aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/kernel
diff options
context:
space:
mode:
authorWill Deacon2021-01-27 23:53:47 +0000
committerPeter Zijlstra2021-01-29 20:02:29 +0100
commit8cf55f24ce6cf90eb8828421e15e9efcd508bd2c (patch)
treeb56b879d2eaf1356eea82db964751a985d36951f /arch/x86/kernel
parentc7bd8010a335260927e3643e79360272f9aca266 (diff)
x86/ldt: Use tlb_gather_mmu_fullmm() when freeing LDT page-tables
free_ldt_pgtables() uses the MMU gather API for batching TLB flushes over the call to free_pgd_range(). However, tlb_gather_mmu() expects to operate on user addresses and so passing LDT_{BASE,END}_ADDR will confuse the range setting logic in __tlb_adjust_range(), causing the gather to identify a range starting at TASK_SIZE. Such a large range will be converted into a 'fullmm' flush by the low-level invalidation code, so change the caller to invoke tlb_gather_mmu_fullmm() directly. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Yu Zhao <yuzhao@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/20210127235347.1402-7-will@kernel.org
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/ldt.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 7ad9834e0d95..aa15132228da 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -398,7 +398,13 @@ static void free_ldt_pgtables(struct mm_struct *mm)
if (!boot_cpu_has(X86_FEATURE_PTI))
return;
- tlb_gather_mmu(&tlb, mm);
+ /*
+ * Although free_pgd_range() is intended for freeing user
+ * page-tables, it also works out for kernel mappings on x86.
+ * We use tlb_gather_mmu_fullmm() to avoid confusing the
+ * range-tracking logic in __tlb_adjust_range().
+ */
+ tlb_gather_mmu_fullmm(&tlb, mm);
free_pgd_range(&tlb, start, end, start, end);
tlb_finish_mmu(&tlb);
#endif