| Message ID | 1ef6b954fb7b0f4dfc78820f1e612d2166c13227.1618506910.git.christophe.leroy@csgroup.eu (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Convert powerpc to GENERIC_PTDUMP | expand |
Hi Christophe, > static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, > - u64 val) > + u64 val, unsigned long page_size) Compilers can warn about unused parameters at -Wextra level. However, reading scripts/Makefile.extrawarn it looks like the warning is explicitly _disabled_ in the kernel at W=1 and not reenabled at W=2 or W=3. So I guess this is fine... > @@ -126,7 +126,7 @@ static int ptdump_hole(unsigned long addr, unsigned long next, > { > struct ptdump_state *st = walk->private; > > - st->note_page(st, addr, depth, 0); > + st->note_page(st, addr, depth, 0, 0); I know it doesn't matter at this point, but I'm not really thrilled by the idea of passing 0 as the size here. Doesn't the hole have a known page size? > > return 0; > } > @@ -153,5 +153,5 @@ void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd) > mmap_read_unlock(mm); > > /* Flush out the last page */ > - st->note_page(st, 0, -1, 0); > + st->note_page(st, 0, -1, 0, 0); I'm more OK with the idea of passing 0 as the size when the depth is -1 (don't know): if we don't know the depth we conceptually can't know the page size. Regards, Daniel
Le 16/04/2021 à 01:12, Daniel Axtens a écrit : > Hi Christophe, > >> static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, >> - u64 val) >> + u64 val, unsigned long page_size) > > Compilers can warn about unused parameters at -Wextra level. However, > reading scripts/Makefile.extrawarn it looks like the warning is > explicitly _disabled_ in the kernel at W=1 and not reenabled at W=2 or > W=3. So I guess this is fine... There are a lot lot lot functions having unused parameters in the kernel , especially the ones that are re-implemented by each architecture. > >> @@ -126,7 +126,7 @@ static int ptdump_hole(unsigned long addr, unsigned long next, >> { >> struct ptdump_state *st = walk->private; >> >> - st->note_page(st, addr, depth, 0); >> + st->note_page(st, addr, depth, 0, 0); > > I know it doesn't matter at this point, but I'm not really thrilled by > the idea of passing 0 as the size here. Doesn't the hole have a known > page size? The hole has a size for sure, I don't think we can call it a page size: On powerpc 8xx, we have 4 page sizes: 8M, 512k, 16k and 4k. A page table will cover 4M areas and will contain pages of size 512k, 16k and 4k. A PGD table contains either entries which points to a page table (covering 4M), or two identical consecutive entries pointing to the same hugepd which contains a single PTE for an 8M page. So, if a PGD entry is empty, the hole is 4M, it corresponds to none of the page sizes the architecture supports. But looking at what is done with that size, it can make sense to pass it to notepage() anyway. Let's do that. > >> >> return 0; >> } >> @@ -153,5 +153,5 @@ void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd) >> mmap_read_unlock(mm); >> >> /* Flush out the last page */ >> - st->note_page(st, 0, -1, 0); >> + st->note_page(st, 0, -1, 0, 0); > > I'm more OK with the idea of passing 0 as the size when the depth is -1 > (don't know): if we don't know the depth we conceptually can't know the > page size. > > Regards, > Daniel >
On 15/04/2021 18:18, Christophe Leroy wrote: > In order to support large pages on powerpc, notepage() > needs to know the page size of the page. > > Add a page_size argument to notepage(). > > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > --- > arch/arm64/mm/ptdump.c | 2 +- > arch/riscv/mm/ptdump.c | 2 +- > arch/s390/mm/dump_pagetables.c | 3 ++- > arch/x86/mm/dump_pagetables.c | 2 +- > include/linux/ptdump.h | 2 +- > mm/ptdump.c | 16 ++++++++-------- > 6 files changed, 14 insertions(+), 13 deletions(-) > [...] > diff --git a/mm/ptdump.c b/mm/ptdump.c > index da751448d0e4..61cd16afb1c8 100644 > --- a/mm/ptdump.c > +++ b/mm/ptdump.c > @@ -17,7 +17,7 @@ static inline int note_kasan_page_table(struct mm_walk *walk, > { > struct ptdump_state *st = walk->private; > > - st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0])); > + st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]), PAGE_SIZE); I'm not completely sure what the page_size is going to be used for, but note that KASAN presents an interesting case here. We short-cut by detecting it's a KASAN region at a high level (PGD/P4D/PUD/PMD) and instead of walking the tree down just call note_page() *once* but with level==4 because we know KASAN sets up the page table like that. However the one call actually covers a much larger region - so while PAGE_SIZE matches the level it doesn't match the region covered. AFAICT this will lead to odd results if you enable KASAN on powerpc. To be honest I don't fully understand why powerpc requires the page_size - it appears to be using it purely to find "holes" in the calls to note_page(), but I haven't worked out why such holes would occur. Steve > > walk->action = ACTION_CONTINUE; > > @@ -41,7 +41,7 @@ static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr, > st->effective_prot(st, 0, pgd_val(val)); > > if (pgd_leaf(val)) > - st->note_page(st, addr, 0, pgd_val(val)); > + st->note_page(st, addr, 0, pgd_val(val), PGDIR_SIZE); > > return 0; > } > @@ -62,7 +62,7 @@ static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr, > st->effective_prot(st, 1, p4d_val(val)); > > if (p4d_leaf(val)) > - st->note_page(st, addr, 1, p4d_val(val)); > + st->note_page(st, addr, 1, p4d_val(val), P4D_SIZE); > > return 0; > } > @@ -83,7 +83,7 @@ static int ptdump_pud_entry(pud_t *pud, unsigned long addr, > st->effective_prot(st, 2, pud_val(val)); > > if (pud_leaf(val)) > - st->note_page(st, addr, 2, pud_val(val)); > + st->note_page(st, addr, 2, pud_val(val), PUD_SIZE); > > return 0; > } > @@ -102,7 +102,7 @@ static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr, > if (st->effective_prot) > st->effective_prot(st, 3, pmd_val(val)); > if (pmd_leaf(val)) > - st->note_page(st, addr, 3, pmd_val(val)); > + st->note_page(st, addr, 3, pmd_val(val), PMD_SIZE); > > return 0; > } > @@ -116,7 +116,7 @@ static int ptdump_pte_entry(pte_t *pte, unsigned long addr, > if (st->effective_prot) > st->effective_prot(st, 4, pte_val(val)); > > - st->note_page(st, addr, 4, pte_val(val)); > + st->note_page(st, addr, 4, pte_val(val), PAGE_SIZE); > > return 0; > } > @@ -126,7 +126,7 @@ static int ptdump_hole(unsigned long addr, unsigned long next, > { > struct ptdump_state *st = walk->private; > > - st->note_page(st, addr, depth, 0); > + st->note_page(st, addr, depth, 0, 0); > > return 0; > } > @@ -153,5 +153,5 @@ void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd) > mmap_read_unlock(mm); > > /* Flush out the last page */ > - st->note_page(st, 0, -1, 0); > + st->note_page(st, 0, -1, 0, 0); > } >
