diff mbox

[V2] arm64: tlbflush: avoid writing RES0 bits

Message ID 1522120877-9136-1-git-send-email-pelcan@codeaurora.org (mailing list archive)
State New, archived
Headers show

Commit Message

Philip Elcan March 27, 2018, 3:21 a.m. UTC
Several of the bits of the TLBI register operand are RES0 per the ARM
ARM, so TLBI operations should avoid writing non-zero values to these
bits.

This patch adds a macro __TLBI_VADDR(addr, asid) that creates the
operand register in the correct format and honors the RES0 bits.

Signed-off-by: Philip Elcan <pelcan@codeaurora.org>
---
 arch/arm64/include/asm/tlbflush.h | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

Comments

Robin Murphy March 27, 2018, 11:34 a.m. UTC | #1
On 27/03/18 04:21, Philip Elcan wrote:
> Several of the bits of the TLBI register operand are RES0 per the ARM
> ARM, so TLBI operations should avoid writing non-zero values to these
> bits.
> 
> This patch adds a macro __TLBI_VADDR(addr, asid) that creates the
> operand register in the correct format and honors the RES0 bits.
> 
> Signed-off-by: Philip Elcan <pelcan@codeaurora.org>
> ---
>   arch/arm64/include/asm/tlbflush.h | 23 ++++++++++++++++-------
>   1 file changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
> index 9e82dd7..b1205e9 100644
> --- a/arch/arm64/include/asm/tlbflush.h
> +++ b/arch/arm64/include/asm/tlbflush.h
> @@ -60,6 +60,15 @@
>   		__tlbi(op, (arg) | USER_ASID_FLAG);				\
>   } while (0)
>   
> +/* This macro creates a properly formatted VA operand for the TLBI */
> +#define __TLBI_VADDR(addr, asid)				\
> +	({							\
> +		unsigned long __ta = (addr) >> 12;		\
> +		__ta &= GENMASK_ULL(43, 0);			\
> +		__ta |= (unsigned long)(asid) << 48;		\
> +		__ta;						\
> +	})

I'd be inclined to make this a static inline function rather than a 
macro, since it doesn't need to do any wacky type-dodging, but either 
way the overall change now looks appropriate;

Acked-by: Robin Murphy <robin.murphy@arm.com>

Thanks,
Robin.

> +
>   /*
>    *	TLB Management
>    *	==============
> @@ -117,7 +126,7 @@ static inline void flush_tlb_all(void)
>   
>   static inline void flush_tlb_mm(struct mm_struct *mm)
>   {
> -	unsigned long asid = ASID(mm) << 48;
> +	unsigned long asid = __TLBI_VADDR(0, ASID(mm));
>   
>   	dsb(ishst);
>   	__tlbi(aside1is, asid);
> @@ -128,7 +137,7 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
>   static inline void flush_tlb_page(struct vm_area_struct *vma,
>   				  unsigned long uaddr)
>   {
> -	unsigned long addr = uaddr >> 12 | (ASID(vma->vm_mm) << 48);
> +	unsigned long addr = __TLBI_VADDR(uaddr, ASID(vma->vm_mm));
>   
>   	dsb(ishst);
>   	__tlbi(vale1is, addr);
> @@ -154,8 +163,8 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
>   		return;
>   	}
>   
> -	start = asid | (start >> 12);
> -	end = asid | (end >> 12);
> +	start = __TLBI_VADDR(start, asid);
> +	end = __TLBI_VADDR(end, asid);
>   
>   	dsb(ishst);
>   	for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12)) {
> @@ -185,8 +194,8 @@ static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
>   		return;
>   	}
>   
> -	start >>= 12;
> -	end >>= 12;
> +	start = __TLBI_VADDR(start, 0);
> +	end = __TLBI_VADDR(end, 0);
>   
>   	dsb(ishst);
>   	for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12))
> @@ -202,7 +211,7 @@ static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
>   static inline void __flush_tlb_pgtable(struct mm_struct *mm,
>   				       unsigned long uaddr)
>   {
> -	unsigned long addr = uaddr >> 12 | (ASID(mm) << 48);
> +	unsigned long addr = __TLBI_VADDR(uaddr, ASID(mm));
>   
>   	__tlbi(vae1is, addr);
>   	__tlbi_user(vae1is, addr);
>
Shanker Donthineni March 27, 2018, 2:53 p.m. UTC | #2
On 03/27/2018 06:34 AM, Robin Murphy wrote:
> On 27/03/18 04:21, Philip Elcan wrote:
>> Several of the bits of the TLBI register operand are RES0 per the ARM
>> ARM, so TLBI operations should avoid writing non-zero values to these
>> bits.
>>
>> This patch adds a macro __TLBI_VADDR(addr, asid) that creates the
>> operand register in the correct format and honors the RES0 bits.
>>
>> Signed-off-by: Philip Elcan <pelcan@codeaurora.org>
>> ---
>>   arch/arm64/include/asm/tlbflush.h | 23 ++++++++++++++++-------
>>   1 file changed, 16 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
>> index 9e82dd7..b1205e9 100644
>> --- a/arch/arm64/include/asm/tlbflush.h
>> +++ b/arch/arm64/include/asm/tlbflush.h
>> @@ -60,6 +60,15 @@
>>           __tlbi(op, (arg) | USER_ASID_FLAG);                \
>>   } while (0)
>>   +/* This macro creates a properly formatted VA operand for the TLBI */
>> +#define __TLBI_VADDR(addr, asid)                \
>> +    ({                            \
>> +        unsigned long __ta = (addr) >> 12;        \
>> +        __ta &= GENMASK_ULL(43, 0);            \
>> +        __ta |= (unsigned long)(asid) << 48;        \
>> +        __ta;                        \
>> +    })
> 
> I'd be inclined to make this a static inline function rather than a macro, since it doesn't need to do any wacky type-dodging, but either way the overall change now looks appropriate;
> 
> Acked-by: Robin Murphy <robin.murphy@arm.com>
> 

