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 <[email protected]>
---
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
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 <[email protected]>
> ---
> 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 <[email protected]>
Will
Hi all,
On Wed, 29 Apr 2020 20:56:20 +0200 Arnd Bergmann <[email protected]> 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 <[email protected]>
> ---
> 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
On Wed, 29 Apr 2020 20:56:20 +0200
Arnd Bergmann <[email protected]> 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 <[email protected]>
> ---
> 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 <[email protected]>
M.
--
Jazz is not dead. It just smells funny...
On Thu, Apr 30, 2020 at 09:02:51AM +0100, Marc Zyngier wrote:
> On Wed, 29 Apr 2020 20:56:20 +0200
> Arnd Bergmann <[email protected]> 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 <[email protected]>
> > ---
> > 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 <[email protected]>
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
Hi Will,
On Thu, 30 Apr 2020 09:29:28 +0100 Will Deacon <[email protected]> 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 <[email protected]> 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
On Thu, Apr 30, 2020 at 07:39:10PM +1000, Stephen Rothwell wrote:
> On Thu, 30 Apr 2020 09:29:28 +0100 Will Deacon <[email protected]> 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 <[email protected]> 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