +0200
Christophe LEROY <christophe.leroy@c-s.fr> wrote:
> Le 03/10/2018 à 07:41, Nicholas Piggin a écrit :
> > On Mon, 1 Oct 2018 12:30:27 +0000 (UTC)
> > Christophe Leroy <christophe.leroy@c-s.fr> wrote:
> >
> >> The table of pointers 'current_set' has been used for retrieving
> >> the stack and current. They used to be thread_info pointers as
> >> they were pointing to the stack and current was taken from the
> >> 'task' field of the thread_info.
> >>
> >> Now, the pointers of 'current_set' table are now both pointers
> >> to task_struct and pointers to thread_info.
> >>
> >> As they are used to get current, and the stack pointer is
> >> retrieved from current's stack field, this patch changes
> >> their type to task_struct, and renames secondary_ti to
> >> secondary_current.
> >
> > I'm not sure if current_set is actually needed is it? Because
> > 64-bit already initializes paca->ksave / PACAKSAVE. That might
> > be a cleanup to do after your series.
>
> head_64.S contains:
>
> __secondary_start:
> /* Set thread priority to MEDIUM */
> HMT_MEDIUM
>
> /* Initialize the kernel stack */
> LOAD_REG_ADDR(r3, current_set)
> sldi r28,r24,3 /* get current_set[cpu#] */
> ldx r14,r3,r28
> addi r14,r14,THREAD_SIZE-STACK_FRAME_OVERHEAD
> std r14,PACAKSAVE(r13)
Right, I don't *think* that's needed because boot CPU should already
have set PACAKSAVE before starting secondaries here. ld r14,PACAKSAVE
should have the same result I think.
But never mind that for your series, just something I saw that could
be cleaned up.
Thanks,
Nick
next prev parent reply other threads:[~2018-10-03 6:09 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-01 12:30 [RFC PATCH v3 0/7] powerpc: Switch to CONFIG_THREAD_INFO_IN_TASK Christophe Leroy
2018-10-01 12:30 ` [RFC PATCH v3 1/7] book3s/64: avoid circular header inclusion in mmu-hash.h Christophe Leroy
2018-10-03 4:24 ` Nicholas Piggin
2018-10-04 8:20 ` Christophe LEROY
2018-10-04 8:23 ` Aneesh Kumar K.V
2018-10-04 8:32 ` Christophe LEROY
2018-10-01 12:30 ` [RFC PATCH v3 2/7] powerpc: Prepare for moving thread_info into task_struct Christophe Leroy
2018-10-03 5:02 ` Nicholas Piggin
2018-10-03 5:49 ` Christophe LEROY
2018-10-03 5:57 ` Nicholas Piggin
2018-10-04 14:29 ` Christophe LEROY
2018-10-01 12:30 ` [RFC PATCH v3 3/7] powerpc: Activate CONFIG_THREAD_INFO_IN_TASK Christophe Leroy
2018-10-03 5:30 ` Nicholas Piggin
2018-10-03 5:47 ` Christophe LEROY
2018-10-03 5:52 ` Nicholas Piggin
2018-10-03 6:04 ` Christophe LEROY
2018-10-03 6:23 ` Nicholas Piggin
2018-10-01 12:30 ` [RFC PATCH v3 4/7] powerpc: regain entire stack space Christophe Leroy
2018-10-03 5:34 ` Nicholas Piggin
2018-10-03 5:52 ` Christophe LEROY
2018-10-03 6:30 ` Nicholas Piggin
2018-10-03 6:45 ` Christophe LEROY
2018-10-03 7:07 ` Nicholas Piggin
2018-10-03 9:30 ` Christophe LEROY
2018-10-01 12:30 ` [RFC PATCH v3 5/7] powerpc: 'current_set' is now a table of task_struct pointers Christophe Leroy
2018-10-03 5:41 ` Nicholas Piggin
2018-10-03 6:00 ` Christophe LEROY
2018-10-03 6:09 ` Nicholas Piggin [this message]
2018-10-01 12:30 ` [RFC PATCH v3 6/7] powerpc/32: Remove CURRENT_THREAD_INFO and rename TI_CPU Christophe Leroy
2018-10-01 12:30 ` [RFC PATCH v3 7/7] powerpc/64: Modify CURRENT_THREAD_INFO() Christophe Leroy
2018-10-03 5:44 ` Nicholas Piggin
2018-10-03 6:01 ` Christophe LEROY
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