Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
On 09/18/2019 11:52 PM, Gerald Schaefer wrote: > On Wed, 18 Sep 2019 18:26:03 +0200 > Christophe Leroy wrote: > > [..] >> My suggestion was not to completely drop the #ifdef but to do like you >> did in pgd_clear_tests() for instance, ie to add the following test on >> top of the function: >> >> if (mm_pud_folded(mm) || is_defined(__ARCH_HAS_5LEVEL_HACK)) >> return; >> > > Ah, very nice, this would also fix the remaining issues for s390. Since > we have dynamic page table folding, neither __PAGETABLE_PXX_FOLDED nor > __ARCH_HAS_XLEVEL_HACK is defined, but mm_pxx_folded() will work. Like Christophe mentioned earlier on the other thread, we will convert all __PGTABLE_PXX_FOLDED checks as mm_pxx_folded() but looks like ARCH_HAS_[4 and 5]LEVEL_HACK macros will still be around. Will respin the series with all agreed upon changes first and probably we can then discuss pending issues from there. > > mm_alloc() returns with a 3-level page table by default on s390, so we > will run into issues in p4d_clear/populate_tests(), and also at the end > with p4d/pud_free() (double free). > > So, adding the mm_pud_folded() check to p4d_clear/populate_tests(), > and also adding mm_p4d/pud_folded() checks at the end before calling> > p4d/pud_free(), would make it all work on s390. Atleast p4d_clear/populate_tests() tests will be taken care. > > BTW, regarding p4d/pud_free(), I'm not sure if we should rather check > the folding inside our s390 functions, similar to how we do it for > p4d/pud_free_tlb(), instead of relying on not being called for folded > p4d/pud. So far, I see no problem with this behavior, all callers of > p4d/pud_free() should be fine because of our folding check within > p4d/pud_present/none(). But that doesn't mean that it is correct not > to check for the folding inside p4d/pud_free(). At least, with this > test module we do now have a caller of p4d/pud_free() on potentially > folded entries, so instead of adding pxx_folded() checks to this > test module, we could add them to our p4d/pud_free() functions. > Any thoughts on this? Agreed, it seems better to do the check inside p4d/pud_free() functions. ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
Le 19/09/2019 à 06:56, Anshuman Khandual a écrit :
On 09/18/2019 09:56 PM, Christophe Leroy wrote:
Le 18/09/2019 à 07:04, Anshuman Khandual a écrit :
On 09/13/2019 03:31 PM, Christophe Leroy wrote:
Le 13/09/2019 à 11:02, Anshuman Khandual a écrit :
+#if !defined(__PAGETABLE_PMD_FOLDED) && !defined(__ARCH_HAS_4LEVEL_HACK)
#ifdefs have to be avoided as much as possible, see below
Yeah but it has been bit difficult to avoid all these $ifdef because of the
availability (or lack of it) for all these pgtable helpers in various config
combinations on all platforms.
As far as I can see these pgtable helpers should exist everywhere at least via
asm-generic/ files.
But they might not actually do the right thing.
Can you spot a particular config which fails ?
Lets consider the following example (after removing the $ifdefs around it)
which though builds successfully but fails to pass the intended test. This
is with arm64 config 4K pages sizes with 39 bits VA space which ends up
with a 3 level page table arrangement.
static void __init p4d_clear_tests(p4d_t *p4dp)
{
p4d_t p4d = READ_ONCE(*p4dp);
My suggestion was not to completely drop the #ifdef but to do like you did in
pgd_clear_tests() for instance, ie to add the following test on top of the
function:
if (mm_pud_folded(mm) || is_defined(__ARCH_HAS_5LEVEL_HACK))
return;
Sometimes this does not really work. On some platforms, combination of
__PAGETABLE_PUD_FOLDED and __ARCH_HAS_5LEVEL_HACK decide whether the
helpers such as __pud() or __pgd() is even available for that platform.
Ideally it should have been through generic falls backs in include/*/
but I guess there might be bugs on the platform or it has not been
changed to adopt 5 level page table framework with required folding
macros etc.
Yes. As I suggested below, most likely that's better to retain the
#ifdef __ARCH_HAS_5LEVEL_HACK but change the #ifdef
__PAGETABLE_PUD_FOLDED by a runtime test of mm_pud_folded(mm)
As pointed by Gerald, some arches don't have __PAGETABLE_PUD_FOLDED
because they are deciding dynamically if they fold the level on not, but
have mm_pud_folded(mm)
p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE);
WRITE_ONCE(*p4dp, p4d);
p4d_clear(p4dp);
p4d = READ_ONCE(*p4dp);
WARN_ON(!p4d_none(p4d));
}
The following test hits an error at WARN_ON(!p4d_none(p4d))
[ 16.757333] [ cut here ]
[ 16.758019] WARNING: CPU: 11 PID: 1 at mm/arch_pgtable_test.c:187
arch_pgtable_tests_init+0x24c/0x474
[...]
[ 16.781282] ---[ end trace 042e6c40c0a3b038 ]---
On arm64 (4K page size|39 bits VA|3 level page table)
#elif CONFIG_PGTABLE_LEVELS == 3 /* Applicable here */
#define __ARCH_USE_5LEVEL_HACK
#include
Which pulls in
#include
which pulls in
#include
which defines
static inline int p4d_none(p4d_t p4d)
{
return 0;
}
which will invariably trigger WARN_ON(!p4d_none(p4d)).
Similarly for next test p4d_populate_tests() which will always be
successful because p4d_bad() invariably returns negative.
static inline int p4d_bad(p4d_t p4d)
{
return 0;
}
static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
pud_t *pudp)
{
p4d_t p4d;
/*
* This entry points to next level page table page.
* Hence this must not qualify as p4d_bad().
*/
pud_clear(pudp);
p4d_clear(p4dp);
p4d_populate(mm, p4dp, pudp);
p4d = READ_ONCE(*p4dp);
WARN_ON(p4d_bad(p4d));
}
We should not run these tests for the above config because they are
not applicable and will invariably produce same result.
[...]
So it shouldn't be an issue. Maybe if a couple of arches miss them, the best
would be to fix the arches, since that's the purpose of your testsuite isn't it
?
The run time failures as explained previously is because of the folding which
needs to be protected as they are not even applicable. The compile time
failures are because pxx_populate() signatures are platform specific depending
on how many page table levels they really support.
So IIUC, the compiletime problem is around __ARCH_HAS_5LEVEL_HACK. For all #if
!defined(__PAGETABLE_PXX_FOLDED), something equivalent to the following should
make the trick.
if (mm_pxx_folded())
return;
For the __ARCH_HAS_5LEVEL_HACK stuff, I think we should be able to regroup all
impacted functions inside a single #ifdef __ARCH_HAS_5LEVEL_HACK
I was wondering if it will be better to
1) Minimize all #ifdefs in the code which might fail on some platforms
2) Restrict proposed test module to platforms where it builds and runs
3) Enable other platforms afterwards after fixing their build problems or other
requirements
I understand that __ARCH_HAS_5LEVEL_HACK is an HACK as its name
suggests, so you can't expect all platforms to go for an
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
On 09/18/2019 09:56 PM, Christophe Leroy wrote:
>
>
> Le 18/09/2019 à 07:04, Anshuman Khandual a écrit :
>>
>>
>> On 09/13/2019 03:31 PM, Christophe Leroy wrote:
>>>
>>>
>>> Le 13/09/2019 à 11:02, Anshuman Khandual a écrit :
>> +#if !defined(__PAGETABLE_PMD_FOLDED) && !defined(__ARCH_HAS_4LEVEL_HACK)
>
> #ifdefs have to be avoided as much as possible, see below
Yeah but it has been bit difficult to avoid all these $ifdef because of the
availability (or lack of it) for all these pgtable helpers in various
config
combinations on all platforms.