Tested-by: Shanker Donthineni <shankerd@codeaurora.org>

> Thanks,
> Robin.
> 
>> +
>>   /*
>>    *    TLB Management
>>    *    ==============
>> @@ -117,7 +126,7 @@ static inline void flush_tlb_all(void)
>>     static inline void flush_tlb_mm(struct mm_struct *mm)
>>   {
>> -    unsigned long asid = ASID(mm) << 48;
>> +    unsigned long asid = __TLBI_VADDR(0, ASID(mm));
>>         dsb(ishst);
>>       __tlbi(aside1is, asid);
>> @@ -128,7 +137,7 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
>>   static inline void flush_tlb_page(struct vm_area_struct *vma,
>>                     unsigned long uaddr)
>>   {
>> -    unsigned long addr = uaddr >> 12 | (ASID(vma->vm_mm) << 48);
>> +    unsigned long addr = __TLBI_VADDR(uaddr, ASID(vma->vm_mm));
>>         dsb(ishst);
>>       __tlbi(vale1is, addr);
>> @@ -154,8 +163,8 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
>>           return;
>>       }
>>   -    start = asid | (start >> 12);
>> -    end = asid | (end >> 12);
>> +    start = __TLBI_VADDR(start, asid);
>> +    end = __TLBI_VADDR(end, asid);
>>         dsb(ishst);
>>       for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12)) {
>> @@ -185,8 +194,8 @@ static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
>>           return;
>>       }
>>   -    start >>= 12;
>> -    end >>= 12;
>> +    start = __TLBI_VADDR(start, 0);
>> +    end = __TLBI_VADDR(end, 0);
>>         dsb(ishst);
>>       for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12))
>> @@ -202,7 +211,7 @@ static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
>>   static inline void __flush_tlb_pgtable(struct mm_struct *mm,
>>                          unsigned long uaddr)
>>   {
>> -    unsigned long addr = uaddr >> 12 | (ASID(mm) << 48);
>> +    unsigned long addr = __TLBI_VADDR(uaddr, ASID(mm));
>>         __tlbi(vae1is, addr);
>>       __tlbi_user(vae1is, addr);
>>
Will Deacon March 27, 2018, 5:36 p.m. UTC | #3
Hi Shanker,