Le 16/04/2021 à 11:28, Steven Price a écrit : > On 15/04/2021 18:18, Christophe Leroy wrote: >> In order to support large pages on powerpc, notepage() >> needs to know the page size of the page. >> >> Add a page_size argument to notepage(). >> >> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> >> --- >> arch/arm64/mm/ptdump.c | 2 +- >> arch/riscv/mm/ptdump.c | 2 +- >> arch/s390/mm/dump_pagetables.c | 3 ++- >> arch/x86/mm/dump_pagetables.c | 2 +- >> include/linux/ptdump.h | 2 +- >> mm/ptdump.c | 16 ++++++++-------- >> 6 files changed, 14 insertions(+), 13 deletions(-) >> > [...] >> diff --git a/mm/ptdump.c b/mm/ptdump.c >> index da751448d0e4..61cd16afb1c8 100644 >> --- a/mm/ptdump.c >> +++ b/mm/ptdump.c >> @@ -17,7 +17,7 @@ static inline int note_kasan_page_table(struct mm_walk *walk, >> { >> struct ptdump_state *st = walk->private; >> - st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0])); >> + st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]), PAGE_SIZE); > > I'm not completely sure what the page_size is going to be used for, but note that KASAN presents an > interesting case here. We short-cut by detecting it's a KASAN region at a high level > (PGD/P4D/PUD/PMD) and instead of walking the tree down just call note_page() *once* but with > level==4 because we know KASAN sets up the page table like that. > > However the one call actually covers a much larger region - so while PAGE_SIZE matches the level it > doesn't match the region covered. AFAICT this will lead to odd results if you enable KASAN on powerpc. Hum .... I successfully tested it with KASAN, I now realise that I tested it with CONFIG_KASAN_VMALLOC selected. In this situation, since https://github.com/torvalds/linux/commit/af3d0a686 we don't have any common shadow page table anymore. I'll test again without CONFIG_KASAN_VMALLOC. > > To be honest I don't fully understand why powerpc requires the page_size - it appears to be using it > purely to find "holes" in the calls to note_page(), but I haven't worked out why such holes would > occur. I was indeed introduced for KASAN. We have a first commit https://github.com/torvalds/linux/commit/cabe8138 which uses page size to detect whether it is a KASAN like stuff. Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a fix. I can't remember what the problem was exactly, something around the use of hugepages for kernel memory, came as part of the series https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ Christophe
On 16/04/2021 11:38, Christophe Leroy wrote: > > > Le 16/04/2021 à 11:28, Steven Price a écrit : >> On 15/04/2021 18:18, Christophe Leroy wrote: >>> In order to support large pages on powerpc, notepage() >>> needs to know the page size of the page. >>> >>> Add a page_size argument to notepage(). >>> >>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> >>> --- >>> arch/arm64/mm/ptdump.c | 2 +- >>> arch/riscv/mm/ptdump.c | 2 +- >>> arch/s390/mm/dump_pagetables.c | 3 ++- >>> arch/x86/mm/dump_pagetables.c | 2 +- >>> include/linux/ptdump.h | 2 +- >>> mm/ptdump.c | 16 ++++++++-------- >>> 6 files changed, 14 insertions(+), 13 deletions(-) >>> >> [...] >>> diff --git a/mm/ptdump.c b/mm/ptdump.c >>> index da751448d0e4..61cd16afb1c8 100644 >>> --- a/mm/ptdump.c >>> +++ b/mm/ptdump.c >>> @@ -17,7 +17,7 @@ static inline int note_kasan_page_table(struct >>> mm_walk *walk, >>> { >>> struct ptdump_state *st = walk->private; >>> - st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0])); >>> + st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]), >>> PAGE_SIZE); >> >> I'm not completely sure what the page_size is going to be used for, >> but note that KASAN presents an interesting case here. We short-cut by >> detecting it's a KASAN region at a high level (PGD/P4D/PUD/PMD) and >> instead of walking the tree down just call note_page() *once* but with >> level==4 because we know KASAN sets up the page table like that. >> >> However the one call actually covers a much larger region - so while >> PAGE_SIZE matches the level it doesn't match the region covered. >> AFAICT this will lead to odd results if you enable KASAN on powerpc. > > Hum .... I successfully tested it with KASAN, I now realise that I > tested it with CONFIG_KASAN_VMALLOC selected. In this situation, since > https://github.com/torvalds/linux/commit/af3d0a686 we don't have any > common shadow page table anymore. > > I'll test again without CONFIG_KASAN_VMALLOC. > >> >> To be honest I don't fully understand why powerpc requires the >> page_size - it appears to be using it purely to find "holes" in the >> calls to note_page(), but I haven't worked out why such holes would >> occur. > > I was indeed introduced for KASAN. We have a first commit > https://github.com/torvalds/linux/commit/cabe8138 which uses page size > to detect whether it is a KASAN like stuff. > > Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a fix. I > can't remember what the problem was exactly, something around the use of > hugepages for kernel memory, came as part of the series > https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ Ah, that's useful context. So it looks like powerpc took a different route to reducing the KASAN output to x86. Given the generic ptdump code has handling for KASAN already it should be possible to drop that from the powerpc arch code, which I think means we don't actually need to provide page size to notepage(). Hopefully that means more code to delete ;) Steve
