From: Michael Ellerman <mpe@ellerman.id.au>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v1 4/9] powerpc/vdso: Remove unnecessary ifdefs in vdso_pagelist initialization
Date: Thu, 27 Aug 2020 23:19:44 +1000 [thread overview]
Message-ID: <87d03c2plb.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <04a968f6-88c0-0603-43aa-202196a68df2@csgroup.eu>
Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> On 08/26/2020 02:58 PM, Michael Ellerman wrote:
>> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
>>> diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
>>> index daef14a284a3..bbb69832fd46 100644
>>> --- a/arch/powerpc/kernel/vdso.c
>>> +++ b/arch/powerpc/kernel/vdso.c
>>> @@ -718,16 +710,14 @@ static int __init vdso_init(void)
>> ...
>>>
>>> -
>>> -#ifdef CONFIG_VDSO32
>>> vdso32_kbase = &vdso32_start;
>>>
>>> /*
>>> @@ -735,8 +725,6 @@ static int __init vdso_init(void)
>>> */
>>> vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
>>> DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages);
>>> -#endif
>>
>> This didn't build for ppc64le:
>>
>> /opt/cross/gcc-8.20_binutils-2.32/powerpc64-unknown-linux-gnu/bin/powerpc64-unknown-linux-gnu-ld: arch/powerpc/kernel/vdso.o:(.toc+0x0): undefined reference to `vdso32_end'
>> /opt/cross/gcc-8.20_binutils-2.32/powerpc64-unknown-linux-gnu/bin/powerpc64-unknown-linux-gnu-ld: arch/powerpc/kernel/vdso.o:(.toc+0x8): undefined reference to `vdso32_start'
>> make[1]: *** [/scratch/michael/build/maint/Makefile:1166: vmlinux] Error 1
>> make: *** [Makefile:185: __sub-make] Error 2
>>
>> So I just put that ifdef back.
>>
>
> The problem is because is_32bit() can still return true even when
> CONFIG_VDSO32 is not set.
Hmm, you're right. My config had CONFIG_COMPAT enabled.
But that seems like a bug, if someone enables COMPAT on ppc64le they are
almost certainly going to want VDSO32 as well.
So I think I'll do a lead up patch as below.
cheers
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index d4fd109f177e..cf2da1e401ef 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -501,13 +501,12 @@ endmenu
config VDSO32
def_bool y
- depends on PPC32 || CPU_BIG_ENDIAN
+ depends on PPC32 || COMPAT
help
This symbol controls whether we build the 32-bit VDSO. We obviously
want to do that if we're building a 32-bit kernel. If we're building
- a 64-bit kernel then we only want a 32-bit VDSO if we're building for
- big endian. That is because the only little endian configuration we
- support is ppc64le which is 64-bit only.
+ a 64-bit kernel then we only want a 32-bit VDSO if we're also enabling
+ COMPAT.
choice
prompt "Endianness selection"
next prev parent reply other threads:[~2020-08-27 13:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-25 13:53 [PATCH v1 1/9] powerpc/vdso: Remove BUG_ON() in vdso_init() Christophe Leroy
2020-08-25 13:54 ` [PATCH v1 2/9] powerpc/vdso: Remove get_page() in vdso_pagelist initialization Christophe Leroy
2020-08-25 13:54 ` [PATCH v1 3/9] powerpc/vdso: Remove NULL termination element in vdso_pagelist Christophe Leroy
2020-08-25 13:54 ` [PATCH v1 4/9] powerpc/vdso: Remove unnecessary ifdefs in vdso_pagelist initialization Christophe Leroy
2020-08-26 14:58 ` Michael Ellerman
2020-08-26 15:21 ` Christophe Leroy
2020-08-27 6:47 ` Christophe Leroy
2020-08-27 13:19 ` Michael Ellerman [this message]
2020-08-28 5:40 ` Christophe Leroy
2020-08-28 5:46 ` Christophe Leroy
2020-08-25 13:54 ` [PATCH v1 5/9] powerpc/vdso: move to _install_special_mapping() and remove arch_vma_name() Christophe Leroy
2020-08-25 13:54 ` [PATCH v1 6/9] powerpc/vdso: Provide vdso_remap() Christophe Leroy
2020-08-25 13:54 ` [PATCH v1 7/9] powerpc/vdso: Move vdso datapage up front Christophe Leroy
2020-08-25 13:54 ` [PATCH v1 8/9] powerpc/vdso: Remove __kernel_datapage_offset and simplify __get_datapage() Christophe Leroy
2020-08-25 13:54 ` [PATCH v1 9/9] powerpc/vdso: Remove unused \tmp param in __get_datapage() Christophe Leroy
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