* Re: [PATCH] arm64: kvm: fix gcc-10 shift warning
2020-04-29 18:56 [PATCH] arm64: kvm: fix gcc-10 shift warning Arnd Bergmann
@ 2020-04-29 21:09 ` Will Deacon
2020-04-29 22:42 ` Stephen Rothwell
2020-04-30 8:02 ` Marc Zyngier
2 siblings, 0 replies; 7+ messages in thread
From: Will Deacon @ 2020-04-29 21:09 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Rich Felker, Geert Uytterhoeven, Catalin Marinas, Paul Mackerras,
kvmarm, Jonas Bonn, Stephen Rothwell, Brian Cain, Marc Zyngier,
Russell King, Ley Foon Tan, Mike Rapoport, Benjamin Herrenschmidt,
Julien Thierry, Fenghua Yu, Suzuki K Poulose, Stefan Kristiansson,
Stafford Horne, Guan Xuetao, linux-arm-kernel, Christophe Leroy,
Tony Luck, Yoshinori Sato, linux-kernel, James Morse,
Michael Ellerman, Paolo Bonzini, Andrew Morton
On Wed, Apr 29, 2020 at 08:56:20PM +0200, Arnd Bergmann wrote:
> gcc-10 warns that the 32-bit zero cannot be shifted more than
> 32 bits to the right:
>
> arch/arm64/kvm/../../../virt/kvm/arm/mmu.c: In function 'clear_hyp_p4d_entry':
> arch/arm64/include/asm/pgtable.h:630:35: error: right shift count >= width of type [-Werror=shift-count-overflow]
> 630 | #define pud_index(addr) (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
> | ^~
> arch/arm64/include/asm/memory.h:271:45: note: in definition of macro '__phys_to_virt'
> 271 | #define __phys_to_virt(x) ((unsigned long)((x) - physvirt_offset))
> | ^
> arch/arm64/include/asm/pgtable.h:633:42: note: in expansion of macro '__va'
> 633 | #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> | ^~~~
> arch/arm64/include/asm/pgtable.h:632:73: note: in expansion of macro 'pud_index'
> 632 | #define pud_offset_phys(dir, addr) (p4d_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
> | ^~~~~~~~~
> arch/arm64/include/asm/pgtable.h:633:47: note: in expansion of macro 'pud_offset_phys'
> 633 | #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> | ^~~~~~~~~~~~~~~
> arch/arm64/kvm/../../../virt/kvm/arm/mmu.c:510:36: note: in expansion of macro 'pud_offset'
> 510 | pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
> | ^~~~~~~~~~
>
> This is harmless, and the warning is a little bit silly for
> a zero constant, but it's trivial to fix by making it an
> unsigned long, so do that.
>
> Fixes: 22998131ab33 ("arm64: add support for folded p4d page tables")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> virt/kvm/arm/mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index 48d4288c5f1b..534d9798c3cb 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -507,7 +507,7 @@ static void clear_hyp_pgd_entry(pgd_t *pgd)
>
> static void clear_hyp_p4d_entry(p4d_t *p4d)
> {
> - pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
> + pud_t *pud_table __maybe_unused = pud_offset(p4d, 0UL);
> VM_BUG_ON(p4d_huge(*p4d));
> p4d_clear(p4d);
> pud_free(NULL, pud_table);
> --
> 2.26.0
Acked-by: Will Deacon <will@kernel.org>
Will
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] arm64: kvm: fix gcc-10 shift warning
2020-04-29 18:56 [PATCH] arm64: kvm: fix gcc-10 shift warning Arnd Bergmann
2020-04-29 21:09 ` Will Deacon
@ 2020-04-29 22:42 ` Stephen Rothwell
2020-04-30 8:02 ` Marc Zyngier
2 siblings, 0 replies; 7+ messages in thread
From: Stephen Rothwell @ 2020-04-29 22:42 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Rich Felker, Geert Uytterhoeven, Catalin Marinas, Paul Mackerras,
Will Deacon, kvmarm, Jonas Bonn, Brian Cain, Marc Zyngier,
Russell King, Ley Foon Tan, Mike Rapoport, Benjamin Herrenschmidt,
Julien Thierry, Fenghua Yu, Suzuki K Poulose, Stefan Kristiansson,
Stafford Horne, Guan Xuetao, linux-arm-kernel, Christophe Leroy,
Tony Luck, Yoshinori Sato, linux-kernel, James Morse,
Michael Ellerman, Paolo Bonzini, Andrew Morton
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Hi all,
On Wed, 29 Apr 2020 20:56:20 +0200 Arnd Bergmann <arnd@arndb.de> wrote:
>
> gcc-10 warns that the 32-bit zero cannot be shifted more than
> 32 bits to the right:
>
> arch/arm64/kvm/../../../virt/kvm/arm/mmu.c: In function 'clear_hyp_p4d_entry':
> arch/arm64/include/asm/pgtable.h:630:35: error: right shift count >= width of type [-Werror=shift-count-overflow]