Le 16/04/2021 à 12:51, Steven Price a écrit : > On 16/04/2021 11:38, Christophe Leroy wrote: >> >> >> Le 16/04/2021 à 11:28, Steven Price a écrit : >>> On 15/04/2021 18:18, Christophe Leroy wrote: >>>> In order to support large pages on powerpc, notepage() >>>> needs to know the page size of the page. >>>> >>>> Add a page_size argument to notepage(). >>>> >>>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> >>>> --- >>>> arch/arm64/mm/ptdump.c | 2 +- >>>> arch/riscv/mm/ptdump.c | 2 +- >>>> arch/s390/mm/dump_pagetables.c | 3 ++- >>>> arch/x86/mm/dump_pagetables.c | 2 +- >>>> include/linux/ptdump.h | 2 +- >>>> mm/ptdump.c | 16 ++++++++-------- >>>> 6 files changed, 14 insertions(+), 13 deletions(-) >>>> >>> [...] >>>> diff --git a/mm/ptdump.c b/mm/ptdump.c >>>> index da751448d0e4..61cd16afb1c8 100644 >>>> --- a/mm/ptdump.c >>>> +++ b/mm/ptdump.c >>>> @@ -17,7 +17,7 @@ static inline int note_kasan_page_table(struct mm_walk *walk, >>>> { >>>> struct ptdump_state *st = walk->private; >>>> - st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0])); >>>> + st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]), PAGE_SIZE); >>> >>> I'm not completely sure what the page_size is going to be used for, but note that KASAN presents >>> an interesting case here. We short-cut by detecting it's a KASAN region at a high level >>> (PGD/P4D/PUD/PMD) and instead of walking the tree down just call note_page() *once* but with >>> level==4 because we know KASAN sets up the page table like that. >>> >>> However the one call actually covers a much larger region - so while PAGE_SIZE matches the level >>> it doesn't match the region covered. AFAICT this will lead to odd results if you enable KASAN on >>> powerpc. >> >> Hum .... I successfully tested it with KASAN, I now realise that I tested it with >> CONFIG_KASAN_VMALLOC selected. In this situation, since >> https://github.com/torvalds/linux/commit/af3d0a686 we don't have any common shadow page table >> anymore. >> >> I'll test again without CONFIG_KASAN_VMALLOC. >> >>> >>> To be honest I don't fully understand why powerpc requires the page_size - it appears to be using >>> it purely to find "holes" in the calls to note_page(), but I haven't worked out why such holes >>> would occur. >> >> I was indeed introduced for KASAN. We have a first commit >> https://github.com/torvalds/linux/commit/cabe8138 which uses page size to detect whether it is a >> KASAN like stuff. >> >> Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a fix. I can't remember what the >> problem was exactly, something around the use of hugepages for kernel memory, came as part of the >> series >> https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ > > > Ah, that's useful context. So it looks like powerpc took a different route to reducing the KASAN > output to x86. > > Given the generic ptdump code has handling for KASAN already it should be possible to drop that from > the powerpc arch code, which I think means we don't actually need to provide page size to > notepage(). Hopefully that means more code to delete ;) > Yes ... and no. It looks like the generic ptdump handles the case when several pgdir entries points to the same kasan_early_shadow_pte. But it doesn't take into account the powerpc case where we have regular page tables where several (if not all) PTEs are pointing to the kasan_early_shadow_page . Christophe
On 16/04/2021 12:08, Christophe Leroy wrote: > > > Le 16/04/2021 à 12:51, Steven Price a écrit : >> On 16/04/2021 11:38, Christophe Leroy wrote: >>> >>> >>> Le 16/04/2021 à 11:28, Steven Price a écrit : >>>> On 15/04/2021 18:18, Christophe Leroy wrote: >>>>> In order to support large pages on powerpc, notepage() >>>>> needs to know the page size of the page. >>>>> >>>>> Add a page_size argument to notepage(). >>>>> >>>>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> >>>>> --- >>>>> arch/arm64/mm/ptdump.c | 2 +- >>>>> arch/riscv/mm/ptdump.c | 2 +- >>>>> arch/s390/mm/dump_pagetables.c | 3 ++- >>>>> arch/x86/mm/dump_pagetables.c | 2 +- >>>>> include/linux/ptdump.h | 2 +- >>>>> mm/ptdump.c | 16 ++++++++-------- >>>>> 6 files changed, 14 insertions(+), 13 deletions(-) >>>>> >>>> [...] >>>>> diff --git a/mm/ptdump.c b/mm/ptdump.c >>>>> index da751448d0e4..61cd16afb1c8 100644 >>>>> --- a/mm/ptdump.c >>>>> +++ b/mm/ptdump.c >>>>> @@ -17,7 +17,7 @@ static inline int note_kasan_page_table(struct >>>>> mm_walk *walk, >>>>> { >>>>> struct ptdump_state *st = walk->private; >>>>> - st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0])); >>>>> + st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]), >>>>> PAGE_SIZE); >>>> >>>> I'm not completely sure what the page_size is going to be used for, >>>> but note that KASAN presents an interesting case here. We short-cut >>>> by detecting it's a KASAN region at a high level (PGD/P4D/PUD/PMD) >>>> and instead of walking the tree down just call note_page() *once* >>>> but with level==4 because we know KASAN sets up the page table like >>>> that. >>>> >>>> However the one call actually covers a much larger region - so while >>>> PAGE_SIZE matches the level it doesn't match the region covered. >>>> AFAICT this will lead to odd results if you enable KASAN on powerpc. >>> >>> Hum .... I successfully tested it with KASAN, I now realise that I >>> tested it with CONFIG_KASAN_VMALLOC selected. In this situation, >>> since https://github.com/torvalds/linux/commit/af3d0a686 we don't >>> have any common shadow page table anymore. >>> >>> I'll test again without CONFIG_KASAN_VMALLOC. >>> >>>> >>>> To be honest I don't fully understand why powerpc requires the >>>> page_size - it appears to be using it purely to find "holes" in the >>>> calls to note_page(), but I haven't worked out why such holes would >>>> occur. >>> >>> I