From: james.morse@arm•com (James Morse)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v8 1/4] arm64: Store struct task_info in sp_el0
Date: Fri, 04 Dec 2015 14:55:12 +0000 [thread overview]
Message-ID: <5661A950.7090009@arm.com> (raw)
In-Reply-To: <20151204132743.GH10123@e104818-lin.cambridge.arm.com>
Hi Catalin,
On 04/12/15 13:27, Catalin Marinas wrote:
> On Fri, Dec 04, 2015 at 11:02:25AM +0000, James Morse wrote:
>> --- a/arch/arm64/kernel/entry.S
>> +++ b/arch/arm64/kernel/entry.S
> [...]
>> @@ -599,6 +606,8 @@ ENTRY(cpu_switch_to)
>> ldp x29, x9, [x8], #16
>> ldr lr, [x8]
>> mov sp, x9
>> + and x9, x9, #~(THREAD_SIZE - 1)
>> + msr sp_el0, x9
>> ret
>> ENDPROC(cpu_switch_to)
>
> At the beginning of the cpu_switch_to function, could we do
> "mrs x9, sp_el0" instead to avoid the "and ... ~(THREAD_SIZE-1)"?
I'm not sure I follow - are you suggesting to store struct thread_info
in the thread_cpu_context?
This would change a ldr to a ldp, and save the 'and', so its definitely
fewer instructions.
James
next prev parent reply other threads:[~2015-12-04 14:55 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-04 11:02 [PATCH v8 0/4] arm64: Add support for IRQ stack James Morse
2015-12-04 11:02 ` [PATCH v8 1/4] arm64: Store struct task_info in sp_el0 James Morse
2015-12-04 13:27 ` Catalin Marinas
2015-12-04 14:55 ` James Morse [this message]
2015-12-04 16:18 ` Catalin Marinas
2015-12-06 13:15 ` Jungseok Lee
2015-12-04 11:02 ` [PATCH v8 2/4] arm64: Modify stack trace and dump for use with irq_stack James Morse
2015-12-04 12:21 ` Jungseok Lee
2015-12-04 14:31 ` Catalin Marinas
2015-12-04 11:02 ` [PATCH v8 3/4] arm64: Add do_softirq_own_stack() and enable irq_stacks James Morse
2015-12-04 13:46 ` Catalin Marinas
2015-12-04 13:47 ` Catalin Marinas
2015-12-07 22:48 ` Catalin Marinas
2015-12-08 11:43 ` Will Deacon
2015-12-08 16:02 ` Jungseok Lee
2015-12-08 17:23 ` James Morse
2015-12-08 17:27 ` Will Deacon
2015-12-08 23:13 ` Jungseok Lee
2015-12-09 9:47 ` James Morse
2015-12-09 11:38 ` Will Deacon
2015-12-09 13:45 ` Will Deacon
2015-12-09 14:36 ` James Morse
2015-12-04 11:02 ` [PATCH v8 4/4] arm64: switch to irq_stack during softirq James Morse
2015-12-04 14:01 ` Catalin Marinas
2015-12-04 14:39 ` James Morse
2015-12-04 18:40 ` Catalin Marinas
2015-12-08 10:29 ` James Morse
2015-12-06 13:51 ` Jungseok Lee
2015-12-04 12:17 ` [PATCH v8 0/4] arm64: Add support for IRQ stack Jungseok Lee
2015-12-06 13:56 ` Jungseok Lee
2015-12-04 13:57 ` Catalin Marinas
2015-12-06 13:33 ` Jungseok Lee
2015-12-10 10:22 ` [PATCH v8 5/4] arm64: Fix off-by-one in stack tracing when stepping off irq stack James Morse
2015-12-10 10:22 ` [PATCH v8 6/4] arm64: Add this_cpu_ptr() assembler macro for use in entry.S James Morse
2015-12-10 10:22 ` [PATCH v8 7/4] arm64: when walking onto the task stack, check sp & fp are in current->stack James Morse
2015-12-10 10:22 ` [PATCH v8 8/4] arm64: don't call C code with el0's fp register James Morse
2015-12-10 14:03 ` [PATCH v8 5/4] arm64: Fix off-by-one in stack tracing when stepping off irq stack Jungseok Lee
2015-12-15 11:21 ` [PATCH v8 9/4] arm64: reduce stack use in irq_handler James Morse
2015-12-18 16:01 ` [PATCH v8 9/4] arm64: remove irq_count and do_softirq_own_stack() James Morse
2015-12-20 11:07 ` Jungseok Lee
2015-12-21 11:30 ` Will Deacon
2015-12-21 12:19 ` James Morse
2015-12-21 12:21 ` Will Deacon
2015-12-21 14:06 ` Jungseok Lee
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