Unverified Commit daef1926 authored by Samuel Holland's avatar Samuel Holland Committed by Palmer Dabbelt
Browse files

riscv: mm: Always use an ASID to flush mm contexts 



Even if multiple ASIDs are not supported, using the single-ASID variant
of the sfence.vma instruction preserves TLB entries for global (kernel)
pages. So it is always more efficient to use the single-ASID code path.

Reviewed-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: default avatarSamuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240327045035.368512-14-samuel.holland@sifive.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 8fc21cc6

arch/riscv/mm/tlbflush.c

+1 −2
Original line number Diff line number Diff line
@@ -109,8 +109,7 @@ static void __flush_tlb_range(struct cpumask *cmask, unsigned long asid, 


static inline unsigned long get_mm_asid(struct mm_struct *mm)

{

	return static_branch_unlikely(&use_asid_allocator) ?

			cntx2asid(atomic_long_read(&mm->context.id)) : FLUSH_TLB_NO_ASID;

	return cntx2asid(atomic_long_read(&mm->context.id));

}



void flush_tlb_mm(struct mm_struct *mm)