>>>
>>> As far as I can see these pgtable helpers should exist everywhere at least
>>> via asm-generic/ files.
>>
>> But they might not actually do the right thing.
>>
>>>
>>> Can you spot a particular config which fails ?
>>
>> Lets consider the following example (after removing the $ifdefs around it)
>> which though builds successfully but fails to pass the intended test. This
>> is with arm64 config 4K pages sizes with 39 bits VA space which ends up
>> with a 3 level page table arrangement.
>>
>> static void __init p4d_clear_tests(p4d_t *p4dp)
>> {
>> p4d_t p4d = READ_ONCE(*p4dp);
>
> My suggestion was not to completely drop the #ifdef but to do like you did in
> pgd_clear_tests() for instance, ie to add the following test on top of the
> function:
>
> if (mm_pud_folded(mm) || is_defined(__ARCH_HAS_5LEVEL_HACK))
> return;
>
Sometimes this does not really work. On some platforms, combination of
__PAGETABLE_PUD_FOLDED and __ARCH_HAS_5LEVEL_HACK decide whether the
helpers such as __pud() or __pgd() is even available for that platform.
Ideally it should have been through generic falls backs in include/*/
but I guess there might be bugs on the platform or it has not been
changed to adopt 5 level page table framework with required folding
macros etc.
>>
>> p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE);
>> WRITE_ONCE(*p4dp, p4d);
>> p4d_clear(p4dp);
>> p4d = READ_ONCE(*p4dp);
>> WARN_ON(!p4d_none(p4d));
>> }
>>
>> The following test hits an error at WARN_ON(!p4d_none(p4d))
>>
>> [ 16.757333] [ cut here ]
>> [ 16.758019] WARNING: CPU: 11 PID: 1 at mm/arch_pgtable_test.c:187
>> arch_pgtable_tests_init+0x24c/0x474
>> [ 16.759455] Modules linked in:
>> [ 16.759952] CPU: 11 PID: 1 Comm: swapper/0 Not tainted
>> 5.3.0-next-20190916-5-g61c218153bb8-dirty #222
>> [ 16.761449] Hardware name: linux,dummy-virt (DT)
>> [ 16.762185] pstate: 0045 (nzcv daif +PAN -UAO)
>> [ 16.762964] pc : arch_pgtable_tests_init+0x24c/0x474
>> [ 16.763750] lr : arch_pgtable_tests_init+0x174/0x474
>> [ 16.764534] sp : ffc011d7bd50
>> [ 16.765065] x29: ffc011d7bd50 x28: 1756bac0
>> [ 16.765908] x27: ff85ddaf3000 x26: 02e8
>> [ 16.766767] x25: ffc0111ce000 x24: ff85ddaf32e8
>> [ 16.767606] x23: ff85ddaef278 x22: 0045cc844000
>> [ 16.768445] x21: 00065daef003 x20: 1754
>> [ 16.769283] x19: ff85ddb6 x18: 0014
>> [ 16.770122] x17: 980426bb x16: 698594c6
>> [ 16.770976] x15: 66e25a88 x14:
>> [ 16.771813] x13: 1754 x12: 000a
>> [ 16.772651] x11: ff85fcfd0a40 x10: 0001
>> [ 16.773488] x9 : 0008 x8 : ffc01143ab26
>> [ 16.774336] x7 : x6 :
>> [ 16.775180] x5 : x4 :
>> [ 16.776018] x3 : 1756bbe8 x2 : 00065daeb003
>> [ 16.776856] x1 : 0065daeb x0 : f000
>> [ 16.777693] Call trace:
>> [ 16.778092] arch_pgtable_tests_init+0x24c/0x474
>> [ 16.778843] do_one_initcall+0x74/0x1b0
>> [ 16.779458] kernel_init_freeable+0x1cc/0x290
>> [ 16.780151] kernel_init+0x10/0x100
>> [ 16.780710] ret_from_fork+0x10/0x18
>> [ 16.781282] ---[ end trace 042e6c40c0a3b038 ]---
>>
>> On arm64 (4K page size|39 bits VA|3 level page table)
>>
>> #elif CONFIG_PGTABLE_LEVELS == 3 /* Applicable here */
>> #define __ARCH_USE_5LEVEL_HACK
>> #include
>>
>> Which pulls in
>>
>> #include
>>
>> which pulls in
>>
>> #include
>>
>> which defines
>>
>> static inline int p4d_none(p4d_t p4d)
>> {
>> return 0;
>> }
>>
>> which will invariably trigger WARN_ON(!p4d_none(p4d)).
>>
>> Similarly for next test p4d_populate_tests() which will always be
>> successful because p4d_bad() invariably returns negative.
>>
>> static inline int p4d_bad(p4d_t p4d)
>> {
>> return 0;
>> }
>>
>> static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
>> pud_t *pudp)
>> {
>> p4d_t p4d;
>>
>> /*
>> * This entry points to next level page table page.
>> * Hence this must not qualify as p4d_bad().
>> */
>> pud_clear(pudp);
>> p4d_clear(p4dp);
>>
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
On Wed, 18 Sep 2019 18:26:03 +0200 Christophe Leroy wrote: [..] > My suggestion was not to completely drop the #ifdef but to do like you > did in pgd_clear_tests() for instance, ie to add the following test on > top of the function: > > if (mm_pud_folded(mm) || is_defined(__ARCH_HAS_5LEVEL_HACK)) > return; > Ah, very nice, this would also fix the remaining issues for s390. Since we have dynamic page table folding, neither __PAGETABLE_PXX_FOLDED nor __ARCH_HAS_XLEVEL_HACK is defined, but mm_pxx_folded() will work. mm_alloc() returns with a 3-level page table by default on s390, so we will run into issues in p4d_clear/populate_tests(), and also at the end with p4d/pud_free() (double free). So, adding the mm_pud_folded() check to p4d_clear/populate_tests(), and also adding mm_p4d/pud_folded() checks at the end before calling p4d/pud_free(), would make it all work on s390. BTW, regarding p4d/pud_free(), I'm not sure if we should rather check the folding inside our s390 functions, similar to how we do it for p4d/pud_free_tlb(), instead of relying on not being called for folded p4d/pud. So far, I see no problem with this behavior, all callers of p4d/pud_free() should be fine because of our folding check within p4d/pud_present/none(). But that doesn't mean that it is correct not to check for the folding inside p4d/pud_free(). At least, with this test module we do now have a caller of p4d/pud_free() on potentially folded entries, so instead of adding pxx_folded() checks to this test module, we could add them to our p4d/pud_free() functions. Any thoughts on this? Regards, Gerald ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
Le 18/09/2019 à 07:04, Anshuman Khandual a écrit :
On 09/13/2019 03:31 PM, Christophe Leroy wrote:
Le 13/09/2019 à 11:02, Anshuman Khandual a écrit :
+#if !defined(__PAGETABLE_PMD_FOLDED) && !defined(__ARCH_HAS_4LEVEL_HACK)
#ifdefs have to be avoided as much as possible, see below
Yeah but it has been bit difficult to avoid all these $ifdef because of the
availability (or lack of it) for all these pgtable helpers in various config
combinations on all platforms.