On Tue, Mar 27, 2018 at 09:53:16AM -0500, Shanker Donthineni wrote:
> On 03/27/2018 06:34 AM, Robin Murphy wrote:
> > On 27/03/18 04:21, Philip Elcan wrote:
> >> Several of the bits of the TLBI register operand are RES0 per the ARM
> >> ARM, so TLBI operations should avoid writing non-zero values to these
> >> bits.
> >>
> >> This patch adds a macro __TLBI_VADDR(addr, asid) that creates the
> >> operand register in the correct format and honors the RES0 bits.
> >>
> >> Signed-off-by: Philip Elcan <pelcan@codeaurora.org>
> >> ---
> >>   arch/arm64/include/asm/tlbflush.h | 23 ++++++++++++++++-------
> >>   1 file changed, 16 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
> >> index 9e82dd7..b1205e9 100644
> >> --- a/arch/arm64/include/asm/tlbflush.h
> >> +++ b/arch/arm64/include/asm/tlbflush.h
> >> @@ -60,6 +60,15 @@
> >>           __tlbi(op, (arg) | USER_ASID_FLAG);                \
> >>   } while (0)
> >>   +/* This macro creates a properly formatted VA operand for the TLBI */
> >> +#define __TLBI_VADDR(addr, asid)                \
> >> +    ({                            \
> >> +        unsigned long __ta = (addr) >> 12;        \
> >> +        __ta &= GENMASK_ULL(43, 0);            \
> >> +        __ta |= (unsigned long)(asid) << 48;        \
> >> +        __ta;                        \
> >> +    })
> > 
> > I'd be inclined to make this a static inline function rather than a
> > macro, since it doesn't need to do any wacky type-dodging, but either
> > way the overall change now looks appropriate;
> > 
> > Acked-by: Robin Murphy <robin.murphy@arm.com>
> > 
> 
> Tested-by: Shanker Donthineni <shankerd@codeaurora.org>

[...]

> >> @@ -154,8 +163,8 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
> >>           return;
> >>       }
> >>   -    start = asid | (start >> 12);
> >> -    end = asid | (end >> 12);
> >> +    start = __TLBI_VADDR(start, asid);
> >> +    end = __TLBI_VADDR(end, asid);

Can you test this bit too, please? ;)

Will
Shanker Donthineni March 28, 2018, 1:03 a.m. UTC | #4
Hi Will,

On 03/27/2018 12:36 PM, Will Deacon wrote:
> Hi Shanker,
> 
> On Tue, Mar 27, 2018 at 09:53:16AM -0500, Shanker Donthineni wrote:
>> On 03/27/2018 06:34 AM, Robin Murphy wrote:
>>> On 27/03/18 04:21, Philip Elcan wrote:
>>>> Several of the bits of the TLBI register operand are RES0 per the ARM
>>>> ARM, so TLBI operations should avoid writing non-zero values to these
>>>> bits.
>>>>
>>>> This patch adds a macro __TLBI_VADDR(addr, asid) that creates the
>>>> operand register in the correct format and honors the RES0 bits.
>>>>
>>>> Signed-off-by: Philip Elcan <pelcan@codeaurora.org>
>>>> ---
>>>>   arch/arm64/include/asm/tlbflush.h | 23 ++++++++++++++++-------
>>>>   1 file changed, 16 insertions(+), 7 deletions(-)
>>>>
>>>> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
>>>> index 9e82dd7..b1205e9 100644
>>>> --- a/arch/arm64/include/asm/tlbflush.h
>>>> +++ b/arch/arm64/include/asm/tlbflush.h
>>>> @@ -60,6 +60,15 @@
>>>>           __tlbi(op, (arg) | USER_ASID_FLAG);                \
>>>>   } while (0)
>>>>   +/* This macro creates a properly formatted VA operand for the TLBI */
>>>> +#define __TLBI_VADDR(addr, asid)                \
>>>> +    ({                            \
>>>> +        unsigned long __ta = (addr) >> 12;        \
>>>> +        __ta &= GENMASK_ULL(43, 0);            \
>>>> +        __ta |= (unsigned long)(asid) << 48;        \
>>>> +        __ta;                        \
>>>> +    })
>>>
>>> I'd be inclined to make this a static inline function rather than a
>>> macro, since it doesn't need to do any wacky type-dodging, but either
>>> way the overall change now looks appropriate;
>>>
>>> Acked-by: Robin Murphy <robin.murphy@arm.com>
>>>
>>
>> Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
> 
> [...]
> 
>>>> @@ -154,8 +163,8 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
>>>>           return;
>>>>       }
>>>>   -    start = asid | (start >> 12);
>>>> -    end = asid | (end >> 12);
>>>> +    start = __TLBI_VADDR(start, asid);
>>>> +    end = __TLBI_VADDR(end, asid);
> 
> Can you test this bit too, please? ;)
> 

I've verified the basic boot functionality on QDF2400 platform. But I can see now
after your comments, it leads to TLB conflicts because of ASID is truncated to zero
due to two times 48bit shift.     