was indeed introduced for KASAN. We have a first commit >>> https://github.com/torvalds/linux/commit/cabe8138 which uses page >>> size to detect whether it is a KASAN like stuff. >>> >>> Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a >>> fix. I can't remember what the problem was exactly, something around >>> the use of hugepages for kernel memory, came as part of the series >>> https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ >> >> >> >> Ah, that's useful context. So it looks like powerpc took a different >> route to reducing the KASAN output to x86. >> >> Given the generic ptdump code has handling for KASAN already it should >> be possible to drop that from the powerpc arch code, which I think >> means we don't actually need to provide page size to notepage(). >> Hopefully that means more code to delete ;) >> > > Yes ... and no. > > It looks like the generic ptdump handles the case when several pgdir > entries points to the same kasan_early_shadow_pte. But it doesn't take > into account the powerpc case where we have regular page tables where > several (if not all) PTEs are pointing to the kasan_early_shadow_page . I'm not sure I follow quite how powerpc is different here. But could you have a similar check for PTEs against kasan_early_shadow_pte as the other levels already have? I'm just worried that page_size isn't well defined in this interface and it's going to cause problems in the future. Steve
Le 16/04/2021 à 15:00, Steven Price a écrit : > On 16/04/2021 12:08, Christophe Leroy wrote: >> >> >> Le 16/04/2021 à 12:51, Steven Price a écrit : >>> On 16/04/2021 11:38, Christophe Leroy wrote: >>>> >>>> >>>> Le 16/04/2021 à 11:28, Steven Price a écrit : >>>>> On 15/04/2021 18:18, Christophe Leroy wrote: >>>>>> In order to support large pages on powerpc, notepage() >>>>>> needs to know the page size of the page. >>>>>> >>>>>> Add a page_size argument to notepage(). >>>>>> >>>>>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> >>>>>> --- >>>>>> arch/arm64/mm/ptdump.c | 2 +- >>>>>> arch/riscv/mm/ptdump.c | 2 +- >>>>>> arch/s390/mm/dump_pagetables.c | 3 ++- >>>>>> arch/x86/mm/dump_pagetables.c | 2 +- >>>>>> include/linux/ptdump.h | 2 +- >>>>>> mm/ptdump.c | 16 ++++++++-------- >>>>>> 6 files changed, 14 insertions(+), 13 deletions(-) >>>>>> >>>>> [...] >>>>>> diff --git a/mm/ptdump.c b/mm/ptdump.c >>>>>> index da751448d0e4..61cd16afb1c8 100644 >>>>>> --- a/mm/ptdump.c >>>>>> +++ b/mm/ptdump.c >>>>>> @@ -17,7 +17,7 @@ static inline int note_kasan_page_table(struct mm_walk *walk, >>>>>> { >>>>>> struct ptdump_state *st = walk->private; >>>>>> - st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0])); >>>>>> + st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]), PAGE_SIZE); >>>>> >>>>> I'm not completely sure what the page_size is going to be used for, but note that KASAN >>>>> presents an interesting case here. We short-cut by detecting it's a KASAN region at a high >>>>> level (PGD/P4D/PUD/PMD) and instead of walking the tree down just call note_page() *once* but >>>>> with level==4 because we know KASAN sets up the page table like that. >>>>> >>>>> However the one call actually covers a much larger region - so while PAGE_SIZE matches the >>>>> level it doesn't match the region covered. AFAICT this will lead to odd results if you enable >>>>> KASAN on powerpc. >>>> >>>> Hum .... I successfully tested it with KASAN, I now realise that I tested it with >>>> CONFIG_KASAN_VMALLOC selected. In this situation, since >>>> https://github.com/torvalds/linux/commit/af3d0a686 we don't have any common shadow page table >>>> anymore. >>>> >>>> I'll test again without CONFIG_KASAN_VMALLOC. >>>> >>>>> >>>>> To be honest I don't fully understand why powerpc requires the page_size - it appears to be >>>>> using it purely to find "holes" in the calls to note_page(), but I haven't worked out why such >>>>> holes would occur. >>>> >>>> I was indeed introduced for KASAN. We have a first commit >>>> https://github.com/torvalds/linux/commit/cabe8138 which uses page size to detect whether it is a >>>> KASAN like stuff. >>>> >>>> Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a fix. I can't remember what the >>>> problem was exactly, something around the use of hugepages for kernel memory, came as part of >>>> the series >>>> https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ >>> >>> >>> >>> >>> Ah, that's useful context. So it looks like powerpc took a different route to reducing the KASAN >>> output to x86. >>> >>> Given the generic ptdump code has handling for KASAN already it should be possible to drop that >>> from the powerpc arch code, which I think means we don't actually need to provide page size to >>> notepage(). Hopefully that means more code to delete ;) >>> >> >> Yes ... and no. >> >> It looks like the generic ptdump handles the case when several pgdir entries points to the same >> kasan_early_shadow_pte. But it doesn't take into account the powerpc case where we have regular >> page tables where several (if not all) PTEs are pointing to the kasan_early_shadow_page . > > I'm not sure I follow quite how powerpc is different here. But could you have a similar check for > PTEs against kasan_early_shadow_pte as the other levels already have? > > I'm just worried that page_size isn't well defined in this interface and it's going to cause > problems in the future. > I'm trying. I reverted the two commits b00ff6d8c and cabe8138. At the moment, I don't get exactly what I expect: For linear memory I get one line for each 8M page whereas before reverting the patches I got one 16M line and one 112M line. And for KASAN shadow area I get two lines for the 2x 8M pages shadowing linear mem then I get one 4M line for each PGDIR entry pointing to kasan_early_shadow_pte. 0xf8000000-0xf87fffff 0x07000000 8M huge rw present 0xf8800000-0xf8ffffff 0x07800000 8M huge rw present 0xf9000000-0xf93fffff 0x01430000 4M r present 0xf9400000-0xf97fffff 0x01430000 4M r present 0xf9800000-0xf9bfffff 0x01430000 4M r present 