As far as I can see these pgtable helpers should exist everywhere at least via
asm-generic/ files.
But they might not actually do the right thing.
Can you spot a particular config which fails ?
Lets consider the following example (after removing the $ifdefs around it)
which though builds successfully but fails to pass the intended test. This
is with arm64 config 4K pages sizes with 39 bits VA space which ends up
with a 3 level page table arrangement.
static void __init p4d_clear_tests(p4d_t *p4dp)
{
p4d_t p4d = READ_ONCE(*p4dp);
My suggestion was not to completely drop the #ifdef but to do like you
did in pgd_clear_tests() for instance, ie to add the following test on
top of the function:
if (mm_pud_folded(mm) || is_defined(__ARCH_HAS_5LEVEL_HACK))
return;
p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE);
WRITE_ONCE(*p4dp, p4d);
p4d_clear(p4dp);
p4d = READ_ONCE(*p4dp);
WARN_ON(!p4d_none(p4d));
}
The following test hits an error at WARN_ON(!p4d_none(p4d))
[ 16.757333] [ cut here ]
[ 16.758019] WARNING: CPU: 11 PID: 1 at mm/arch_pgtable_test.c:187
arch_pgtable_tests_init+0x24c/0x474
[ 16.759455] Modules linked in:
[ 16.759952] CPU: 11 PID: 1 Comm: swapper/0 Not tainted
5.3.0-next-20190916-5-g61c218153bb8-dirty #222
[ 16.761449] Hardware name: linux,dummy-virt (DT)
[ 16.762185] pstate: 0045 (nzcv daif +PAN -UAO)
[ 16.762964] pc : arch_pgtable_tests_init+0x24c/0x474
[ 16.763750] lr : arch_pgtable_tests_init+0x174/0x474
[ 16.764534] sp : ffc011d7bd50
[ 16.765065] x29: ffc011d7bd50 x28: 1756bac0
[ 16.765908] x27: ff85ddaf3000 x26: 02e8
[ 16.766767] x25: ffc0111ce000 x24: ff85ddaf32e8
[ 16.767606] x23: ff85ddaef278 x22: 0045cc844000
[ 16.768445] x21: 00065daef003 x20: 1754
[ 16.769283] x19: ff85ddb6 x18: 0014
[ 16.770122] x17: 980426bb x16: 698594c6
[ 16.770976] x15: 66e25a88 x14:
[ 16.771813] x13: 1754 x12: 000a
[ 16.772651] x11: ff85fcfd0a40 x10: 0001
[ 16.773488] x9 : 0008 x8 : ffc01143ab26
[ 16.774336] x7 : x6 :
[ 16.775180] x5 : x4 :
[ 16.776018] x3 : 1756bbe8 x2 : 00065daeb003
[ 16.776856] x1 : 0065daeb x0 : f000
[ 16.777693] Call trace:
[ 16.778092] arch_pgtable_tests_init+0x24c/0x474
[ 16.778843] do_one_initcall+0x74/0x1b0
[ 16.779458] kernel_init_freeable+0x1cc/0x290
[ 16.780151] kernel_init+0x10/0x100
[ 16.780710] ret_from_fork+0x10/0x18
[ 16.781282] ---[ end trace 042e6c40c0a3b038 ]---
On arm64 (4K page size|39 bits VA|3 level page table)
#elif CONFIG_PGTABLE_LEVELS == 3/* Applicable here */
#define __ARCH_USE_5LEVEL_HACK
#include
Which pulls in
#include
which pulls in
#include
which defines
static inline int p4d_none(p4d_t p4d)
{
return 0;
}
which will invariably trigger WARN_ON(!p4d_none(p4d)).
Similarly for next test p4d_populate_tests() which will always be
successful because p4d_bad() invariably returns negative.
static inline int p4d_bad(p4d_t p4d)
{
return 0;
}
static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
pud_t *pudp)
{
p4d_t p4d;
/*
* This entry points to next level page table page.
* Hence this must not qualify as p4d_bad().
*/
pud_clear(pudp);
p4d_clear(p4dp);
p4d_populate(mm, p4dp, pudp);
p4d = READ_ONCE(*p4dp);
WARN_ON(p4d_bad(p4d));
}
We should not run these tests for the above config because they are
not applicable and will invariably produce same result.
[...]
+#if !defined(__PAGETABLE_PUD_FOLDED) && !defined(__ARCH_HAS_5LEVEL_HACK)
The same can be done here.
IIRC not only the page table helpers but there are data types (pxx_t) which
were not present on various configs and these wrappers help prevent build
failures. Any ways will try and see if this can be improved further. But
meanwhile if you have some suggestions, please do let me know.
pgt_t and pmd_t are everywhere I guess.
then pud_t and p4d_t have fallbacks in asm-generic files.
Lets take another example where it fails to compile. On arm64 with 16K
page size, 48 bits VA, 4
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
On 09/13/2019 03:31 PM, Christophe Leroy wrote:
>
>
> Le 13/09/2019 à 11:02, Anshuman Khandual a écrit :
>>
+#if !defined(__PAGETABLE_PMD_FOLDED) && !defined(__ARCH_HAS_4LEVEL_HACK)
>>>
>>> #ifdefs have to be avoided as much as possible, see below
>>
>> Yeah but it has been bit difficult to avoid all these $ifdef because of the
>> availability (or lack of it) for all these pgtable helpers in various config
>> combinations on all platforms.
>
> As far as I can see these pgtable helpers should exist everywhere at least
> via asm-generic/ files.
But they might not actually do the right thing.
>
> Can you spot a particular config which fails ?