Thanks for catching this one.

@@ -146,7 +155,7 @@ static inline void __flush_tlb_range(structvm_area_struct *
                                     unsigned long start, unsigned long end,
                                     bool last_level)
{
-       unsigned long asid = ASID(vma->vm_mm) << 48;
+       unsigned long asid = ASID(vma->vm_mm);
        unsigned long addr;
 
        if ((end - start) > MAX_TLB_RANGE) {
@@ -154,8 +163,8 @@ static inline void __flush_tlb_range(struct
vm_area_struct *
                return;
        }

-       start = asid | (start >> 12);
-       end = asid | (end >> 12);
+       start = __TLBI_VADDR(start, asid);
+       end = __TLBI_VADDR(end, asid);


> Will
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
Philip Elcan March 28, 2018, 1:08 a.m. UTC | #5
On 3/27/2018 9:03 PM, Shanker Donthineni wrote:
> Hi Will,
> 
> On 03/27/2018 12:36 PM, Will Deacon wrote:
>> Hi Shanker,
>>
>> On Tue, Mar 27, 2018 at 09:53:16AM -0500, Shanker Donthineni wrote:
>>> On 03/27/2018 06:34 AM, Robin Murphy wrote:
>>>> On 27/03/18 04:21, Philip Elcan wrote:
>>>>> Several of the bits of the TLBI register operand are RES0 per the ARM
>>>>> ARM, so TLBI operations should avoid writing non-zero values to these
>>>>> bits.
>>>>>
>>>>> This patch adds a macro __TLBI_VADDR(addr, asid) that creates the
>>>>> operand register in the correct format and honors the RES0 bits.
>>>>>
>>>>> Signed-off-by: Philip Elcan <pelcan@codeaurora.org>
>>>>> ---
>>>>>   arch/arm64/include/asm/tlbflush.h | 23 ++++++++++++++++-------
>>>>>   1 file changed, 16 insertions(+), 7 deletions(-)
>>>>>
>>>>> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
>>>>> index 9e82dd7..b1205e9 100644
>>>>> --- a/arch/arm64/include/asm/tlbflush.h
>>>>> +++ b/arch/arm64/include/asm/tlbflush.h
>>>>> @@ -60,6 +60,15 @@
>>>>>           __tlbi(op, (arg) | USER_ASID_FLAG);                \
>>>>>   } while (0)
>>>>>   +/* This macro creates a properly formatted VA operand for the TLBI */
>>>>> +#define __TLBI_VADDR(addr, asid)                \
>>>>> +    ({                            \
>>>>> +        unsigned long __ta = (addr) >> 12;        \
>>>>> +        __ta &= GENMASK_ULL(43, 0);            \
>>>>> +        __ta |= (unsigned long)(asid) << 48;        \
>>>>> +        __ta;                        \
>>>>> +    })
>>>>
>>>> I'd be inclined to make this a static inline function rather than a
>>>> macro, since it doesn't need to do any wacky type-dodging, but either
>>>> way the overall change now looks appropriate;
>>>>
>>>> Acked-by: Robin Murphy <robin.murphy@arm.com>
>>>>
>>>
>>> Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
>>
>> [...]
>>
>>>>> @@ -154,8 +163,8 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
>>>>>           return;
>>>>>       }
>>>>>   -    start = asid | (start >> 12);
>>>>> -    end = asid | (end >> 12);
>>>>> +    start = __TLBI_VADDR(start, asid);
>>>>> +    end = __TLBI_VADDR(end, asid);
>>
>> Can you test this bit too, please? ;)
>>
> 
> I've verified the basic boot functionality on QDF2400 platform. But I can see now
> after your comments, it leads to TLB conflicts because of ASID is truncated to zero
> due to two times 48bit shift.     
> 
> Thanks for catching this one.
> 
> @@ -146,7 +155,7 @@ static inline void __flush_tlb_range(structvm_area_struct *
>                                      unsigned long start, unsigned long end,
>                                      bool last_level)
> {
> -       unsigned long asid = ASID(vma->vm_mm) << 48;
> +       unsigned long asid = ASID(vma->vm_mm);
>         unsigned long addr;
>  
>         if ((end - start) > MAX_TLB_RANGE) {
> @@ -154,8 +163,8 @@ static inline void __flush_tlb_range(struct
> vm_area_struct *
>                 return;
>         }
> 
> -       start = asid | (start >> 12);
> -       end = asid | (end >> 12);
> +       start = __TLBI_VADDR(start, asid);
> +       end = __TLBI_VADDR(end, asid);
> 
> 
>> Will
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
> 

Thanks for catching that.  I'll address with a v3 patch.

