linux-kernel - Re: [PATCH v2 10/14] loongarch: Handle KCOV _

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Message-ID: <B5A11282-CB0E-46E0-A5D7-EF4D8BFC23B4@kernel.org>
Date: Tue, 24 Jun 2025 18:09:18 -0700
From: Kees Cook <kees@...nel.org>
To: Huacai Chen <chenhuacai@...nel.org>
CC: Arnd Bergmann <arnd@...db.de>, WANG Xuerui <kernel@...0n.name>,
 Thomas Gleixner <tglx@...utronix.de>,
 Tianyang Zhang <zhangtianyang@...ngson.cn>, Bibo Mao <maobibo@...ngson.cn>,
 Jiaxun Yang <jiaxun.yang@...goat.com>, loongarch@...ts.linux.dev,
 "Gustavo A. R. Silva" <gustavoars@...nel.org>,
 Christoph Hellwig <hch@....de>, Marco Elver <elver@...gle.com>,
 Andrey Konovalov <andreyknvl@...il.com>,
 Andrey Ryabinin <ryabinin.a.a@...il.com>, Ard Biesheuvel <ardb@...nel.org>,
 Masahiro Yamada <masahiroy@...nel.org>,
 Nathan Chancellor <nathan@...nel.org>,
 Nicolas Schier <nicolas.schier@...ux.dev>,
 Nick Desaulniers <nick.desaulniers+lkml@...il.com>,
 Bill Wendling <morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>,
 linux-kernel@...r.kernel.org, x86@...nel.org, kasan-dev@...glegroups.com,
 linux-doc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 kvmarm@...ts.linux.dev, linux-riscv@...ts.infradead.org,
 linux-s390@...r.kernel.org, linux-efi@...r.kernel.org,
 linux-hardening@...r.kernel.org, linux-kbuild@...r.kernel.org,
 linux-security-module@...r.kernel.org, linux-kselftest@...r.kernel.org,
 sparclinux@...r.kernel.org, llvm@...ts.linux.dev
Subject: Re: [PATCH v2 10/14] loongarch: Handle KCOV __init vs inline mismatches



On June 24, 2025 5:31:12 AM PDT, Huacai Chen <chenhuacai@...nel.org> wrote:
>Hi, Kees,
>
>On Thu, Jun 19, 2025 at 4:55 PM Huacai Chen <chenhuacai@...nel.org> wrote:
>>
>> Hi, Kees,
>>
>> On Fri, May 23, 2025 at 12:39 PM Kees Cook <kees@...nel.org> wrote:
>> >
>> > When KCOV is enabled all functions get instrumented, unless
>> > the __no_sanitize_coverage attribute is used. To prepare for
>> > __no_sanitize_coverage being applied to __init functions, we have to
>> > handle differences in how GCC's inline optimizations get resolved. For
>> > loongarch this exposed several places where __init annotations were
>> > missing but ended up being "accidentally correct". Fix these cases and
>> > force one function to be inline with __always_inline.
>> >
>> > Signed-off-by: Kees Cook <kees@...nel.org>
>> > ---
>> > Cc: Huacai Chen <chenhuacai@...nel.org>
>> > Cc: WANG Xuerui <kernel@...0n.name>
>> > Cc: Thomas Gleixner <tglx@...utronix.de>
>> > Cc: Tianyang Zhang <zhangtianyang@...ngson.cn>
>> > Cc: Bibo Mao <maobibo@...ngson.cn>
>> > Cc: Jiaxun Yang <jiaxun.yang@...goat.com>
>> > Cc: <loongarch@...ts.linux.dev>
>> > ---
>> >  arch/loongarch/include/asm/smp.h | 2 +-
>> >  arch/loongarch/kernel/time.c     | 2 +-
>> >  arch/loongarch/mm/ioremap.c      | 4 ++--
>> >  3 files changed, 4 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
>> > index ad0bd234a0f1..88e19d8a11f4 100644
>> > --- a/arch/loongarch/include/asm/smp.h
>> > +++ b/arch/loongarch/include/asm/smp.h
>> > @@ -39,7 +39,7 @@ int loongson_cpu_disable(void);
>> >  void loongson_cpu_die(unsigned int cpu);
>> >  #endif
>> >
>> > -static inline void plat_smp_setup(void)
>> > +static __always_inline void plat_smp_setup(void)
>> Similar to x86 and arm, I prefer to mark it as __init rather than
>> __always_inline.
>If you have no objections, I will apply this patch with the above modification.

That's fine by me; thank you! I didn't have a chance yet to verify that it actually fixes the mismatches I saw, but if it looks good to you, yes please. :)

-Kees

>
>
>Huacai
>
>>
>> Huacai
>>
>> >  {
>> >         loongson_smp_setup();
>> >  }
>> > diff --git a/arch/loongarch/kernel/time.c b/arch/loongarch/kernel/time.c
>> > index bc75a3a69fc8..367906b10f81 100644
>> > --- a/arch/loongarch/kernel/time.c
>> > +++ b/arch/loongarch/kernel/time.c
>> > @@ -102,7 +102,7 @@ static int constant_timer_next_event(unsigned long delta, struct clock_event_dev
>> >         return 0;
>> >  }
>> >
>> > -static unsigned long __init get_loops_per_jiffy(void)
>> > +static unsigned long get_loops_per_jiffy(void)
>> >  {
>> >         unsigned long lpj = (unsigned long)const_clock_freq;
>> >
>> > diff --git a/arch/loongarch/mm/ioremap.c b/arch/loongarch/mm/ioremap.c
>> > index 70ca73019811..df949a3d0f34 100644
>> > --- a/arch/loongarch/mm/ioremap.c
>> > +++ b/arch/loongarch/mm/ioremap.c
>> > @@ -16,12 +16,12 @@ void __init early_iounmap(void __iomem *addr, unsigned long size)
>> >
>> >  }
>> >
>> > -void *early_memremap_ro(resource_size_t phys_addr, unsigned long size)
>> > +void * __init early_memremap_ro(resource_size_t phys_addr, unsigned long size)
>> >  {
>> >         return early_memremap(phys_addr, size);
>> >  }
>> >
>> > -void *early_memremap_prot(resource_size_t phys_addr, unsigned long size,
>> > +void * __init early_memremap_prot(resource_size_t phys_addr, unsigned long size,
>> >                     unsigned long prot_val)
>> >  {
>> >         return early_memremap(phys_addr, size);
>> > --
>> > 2.34.1
>> >

-- 
Kees Cook