> 630 | #define pud_index(addr) (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
> | ^~
> arch/arm64/include/asm/memory.h:271:45: note: in definition of macro '__phys_to_virt'
> 271 | #define __phys_to_virt(x) ((unsigned long)((x) - physvirt_offset))
> | ^
> arch/arm64/include/asm/pgtable.h:633:42: note: in expansion of macro '__va'
> 633 | #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> | ^~~~
> arch/arm64/include/asm/pgtable.h:632:73: note: in expansion of macro 'pud_index'
> 632 | #define pud_offset_phys(dir, addr) (p4d_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
> | ^~~~~~~~~
> arch/arm64/include/asm/pgtable.h:633:47: note: in expansion of macro 'pud_offset_phys'
> 633 | #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> | ^~~~~~~~~~~~~~~
> arch/arm64/kvm/../../../virt/kvm/arm/mmu.c:510:36: note: in expansion of macro 'pud_offset'
> 510 | pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
> | ^~~~~~~~~~
>
> This is harmless, and the warning is a little bit silly for
> a zero constant, but it's trivial to fix by making it an
> unsigned long, so do that.
>
> Fixes: 22998131ab33 ("arm64: add support for folded p4d page tables")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> virt/kvm/arm/mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index 48d4288c5f1b..534d9798c3cb 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -507,7 +507,7 @@ static void clear_hyp_pgd_entry(pgd_t *pgd)
>
> static void clear_hyp_p4d_entry(p4d_t *p4d)
> {
> - pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
> + pud_t *pud_table __maybe_unused = pud_offset(p4d, 0UL);
> VM_BUG_ON(p4d_huge(*p4d));
> p4d_clear(p4d);
> pud_free(NULL, pud_table);
> --
> 2.26.0
>
I have added that patch to linux-next today.
--
Cheers,
Stephen Rothwell
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] arm64: kvm: fix gcc-10 shift warning
2020-04-29 18:56 [PATCH] arm64: kvm: fix gcc-10 shift warning Arnd Bergmann
2020-04-29 21:09 ` Will Deacon
2020-04-29 22:42 ` Stephen Rothwell
@ 2020-04-30 8:02 ` Marc Zyngier
2020-04-30 8:29 ` Will Deacon
2 siblings, 1 reply; 7+ messages in thread
From: Marc Zyngier @ 2020-04-30 8:02 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Rich Felker, Geert Uytterhoeven, Benjamin Herrenschmidt,
Paul Mackerras, Will Deacon, kvmarm, Jonas Bonn, Stephen Rothwell,
Brian Cain, Michael Ellerman, Russell King, Ley Foon Tan,
Mike Rapoport, Catalin Marinas, Julien Thierry, Fenghua Yu,
Suzuki K Poulose, Stefan Kristiansson, Stafford Horne,
Guan Xuetao, linux-arm-kernel, Christophe Leroy, Tony Luck,
Yoshinori Sato, linux-kernel, James Morse, Paolo Bonzini,
Andrew Morton
On Wed, 29 Apr 2020 20:56:20 +0200
Arnd Bergmann <arnd@arndb.de> wrote:
> gcc-10 warns that the 32-bit zero cannot be shifted more than
> 32 bits to the right:
>
> arch/arm64/kvm/../../../virt/kvm/arm/mmu.c: In function 'clear_hyp_p4d_entry':
> arch/arm64/include/asm/pgtable.h:630:35: error: right shift count >= width of type [-Werror=shift-count-overflow]
> 630 | #define pud_index(addr) (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
> | ^~
> arch/arm64/include/asm/memory.h:271:45: note: in definition of macro '__phys_to_virt'
> 271 | #define __phys_to_virt(x) ((unsigned long)((x) - physvirt_offset))
> | ^
> arch/arm64/include/asm/pgtable.h:633:42: note: in expansion of macro '__va'
> 633 | #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> | ^~~~
> arch/arm64/include/asm/pgtable.h:632:73: note: in expansion of macro 'pud_index'
> 632 | #define pud_offset_phys(dir, addr) (p4d_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
> | ^~~~~~~~~
> arch/arm64/include/asm/pgtable.h:633:47: note: in expansion of macro 'pud_offset_phys'
> 633 | #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> | ^~~~~~~~~~~~~~~
> arch/arm64/kvm/../../../virt/kvm/arm/mmu.c:510:36: note: in expansion of macro 'pud_offset'
> 510 | pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
> | ^~~~~~~~~~
>
> This is harmless, and the warning is a little bit silly for
> a zero constant, but it's trivial to fix by making it an
> unsigned long, so do that.