Philip
Will Deacon March 28, 2018, 11:58 a.m. UTC | #6
On Tue, Mar 27, 2018 at 08:03:07PM -0500, Shanker Donthineni wrote:
> On 03/27/2018 12:36 PM, Will Deacon wrote:
> > On Tue, Mar 27, 2018 at 09:53:16AM -0500, Shanker Donthineni wrote:
> >>>> @@ -154,8 +163,8 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
> >>>>           return;
> >>>>       }
> >>>>   -    start = asid | (start >> 12);
> >>>> -    end = asid | (end >> 12);
> >>>> +    start = __TLBI_VADDR(start, asid);
> >>>> +    end = __TLBI_VADDR(end, asid);
> > 
> > Can you test this bit too, please? ;)
> > 
> 
> I've verified the basic boot functionality on QDF2400 platform. But I can see now
> after your comments, it leads to TLB conflicts because of ASID is truncated to zero
> due to two times 48bit shift.     
> 
> Thanks for catching this one.

I just noticed it during review. In general, if you're making changes
relating to virtual memory stuff I'd *strongly* advise you to do more
than a basic boot test. It's amazing how much appears to run fine when
stuff like TLB invalidation is completely broken.

Anyway, thanks for turning around a new version so quickly.

Will
diff mbox

Patch

diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index 9e82dd7..b1205e9 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -60,6 +60,15 @@ 
 		__tlbi(op, (arg) | USER_ASID_FLAG);				\
 } while (0)
 
+/* This macro creates a properly formatted VA operand for the TLBI */
+#define __TLBI_VADDR(addr, asid)				\
+	({							\
+		unsigned long __ta = (addr) >> 12;		\
+		__ta &= GENMASK_ULL(43, 0);			\
+		__ta |= (unsigned long)(asid) << 48;		\
+		__ta;						\
+	})
+
 /*
  *	TLB Management
  *	==============
@@ -117,7 +126,7 @@  static inline void flush_tlb_all(void)
 
 static inline void flush_tlb_mm(struct mm_struct *mm)
 {
-	unsigned long asid = ASID(mm) << 48;
+	unsigned long asid = __TLBI_VADDR(0, ASID(mm));
 
 	dsb(ishst);
 	__tlbi(aside1is, asid);
@@ -128,7 +137,7 @@  static inline void flush_tlb_mm(struct mm_struct *mm)
 static inline void flush_tlb_page(struct vm_area_struct *vma,
 				  unsigned long uaddr)
 {
-	unsigned long addr = uaddr >> 12 | (ASID(vma->vm_mm) << 48);
+	unsigned long addr = __TLBI_VADDR(uaddr, ASID(vma->vm_mm));
 
 	dsb(ishst);
 	__tlbi(vale1is, addr);
@@ -154,8 +163,8 @@  static inline void __flush_tlb_range(struct vm_area_struct *vma,
 		return;
 	}
 
-	start = asid | (start >> 12);
-	end = asid | (end >> 12);
+	start = __TLBI_VADDR(start, asid);
+	end = __TLBI_VADDR(end, asid);
 
 	dsb(ishst);
 	for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12)) {
@@ -185,8 +194,8 @@  static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
 		return;
 	}
 
-	start >>= 12;
-	end >>= 12;
+	start = __TLBI_VADDR(start, 0);
+	end = __TLBI_VADDR(end, 0);
 
 	dsb(ishst);
 	for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12))
@@ -202,7 +211,7 @@  static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
 static inline void __flush_tlb_pgtable(struct mm_struct *mm,
 				       unsigned long uaddr)
 {
-	unsigned long addr = uaddr >> 12 | (ASID(mm) << 48);
+	unsigned long addr = __TLBI_VADDR(uaddr, ASID(mm));
 
 	__tlbi(vae1is, addr);
 	__tlbi_user(vae1is, addr);