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authorDan Williams <dan.j.williams@intel.com>2018-12-04 22:37:27 +0100
committerIngo Molnar <mingo@kernel.org>2018-12-05 09:03:07 +0100
commitba6f508d0ec4adb09f0a939af6d5e19cdfa8667d (patch)
tree9aae8f98e669787e78ed873d49d82c04289a98fb /arch/x86/mm
parentx86/mm: Validate kernel_physical_mapping_init() PTE population (diff)
downloadlinux-ba6f508d0ec4adb09f0a939af6d5e19cdfa8667d.tar.xz
linux-ba6f508d0ec4adb09f0a939af6d5e19cdfa8667d.zip
x86/mm: Drop usage of __flush_tlb_all() in kernel_physical_mapping_init()
Commit: f77084d96355 "x86/mm/pat: Disable preemption around __flush_tlb_all()" addressed a case where __flush_tlb_all() is called without preemption being disabled. It also left a warning to catch other cases where preemption is not disabled. That warning triggers for the memory hotplug path which is also used for persistent memory enabling: WARNING: CPU: 35 PID: 911 at ./arch/x86/include/asm/tlbflush.h:460 RIP: 0010:__flush_tlb_all+0x1b/0x3a [..] Call Trace: phys_pud_init+0x29c/0x2bb kernel_physical_mapping_init+0xfc/0x219 init_memory_mapping+0x1a5/0x3b0 arch_add_memory+0x2c/0x50 devm_memremap_pages+0x3aa/0x610 pmem_attach_disk+0x585/0x700 [nd_pmem] Andy wondered why a path that can sleep was using __flush_tlb_all() [1] and Dave confirmed the expectation for TLB flush is for modifying / invalidating existing PTE entries, but not initial population [2]. Drop the usage of __flush_tlb_all() in phys_{p4d,pud,pmd}_init() on the expectation that this path is only ever populating empty entries for the linear map. Note, at linear map teardown time there is a call to the all-cpu flush_tlb_all() to invalidate the removed mappings. [1]: https://lkml.kernel.org/r/9DFD717D-857D-493D-A606-B635D72BAC21@amacapital.net [2]: https://lkml.kernel.org/r/749919a4-cdb1-48a3-adb4-adb81a5fa0b5@intel.com [ mingo: Minor readability edits. ] Suggested-by: Dave Hansen <dave.hansen@linux.intel.com> Reported-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave.hansen@intel.com Fixes: f77084d96355 ("x86/mm/pat: Disable preemption around __flush_tlb_all()") Link: http://lkml.kernel.org/r/154395944713.32119.15611079023837132638.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/init_64.c6
1 files changed, 0 insertions, 6 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 3e25ac2793ef..484c1b92f078 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -584,7 +584,6 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end,
paddr_end,
page_size_mask,
prot);
- __flush_tlb_all();
continue;
}
/*
@@ -627,7 +626,6 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end,
pud_populate_safe(&init_mm, pud, pmd);
spin_unlock(&init_mm.page_table_lock);
}
- __flush_tlb_all();
update_page_count(PG_LEVEL_1G, pages);
@@ -668,7 +666,6 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end,
paddr_last = phys_pud_init(pud, paddr,
paddr_end,
page_size_mask);
- __flush_tlb_all();
continue;
}
@@ -680,7 +677,6 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end,
p4d_populate_safe(&init_mm, p4d, pud);
spin_unlock(&init_mm.page_table_lock);
}
- __flush_tlb_all();
return paddr_last;
}
@@ -733,8 +729,6 @@ kernel_physical_mapping_init(unsigned long paddr_start,
if (pgd_changed)
sync_global_pgds(vaddr_start, vaddr_end - 1);
- __flush_tlb_all();
-
return paddr_last;
}