0xf9c00000-0xf9ffffff 0x01430000 4M r present 0xfa000000-0xfa3fffff 0x01430000 4M r present 0xfa400000-0xfa7fffff 0x01430000 4M r present 0xfa800000-0xfabfffff 0x01430000 4M r present 0xfac00000-0xfaffffff 0x01430000 4M r present 0xfb000000-0xfb3fffff 0x01430000 4M r present 0xfb400000-0xfb7fffff 0x01430000 4M r present 0xfb800000-0xfbbfffff 0x01430000 4M r present 0xfbc00000-0xfbffffff 0x01430000 4M r present 0xfc000000-0xfc3fffff 0x01430000 4M r present 0xfc400000-0xfc7fffff 0x01430000 4M r present 0xfc800000-0xfcbfffff 0x01430000 4M r present 0xfcc00000-0xfcffffff 0x01430000 4M r present 0xfd000000-0xfd3fffff 0x01430000 4M r present 0xfd400000-0xfd7fffff 0x01430000 4M r present 0xfd800000-0xfdbfffff 0x01430000 4M r present 0xfdc00000-0xfdffffff 0x01430000 4M r present 0xfe000000-0xfe3fffff 0x01430000 4M r present 0xfe400000-0xfe7fffff 0x01430000 4M r present 0xfe800000-0xfebfffff 0x01430000 4M r present 0xfec00000-0xfeffffff 0x01430000 4M r present Any idea ? Christophe
Le 16/04/2021 à 16:40, Christophe Leroy a écrit : > > > Le 16/04/2021 à 15:00, Steven Price a écrit : >> On 16/04/2021 12:08, Christophe Leroy wrote: >>> >>> >>> Le 16/04/2021 à 12:51, Steven Price a écrit : >>>> On 16/04/2021 11:38, Christophe Leroy wrote: >>>>> >>>>> >>>>> Le 16/04/2021 à 11:28, Steven Price a écrit : >>>>>> To be honest I don't fully understand why powerpc requires the page_size - it appears to be >>>>>> using it purely to find "holes" in the calls to note_page(), but I haven't worked out why such >>>>>> holes would occur. >>>>> >>>>> I was indeed introduced for KASAN. We have a first commit >>>>> https://github.com/torvalds/linux/commit/cabe8138 which uses page size to detect whether it is >>>>> a KASAN like stuff. >>>>> >>>>> Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a fix. I can't remember what >>>>> the problem was exactly, something around the use of hugepages for kernel memory, came as part >>>>> of the series >>>>> https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ >>>> >>>> >>>> >>>> >>>> >>>> Ah, that's useful context. So it looks like powerpc took a different route to reducing the KASAN >>>> output to x86. >>>> >>>> Given the generic ptdump code has handling for KASAN already it should be possible to drop that >>>> from the powerpc arch code, which I think means we don't actually need to provide page size to >>>> notepage(). Hopefully that means more code to delete ;) >>>> >>> >>> Yes ... and no. >>> >>> It looks like the generic ptdump handles the case when several pgdir entries points to the same >>> kasan_early_shadow_pte. But it doesn't take into account the powerpc case where we have regular >>> page tables where several (if not all) PTEs are pointing to the kasan_early_shadow_page . >> >> I'm not sure I follow quite how powerpc is different here. But could you have a similar check for >> PTEs against kasan_early_shadow_pte as the other levels already have? >> >> I'm just worried that page_size isn't well defined in this interface and it's going to cause >> problems in the future. >> > > I'm trying. I reverted the two commits b00ff6d8c and cabe8138. > > At the moment, I don't get exactly what I expect: For linear memory I get one line for each 8M page > whereas before reverting the patches I got one 16M line and one 112M line. > > And for KASAN shadow area I get two lines for the 2x 8M pages shadowing linear mem then I get one 4M > line for each PGDIR entry pointing to kasan_early_shadow_pte. > > 0xf8000000-0xf87fffff 0x07000000 8M huge rw present > 0xf8800000-0xf8ffffff 0x07800000 8M huge rw present > 0xf9000000-0xf93fffff 0x01430000 4M r present ... > 0xfec00000-0xfeffffff 0x01430000 4M r present > > Any idea ? > I think the different with other architectures is here: } else if (flag != st->current_flags || level != st->level || addr >= st->marker[1].start_address || pa != st->last_pa + PAGE_SIZE) { In addition to the checks everyone do, powerpc also checks "pa != st->last_pa + PAGE_SIZE". And it is definitely for that test that page_size argument add been added. I see that other architectures except RISCV don't dump the physical address. But even RISCV doesn't include that check. That physical address dump was added by commit aaa229529244 ("powerpc/mm: Add physical address to Linux page table dump") [https://github.com/torvalds/linux/commit/aaa2295] How do other architectures deal with the problem described by the commit log of that patch ? Christophe
Le 16/04/2021 à 17:04, Christophe Leroy a écrit : > > > Le 16/04/2021 à 16:40, Christophe Leroy a écrit : >> >> >> Le 16/04/2021 à 15:00, Steven Price a écrit : >>> On 16/04/2021 12:08, Christophe Leroy wrote: >>>> >>>> >>>> Le 16/04/2021 à 12:51, Steven Price a écrit : >>>>> On 16/04/2021 11:38, Christophe Leroy wrote: >>>>>> >>>>>> >>>>>> Le 16/04/2021 à 11:28, Steven Price a écrit : >>>>>>> To be honest I don't fully understand why powerpc requires the page_size - it appears to be >>>>>>> using it purely to find "holes" in the calls to note_page(), but I haven't worked out why >>>>>>> such holes would occur. >>>>>> >>>>>> I was indeed introduced for KASAN. We have a first commit >>>>>> https://github.com/torvalds/linux/commit/cabe8138 which uses page size to detect whether it is >>>>>> a KASAN like stuff. >>>>>> >>>>>> Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a fix. I can't remember what >>>>>> the problem was exactly, something around the use of hugepages for kernel memory, came as part >>>>>> of the series >>>>>> https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> Ah, that's useful context. So it looks like powerpc took a different route to reducing the >>>>> KASAN output to x86. >>>>> >>>>> Given the generic ptdump code has handling for KASAN already it should be possible to drop that >>>>> from the powerpc arch code, which I think means we don't actually need to provide page size to >>>>> notepage(). Hopefully that means more code to delete ;) >>>>> >>>> >>>> Yes ... and no. >>>> >>>> It looks like the generic ptdump handles the case when