Lets consider the following example (after removing the $ifdefs around it)
which though builds successfully but fails to pass the intended test. This
is with arm64 config 4K pages sizes with 39 bits VA space which ends up
with a 3 level page table arrangement.
static void __init p4d_clear_tests(p4d_t *p4dp)
{
p4d_t p4d = READ_ONCE(*p4dp);
p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE);
WRITE_ONCE(*p4dp, p4d);
p4d_clear(p4dp);
p4d = READ_ONCE(*p4dp);
WARN_ON(!p4d_none(p4d));
}
The following test hits an error at WARN_ON(!p4d_none(p4d))
[ 16.757333] [ cut here ]
[ 16.758019] WARNING: CPU: 11 PID: 1 at mm/arch_pgtable_test.c:187
arch_pgtable_tests_init+0x24c/0x474
[ 16.759455] Modules linked in:
[ 16.759952] CPU: 11 PID: 1 Comm: swapper/0 Not tainted
5.3.0-next-20190916-5-g61c218153bb8-dirty #222
[ 16.761449] Hardware name: linux,dummy-virt (DT)
[ 16.762185] pstate: 0045 (nzcv daif +PAN -UAO)
[ 16.762964] pc : arch_pgtable_tests_init+0x24c/0x474
[ 16.763750] lr : arch_pgtable_tests_init+0x174/0x474
[ 16.764534] sp : ffc011d7bd50
[ 16.765065] x29: ffc011d7bd50 x28: 1756bac0
[ 16.765908] x27: ff85ddaf3000 x26: 02e8
[ 16.766767] x25: ffc0111ce000 x24: ff85ddaf32e8
[ 16.767606] x23: ff85ddaef278 x22: 0045cc844000
[ 16.768445] x21: 00065daef003 x20: 1754
[ 16.769283] x19: ff85ddb6 x18: 0014
[ 16.770122] x17: 980426bb x16: 698594c6
[ 16.770976] x15: 66e25a88 x14:
[ 16.771813] x13: 1754 x12: 000a
[ 16.772651] x11: ff85fcfd0a40 x10: 0001
[ 16.773488] x9 : 0008 x8 : ffc01143ab26
[ 16.774336] x7 : x6 :
[ 16.775180] x5 : x4 :
[ 16.776018] x3 : 1756bbe8 x2 : 00065daeb003
[ 16.776856] x1 : 0065daeb x0 : f000
[ 16.777693] Call trace:
[ 16.778092] arch_pgtable_tests_init+0x24c/0x474
[ 16.778843] do_one_initcall+0x74/0x1b0
[ 16.779458] kernel_init_freeable+0x1cc/0x290
[ 16.780151] kernel_init+0x10/0x100
[ 16.780710] ret_from_fork+0x10/0x18
[ 16.781282] ---[ end trace 042e6c40c0a3b038 ]---
On arm64 (4K page size|39 bits VA|3 level page table)
#elif CONFIG_PGTABLE_LEVELS == 3/* Applicable here */
#define __ARCH_USE_5LEVEL_HACK
#include
Which pulls in
#include
which pulls in
#include
which defines
static inline int p4d_none(p4d_t p4d)
{
return 0;
}
which will invariably trigger WARN_ON(!p4d_none(p4d)).
Similarly for next test p4d_populate_tests() which will always be
successful because p4d_bad() invariably returns negative.
static inline int p4d_bad(p4d_t p4d)
{
return 0;
}
static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp,
pud_t *pudp)
{
p4d_t p4d;
/*
* This entry points to next level page table page.
* Hence this must not qualify as p4d_bad().
*/
pud_clear(pudp);
p4d_clear(p4dp);
p4d_populate(mm, p4dp, pudp);
p4d = READ_ONCE(*p4dp);
WARN_ON(p4d_bad(p4d));
}
We should not run these tests for the above config because they are
not applicable and will invariably produce same result.
>
>>
>>>
>
> [...]
>
+#if !defined(__PAGETABLE_PUD_FOLDED) && !defined(__ARCH_HAS_5LEVEL_HACK)
>>>
>>> The same can be done here.
>>
>> IIRC not only the page table helpers but there are data types (pxx_t) which
>> were not present on various configs and these wrappers help prevent build
>> failures. Any ways will try and see if this can be improved further. But
>> meanwhile if you have some suggestions, please do let me know.
>
> pgt_t and pmd_t are everywhere I guess.
> then pud_t and p4d_t have fallbacks in asm-generic files.
Lets take another example where it fails to compile. On arm64 with 16K
page size, 48 bits VA, 4 level page table arrangement in the following
test, pgd_populate() does not have the required signature.
static void pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, p4d_t *p4dp)
{
pgd_t pgd;
if (mm_p4d_folded(mm))
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
Le 13/09/2019 à 11:02, Anshuman Khandual a écrit : +#if !defined(__PAGETABLE_PMD_FOLDED) && !defined(__ARCH_HAS_4LEVEL_HACK) #ifdefs have to be avoided as much as possible, see below Yeah but it has been bit difficult to avoid all these $ifdef because of the availability (or lack of it) for all these pgtable helpers in various config combinations on all platforms. As far as I can see these pgtable helpers should exist everywhere at least via asm-generic/ files. Can you spot a particular config which fails ? [...] +#if !defined(__PAGETABLE_PUD_FOLDED) && !defined(__ARCH_HAS_5LEVEL_HACK) The same can be done here. IIRC not only the page table helpers but there are data types (pxx_t) which were not present on various configs and these wrappers help prevent build failures. Any ways will try and see if this can be improved further. But meanwhile if you have some suggestions, please do let me know. pgt_t and pmd_t are everywhere I guess. then pud_t and p4d_t have fallbacks in asm-generic files. So it shouldn't be an issue. Maybe if a couple of arches miss them, the best would be to fix the arches, since that's the purpose of your testsuite isn't it ? Christophe ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
On Fri, Sep 13, 2019 at 02:32:04PM +0530, Anshuman Khandual wrote: > > On 09/12/2019 10:44 PM, Christophe Leroy wrote: > > > > > > Le 12/09/2019 à 08:02, Anshuman Khandual a écrit : > >> This adds a test module which will validate architecture page table helpers > >> and accessors regarding compliance with generic MM semantics expectations. > >> This will help various architectures in validating changes to the existing > >> page table helpers or addition of new ones. > >> > >> Test page table and memory pages creating it's entries at various level are > >> all allocated from system memory with required alignments. If memory pages > >> with required size and alignment could not be allocated, then all depending > >> individual tests are skipped. > >> > > > > [...] > > > >> > >> Suggested-by: Catalin Marinas > >> Signed-off-by: Anshuman Khandual > >> --- > >> arch/x86/include/asm/pgtable_64_types.h | 2 + > >> mm/Kconfig.debug | 14 + > >> mm/Makefile | 1 + > >> mm/arch_pgtable_test.c | 429 > >> 4 files changed, 446 insertions(+) > >> create mode 100644 mm/arch_pgtable_test.c > >> > >> diff --git a/arch/x86/include/asm/pgtable_64_types.h > >> b/arch/x86/include/asm/pgtable_64_types.h > >> index 52e5f5f2240d..b882792a3999 100644 > >> --- a/arch/x86/include/asm/pgtable_64_types.h > >> +++ b/arch/x86/include/asm/pgtable_64_types.h > >> @@ -40,6 +40,8 @@ static inline bool pgtable_l5_enabled(void) > >> #define pgtable_l5_enabled() 0 > >> #endif /* CONFIG_X86_5LEVEL */ > >> +#define mm_p4d_folded(mm) (!pgtable_l5_enabled()) > >> + > > > > This is specific to x86, should go in a separate patch. > > Thought about it but its just a single line. Kirill suggested this in the > previous version. There is a generic fallback definition but s390 has it's > own. This change overrides the generic one for x86 probably as a fix or as > an improvement. Kirill should be able to help classify it in which case it > can be a separate patch. I don't think it worth a separate patch. -- Kirill A. Shutemov ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
