| Message ID | 20240416122254.868007168-6-mbland@motorola.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: code and data partitioning improvements | expand |
On Mon, 15 Apr 2024 14:51:32 -0500 Maxwell Bland <mbland@motorola.com> wrote: > ptdump can now note non-leaf descriptor entries, a useful addition for > debugging table descriptor permissions when working on related code > > Signed-off-by: Maxwell Bland <mbland@motorola.com> > --- > arch/arm64/mm/ptdump.c | 6 ++++-- > arch/powerpc/mm/ptdump/ptdump.c | 2 ++ > arch/riscv/mm/ptdump.c | 6 ++++-- > arch/s390/mm/dump_pagetables.c | 6 ++++-- > arch/x86/mm/dump_pagetables.c | 3 ++- > include/linux/ptdump.h | 1 + > mm/ptdump.c | 13 +++++++++++++ > 7 files changed, 30 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c > index 796231a4fd63..1a6f4a3513e5 100644 > --- a/arch/arm64/mm/ptdump.c > +++ b/arch/arm64/mm/ptdump.c > @@ -299,7 +299,8 @@ void ptdump_walk(struct seq_file *s, struct ptdump_info *info) > .range = (struct ptdump_range[]){ > {info->base_addr, end}, > {0, 0} > - } > + }, > + .note_non_leaf = false > } It would be acceptable to omit all of these and rely upon the runtime zeroing which the compiler will emit. Documentation/arch/arm64/ptdump.rst might need updating. Please include sample output in the changelog so we can better understand the user's view of this change.
> On Tuesday, April 16, 2024 3:11 PM, Andrew Morton wrote: > On Mon, 15 Apr 2024 14:51:32 -0500 Maxwell Bland <mbland@motorola.com> > wrote: > > > arch/arm64/mm/ptdump.c | 6 ++++-- > > arch/powerpc/mm/ptdump/ptdump.c | 2 ++ > > arch/riscv/mm/ptdump.c | 6 ++++-- > > arch/s390/mm/dump_pagetables.c | 6 ++++-- > > arch/x86/mm/dump_pagetables.c | 3 ++- > > include/linux/ptdump.h | 1 + > > mm/ptdump.c | 13 +++++++++++++ > > 7 files changed, 30 insertions(+), 7 deletions(-) > > > > diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c > > index 796231a4fd63..1a6f4a3513e5 100644 > > --- a/arch/arm64/mm/ptdump.c > > +++ b/arch/arm64/mm/ptdump.c > > @@ -299,7 +299,8 @@ void ptdump_walk(struct seq_file *s, struct ptdump_info > *info) > > .range = (struct ptdump_range[]){ > > {info->base_addr, end}, > > {0, 0} > > - } > > + }, > > + .note_non_leaf = false > > } > > It would be acceptable to omit all of these and rely upon the runtime > zeroing which the compiler will emit. Ah, thank you for the pointer to C99 6.7.8.21. I had always figured since structs are stack allocated they are potentially non-initialized! > Documentation/arch/arm64/ptdump.rst might need updating. > > Please include sample output in the changelog so we can better > understand the user's view of this change. Thanks, I will do both in the next few days everything permitting! Right now this patch results in no change until note_non_leaf = true is adopted for each arch. My plan: I will polish then include output of my personal fixes for arm64. Specifically, printing expanded PMD flags and tab indenting the layout according to each level. Hopefully just adding arm64 support for now is OK, unless maybe we want to default this to true on all arches? IMO default true would be sweet, but I wasn't sure everyone would agree. BRs, Maxwell Bland
diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c index 796231a4fd63..1a6f4a3513e5 100644 --- a/arch/arm64/mm/ptdump.c +++ b/arch/arm64/mm/ptdump.c @@ -299,7 +299,8 @@ void ptdump_walk(struct seq_file *s, struct ptdump_info *info) .range = (struct ptdump_range[]){ {info->base_addr, end}, {0, 0} - } + }, + .note_non_leaf = false } }; @@ -335,7 +336,8 @@ bool ptdump_check_wx(void) .range = (struct ptdump_range[]) { {_PAGE_OFFSET(vabits_actual), ~0UL}, {0, 0} - } + }, + .note_non_leaf = false } }; diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c index 9dc239967b77..89e673f5fd3d 100644 --- a/arch/powerpc/mm/ptdump/ptdump.c +++ b/arch/powerpc/mm/ptdump/ptdump.c @@ -307,6 +307,7 @@ static int ptdump_show(struct seq_file *m, void *v) .ptdump = { .note_page = note_page, .range = ptdump_range, + .note_non_leaf = false } }; @@ -340,6 +341,7 @@ bool ptdump_check_wx(void) .ptdump = { .note_page = note_page, .range = ptdump_range, + .note_non_leaf = false } }; diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c index 1289cc6d3700..b355633afcaf 100644 --- a/arch/riscv/mm/ptdump.c +++ b/arch/riscv/mm/ptdump.c @@ -328,7 +328,8 @@ static void ptdump_walk(struct seq_file *s, struct ptd_mm_info *pinfo) .range = (struct ptdump_range[]) { {pinfo->base_addr, pinfo->end}, {0, 0} - } + }, + .note_non_leaf = false } }; @@ -350,7 +351,8 @@ bool ptdump_check_wx(void) .range = (struct ptdump_range[]) { {KERN_VIRT_START, ULONG_MAX}, {0, 0} - } + }, + .note_non_leaf = false } }; diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c index ffd07ed7b4af..6468cfd53e2a 100644 --- a/arch/s390/mm/dump_pagetables.c +++ b/arch/s390/mm/dump_pagetables.c @@ -200,7 +200,8 @@ bool ptdump_check_wx(void) .range = (struct ptdump_range[]) { {.start = 0, .end = max_addr}, {.start = 0, .end = 0}, - } + }, + .note_non_leaf = false }, .seq = NULL, .level = -1, @@ -239,7 +240,8 @@ static int ptdump_show(struct seq_file *m, void *v) .range = (struct ptdump_range[]) { {.start = 0, .end = max_addr}, {.start = 0, .end = 0}, - } + }, + .note_non_leaf = false }, .seq = m, .level = -1, diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 89079ea73e65..43f00dfb955f 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -380,7 +380,8 @@ bool ptdump_walk_pgd_level_core(struct seq_file *m, .ptdump = { .note_page = note_page, .effective_prot = effective_prot, - .range = ptdump_ranges + .range = ptdump_ranges, + .note_non_leaf = false }, .level = -1, .to_dmesg = dmesg, diff --git a/include/linux/ptdump.h b/include/linux/ptdump.h index 8dbd51ea8626..b3e793a5c77f 100644 --- a/include/linux/ptdump.h +++ b/include/linux/ptdump.h @@ -16,6 +16,7 @@ struct ptdump_state { int level, u64 val); void (*effective_prot)(struct ptdump_state *st, int level, u64 val); const struct ptdump_range *range; + bool note_non_leaf; }; bool ptdump_walk_pgd_level_core(struct seq_file *m, diff --git a/mm/ptdump.c b/mm/ptdump.c index 106e1d66e9f9..97da7a765b22 100644 --- a/mm/ptdump.c +++ b/mm/ptdump.c @@ -41,6 +41,9 @@ static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr, if (st->effective_prot) st->effective_prot(st, 0, pgd_val(val)); + if (st->note_non_leaf && !pgd_leaf(val)) + st->note_page(st, addr, 0, pgd_val(val)); + if (pgd_leaf(val)) { st->note_page(st, addr, 0, pgd_val(val)); walk->action = ACTION_CONTINUE; @@ -64,6 +67,9 @@ static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr, if (st->effective_prot) st->effective_prot(st, 1, p4d_val(val)); + if (st->note_non_leaf && !p4d_leaf(val)) + st->note_page(st, addr, 1, p4d_val(val)); + if (p4d_leaf(val)) { st->note_page(st, addr, 1, p4d_val(val)); walk->action = ACTION_CONTINUE; @@ -87,6 +93,9 @@ static int ptdump_pud_entry(pud_t *pud, unsigned long addr, if (st->effective_prot) st->effective_prot(st, 2, pud_val(val)); + if (st->note_non_leaf && !pud_leaf(val)) + st->note_page(st, addr, 2, pud_val(val)); + if (pud_leaf(val)) { st->note_page(st, addr, 2, pud_val(val)); walk->action = ACTION_CONTINUE; @@ -108,6 +117,10 @@ static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr, if (st->effective_prot) st->effective_prot(st, 3, pmd_val(val)); + + if (st->note_non_leaf && !pmd_leaf(val)) + st->note_page(st, addr, 3, pmd_val(val)); + if (pmd_leaf(val)) { st->note_page(st, addr, 3, pmd_val(val)); walk->action = ACTION_CONTINUE;
ptdump can now note non-leaf descriptor entries, a useful addition for debugging table descriptor permissions when working on related code Signed-off-by: Maxwell Bland <mbland@motorola.com> --- arch/arm64/mm/ptdump.c | 6 ++++-- arch/powerpc/mm/ptdump/ptdump.c | 2 ++ arch/riscv/mm/ptdump.c | 6 ++++-- arch/s390/mm/dump_pagetables.c | 6 ++++-- arch/x86/mm/dump_pagetables.c | 3 ++- include/linux/ptdump.h | 1 + mm/ptdump.c | 13 +++++++++++++ 7 files changed, 30 insertions(+), 7 deletions(-)