From: Fenghua Yu <[email protected]>
Define a helper, update_pkey_val(), which will be used to support both
Protection Key User (PKU) and the new Protection Key for Supervisor
(PKS) in subsequent patches.
Co-developed-by: Ira Weiny <[email protected]>
Signed-off-by: Ira Weiny <[email protected]>
Signed-off-by: Fenghua Yu <[email protected]>
---
arch/x86/include/asm/pkeys.h | 2 ++
arch/x86/kernel/fpu/xstate.c | 22 ++++------------------
arch/x86/mm/pkeys.c | 21 +++++++++++++++++++++
3 files changed, 27 insertions(+), 18 deletions(-)
diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
index f9feba80894b..4526245b03e5 100644
--- a/arch/x86/include/asm/pkeys.h
+++ b/arch/x86/include/asm/pkeys.h
@@ -136,4 +136,6 @@ static inline int vma_pkey(struct vm_area_struct *vma)
return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
}
+u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags);
+
#endif /*_ASM_X86_PKEYS_H */
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index b55cf3acd82a..725f10670d0a 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -990,9 +990,7 @@ const void *get_xsave_field_ptr(int xfeature_nr)
int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
unsigned long init_val)
{
- u32 old_pkru;
- int pkey_shift = (pkey * PKR_BITS_PER_PKEY);
- u32 new_pkru_bits = 0;
+ u32 pkru;
/*
* This check implies XSAVE support. OSPKE only gets
@@ -1008,21 +1006,9 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
*/
WARN_ON_ONCE(pkey >= arch_max_pkey());
- /* Set the bits we need in PKRU: */
- if (init_val & PKEY_DISABLE_ACCESS)
- new_pkru_bits |= PKR_AD_BIT;
- if (init_val & PKEY_DISABLE_WRITE)
- new_pkru_bits |= PKR_WD_BIT;
-
- /* Shift the bits in to the correct place in PKRU for pkey: */
- new_pkru_bits <<= pkey_shift;
-
- /* Get old PKRU and mask off any old bits in place: */
- old_pkru = read_pkru();
- old_pkru &= ~((PKR_AD_BIT|PKR_WD_BIT) << pkey_shift);
-
- /* Write old part along with new part: */
- write_pkru(old_pkru | new_pkru_bits);
+ pkru = read_pkru();
+ pkru = update_pkey_val(pkru, pkey, init_val);
+ write_pkru(pkru);
return 0;
}
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index f5efb4007e74..3cf8f775f36d 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -208,3 +208,24 @@ static __init int setup_init_pkru(char *opt)
return 1;
}
__setup("init_pkru=", setup_init_pkru);
+
+/*
+ * Update the pk_reg value and return it.
+ *
+ * Kernel users use the same flags as user space:
+ * PKEY_DISABLE_ACCESS
+ * PKEY_DISABLE_WRITE
+ */
+u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags)
+{
+ int pkey_shift = pkey * PKR_BITS_PER_PKEY;
+
+ pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift);
+
+ if (flags & PKEY_DISABLE_ACCESS)
+ pk_reg |= PKR_AD_BIT << pkey_shift;
+ if (flags & PKEY_DISABLE_WRITE)
+ pk_reg |= PKR_WD_BIT << pkey_shift;
+
+ return pk_reg;
+}
--
2.28.0.rc0.12.gb6a658bd00c9
On 10/9/20 12:42 PM, [email protected] wrote:
> +/*
> + * Update the pk_reg value and return it.
How about:
Replace disable bits for @pkey with values from @flags.
> + * Kernel users use the same flags as user space:
> + * PKEY_DISABLE_ACCESS
> + * PKEY_DISABLE_WRITE
> + */
> +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags)
> +{
> + int pkey_shift = pkey * PKR_BITS_PER_PKEY;
> +
> + pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift);
> +
> + if (flags & PKEY_DISABLE_ACCESS)
> + pk_reg |= PKR_AD_BIT << pkey_shift;
> + if (flags & PKEY_DISABLE_WRITE)
> + pk_reg |= PKR_WD_BIT << pkey_shift;
I still think this deserves two lines of comments:
/* Mask out old bit values */
/* Or in new values */
On Tue, Oct 13, 2020 at 10:50:05AM -0700, Dave Hansen wrote:
> On 10/9/20 12:42 PM, [email protected] wrote:
> > +/*
> > + * Update the pk_reg value and return it.
>
> How about:
>
> Replace disable bits for @pkey with values from @flags.
Done.
>
> > + * Kernel users use the same flags as user space:
> > + * PKEY_DISABLE_ACCESS
> > + * PKEY_DISABLE_WRITE
> > + */
> > +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags)
> > +{
> > + int pkey_shift = pkey * PKR_BITS_PER_PKEY;
> > +
> > + pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift);
> > +
> > + if (flags & PKEY_DISABLE_ACCESS)
> > + pk_reg |= PKR_AD_BIT << pkey_shift;
> > + if (flags & PKEY_DISABLE_WRITE)
> > + pk_reg |= PKR_WD_BIT << pkey_shift;
>
> I still think this deserves two lines of comments:
>
> /* Mask out old bit values */
>
> /* Or in new values */
Sure, done.
Ira
On Fri, Oct 09, 2020 at 12:42:51PM -0700, [email protected] wrote:
> From: Fenghua Yu <[email protected]>
>
> Define a helper, update_pkey_val(), which will be used to support both
> Protection Key User (PKU) and the new Protection Key for Supervisor
> (PKS) in subsequent patches.