On 09/12/2019 10:44 PM, Christophe Leroy wrote: > > > Le 12/09/2019 à 08:02, Anshuman Khandual a écrit : >> This adds a test module which will validate architecture page table helpers >> and accessors regarding compliance with generic MM semantics expectations. >> This will help various architectures in validating changes to the existing >> page table helpers or addition of new ones. >> >> Test page table and memory pages creating it's entries at various level are >> all allocated from system memory with required alignments. If memory pages >> with required size and alignment could not be allocated, then all depending >> individual tests are skipped. >> > > [...] > >> >> Suggested-by: Catalin Marinas >> Signed-off-by: Anshuman Khandual >> --- >> arch/x86/include/asm/pgtable_64_types.h | 2 + >> mm/Kconfig.debug | 14 + >> mm/Makefile | 1 + >> mm/arch_pgtable_test.c | 429 >> 4 files changed, 446 insertions(+) >> create mode 100644 mm/arch_pgtable_test.c >> >> diff --git a/arch/x86/include/asm/pgtable_64_types.h >> b/arch/x86/include/asm/pgtable_64_types.h >> index 52e5f5f2240d..b882792a3999 100644 >> --- a/arch/x86/include/asm/pgtable_64_types.h >> +++ b/arch/x86/include/asm/pgtable_64_types.h >> @@ -40,6 +40,8 @@ static inline bool pgtable_l5_enabled(void) >> #define pgtable_l5_enabled() 0 >> #endif /* CONFIG_X86_5LEVEL */ >> +#define mm_p4d_folded(mm) (!pgtable_l5_enabled()) >> + > > This is specific to x86, should go in a separate patch. Thought about it but its just a single line. Kirill suggested this in the previous version. There is a generic fallback definition but s390 has it's own. This change overrides the generic one for x86 probably as a fix or as an improvement. Kirill should be able to help classify it in which case it can be a separate patch. > >> extern unsigned int pgdir_shift; >> extern unsigned int ptrs_per_p4d; >> diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug >> index 327b3ebf23bf..ce9c397f7b07 100644 >> --- a/mm/Kconfig.debug >> +++ b/mm/Kconfig.debug >> @@ -117,3 +117,17 @@ config DEBUG_RODATA_TEST >> depends on STRICT_KERNEL_RWX >> ---help--- >> This option enables a testcase for the setting rodata read-only. >> + >> +config DEBUG_ARCH_PGTABLE_TEST >> + bool "Test arch page table helpers for semantics compliance" >> + depends on MMU >> + depends on DEBUG_KERNEL >> + help >> + This options provides a kernel module which can be used to test >> + architecture page table helper functions on various platform in >> + verifying if they comply with expected generic MM semantics. This >> + will help architectures code in making sure that any changes or >> + new additions of these helpers will still conform to generic MM >> + expected semantics. >> + >> + If unsure, say N. >> diff --git a/mm/Makefile b/mm/Makefile >> index d996846697ef..bb572c5aa8c5 100644 >> --- a/mm/Makefile >> +++ b/mm/Makefile >> @@ -86,6 +86,7 @@ obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o >> obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o >> obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o >> obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o >> +obj-$(CONFIG_DEBUG_ARCH_PGTABLE_TEST) += arch_pgtable_test.o >> obj-$(CONFIG_PAGE_OWNER) += page_owner.o >> obj-$(CONFIG_CLEANCACHE) += cleancache.o >> obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o >> diff --git a/mm/arch_pgtable_test.c b/mm/arch_pgtable_test.c >> new file mode 100644 >> index ..8b4a92756ad8 >> --- /dev/null >> +++ b/mm/arch_pgtable_test.c >> @@ -0,0 +1,429 @@ >> +// SPDX-License-Identifier: GPL-2.0-only >> +/* >> + * This kernel module validates architecture page table helpers & >> + * accessors and helps in verifying their continued compliance with >> + * generic MM semantics. >> + * >> + * Copyright (C) 2019 ARM Ltd. >> + * >> + * Author: Anshuman Khandual >> + */ >> +#define pr_fmt(fmt) "arch_pgtable_test: %s " fmt, __func__ >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include > > Add (see other mails, build failure on ppc book3s/32) Okay. > >> +#include >> +#include >> + >> +/* >> + * Basic operations >> + * >> + * mkold(entry) = An old and not a young entry >> + * mkyoung(entry) = A young and not an old entry >> + * mkdirty(entry) = A dirty and not a clean entry >> + * mkclean(entry) = A clean and not a dirty entry >> + * mkwrite(entry) = A write and not a write protected entry >> + * wrprotect(entry) = A write protected and not a write entry >> + * pxx_bad(entry) = A mapped and non-table entry >> + * pxx_same(entry1, entry2) = Both entries hold the exact same value >> + */ >> +#define VMFLAGS
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
Le 12/09/2019 à 17:52, Christophe Leroy a écrit : Le 12/09/2019 à 17:36, Christophe Leroy a écrit : Le 12/09/2019 à 17:00, Christophe Leroy a écrit : On 09/12/2019 06:02 AM, Anshuman Khandual wrote: This adds a test module which will validate architecture page table helpers and accessors regarding compliance with generic MM semantics expectations. This will help various architectures in validating changes to the existing page table helpers or addition of new ones. Test page table and memory pages creating it's entries at various level are all allocated from system memory with required alignments. If memory pages with required size and alignment could not be allocated, then all depending individual tests are skipped. Build failure on powerpc book3s/32. This is because asm/highmem.h is missing. It can't be included from asm/book3s/32/pgtable.h because it creates circular dependency. So it has to be included from mm/arch_pgtable_test.c In fact it is that needs to be added, adding directly provokes build failure at link time. I get the following failure, [ 0.704685] [ cut here ] [ 0.709239] initcall arch_pgtable_tests_init+0x0/0x228 returned with preemption imbalance preempt_disable() is called from kmap_atomic() which is called from pte_alloc_map() via pte_offset_map(). pte_unmap() has to be called to release the mapped pte and re-enable preemtion. Christophe [ 0.717539] WARNING: CPU: 0 PID: 1 at init/main.c:952 do_one_initcall+0x18c/0x1d4 [ 0.724922] CPU: 0 PID: 1 Comm: swapper Not tainted 5.3.0-rc7-s3k-dev-00880-g28fd02a838e5-dirty #2307 [ 0.734070] NIP: c070e674 LR: c070e674 CTR: c001292c [ 0.739084] REGS: df4a5dd0 TRAP: 0700 Not tainted (5.3.0-rc7-s3k-dev-00880-g28fd02a838e5-dirty) [ 0.747975] MSR: 00029032 CR: 28000222 XER: [ 0.754628] [ 0.754628] GPR00: c070e674 df4a5e88 df4a 004e 000a 00ca 38207265 [ 0.754628] GPR08: 1032 0800 22000422 c0004a7c [ 0.754628] GPR16: c081 c080 c0816f30 [ 0.754628] GPR24: c070dc20 c074702c 0006 009c c0724494 c074e140 [ 0.789339] NIP [c070e674] do_one_initcall+0x18c/0x1d4 [ 0.794435] LR [c070e674] do_one_initcall+0x18c/0x1d4 [ 0.799437] Call Trace: [ 0.801867] [df4a5e88] [c070e674] do_one_initcall+0x18c/0x1d4 (unreliable) [ 0.808694] [df4a5ee8] [c070e8c0] kernel_init_freeable+0x204/0x2dc [ 0.814830] [df4a5f28] [c0004a94] kernel_init+0x18/0x110 [ 0.820107] [df4a5f38] [c00122ac] ret_from_kernel_thread+0x14/0x1c [ 0.826220] Instruction dump: [ 0.829161] 4beb1069 7d2000a6 61298000 7d200124 89210008 2f89 41be0048 3c60c06a [ 0.836849] 38a10008 7fa4eb78 3863cacc 4b915115 <0fe0> 482c 81220070 712a0004 [ 0.844723] ---[ end trace 969d686308d40b33 ]--- Then starting init fails: [ 3.894074] Run /init as init process [ 3.898403] Failed to execute /init (error -14) [ 3.903009] Run /sbin/init as init process [ 3.907172] Run /etc/init as init process [ 3.911251] Run /bin/init as init process [ 3.915513] Run /bin/sh as init process [ 3.919471] Starting init: /bin/sh exists but couldn't execute it (error -14) [ 3.926732] Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance. [ 3.940864] CPU: 0 PID: 1 Comm: init Tainted: G W 5.3.0-rc7-s3k-dev-00880-g28fd02a838e5-dirty #2307 [ 3.951165] Call Trace: [ 3.953617] [df4a5ec8] [c002392c] panic+0x12c/0x320 (unreliable) [ 3.959621] [df4a5f28] [c0004b8c] rootfs_mount+0x0/0x2c [ 3.964849] [df4a5f38] [c00122ac] ret_from_kernel_thread+0x14/0x1c Christophe ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
Le 12/09/2019 à 08:02, Anshuman Khandual a écrit :
This adds a test module which will validate architecture page table helpers
and accessors regarding compliance with generic MM semantics expectations.
