On 03/02/2020 11:15 PM, Catalin Marinas wrote: > On Mon, Mar 02, 2020 at 03:54:43PM +0200, Mike Rapoport wrote: >> On Mon, Mar 02, 2020 at 10:47:27AM +0000, Will Deacon wrote: >>> [+Anshuman and Catalin] >>> >>> On Mon, Mar 02, 2020 at 01:58:26PM +0530, Naresh Kamboju wrote: >>>> Linux-Next 20200302 arm64 build failed due to below errors, >>>> Suspecting patch causing this build break. >>>> >>>> 87d900aef3e2 arm/arm64: add support for folded p4d page tables >>>> >>>> Error log, >>>> ------------- >>>> arch/arm64/mm/mmu.c: In function 'unmap_hotplug_pud_range': >>>> include/linux/compiler.h:284:1: error: incompatible type for argument >>>> 1 of 'p4d_page_paddr' >>>> ({ \ >>>> ^ >>>> arch/arm64/include/asm/memory.h:270:45: note: in definition of macro >>>> '__phys_to_virt' >>>> #define __phys_to_virt(x) ((unsigned long)((x) - physvirt_offset)) >>>> ^ >>>> arch/arm64/include/asm/pgtable.h:629:42: note: in expansion of macro '__va' >>>> #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr)))) >>>> ^~~~ >>>> include/linux/compiler.h:293:22: note: in expansion of macro '__READ_ONCE' >>>> #define READ_ONCE(x) __READ_ONCE(x, 1) >>>> ^~~~~~~~~~~ >>>> arch/arm64/include/asm/pgtable.h:628:52: note: in expansion of macro 'READ_ONCE' >>>> #define pud_offset_phys(dir, addr) (p4d_page_paddr(READ_ONCE(*(dir))) >>>> + pud_index(addr) * sizeof(pud_t)) >>>> ^~~~~~~~~ >>>> arch/arm64/include/asm/pgtable.h:629:47: note: in expansion of macro >>>> 'pud_offset_phys' >>>> #define pud_offset(dir, addr) ((pud_t *)__va(pud_offset_phys((dir), (addr)))) >>>> ^~~~~~~~~~~~~~~ >>>> arch/arm64/mm/mmu.c:827:10: note: in expansion of macro 'pud_offset' >>>> pudp = pud_offset(pgdp, addr); >>>> ^~~~~~~~~~ >>> >>> Looks like we need an implementation of unmap_hotplug_p4d_range() to >>> walk the dummy p4d level. Unfortunately, we don't have the folded p4d >>> patches in the arm64 tree so we'll either need a common branch or the >>> hotplug patches will need to be dropped for the moment. >> >> unmap_hotplug_p4d_range() is easy :) >> >> From c7a5d08ff51ca2057b6b0289c4423bdfd7643518 Mon Sep 17 00:00:00 2001 >> From: Mike Rapoport <rppt@xxxxxxxxxxxxx> >> Date: Mon, 2 Mar 2020 15:53:17 +0200 >> Subject: [PATCH] arm64/mm: implement unmap_hotplug_p4d_range >> >> Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> >> --- >> arch/arm64/mm/mmu.c | 20 +++++++++++++++++++- >> 1 file changed, 19 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index 05ec8e5f1436..c76b11577558 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -840,6 +840,24 @@ static void unmap_hotplug_pud_range(pgd_t *pgdp, unsigned long addr, >> } while (addr = next, addr < end); >> } >> >> +static void unmap_hotplug_p4d_range(pgd_t *pgd, unsigned long addr, >> + unsigned long end, bool free_mapped) >> +{ >> + unsigned long next; >> + pgd_t *p4dp, p4d; >> + >> + do { >> + next = p4d_addr_end(addr, end); >> + p4dp = p4d_offset(pgd, addr); >> + p4d = READ_ONCE(*p4dp); >> + if (p4d_none(p4d)) >> + continue; >> + >> + WARN_ON(!p4d_present(p4d)); >> + unmap_hotplug_pud_range(p4dp, addr, next, free_mapped); >> + } while (addr = next, addr < end); >> +} >> + >> static void unmap_hotplug_range(unsigned long addr, unsigned long end, >> bool free_mapped) >> { >> @@ -854,7 +872,7 @@ static void unmap_hotplug_range(unsigned long addr, unsigned long end, >> continue; >> >> WARN_ON(!pgd_present(pgd)); >> - unmap_hotplug_pud_range(pgdp, addr, next, free_mapped); >> + unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped); >> } while (addr = next, addr < end); >> } > > Thanks Mike. With the additional diff below, I can get it to build with > and without the p4d clean-up patches in -next. If Anshuman confirms that > they work, I can add them on top of