several pgdir entries points to the same >>>> kasan_early_shadow_pte. But it doesn't take into account the powerpc case where we have regular >>>> page tables where several (if not all) PTEs are pointing to the kasan_early_shadow_page . >>> >>> I'm not sure I follow quite how powerpc is different here. But could you have a similar check for >>> PTEs against kasan_early_shadow_pte as the other levels already have? >>> >>> I'm just worried that page_size isn't well defined in this interface and it's going to cause >>> problems in the future. >>> >> >> I'm trying. I reverted the two commits b00ff6d8c and cabe8138. >> >> At the moment, I don't get exactly what I expect: For linear memory I get one line for each 8M >> page whereas before reverting the patches I got one 16M line and one 112M line. >> >> And for KASAN shadow area I get two lines for the 2x 8M pages shadowing linear mem then I get one >> 4M line for each PGDIR entry pointing to kasan_early_shadow_pte. >> >> 0xf8000000-0xf87fffff 0x07000000 8M huge rw present >> 0xf8800000-0xf8ffffff 0x07800000 8M huge rw present >> 0xf9000000-0xf93fffff 0x01430000 4M r present > ... >> 0xfec00000-0xfeffffff 0x01430000 4M r present >> >> Any idea ? >> > > > I think the different with other architectures is here: > > } else if (flag != st->current_flags || level != st->level || > addr >= st->marker[1].start_address || > pa != st->last_pa + PAGE_SIZE) { > > > In addition to the checks everyone do, powerpc also checks "pa != st->last_pa + PAGE_SIZE". > And it is definitely for that test that page_size argument add been added. By replacing that test by (pa - st->start_pa != addr - st->start_address) it works again. So we definitely don't need the real page size. > > I see that other architectures except RISCV don't dump the physical address. But even RISCV doesn't > include that check. > > That physical address dump was added by commit aaa229529244 ("powerpc/mm: Add physical address to > Linux page table dump") [https://github.com/torvalds/linux/commit/aaa2295] > > How do other architectures deal with the problem described by the commit log of that patch ? > > Christophe
On 16/04/2021 16:15, Christophe Leroy wrote: > > > Le 16/04/2021 à 17:04, Christophe Leroy a écrit : >> >> >> Le 16/04/2021 à 16:40, Christophe Leroy a écrit : >>> >>> >>> Le 16/04/2021 à 15:00, Steven Price a écrit : >>>> On 16/04/2021 12:08, Christophe Leroy wrote: >>>>> >>>>> >>>>> Le 16/04/2021 à 12:51, Steven Price a écrit : >>>>>> On 16/04/2021 11:38, Christophe Leroy wrote: >>>>>>> >>>>>>> >>>>>>> Le 16/04/2021 à 11:28, Steven Price a écrit : >>>>>>>> To be honest I don't fully understand why powerpc requires the >>>>>>>> page_size - it appears to be using it purely to find "holes" in >>>>>>>> the calls to note_page(), but I haven't worked out why such >>>>>>>> holes would occur. >>>>>>> >>>>>>> I was indeed introduced for KASAN. We have a first commit >>>>>>> https://github.com/torvalds/linux/commit/cabe8138 which uses page >>>>>>> size to detect whether it is a KASAN like stuff. >>>>>>> >>>>>>> Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a >>>>>>> fix. I can't remember what the problem was exactly, something >>>>>>> around the use of hugepages for kernel memory, came as part of >>>>>>> the series >>>>>>> https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> Ah, that's useful context. So it looks like powerpc took a >>>>>> different route to reducing the KASAN output to x86. >>>>>> >>>>>> Given the generic ptdump code has handling for KASAN already it >>>>>> should be possible to drop that from the powerpc arch code, which >>>>>> I think means we don't actually need to provide page size to >>>>>> notepage(). Hopefully that means more code to delete ;) >>>>>> >>>>> >>>>> Yes ... and no. >>>>> >>>>> It looks like the generic ptdump handles the case when several >>>>> pgdir entries points to the same kasan_early_shadow_pte. But it >>>>> doesn't take into account the powerpc case where we have regular >>>>> page tables where several (if not all) PTEs are pointing to the >>>>> kasan_early_shadow_page . >>>> >>>> I'm not sure I follow quite how powerpc is different here. But could >>>> you have a similar check for PTEs against kasan_early_shadow_pte as >>>> the other levels already have? >>>> >>>> I'm just worried that page_size isn't well defined in this interface >>>> and it's going to cause problems in the future. >>>> >>> >>> I'm trying. I reverted the two commits b00ff6d8c and cabe8138. >>> >>> At the moment, I don't get exactly what I expect: For linear memory I >>> get one line for each 8M page whereas before reverting the patches I >>> got one 16M line and one 112M line. >>> >>> And for KASAN shadow area I get two lines for the 2x 8M pages >>> shadowing linear mem then I get one 4M line for each PGDIR entry >>> pointing to kasan_early_shadow_pte. >>> >>> 0xf8000000-0xf87fffff 0x07000000 8M huge rw >>> present >>> 0xf8800000-0xf8ffffff 0x07800000 8M huge rw >>> present >>> 0xf9000000-0xf93fffff 0x01430000 4M r >>> present >> ... >>> 0xfec00000-0xfeffffff 0x01430000 4M r >>> present >>> >>> Any idea ? >>> >> >> >> I think the different with other architectures is here: >> >> } else if (flag != st->current_flags || level != st->level || >> addr >= st->marker[1].start_address || >> pa != st->last_pa + PAGE_SIZE) { >> >> >> In addition to the checks everyone do, powerpc also checks "pa != >> st->last_pa + PAGE_SIZE". >> And it is definitely for that test that page_size argument add been >> added. > > By replacing that test by (pa - st->start_pa != addr - > st->start_address) it works again. So we definitely don't need the real > page size. Yes that should work. Thanks for figuring it out! > >> >> I see that other architectures except RISCV don't dump the physical >> address. But even RISCV doesn't include that check. Yes not having the physical address certainly simplifies things - although I can see why that can be handy to see. The disadvantage is that user space or vmalloc()'d memory will produce a lot of output because the physical addresses are unlikely to be contiguous. And for most uses you don't need the information. >> That physical address dump was added by commit aaa229529244 >> ("powerpc/mm: Add physical address to Linux page table dump") >> [https://github.com/torvalds/linux/commit/aaa2295] >> >> How do other architectures deal with the problem described by the >> commit log of that patch ? AFAIK other architectures are "broken" in this regard. In practice I don't think it often causes an issue though. Steve
