| Message ID | 20230310094539.764357-3-alexghiti@rivosinc.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | riscv: Use PUD/P4D/PGD pages for the linear mapping | expand |
Hi Alexandre, On Fri, Mar 10, 2023 at 10:45:37AM +0100, Alexandre Ghiti wrote: > This function allows to split a region in memblock.memory and will be > useful when setting up the linear mapping with STRICT_KERNEL_RWX: it > allows to isolate the kernel text/rodata and then avoid to map those > regions with a PUD/P4D/PGD. > > Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> > --- > include/linux/memblock.h | 1 + > mm/memblock.c | 22 +++++++++++++++++++++- > 2 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 50ad19662a32..2f7ef97c0da7 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -125,6 +125,7 @@ int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); > int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); > int memblock_mark_nomap(phys_addr_t base, phys_addr_t size); > int memblock_clear_nomap(phys_addr_t base, phys_addr_t size); > +int memblock_isolate_memory(phys_addr_t base, phys_addr_t size); > > void memblock_free_all(void); > void memblock_free(void *ptr, size_t size); > diff --git a/mm/memblock.c b/mm/memblock.c > index 25fd0626a9e7..d8cf1c9eccf0 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -753,7 +753,8 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, > int idx; > struct memblock_region *rgn; > > - *start_rgn = *end_rgn = 0; > + if (start_rgn && end_rgn) > + *start_rgn = *end_rgn = 0; Generally, it's possible that either start_rgn or end_rgn will be a valid pointer and this should be handled here and below. My preference, though would be to leave memblock_isolate_range() as is and have unused start_rgn and end_rgn in memblock_isolate_memory(). > > if (!size) > return 0; > @@ -795,6 +796,9 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, > memblock_get_region_node(rgn), > rgn->flags); > } else { > + if (!end_rgn || !start_rgn) > + continue; > + > /* @rgn is fully contained, record it */ > if (!*end_rgn) > *start_rgn = idx; > @@ -805,6 +809,22 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, > return 0; > } > > +/** > + * memblock_isolate_memory - isolate given range from memblock.memory I think it'd better to use "... range in memblock.memory" > + * @base: base of range to isolate > + * @size: size of range to isolate > + * > + * Call memblock_isolate_range on memblock.memory to isolate the given range. Please elaborate that isolate means that the range does not share regions with other ranges. > + * > + * Return: > + * 0 on success, -errno on failure. > + */ > + > +int __init_memblock memblock_isolate_memory(phys_addr_t base, phys_addr_t size) > +{ > + return memblock_isolate_range(&memblock.memory, base, size, NULL, NULL); > +} > + > static int __init_memblock memblock_remove_range(struct memblock_type *type, > phys_addr_t base, phys_addr_t size) > { > -- > 2.37.2 >
On 3/12/23 10:35, Mike Rapoport wrote: > Hi Alexandre, > > On Fri, Mar 10, 2023 at 10:45:37AM +0100, Alexandre Ghiti wrote: >> This function allows to split a region in memblock.memory and will be >> useful when setting up the linear mapping with STRICT_KERNEL_RWX: it >> allows to isolate the kernel text/rodata and then avoid to map those >> regions with a PUD/P4D/PGD. >> >> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> >> --- >> include/linux/memblock.h | 1 + >> mm/memblock.c | 22 +++++++++++++++++++++- >> 2 files changed, 22 insertions(+), 1 deletion(-) >> >> diff --git a/include/linux/memblock.h b/include/linux/memblock.h >> index 50ad19662a32..2f7ef97c0da7 100644 >> --- a/include/linux/memblock.h >> +++ b/include/linux/memblock.h >> @@ -125,6 +125,7 @@ int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); >> int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); >> int memblock_mark_nomap(phys_addr_t base, phys_addr_t size); >> int memblock_clear_nomap(phys_addr_t base, phys_addr_t size); >> +int memblock_isolate_memory(phys_addr_t base, phys_addr_t size); >> >> void memblock_free_all(void); >> void memblock_free(void *ptr, size_t size); >> diff --git a/mm/memblock.c b/mm/memblock.c >> index 25fd0626a9e7..d8cf1c9eccf0 100644 >> --- a/mm/memblock.c >> +++ b/mm/memblock.c >> @@ -753,7 +753,8 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, >> int idx; >> struct memblock_region *rgn; >> >> - *start_rgn = *end_rgn = 0; >> + if (start_rgn && end_rgn) >> + *start_rgn = *end_rgn = 0; > Generally, it's possible that either start_rgn or end_rgn will be a valid > pointer and this should be handled here and below. > > My preference, though would be to leave memblock_isolate_range() as is and > have unused start_rgn and end_rgn in memblock_isolate_memory(). Sure, I'll do that then. > >> >> if (!size) >> return 0; >> @@ -795,6 +796,9 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, >> memblock_get_region_node(rgn), >> rgn->flags); >> } else { >> + if (!end_rgn || !start_rgn) >> + continue; >> + >> /* @rgn is fully contained, record it */ >> if (!*end_rgn) >> *start_rgn = idx; >> @@ -805,6 +809,22 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, >> return 0; >> } >> >> +/** >> + * memblock_isolate_memory - isolate given range from memblock.memory > I think it'd better to use "... range in memblock.memory" Ok > >> + * @base: base of range to isolate >> + * @size: size of range to isolate >> + * >> + * Call memblock_isolate_range on memblock.memory to isolate the given range. > Please elaborate that isolate means that the range does not share regions > with other ranges. Sure, thanks, I'll come up with a v8 tomorrow along with other fixes (rv32 and arm64 comments that I forgot to remove). Thanks again, Alex >> + * >> + * Return: >> + * 0 on success, -errno on failure. >> + */ >> + >> +int __init_memblock memblock_isolate_memory(phys_addr_t base, phys_addr_t size) >> +{ >> + return memblock_isolate_range(&memblock.memory, base, size, NULL, NULL); >> +} >> + >> static int __init_memblock memblock_remove_range(struct memblock_type *type, >> phys_addr_t base, phys_addr_t size) >> { >> -- >> 2.37.2 >>
diff --git a/include/linux/memblock.h b/include/linux/memblock.h index 50ad19662a32..2f7ef97c0da7 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -125,6 +125,7 @@ int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); int memblock_mark_nomap(phys_addr_t base, phys_addr_t size); int memblock_clear_nomap(phys_addr_t base, phys_addr_t size); +int memblock_isolate_memory(phys_addr_t base, phys_addr_t size); void memblock_free_all(void); void memblock_free(void *ptr, size_t size); diff --git a/mm/memblock.c b/mm/memblock.c index 25fd0626a9e7..d8cf1c9eccf0 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -753,7 +753,8 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, int idx; struct memblock_region *rgn; - *start_rgn = *end_rgn = 0; + if (start_rgn && end_rgn) + *start_rgn = *end_rgn = 0; if (!size) return 0; @@ -795,6 +796,9 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, memblock_get_region_node(rgn), rgn->flags); } else { + if (!end_rgn || !start_rgn) + continue; + /* @rgn is fully contained, record it */ if (!*end_rgn) *start_rgn = idx; @@ -805,6 +809,22 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, return 0; } +/** + * memblock_isolate_memory - isolate given range from memblock.memory + * @base: base of range to isolate + * @size: size of range to isolate + * + * Call memblock_isolate_range on memblock.memory to isolate the given range. + * + * Return: + * 0 on success, -errno on failure. + */ + +int __init_memblock memblock_isolate_memory(phys_addr_t base, phys_addr_t size) +{ + return memblock_isolate_range(&memblock.memory, base, size, NULL, NULL); +} + static int __init_memblock memblock_remove_range(struct memblock_type *type, phys_addr_t base, phys_addr_t size) {
This function allows to split a region in memblock.memory and will be useful when setting up the linear mapping with STRICT_KERNEL_RWX: it allows to isolate the kernel text/rodata and then avoid to map those regions with a PUD/P4D/PGD. Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> --- include/linux/memblock.h | 1 + mm/memblock.c | 22 +++++++++++++++++++++- 2 files changed, 22 insertions(+), 1 deletion(-)