| Message ID | 1612239114-28428-3-git-send-email-anshuman.khandual@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64/mm: Fix pfn_valid() for ZONE_DEVICE based memory | expand |
On 02.02.21 05:11, Anshuman Khandual wrote: > There are multiple instances of pfn_to_section_nr() and __pfn_to_section() > when CONFIG_SPARSEMEM is enabled. This can be optimized if memory section > is fetched earlier. This replaces the open coded PFN and ADDR conversion > with PFN_PHYS() and PHYS_PFN() helpers. While there, also add a comment. > This does not cause any functional change. > > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> > --- > arch/arm64/mm/init.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 1141075e4d53..5d8fd5360a68 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -219,16 +219,25 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) > > int pfn_valid(unsigned long pfn) > { > - phys_addr_t addr = pfn << PAGE_SHIFT; > + phys_addr_t addr = PFN_PHYS(pfn); > > - if ((addr >> PAGE_SHIFT) != pfn) > + /* > + * Ensure the upper PAGE_SHIFT bits are clear in the > + * pfn. Else it might lead to false positives when > + * some of the upper bits are set, but the lower bits > + * match a valid pfn. > + */ > + if (PHYS_PFN(addr) != pfn) > return 0; > > #ifdef CONFIG_SPARSEMEM > +{ > + struct mem_section *ms = __pfn_to_section(pfn); > + > if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) > return 0; > > - if (!valid_section(__pfn_to_section(pfn))) > + if (!valid_section(ms)) > return 0; > > /* > @@ -240,8 +249,9 @@ int pfn_valid(unsigned long pfn) > * memory sections covering all of hotplug memory including > * both normal and ZONE_DEVICE based. > */ > - if (!early_section(__pfn_to_section(pfn))) > - return pfn_section_valid(__pfn_to_section(pfn), pfn); > + if (!early_section(ms)) > + return pfn_section_valid(ms, pfn); > +} > #endif > return memblock_is_map_memory(addr); > } > Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 1141075e4d53..5d8fd5360a68 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -219,16 +219,25 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) int pfn_valid(unsigned long pfn) { - phys_addr_t addr = pfn << PAGE_SHIFT; + phys_addr_t addr = PFN_PHYS(pfn); - if ((addr >> PAGE_SHIFT) != pfn) + /* + * Ensure the upper PAGE_SHIFT bits are clear in the + * pfn. Else it might lead to false positives when + * some of the upper bits are set, but the lower bits + * match a valid pfn. + */ + if (PHYS_PFN(addr) != pfn) return 0; #ifdef CONFIG_SPARSEMEM +{ + struct mem_section *ms = __pfn_to_section(pfn); + if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) return 0; - if (!valid_section(__pfn_to_section(pfn))) + if (!valid_section(ms)) return 0; /* @@ -240,8 +249,9 @@ int pfn_valid(unsigned long pfn) * memory sections covering all of hotplug memory including * both normal and ZONE_DEVICE based. */ - if (!early_section(__pfn_to_section(pfn))) - return pfn_section_valid(__pfn_to_section(pfn), pfn); + if (!early_section(ms)) + return pfn_section_valid(ms, pfn); +} #endif return memblock_is_map_memory(addr); }
There are multiple instances of pfn_to_section_nr() and __pfn_to_section() when CONFIG_SPARSEMEM is enabled. This can be optimized if memory section is fetched earlier. This replaces the open coded PFN and ADDR conversion with PFN_PHYS() and PHYS_PFN() helpers. While there, also add a comment. This does not cause any functional change. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- arch/arm64/mm/init.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)