Le 16/04/2021 à 12:51, Steven Price a écrit : > On 16/04/2021 11:38, Christophe Leroy wrote: >> >> >> Le 16/04/2021 à 11:28, Steven Price a écrit : >>> On 15/04/2021 18:18, Christophe Leroy wrote: >>> >>> To be honest I don't fully understand why powerpc requires the page_size - it appears to be using >>> it purely to find "holes" in the calls to note_page(), but I haven't worked out why such holes >>> would occur. >> >> I was indeed introduced for KASAN. We have a first commit >> https://github.com/torvalds/linux/commit/cabe8138 which uses page size to detect whether it is a >> KASAN like stuff. >> >> Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a fix. I can't remember what the >> problem was exactly, something around the use of hugepages for kernel memory, came as part of the >> series >> https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ > > > Ah, that's useful context. So it looks like powerpc took a different route to reducing the KASAN > output to x86. > > Given the generic ptdump code has handling for KASAN already it should be possible to drop that from > the powerpc arch code, which I think means we don't actually need to provide page size to > notepage(). Hopefully that means more code to delete ;) > Looking at how the generic ptdump code handles KASAN, I'm a bit sceptic. IIUC, it is checking that kasan_early_shadow_pte is in the same page as the pgtable referred by the PMD entry. But what happens if that PMD entry is referring another pgtable which is inside the same page as kasan_early_shadow_pte ? Shouldn't the test be if (pmd_page_vaddr(val) == lm_alias(kasan_early_shadow_pte)) return note_kasan_page_table(walk, addr); Christophe
On 19/04/2021 14:14, Christophe Leroy wrote: > > > Le 16/04/2021 à 12:51, Steven Price a écrit : >> On 16/04/2021 11:38, Christophe Leroy wrote: >>> >>> >>> Le 16/04/2021 à 11:28, Steven Price a écrit : >>>> On 15/04/2021 18:18, Christophe Leroy wrote: >>>> >>>> To be honest I don't fully understand why powerpc requires the >>>> page_size - it appears to be using it purely to find "holes" in the >>>> calls to note_page(), but I haven't worked out why such holes would >>>> occur. >>> >>> I was indeed introduced for KASAN. We have a first commit >>> https://github.com/torvalds/linux/commit/cabe8138 which uses page >>> size to detect whether it is a KASAN like stuff. >>> >>> Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a >>> fix. I can't remember what the problem was exactly, something around >>> the use of hugepages for kernel memory, came as part of the series >>> https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ >> >> >> >> Ah, that's useful context. So it looks like powerpc took a different >> route to reducing the KASAN output to x86. >> >> Given the generic ptdump code has handling for KASAN already it should >> be possible to drop that from the powerpc arch code, which I think >> means we don't actually need to provide page size to notepage(). >> Hopefully that means more code to delete ;) >> > > Looking at how the generic ptdump code handles KASAN, I'm a bit sceptic. > > IIUC, it is checking that kasan_early_shadow_pte is in the same page as > the pgtable referred by the PMD entry. But what happens if that PMD > entry is referring another pgtable which is inside the same page as > kasan_early_shadow_pte ? > > Shouldn't the test be > > if (pmd_page_vaddr(val) == lm_alias(kasan_early_shadow_pte)) > return note_kasan_page_table(walk, addr); Now I come to look at this code again, I think you're right. On arm64 this doesn't cause a problem - page tables are page sized and page aligned, so there couldn't be any non-KASAN pgtables sharing the page. Obviously that's not necessarily true of other architectures. Feel free to add a patch to your series ;) Steve
Le 19/04/2021 à 16:00, Steven Price a écrit : > On 19/04/2021 14:14, Christophe Leroy wrote: >> >> >> Le 16/04/2021 à 12:51, Steven Price a écrit : >>> On 16/04/2021 11:38, Christophe Leroy wrote: >>>> >>>> >>>> Le 16/04/2021 à 11:28, Steven Price a écrit : >>>>> On 15/04/2021 18:18, Christophe Leroy wrote: >>>>> >>>>> To be honest I don't fully understand why powerpc requires the page_size - it appears to be >>>>> using it purely to find "holes" in the calls to note_page(), but I haven't worked out why such >>>>> holes would occur. >>>> >>>> I was indeed introduced for KASAN. We have a first commit >>>> https://github.com/torvalds/linux/commit/cabe8138 which uses page size to detect whether it is a >>>> KASAN like stuff. >>>> >>>> Then came https://github.com/torvalds/linux/commit/b00ff6d8c as a fix. I can't remember what the >>>> problem was exactly, something around the use of hugepages for kernel memory, came as part of >>>> the series >>>> https://patchwork.ozlabs.org/project/linuxppc-dev/cover/cover.1589866984.git.christophe.leroy@csgroup.eu/ >>> >>> >>> >>> >>> Ah, that's useful context. So it looks like powerpc took a different route to reducing the KASAN >>> output to x86. >>> >>> Given the generic ptdump code has handling for KASAN already it should be possible to drop that >>> from the powerpc arch code, which I think means we don't actually need to provide page size to >>> notepage(). Hopefully that means more code to delete ;) >>> >> >> Looking at how the generic ptdump code handles KASAN, I'm a bit sceptic. >> >> IIUC, it is checking that kasan_early_shadow_pte is in the same page as the pgtable referred by >> the PMD entry. But what happens if that PMD entry is referring another