>
> Fixes: 22998131ab33 ("arm64: add support for folded p4d page tables")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> virt/kvm/arm/mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> index 48d4288c5f1b..534d9798c3cb 100644
> --- a/virt/kvm/arm/mmu.c
> +++ b/virt/kvm/arm/mmu.c
> @@ -507,7 +507,7 @@ static void clear_hyp_pgd_entry(pgd_t *pgd)
>
> static void clear_hyp_p4d_entry(p4d_t *p4d)
> {
> - pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
> + pud_t *pud_table __maybe_unused = pud_offset(p4d, 0UL);
> VM_BUG_ON(p4d_huge(*p4d));
> p4d_clear(p4d);
> pud_free(NULL, pud_table);
Acked-by: Marc Zyngier <maz@kernel.org>
M.
--
Jazz is not dead. It just smells funny...
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] arm64: kvm: fix gcc-10 shift warning
2020-04-30 8:02 ` Marc Zyngier
@ 2020-04-30 8:29 ` Will Deacon
2020-04-30 9:39 ` Stephen Rothwell
0 siblings, 1 reply; 7+ messages in thread
From: Will Deacon @ 2020-04-30 8:29 UTC (permalink / raw)
To: Marc Zyngier
Cc: Rich Felker, Geert Uytterhoeven, Benjamin Herrenschmidt,
Paul Mackerras, kvmarm, Jonas Bonn, Stephen Rothwell, Brian Cain,
Michael Ellerman, Russell King, Ley Foon Tan, Mike Rapoport,
Catalin Marinas, Julien Thierry, Fenghua Yu, Arnd Bergmann,
Suzuki K Poulose, Stefan Kristiansson, Stafford Horne,
Guan Xuetao, linux-arm-kernel, Christophe Leroy, Tony Luck,
Yoshinori Sato, linux-kernel, James Morse, Paolo Bonzini,
Andrew Morton
On Thu, Apr 30, 2020 at 09:02:51AM +0100, Marc Zyngier wrote:
> On Wed, 29 Apr 2020 20:56:20 +0200
> Arnd Bergmann <arnd@arndb.de> wrote:
>
> > gcc-10 warns that the 32-bit zero cannot be shifted more than
> > 32 bits to the right:
> >
> > arch/arm64/kvm/../../../virt/kvm/arm/mmu.c: In function 'clear_hyp_p4d_entry':
> > arch/arm64/include/asm/pgtable.h:630:35: error: right shift count >= width of type [-Werror=shift-count-overflow]
> > 630 | #define pud_index(addr) (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
> > | ^~
> > arch/arm64/include/asm/memory.h:271:45: note: in definition of macro '__phys_to_virt'
> > 271 | #define __phys_to_virt(x) ((unsigned long)((x) - physvirt_offset))
> > | ^
> > arch/arm64/include/asm/pgtable.h:633:42: note: in expansion of macro '__va'
> > 633 | #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> > | ^~~~
> > arch/arm64/include/asm/pgtable.h:632:73: note: in expansion of macro 'pud_index'
> > 632 | #define pud_offset_phys(dir, addr) (p4d_page_paddr(READ_ONCE(*(dir))) + pud_index(addr) * sizeof(pud_t))
> > | ^~~~~~~~~
> > arch/arm64/include/asm/pgtable.h:633:47: note: in expansion of macro 'pud_offset_phys'
> > 633 | #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr))))
> > | ^~~~~~~~~~~~~~~
> > arch/arm64/kvm/../../../virt/kvm/arm/mmu.c:510:36: note: in expansion of macro 'pud_offset'
> > 510 | pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
> > | ^~~~~~~~~~
> >
> > This is harmless, and the warning is a little bit silly for
> > a zero constant, but it's trivial to fix by making it an
> > unsigned long, so do that.