the arm64 for-next/memory-hotremove > branch. These two patches applied on next-20200302 works fine for hot-remove. As the second patch also fixes the first one, IMHO both should be folded into a single one instead. Just wondering if this combined patch which enables P4D page table should be posted on the list or do I need to respin original hot remove patches again. - Anshuman > > ----------8<------------------------ > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 56bd9227937f..2faf11860097 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -816,7 +816,7 @@ static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, > } while (addr = next, addr < end); > } > > -static void unmap_hotplug_pud_range(pgd_t *pgdp, unsigned long addr, > +static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, > unsigned long end, bool free_mapped) > { > unsigned long next; > @@ -824,7 +824,7 @@ static void unmap_hotplug_pud_range(pgd_t *pgdp, unsigned long addr, > > do { > next = pud_addr_end(addr, end); > - pudp = pud_offset(pgdp, addr); > + pudp = pud_offset(p4dp, addr); > pud = READ_ONCE(*pudp); > if (pud_none(pud)) > continue; > @@ -848,15 +848,15 @@ static void unmap_hotplug_pud_range(pgd_t *pgdp, unsigned long addr, > } while (addr = next, addr < end); > } > > -static void unmap_hotplug_p4d_range(pgd_t *pgd, unsigned long addr, > - unsigned long end, bool free_mapped) > +static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, > + unsigned long end, bool free_mapped) > { > unsigned long next; > - pgd_t *p4dp, p4d; > + p4d_t *p4dp, p4d; > > do { > next = p4d_addr_end(addr, end); > - p4dp = p4d_offset(pgd, addr); > + p4dp = p4d_offset(pgdp, addr); > p4d = READ_ONCE(*p4dp); > if (p4d_none(p4d)) > continue; > @@ -961,7 +961,7 @@ static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, > free_hotplug_pgtable_page(virt_to_page(pmdp)); > } > > -static void free_empty_pud_table(pgd_t *pgdp, unsigned long addr, > +static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, > unsigned long end, unsigned long floor, > unsigned long ceiling) > { > @@ -970,7 +970,7 @@ static void free_empty_pud_table(pgd_t *pgdp, unsigned long addr, > > do { > next = pud_addr_end(addr, end); > - pudp = pud_offset(pgdp, addr); > + pudp = pud_offset(p4dp, addr); > pud = READ_ONCE(*pudp); > if (pud_none(pud)) > continue; > @@ -990,17 +990,36 @@ static void free_empty_pud_table(pgd_t *pgdp, unsigned long addr, > * entries are empty. Overlap with other regions have been > * handled by the floor/ceiling check. > */ > - pudp = pud_offset(pgdp, 0UL); > + pudp = pud_offset(p4dp, 0UL); > for (i = 0; i < PTRS_PER_PUD; i++) { > if (!pud_none(READ_ONCE(pudp[i]))) > return; > } > > - pgd_clear(pgdp); > + p4d_clear(p4dp); > __flush_tlb_kernel_pgtable(start); > free_hotplug_pgtable_page(virt_to_page(pudp)); > } > > +static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, > + unsigned long end, unsigned long floor, > + unsigned long ceiling) > +{ > + p4d_t *p4dp, p4d; > + unsigned long next; > + > + do { > + next = p4d_addr_end(addr, end); > + p4dp = p4d_offset(pgdp, addr); > + p4d = READ_ONCE(*p4dp); > + if (p4d_none(p4d)) > + continue; > + > + WARN_ON(!p4d_present(p4d)); > + free_empty_pud_table(p4dp, addr, next, floor, ceiling); > + } while (addr = next, addr < end); > +} > + > static void free_empty_tables(unsigned long addr, unsigned long end, > unsigned long floor, unsigned long ceiling) > { > @@ -1015,7 +1034,7 @@ static void free_empty_tables(unsigned long addr, unsigned long end, > continue; > > WARN_ON(!pgd_present(pgd)); > - free_empty_pud_table(pgdp, addr, next, floor, ceiling); > + free_empty_p4d_table(pgdp, addr, next, floor, ceiling); > } while (addr = next, addr < end); > } > #endif >