This will help various architectures in validating changes to the existing
page table helpers or addition of new ones.
Test page table and memory pages creating it's entries at various level are
all allocated from system memory with required alignments. If memory pages
with required size and alignment could not be allocated, then all depending
individual tests are skipped.
[...]
Suggested-by: Catalin Marinas
Signed-off-by: Anshuman Khandual
---
arch/x86/include/asm/pgtable_64_types.h | 2 +
mm/Kconfig.debug| 14 +
mm/Makefile | 1 +
mm/arch_pgtable_test.c | 429
4 files changed, 446 insertions(+)
create mode 100644 mm/arch_pgtable_test.c
diff --git a/arch/x86/include/asm/pgtable_64_types.h
b/arch/x86/include/asm/pgtable_64_types.h
index 52e5f5f2240d..b882792a3999 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -40,6 +40,8 @@ static inline bool pgtable_l5_enabled(void)
#define pgtable_l5_enabled() 0
#endif /* CONFIG_X86_5LEVEL */
+#define mm_p4d_folded(mm) (!pgtable_l5_enabled())
+
This is specific to x86, should go in a separate patch.
extern unsigned int pgdir_shift;
extern unsigned int ptrs_per_p4d;
diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug
index 327b3ebf23bf..ce9c397f7b07 100644
--- a/mm/Kconfig.debug
+++ b/mm/Kconfig.debug
@@ -117,3 +117,17 @@ config DEBUG_RODATA_TEST
depends on STRICT_KERNEL_RWX
---help---
This option enables a testcase for the setting rodata read-only.
+
+config DEBUG_ARCH_PGTABLE_TEST
+ bool "Test arch page table helpers for semantics compliance"
+ depends on MMU
+ depends on DEBUG_KERNEL
+ help
+ This options provides a kernel module which can be used to test
+ architecture page table helper functions on various platform in
+ verifying if they comply with expected generic MM semantics. This
+ will help architectures code in making sure that any changes or
+ new additions of these helpers will still conform to generic MM
+ expected semantics.
+
+ If unsure, say N.
diff --git a/mm/Makefile b/mm/Makefile
index d996846697ef..bb572c5aa8c5 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -86,6 +86,7 @@ obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o
obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o
+obj-$(CONFIG_DEBUG_ARCH_PGTABLE_TEST) += arch_pgtable_test.o
obj-$(CONFIG_PAGE_OWNER) += page_owner.o
obj-$(CONFIG_CLEANCACHE) += cleancache.o
obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
diff --git a/mm/arch_pgtable_test.c b/mm/arch_pgtable_test.c
new file mode 100644
index ..8b4a92756ad8
--- /dev/null
+++ b/mm/arch_pgtable_test.c
@@ -0,0 +1,429 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This kernel module validates architecture page table helpers &
+ * accessors and helps in verifying their continued compliance with
+ * generic MM semantics.
+ *
+ * Copyright (C) 2019 ARM Ltd.
+ *
+ * Author: Anshuman Khandual
+ */
+#define pr_fmt(fmt) "arch_pgtable_test: %s " fmt, __func__
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
Add (see other mails, build failure on ppc book3s/32)
+#include
+#include
+
+/*
+ * Basic operations
+ *
+ * mkold(entry)= An old and not a young entry
+ * mkyoung(entry) = A young and not an old entry
+ * mkdirty(entry) = A dirty and not a clean entry
+ * mkclean(entry) = A clean and not a dirty entry
+ * mkwrite(entry) = A write and not a write protected entry
+ * wrprotect(entry)= A write protected and not a write entry
+ * pxx_bad(entry) = A mapped and non-table entry
+ * pxx_same(entry1, entry2)= Both entries hold the exact same value
+ */
+#define VMFLAGS(VM_READ|VM_WRITE|VM_EXEC)
+
+/*
+ * On s390 platform, the lower 12 bits are used to identify given page table
+ * entry type and for other arch specific requirements. But these bits might
+ * affect the ability to clear entries with pxx_clear(). So while loading up
+ * the entries skip all lower 12 bits in order to accommodate s390 platform.
+ * It does not have affect any other platform.
