From: Sergey Matyukevich sergey.matyukevich@syntacore.com
commit e921050022f1f12d5029d1487a7dfc46cde15523 upstream.
This reverts the remaining bits of commit 4bd1d80efb5a ("riscv: mm: notify remote harts harts about mmu cache updates").
According to bug reports, suggested approach to fix stale TLB entries is not sufficient. It needs to be replaced by a more robust solution.
Fixes: 4bd1d80efb5a ("riscv: mm: notify remote harts about mmu cache updates") Reported-by: Zong Li zong.li@sifive.com Reported-by: Lad Prabhakar prabhakar.mahadev-lad.rj@bp.renesas.com Signed-off-by: Sergey Matyukevich sergey.matyukevich@syntacore.com Cc: stable@vger.kernel.org Reviewed-by: Guo Ren guoren@kernel.org Link: https://lore.kernel.org/r/20230226150137.1919750-2-geomatsi@gmail.com Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/include/asm/mmu.h | 2 -- arch/riscv/include/asm/tlbflush.h | 18 ------------------ arch/riscv/mm/context.c | 10 ---------- arch/riscv/mm/tlbflush.c | 28 +++++++++++++++++----------- 4 files changed, 17 insertions(+), 41 deletions(-)
--- a/arch/riscv/include/asm/mmu.h +++ b/arch/riscv/include/asm/mmu.h @@ -19,8 +19,6 @@ typedef struct { #ifdef CONFIG_SMP /* A local icache flush is needed before user execution can resume. */ cpumask_t icache_stale_mask; - /* A local tlb flush is needed before user execution can resume. */ - cpumask_t tlb_stale_mask; #endif } mm_context_t;
--- a/arch/riscv/include/asm/tlbflush.h +++ b/arch/riscv/include/asm/tlbflush.h @@ -22,24 +22,6 @@ static inline void local_flush_tlb_page( { ALT_FLUSH_TLB_PAGE(__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory")); } - -static inline void local_flush_tlb_all_asid(unsigned long asid) -{ - __asm__ __volatile__ ("sfence.vma x0, %0" - : - : "r" (asid) - : "memory"); -} - -static inline void local_flush_tlb_page_asid(unsigned long addr, - unsigned long asid) -{ - __asm__ __volatile__ ("sfence.vma %0, %1" - : - : "r" (addr), "r" (asid) - : "memory"); -} - #else /* CONFIG_MMU */ #define local_flush_tlb_all() do { } while (0) #define local_flush_tlb_page(addr) do { } while (0) --- a/arch/riscv/mm/context.c +++ b/arch/riscv/mm/context.c @@ -196,16 +196,6 @@ switch_mm_fast:
if (need_flush_tlb) local_flush_tlb_all(); -#ifdef CONFIG_SMP - else { - cpumask_t *mask = &mm->context.tlb_stale_mask; - - if (cpumask_test_cpu(cpu, mask)) { - cpumask_clear_cpu(cpu, mask); - local_flush_tlb_all_asid(cntx & asid_mask); - } - } -#endif }
static void set_mm_noasid(struct mm_struct *mm) --- a/arch/riscv/mm/tlbflush.c +++ b/arch/riscv/mm/tlbflush.c @@ -5,7 +5,23 @@ #include <linux/sched.h> #include <asm/sbi.h> #include <asm/mmu_context.h> -#include <asm/tlbflush.h> + +static inline void local_flush_tlb_all_asid(unsigned long asid) +{ + __asm__ __volatile__ ("sfence.vma x0, %0" + : + : "r" (asid) + : "memory"); +} + +static inline void local_flush_tlb_page_asid(unsigned long addr, + unsigned long asid) +{ + __asm__ __volatile__ ("sfence.vma %0, %1" + : + : "r" (addr), "r" (asid) + : "memory"); +}
void flush_tlb_all(void) { @@ -15,7 +31,6 @@ void flush_tlb_all(void) static void __sbi_tlb_flush_range(struct mm_struct *mm, unsigned long start, unsigned long size, unsigned long stride) { - struct cpumask *pmask = &mm->context.tlb_stale_mask; struct cpumask *cmask = mm_cpumask(mm); unsigned int cpuid; bool broadcast; @@ -29,15 +44,6 @@ static void __sbi_tlb_flush_range(struct if (static_branch_unlikely(&use_asid_allocator)) { unsigned long asid = atomic_long_read(&mm->context.id);
- /* - * TLB will be immediately flushed on harts concurrently - * executing this MM context. TLB flush on other harts - * is deferred until this MM context migrates there. - */ - cpumask_setall(pmask); - cpumask_clear_cpu(cpuid, pmask); - cpumask_andnot(pmask, pmask, cmask); - if (broadcast) { sbi_remote_sfence_vma_asid(cmask, start, size, asid); } else if (size <= stride) {