pgtable which is inside the >> same page as kasan_early_shadow_pte ? >> >> Shouldn't the test be >> >> if (pmd_page_vaddr(val) == lm_alias(kasan_early_shadow_pte)) >> return note_kasan_page_table(walk, addr); > > Now I come to look at this code again, I think you're right. On arm64 this doesn't cause a problem - > page tables are page sized and page aligned, so there couldn't be any non-KASAN pgtables sharing the > page. Obviously that's not necessarily true of other architectures. > > Feel free to add a patch to your series ;) > Ok. I'll leave that outside of the series, it is not a show stopper because early shadow page directories are all tagged __bss_page_aligned so we can't have two of them in the same page and it is really unlikely that we'll have any other statically defined page directory in the same pages either. And for the special case of powerpc 8xx which is the only one for which we have both KASAN and HUGEPD at the time being, there are only two levels of page directories so no issue. Christophe
diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c index 0e050d76b83a..ea1a1c3a3ea0 100644 --- a/arch/arm64/mm/ptdump.c +++ b/arch/arm64/mm/ptdump.c @@ -257,7 +257,7 @@ static void note_prot_wx(struct pg_state *st, unsigned long addr) } static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, - u64 val) + u64 val, unsigned long page_size) { struct pg_state *st = container_of(pt_st, struct pg_state, ptdump); static const char units[] = "KMGTPE"; diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c index ace74dec7492..0a7f276ba799 100644 --- a/arch/riscv/mm/ptdump.c +++ b/arch/riscv/mm/ptdump.c @@ -235,7 +235,7 @@ static void note_prot_wx(struct pg_state *st, unsigned long addr) } static void note_page(struct ptdump_state *pt_st, unsigned long addr, - int level, u64 val) + int level, u64 val, unsigned long page_size) { struct pg_state *st = container_of(pt_st, struct pg_state, ptdump); u64 pa = PFN_PHYS(pte_pfn(__pte(val))); diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c index e40a30647d99..29673c38e773 100644 --- a/arch/s390/mm/dump_pagetables.c +++ b/arch/s390/mm/dump_pagetables.c @@ -116,7 +116,8 @@ static void note_prot_wx(struct pg_state *st, unsigned long addr) #endif /* CONFIG_DEBUG_WX */ } -static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, u64 val) +static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, + u64 val, unsigned long page_size) { int width = sizeof(unsigned long) * 2; static const char units[] = "KMGTPE"; diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index e1b599ecbbc2..2ec76737c1f1 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -272,7 +272,7 @@ static void effective_prot(struct ptdump_state *pt_st, int level, u64 val) * print what we collected so far. */ static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, - u64 val) + u64 val, unsigned long page_size) { struct pg_state *st = container_of(pt_st, struct pg_state, ptdump); pgprotval_t new_prot, new_eff; diff --git a/include/linux/ptdump.h b/include/linux/ptdump.h index 2a3a95586425..3a971fadc95e 100644 --- a/include/linux/ptdump.h +++ b/include/linux/ptdump.h @@ -13,7 +13,7 @@ struct ptdump_range { struct ptdump_state { /* level is 0:PGD to 4:PTE, or -1 if unknown */ void (*note_page)(struct ptdump_state *st, unsigned long addr, - int level, u64 val); + int level, u64 val, unsigned long page_size); void (*effective_prot)(struct ptdump_state *st, int level, u64 val); const struct ptdump_range *range; }; diff --git a/mm/ptdump.c b/mm/ptdump.c index da751448d0e4..61cd16afb1c8 100644 --- a/mm/ptdump.c +++ b/mm/ptdump.c @@ -17,7 +17,7 @@ static inline int note_kasan_page_table(struct mm_walk *walk, { struct ptdump_state *st = walk->private; - st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0])); + st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]), PAGE_SIZE); walk->action = ACTION_CONTINUE; @@ -41,7 +41,7 @@ static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr, st->effective_prot(st, 0, pgd_val(val)); if (pgd_leaf(val)) - st->note_page(st, addr, 0, pgd_val(val)); + st->note_page(st, addr, 0, pgd_val(val), PGDIR_SIZE); return 0; } @@ -62,7 +62,7 @@ static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr, st->effective_prot(st, 1, p4d_val(val)); if (p4d_leaf(val)) - st->note_page(st, addr, 1, p4d_val(val)); + st->note_page(st, addr, 1, p4d_val(val), P4D_SIZE); return 0; } @@ -83,7 +83,7 @@ static int ptdump_pud_entry(pud_t *pud, unsigned long addr, st->effective_prot(st, 2, pud_val(val)); if (pud_leaf(val)) - st->note_page(st, addr, 2, pud_val(val)); + st->note_page(st, addr, 2, pud_val(val), PUD_SIZE); return 0; } @@ -102,7 +102,7 @@ static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr, if (st->effective_prot) st->effective_prot(st, 3, pmd_val(val)); if (pmd_leaf(val)) - st->note_page(st, addr, 3, pmd_val(val)); + st->note_page(st, addr, 3, pmd_val(val), PMD_SIZE); return 0; } @@ -116,7 +116,7 @@ static int ptdump_pte_entry(pte_t *pte, unsigned long addr, if (st->effective_prot) st->effective_prot(st, 4, pte_val(val)); - st->note_page(st, addr, 4, pte_val(val)); + st->note_page(st, addr, 4, pte_val(val), PAGE_SIZE); return 0; } @@ -126,7 +126,7 @@ static int ptdump_hole(unsigned long addr, unsigned long next, { struct ptdump_state *st = walk->private; - st->note_page(st, addr, depth, 0); + st->note_page(st, addr, depth, 0, 0); return 0; } @@ -153,5 +153,5 @@ void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd) mmap_read_unlock(mm); /* Flush out the last page */ - st->note_page(st, 0, -1, 0); + st->note_page(st, 0, -1, 0, 0); }
In order to support large pages on powerpc, notepage() needs to know the page size of the page. Add a page_size argument to notepage(). Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- arch/arm64/mm/ptdump.c | 2 +- arch/riscv/mm/ptdump.c | 2 +- arch/s390/mm/dump_pagetables.c | 3 ++- arch/x86/mm/dump_pagetables.c | 2 +- include/linux/ptdump.h | 2 +- mm/ptdump.c | 16 ++++++++-------- 6 files changed, 14 insertions(+), 13 deletions(-)