+ */
+#define RANDOM_ORVALUE (0xf000UL)
+#define RANDOM_NZVALUE (0xff)
+
+static bool pud_aligned;
+static bool pmd_aligned;
+
+static void pte_basic_tests(struct page *page, pgprot_t prot)
+{
+ pte_t pte = mk_pte(page, prot);
+
+ WARN_ON(!pte_same(pte,
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
Le 12/09/2019 à 17:36, Christophe Leroy a écrit : Le 12/09/2019 à 17:00, Christophe Leroy a écrit : On 09/12/2019 06:02 AM, Anshuman Khandual wrote: This adds a test module which will validate architecture page table helpers and accessors regarding compliance with generic MM semantics expectations. This will help various architectures in validating changes to the existing page table helpers or addition of new ones. Test page table and memory pages creating it's entries at various level are all allocated from system memory with required alignments. If memory pages with required size and alignment could not be allocated, then all depending individual tests are skipped. Build failure on powerpc book3s/32. This is because asm/highmem.h is missing. It can't be included from asm/book3s/32/pgtable.h because it creates circular dependency. So it has to be included from mm/arch_pgtable_test.c In fact it is that needs to be added, adding directly provokes build failure at link time. I get the following failure, [0.704685] [ cut here ] [0.709239] initcall arch_pgtable_tests_init+0x0/0x228 returned with preemption imbalance [0.717539] WARNING: CPU: 0 PID: 1 at init/main.c:952 do_one_initcall+0x18c/0x1d4 [0.724922] CPU: 0 PID: 1 Comm: swapper Not tainted 5.3.0-rc7-s3k-dev-00880-g28fd02a838e5-dirty #2307 [0.734070] NIP: c070e674 LR: c070e674 CTR: c001292c [0.739084] REGS: df4a5dd0 TRAP: 0700 Not tainted (5.3.0-rc7-s3k-dev-00880-g28fd02a838e5-dirty) [0.747975] MSR: 00029032 CR: 28000222 XER: [0.754628] [0.754628] GPR00: c070e674 df4a5e88 df4a 004e 000a 00ca 38207265 [0.754628] GPR08: 1032 0800 22000422 c0004a7c [0.754628] GPR16: c081 c080 c0816f30 [0.754628] GPR24: c070dc20 c074702c 0006 009c c0724494 c074e140 [0.789339] NIP [c070e674] do_one_initcall+0x18c/0x1d4 [0.794435] LR [c070e674] do_one_initcall+0x18c/0x1d4 [0.799437] Call Trace: [0.801867] [df4a5e88] [c070e674] do_one_initcall+0x18c/0x1d4 (unreliable) [0.808694] [df4a5ee8] [c070e8c0] kernel_init_freeable+0x204/0x2dc [0.814830] [df4a5f28] [c0004a94] kernel_init+0x18/0x110 [0.820107] [df4a5f38] [c00122ac] ret_from_kernel_thread+0x14/0x1c [0.826220] Instruction dump: [0.829161] 4beb1069 7d2000a6 61298000 7d200124 89210008 2f89 41be0048 3c60c06a [0.836849] 38a10008 7fa4eb78 3863cacc 4b915115 <0fe0> 482c 81220070 712a0004 [0.844723] ---[ end trace 969d686308d40b33 ]--- Then starting init fails: [3.894074] Run /init as init process [3.898403] Failed to execute /init (error -14) [3.903009] Run /sbin/init as init process [3.907172] Run /etc/init as init process [3.911251] Run /bin/init as init process [3.915513] Run /bin/sh as init process [3.919471] Starting init: /bin/sh exists but couldn't execute it (error -14) [3.926732] Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance. [3.940864] CPU: 0 PID: 1 Comm: init Tainted: GW 5.3.0-rc7-s3k-dev-00880-g28fd02a838e5-dirty #2307 [3.951165] Call Trace: [3.953617] [df4a5ec8] [c002392c] panic+0x12c/0x320 (unreliable) [3.959621] [df4a5f28] [c0004b8c] rootfs_mount+0x0/0x2c [3.964849] [df4a5f38] [c00122ac] ret_from_kernel_thread+0x14/0x1c Christophe ___ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
Le 12/09/2019 à 17:00, Christophe Leroy a écrit : On 09/12/2019 06:02 AM, Anshuman Khandual wrote: This adds a test module which will validate architecture page table helpers and accessors regarding compliance with generic MM semantics expectations. This will help various architectures in validating changes to the existing page table helpers or addition of new ones. Test page table and memory pages creating it's entries at various level are all allocated from system memory with required alignments. If memory pages with required size and alignment could not be allocated, then all depending individual tests are skipped. Build failure on powerpc book3s/32. This is because asm/highmem.h is missing. It can't be included from asm/book3s/32/pgtable.h because it creates circular dependency. So it has to be included from mm/arch_pgtable_test.c In fact it is that needs to be added, adding directly provokes build failure at link time. Christophe CC mm/arch_pgtable_test.o In file included from ./arch/powerpc/include/asm/book3s/pgtable.h:8:0, from ./arch/powerpc/include/asm/pgtable.h:18, from ./include/linux/mm.h:99, from ./arch/powerpc/include/asm/io.h:29, from ./include/linux/io.h:13, from ./include/linux/irq.h:20, from ./arch/powerpc/include/asm/hardirq.h:6, from ./include/linux/hardirq.h:9, from ./include/linux/interrupt.h:11, from ./include/linux/kernel_stat.h:9, from ./include/linux/cgroup.h:26, from ./include/linux/hugetlb.h:9, from mm/arch_pgtable_test.c:14: mm/arch_pgtable_test.c: In function 'arch_pgtable_tests_init': ./arch/powerpc/include/asm/book3s/32/pgtable.h:365:13: error: implicit declaration of function 'kmap_atomic' [-Werror=implicit-function-declaration] ((pte_t *)(kmap_atomic(pmd_page(*(dir))) + \ ^ ./include/linux/mm.h:2008:31: note: in expansion of macro 'pte_offset_map' (pte_alloc(mm, pmd) ? NULL : pte_offset_map(pmd, address)) ^ mm/arch_pgtable_test.c:377:9: note: in expansion of macro 'pte_alloc_map' ptep = pte_alloc_map(mm, pmdp, vaddr); ^ cc1: some warnings being treated as errors make[2]: *** [mm/arch_pgtable_test.o] Error 1 Christophe Cc: Andrew Morton Cc: Vlastimil Babka Cc: Greg Kroah-Hartman Cc: Thomas Gleixner Cc: Mike Rapoport Cc: Jason Gunthorpe Cc: Dan Williams Cc: Peter Zijlstra Cc: Michal Hocko Cc: Mark Rutland Cc: Mark Brown Cc: Steven Price Cc: Ard Biesheuvel Cc: Masahiro Yamada Cc: Kees Cook Cc: Tetsuo Handa Cc: Matthew Wilcox Cc: Sri Krishna chowdary Cc: Dave Hansen Cc: Russell King - ARM Linux Cc: Michael Ellerman Cc: Paul Mackerras Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: "David S. Miller" Cc: Vineet Gupta Cc: James Hogan Cc: Paul Burton Cc: Ralf Baechle Cc: Kirill A. Shutemov Cc: Gerald Schaefer Cc: Christophe Leroy Cc: linux-snps-arc@lists.infradead.org Cc: linux-m...@vger.kernel.org Cc: linux-arm-ker...@lists.infradead.org Cc: linux-i...@vger.kernel.org Cc: linuxppc-...@lists.ozlabs.org Cc: linux-s...@vger.kernel.org Cc: linux...@vger.kernel.org Cc: sparcli...@vger.kernel.org Cc: x...@kernel.org Cc: linux-ker...