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Date: Tue, 6 Dec 2016 11:12:18 -0800
From: Laura Abbott <labbott@...hat.com>
To: Mark Rutland <mark.rutland@....com>
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Will Deacon <will.deacon@....com>,
Catalin Marinas <catalin.marinas@....com>,
Christoffer Dall <christoffer.dall@...aro.org>,
Marc Zyngier <marc.zyngier@....com>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
Andrew Morton <akpm@...ux-foundation.org>,
Marek Szyprowski <m.szyprowski@...sung.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCHv4 05/10] arm64: Use __pa_symbol for kernel symbols
On 12/06/2016 09:02 AM, Mark Rutland wrote:
> Hi,
>
> As a heads-up, it looks like this got mangled somewhere. In the hunk at
> arch/arm64/mm/kasan_init.c:68, 'do' in the context became 'edo'.
> Deleting the 'e' makes it apply.
>
Argh, this must have come in while editing the .patch before e-mailing.
Sorry about that.
> I think this is almost there; other than James's hibernate bug I only
> see one real issue, and everything else is a minor nit.
>
> On Tue, Nov 29, 2016 at 10:55:24AM -0800, Laura Abbott wrote:
>> __pa_symbol is technically the marco that should be used for kernel
>> symbols. Switch to this as a pre-requisite for DEBUG_VIRTUAL which
>> will do bounds checking. As part of this, introduce lm_alias, a
>> macro which wraps the __va(__pa(...)) idiom used a few places to
>> get the alias.
>
> I think the addition of the lm_alias() macro under include/mm should be
> a separate preparatory patch. That way it's separate from the
> arm64-specific parts, and more obvious to !arm64 people reviewing the
> other parts.
>
I debated if it was more obvious to show how it was used in context
vs a stand alone patch. I think you're right that for non-arm64 reviewers
the separate patch would be easier to find.
>> Signed-off-by: Laura Abbott <labbott@...hat.com>
>> ---
>> v4: Stop calling __va early, conversion of a few more sites. I decided against
>> wrapping the __p*d_populate calls into new functions since the call sites
>> should be limited.
>> ---
>> arch/arm64/include/asm/kvm_mmu.h | 4 ++--
>> arch/arm64/include/asm/memory.h | 2 ++
>> arch/arm64/include/asm/mmu_context.h | 6 +++---
>> arch/arm64/include/asm/pgtable.h | 2 +-
>> arch/arm64/kernel/acpi_parking_protocol.c | 2 +-
>> arch/arm64/kernel/cpu-reset.h | 2 +-
>> arch/arm64/kernel/cpufeature.c | 2 +-
>> arch/arm64/kernel/hibernate.c | 13 +++++--------
>> arch/arm64/kernel/insn.c | 2 +-
>> arch/arm64/kernel/psci.c | 2 +-
>> arch/arm64/kernel/setup.c | 8 ++++----
>> arch/arm64/kernel/smp_spin_table.c | 2 +-
>> arch/arm64/kernel/vdso.c | 4 ++--
>> arch/arm64/mm/init.c | 11 ++++++-----
>> arch/arm64/mm/kasan_init.c | 21 +++++++++++++-------
>> arch/arm64/mm/mmu.c | 32 +++++++++++++++++++------------
>> drivers/firmware/psci.c | 2 +-
>> include/linux/mm.h | 4 ++++
>> 18 files changed, 70 insertions(+), 51 deletions(-)
>
> It looks like we need to make sure these (directly) include <linux/mm.h>
> for __pa_symbol() and lm_alias(), or there's some fragility, e.g.
>
> [mark@...erpostej:~/src/linux]% uselinaro 15.08 make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -j10 -s
> arch/arm64/kernel/psci.c: In function 'cpu_psci_cpu_boot':
> arch/arm64/kernel/psci.c:48:50: error: implicit declaration of function '__pa_symbol' [-Werror=implicit-function-declaration]
> int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa_symbol(secondary_entry));
> ^
> cc1: some warnings being treated as errors
> make[1]: *** [arch/arm64/kernel/psci.o] Error 1
> make: *** [arch/arm64/kernel] Error 2
> make: *** Waiting for unfinished jobs....
>
Right, I'll double check.
>> --- a/arch/arm64/include/asm/memory.h
>> +++ b/arch/arm64/include/asm/memory.h
>> @@ -205,6 +205,8 @@ static inline void *phys_to_virt(phys_addr_t x)
>> #define __va(x) ((void *)__phys_to_virt((phys_addr_t)(x)))
>> #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
>> #define virt_to_pfn(x) __phys_to_pfn(__virt_to_phys((unsigned long)(x)))
>> +#define sym_to_pfn(x) __phys_to_pfn(__pa_symbol(x))
>> +#define lm_alias(x) __va(__pa_symbol(x))
>
> As Catalin mentioned, we should be able to drop this copy of lm_alias(),
> given we have the same in the core headers.
>
>> diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
>> index a2c2478..79cd86b 100644
>> --- a/arch/arm64/kernel/vdso.c
>> +++ b/arch/arm64/kernel/vdso.c
>> @@ -140,11 +140,11 @@ static int __init vdso_init(void)
>> return -ENOMEM;
>>
>> /* Grab the vDSO data page. */
>> - vdso_pagelist[0] = pfn_to_page(PHYS_PFN(__pa(vdso_data)));
>> + vdso_pagelist[0] = phys_to_page(__pa_symbol(vdso_data));
>>
>> /* Grab the vDSO code pages. */
>> for (i = 0; i < vdso_pages; i++)
>> - vdso_pagelist[i + 1] = pfn_to_page(PHYS_PFN(__pa(&vdso_start)) + i);
>> + vdso_pagelist[i + 1] = pfn_to_page(PHYS_PFN(__pa_symbol(&vdso_start)) + i);
>
> I see you added sym_to_pfn(), which we can use here to keep this short
> and legible. It might also be worth using a temporary pfn_t, e.g.
>
> pfn = sym_to_pfn(&vdso_start);
>
> for (i = 0; i < vdso_pages; i++)
> vdso_pagelist[i + 1] = pfn_to_page(pfn + i);
>
Good idea.
>> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
>> index 8263429..9defbe2 100644
>> --- a/drivers/firmware/psci.c
>> +++ b/drivers/firmware/psci.c
>> @@ -383,7 +383,7 @@ static int psci_suspend_finisher(unsigned long index)
>> u32 *state = __this_cpu_read(psci_power_state);
>>
>> return psci_ops.cpu_suspend(state[index - 1],
>> - virt_to_phys(cpu_resume));
>> + __pa_symbol(cpu_resume));
>> }
>>
>> int psci_cpu_suspend_enter(unsigned long index)
>
> This should probably be its own patch since it's not under arch/arm64/.
>
Fine by me.
> I'm happy for this to go via the arm64 tree with the rest regardless
> (assuming Lorenzo has no objections).
>
> Thanks,
> Mark.
>
Thanks,
Laura
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