> >
> > Fixes: 22998131ab33 ("arm64: add support for folded p4d page tables")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > virt/kvm/arm/mmu.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
> > index 48d4288c5f1b..534d9798c3cb 100644
> > --- a/virt/kvm/arm/mmu.c
> > +++ b/virt/kvm/arm/mmu.c
> > @@ -507,7 +507,7 @@ static void clear_hyp_pgd_entry(pgd_t *pgd)
> >
> > static void clear_hyp_p4d_entry(p4d_t *p4d)
> > {
> > - pud_t *pud_table __maybe_unused = pud_offset(p4d, 0);
> > + pud_t *pud_table __maybe_unused = pud_offset(p4d, 0UL);
> > VM_BUG_ON(p4d_huge(*p4d));
> > p4d_clear(p4d);
> > pud_free(NULL, pud_table);
>
> Acked-by: Marc Zyngier <maz@kernel.org>
Happy to queue via arm64 for 5.8. Does that work for you, Arnd, or were you
planning to get this in sooner than that?
Cheers,
Will
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] arm64: kvm: fix gcc-10 shift warning
2020-04-30 8:29 ` Will Deacon
@ 2020-04-30 9:39 ` Stephen Rothwell
2020-04-30 9:50 ` Will Deacon
0 siblings, 1 reply; 7+ messages in thread
From: Stephen Rothwell @ 2020-04-30 9:39 UTC (permalink / raw)
To: Will Deacon
Cc: Rich Felker, Geert Uytterhoeven, Catalin Marinas, Paul Mackerras,
kvmarm, Jonas Bonn, Brian Cain, Marc Zyngier, Russell King,
Ley Foon Tan, Mike Rapoport, Benjamin Herrenschmidt,
Julien Thierry, Fenghua Yu, Arnd Bergmann, Suzuki K Poulose,
Stefan Kristiansson, Stafford Horne, Guan Xuetao,
linux-arm-kernel, Christophe Leroy, Tony Luck, Yoshinori Sato,
linux-kernel, James Morse, Michael Ellerman, Paolo Bonzini,
Andrew Morton
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Hi Will,
On Thu, 30 Apr 2020 09:29:28 +0100 Will Deacon <will@kernel.org> wrote:
>
> On Thu, Apr 30, 2020 at 09:02:51AM +0100, Marc Zyngier wrote:
> > On Wed, 29 Apr 2020 20:56:20 +0200
> > Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > > Fixes: 22998131ab33 ("arm64: add support for folded p4d page tables")
>
> Happy to queue via arm64 for 5.8. Does that work for you, Arnd, or were you
> planning to get this in sooner than that?
The commit that this fixes is in Andrew's patch series in linux-next,
so it should just go in there.
--
Cheers,
Stephen Rothwell
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] arm64: kvm: fix gcc-10 shift warning
2020-04-30 9:39 ` Stephen Rothwell
@ 2020-04-30 9:50 ` Will Deacon
0 siblings, 0 replies; 7+ messages in thread
From: Will Deacon @ 2020-04-30 9:50 UTC (permalink / raw)
To: Stephen Rothwell
Cc: Rich Felker, Geert Uytterhoeven, Catalin Marinas, Paul Mackerras,
kvmarm, Jonas Bonn, Brian Cain, Marc Zyngier, Russell King,
Ley Foon Tan, Mike Rapoport, Benjamin Herrenschmidt,
Julien Thierry, Fenghua Yu, Arnd Bergmann, Suzuki K Poulose,
Stefan Kristiansson, Stafford Horne, Guan Xuetao,
linux-arm-kernel, Christophe Leroy, Tony Luck, Yoshinori Sato,
linux-kernel, James Morse, Michael Ellerman, Paolo Bonzini,
Andrew Morton
On Thu, Apr 30, 2020 at 07:39:10PM +1000, Stephen Rothwell wrote:
> On Thu, 30 Apr 2020 09:29:28 +0100 Will Deacon <will@kernel.org> wrote:
> > On Thu, Apr 30, 2020 at 09:02:51AM +0100, Marc Zyngier wrote:
> > > On Wed, 29 Apr 2020 20:56:20 +0200
> > > Arnd Bergmann <arnd@arndb.de> wrote:
> > >
> > > > Fixes: 22998131ab33 ("arm64: add support for folded p4d page tables")
> >
> > Happy to queue via arm64 for 5.8. Does that work for you, Arnd, or were you
> > planning to get this in sooner than that?
>
> The commit that this fixes is in Andrew's patch series in linux-next,
> so it should just go in there.
Yes, you're right. Sorry for the noise.
Will
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^ permalink raw reply [flat|nested] 7+ messages in thread