@vger.kernel.org Suggested-by: Catalin Marinas Signed-off-by: Anshuman Khandual --- arch/x86/include/asm/pgtable_64_types.h | 2 + mm/Kconfig.debug | 14 + mm/Makefile | 1 + mm/arch_pgtable_test.c | 429 4 files changed, 446 insertions(+) create mode 100644 mm/arch_pgtable_test.c diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h index 52e5f5f2240d..b882792a3999 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -40,6 +40,8 @@ static inline bool pgtable_l5_enabled(void) #define pgtable_l5_enabled() 0 #endif /* CONFIG_X86_5LEVEL */ +#define mm_p4d_folded(mm) (!pgtable_l5_enabled()) + extern unsigned int pgdir_shift; extern unsigned int ptrs_per_p4d; diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 327b3ebf23bf..ce9c397f7b07 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -117,3 +117,17 @@ config DEBUG_RODATA_TEST depends on STRICT_KERNEL_RWX ---help--- This option enables a testcase for the setting rodata read-only. + +config DEBUG_ARCH_PGTABLE_TEST + bool "Test arch page table helpers for semantics compliance" + depends on MMU + depends on DEBUG_KERNEL + help + This options provides a kernel module which can be used to test + architecture page table helper functions on various platform in + verifying if they comply with expected generic MM semantics. This + will help architectures code in making sure that any changes or +
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
On 09/12/2019 06:02 AM, Anshuman Khandual wrote: This adds a test module which will validate architecture page table helpers and accessors regarding compliance with generic MM semantics expectations. This will help various architectures in validating changes to the existing page table helpers or addition of new ones. Test page table and memory pages creating it's entries at various level are all allocated from system memory with required alignments. If memory pages with required size and alignment could not be allocated, then all depending individual tests are skipped. Build failure on powerpc book3s/32. This is because asm/highmem.h is missing. It can't be included from asm/book3s/32/pgtable.h because it creates circular dependency. So it has to be included from mm/arch_pgtable_test.c CC mm/arch_pgtable_test.o In file included from ./arch/powerpc/include/asm/book3s/pgtable.h:8:0, from ./arch/powerpc/include/asm/pgtable.h:18, from ./include/linux/mm.h:99, from ./arch/powerpc/include/asm/io.h:29, from ./include/linux/io.h:13, from ./include/linux/irq.h:20, from ./arch/powerpc/include/asm/hardirq.h:6, from ./include/linux/hardirq.h:9, from ./include/linux/interrupt.h:11, from ./include/linux/kernel_stat.h:9, from ./include/linux/cgroup.h:26, from ./include/linux/hugetlb.h:9, from mm/arch_pgtable_test.c:14: mm/arch_pgtable_test.c: In function 'arch_pgtable_tests_init': ./arch/powerpc/include/asm/book3s/32/pgtable.h:365:13: error: implicit declaration of function 'kmap_atomic' [-Werror=implicit-function-declaration] ((pte_t *)(kmap_atomic(pmd_page(*(dir))) + \ ^ ./include/linux/mm.h:2008:31: note: in expansion of macro 'pte_offset_map' (pte_alloc(mm, pmd) ? NULL : pte_offset_map(pmd, address)) ^ mm/arch_pgtable_test.c:377:9: note: in expansion of macro 'pte_alloc_map' ptep = pte_alloc_map(mm, pmdp, vaddr); ^ cc1: some warnings being treated as errors make[2]: *** [mm/arch_pgtable_test.o] Error 1 Christophe Cc: Andrew Morton Cc: Vlastimil Babka Cc: Greg Kroah-Hartman Cc: Thomas Gleixner Cc: Mike Rapoport Cc: Jason Gunthorpe Cc: Dan Williams Cc: Peter Zijlstra Cc: Michal Hocko Cc: Mark Rutland Cc: Mark Brown Cc: Steven Price Cc: Ard Biesheuvel Cc: Masahiro Yamada Cc: Kees Cook Cc: Tetsuo Handa Cc: Matthew Wilcox Cc: Sri Krishna chowdary Cc: Dave Hansen Cc: Russell King - ARM Linux Cc: Michael Ellerman Cc: Paul Mackerras Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: "David S. Miller" Cc: Vineet Gupta Cc: James Hogan Cc: Paul Burton Cc: Ralf Baechle Cc: Kirill A. Shutemov Cc: Gerald Schaefer Cc: Christophe Leroy Cc: linux-snps-arc@lists.infradead.org Cc: linux-m...@vger.kernel.org Cc: linux-arm-ker...@lists.infradead.org Cc: linux-i...@vger.kernel.org Cc: linuxppc-...@lists.ozlabs.org Cc: linux-s...@vger.kernel.org Cc: linux...@vger.kernel.org Cc: sparcli...@vger.kernel.org Cc: x...@kernel.org Cc: linux-ker...@vger.kernel.org Suggested-by: Catalin Marinas Signed-off-by: Anshuman Khandual --- arch/x86/include/asm/pgtable_64_types.h | 2 + mm/Kconfig.debug| 14 + mm/Makefile | 1 + mm/arch_pgtable_test.c | 429 4 files changed, 446 insertions(+) create mode 100644 mm/arch_pgtable_test.c diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h index 52e5f5f2240d..b882792a3999 100644 --- a/arch/x86/include/asm/pgtable_64_types.h +++ b/arch/x86/include/asm/pgtable_64_types.h @@ -40,6 +40,8 @@ static inline bool pgtable_l5_enabled(void) #define pgtable_l5_enabled() 0 #endif /* CONFIG_X86_5LEVEL */ +#define mm_p4d_folded(mm) (!pgtable_l5_enabled()) + extern unsigned int pgdir_shift; extern unsigned int ptrs_per_p4d; diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 327b3ebf23bf..ce9c397f7b07 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -117,3 +117,17 @@ config DEBUG_RODATA_TEST depends on STRICT_KERNEL_RWX ---help--- This option enables a testcase for the setting rodata read-only. + +config DEBUG_ARCH_PGTABLE_TEST + bool "Test arch page table helpers for semantics compliance" + depends on MMU + depends on DEBUG_KERNEL + help + This options provides a kernel module which can be used to test + architecture page table helper functions on various platform in + verifying if they comply with expected generic MM semantics. This + will help architectures code in making sure that any changes or + new additions of these helpers will still conform to generic MM + expected semantics. + + If unsure, say N. diff --git a/mm/Makefile
Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
On 09/12/2019 04:30 PM, Kirill A. Shutemov wrote:
> On Thu, Sep 12, 2019 at 11:32:53AM +0530, Anshuman Khandual wrote:
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR("Anshuman Khandual ");
>> +MODULE_DESCRIPTION("Test architecture page table helpers");
>
> It's not module. Why?
Not any more. Nothing in particular. Just that module_init() code gets
executed after page allocator init which is needed here. But I guess
probably not a great way to get this test started.
>
> BTW, I think we should make all code here __init (or it's variants) so it
> can be discarded on boot. It has not use after that.
Sounds good, will change. Will mark all these functions as __init and
will trigger the test with late_initcall().
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Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
On Thu, Sep 12, 2019 at 11:32:53AM +0530, Anshuman Khandual wrote:
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Anshuman Khandual ");
> +MODULE_DESCRIPTION("Test architecture page table helpers");
It's not module. Why?
BTW, I think we should make all code here __init (or it's variants) so it
can be discarded on boot. It has not use after that.
--
Kirill A. Shutemov
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