>
> Co-developed-by: Ira Weiny <[email protected]>
> Signed-off-by: Ira Weiny <[email protected]>
> Signed-off-by: Fenghua Yu <[email protected]>
> ---
> arch/x86/include/asm/pkeys.h | 2 ++
> arch/x86/kernel/fpu/xstate.c | 22 ++++------------------
> arch/x86/mm/pkeys.c | 21 +++++++++++++++++++++
> 3 files changed, 27 insertions(+), 18 deletions(-)
This is not from Fenghua.
https://lkml.kernel.org/r/[email protected]
This is your patch based on the code I wrote.
> diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
> index f5efb4007e74..3cf8f775f36d 100644
> --- a/arch/x86/mm/pkeys.c
> +++ b/arch/x86/mm/pkeys.c
> @@ -208,3 +208,24 @@ static __init int setup_init_pkru(char *opt)
> return 1;
> }
> __setup("init_pkru=", setup_init_pkru);
> +
> +/*
> + * Update the pk_reg value and return it.
> + *
> + * Kernel users use the same flags as user space:
> + * PKEY_DISABLE_ACCESS
> + * PKEY_DISABLE_WRITE
> + */
> +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags)
> +{
> + int pkey_shift = pkey * PKR_BITS_PER_PKEY;
> +
> + pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift);
> +
> + if (flags & PKEY_DISABLE_ACCESS)
> + pk_reg |= PKR_AD_BIT << pkey_shift;
> + if (flags & PKEY_DISABLE_WRITE)
> + pk_reg |= PKR_WD_BIT << pkey_shift;
> +
> + return pk_reg;
> +}
> --
> 2.28.0.rc0.12.gb6a658bd00c9
>
On Fri, Oct 16, 2020 at 12:57:43PM +0200, Peter Zijlstra wrote:
> On Fri, Oct 09, 2020 at 12:42:51PM -0700, [email protected] wrote:
> > From: Fenghua Yu <[email protected]>
> >
> > Define a helper, update_pkey_val(), which will be used to support both
> > Protection Key User (PKU) and the new Protection Key for Supervisor
> > (PKS) in subsequent patches.
> >
> > Co-developed-by: Ira Weiny <[email protected]>
> > Signed-off-by: Ira Weiny <[email protected]>
> > Signed-off-by: Fenghua Yu <[email protected]>
> > ---
> > arch/x86/include/asm/pkeys.h | 2 ++
> > arch/x86/kernel/fpu/xstate.c | 22 ++++------------------
> > arch/x86/mm/pkeys.c | 21 +++++++++++++++++++++
> > 3 files changed, 27 insertions(+), 18 deletions(-)
>
> This is not from Fenghua.
>
> https://lkml.kernel.org/r/[email protected]
>
> This is your patch based on the code I wrote.
Ok, I apologize. Yes the code below was all yours.
Is it ok to add?
Co-developed-by: Peter Zijlstra <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
?
Thanks,
Ira
>
> > diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
> > index f5efb4007e74..3cf8f775f36d 100644
> > --- a/arch/x86/mm/pkeys.c
> > +++ b/arch/x86/mm/pkeys.c
> > @@ -208,3 +208,24 @@ static __init int setup_init_pkru(char *opt)
> > return 1;
> > }
> > __setup("init_pkru=", setup_init_pkru);
> > +
> > +/*
> > + * Update the pk_reg value and return it.
> > + *
> > + * Kernel users use the same flags as user space:
> > + * PKEY_DISABLE_ACCESS
> > + * PKEY_DISABLE_WRITE
> > + */
> > +u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags)
> > +{
> > + int pkey_shift = pkey * PKR_BITS_PER_PKEY;
> > +
> > + pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift);
> > +
> > + if (flags & PKEY_DISABLE_ACCESS)
> > + pk_reg |= PKR_AD_BIT << pkey_shift;
> > + if (flags & PKEY_DISABLE_WRITE)
> > + pk_reg |= PKR_WD_BIT << pkey_shift;
> > +
> > + return pk_reg;
> > +}
> > --
> > 2.28.0.rc0.12.gb6a658bd00c9
> >
On Fri, Oct 16, 2020 at 08:32:03PM -0700, Ira Weiny wrote:
> On Fri, Oct 16, 2020 at 12:57:43PM +0200, Peter Zijlstra wrote:
> > On Fri, Oct 09, 2020 at 12:42:51PM -0700, [email protected] wrote:
> > > From: Fenghua Yu <[email protected]>
> > >
> > > Define a helper, update_pkey_val(), which will be used to support both
> > > Protection Key User (PKU) and the new Protection Key for Supervisor
> > > (PKS) in subsequent patches.
> > >
> > > Co-developed-by: Ira Weiny <[email protected]>
> > > Signed-off-by: Ira Weiny <[email protected]>
> > > Signed-off-by: Fenghua Yu <[email protected]>
> > > ---
> > > arch/x86/include/asm/pkeys.h | 2 ++
> > > arch/x86/kernel/fpu/xstate.c | 22 ++++------------------
> > > arch/x86/mm/pkeys.c | 21 +++++++++++++++++++++
> > > 3 files changed, 27 insertions(+), 18 deletions(-)
> >
> > This is not from Fenghua.
> >
> > https://lkml.kernel.org/r/[email protected]
> >
> > This is your patch based on the code I wrote.
>
> Ok, I apologize. Yes the code below was all yours.
>
> Is it ok to add?
>
> Co-developed-by: Peter Zijlstra <[email protected]>
> Signed-off-by: Peter Zijlstra <[email protected]>
>
Sure, thanks!