powerpc/mm/radix: Use tlbiel only if we ever ran on the current cpu

commit bd77c4498616e27d5725b5959d880ce2272fefa9 upstream.

Before this patch, we used tlbiel, if we ever ran only on this core.
That was mostly derived from the nohash usage of the same. But is
incorrect, the ISA 3.0 clarifies tlbiel such that:

"All TLB entries that have all of the following properties are made
invalid on the thread executing the tlbiel instruction"

ie. tlbiel only invalidates TLB entries on the current thread. So if the
mm has been used on any other thread (aka. cpu) then we must broadcast
the invalidate.

This bug could lead to invalid TLB entries if a program runs on multiple
threads of a core.

Hence use tlbiel, if we only ever ran on only the current cpu.

Fixes: 1a472c9dba6b ("powerpc/mm/radix: Add tlbflush routines")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/include/asm/tlb.h b/arch/powerpc/include/asm/tlb.h
index f6f68f73e8581147772bad3100f74ed5950987bd..99e1397b71dac78dae0cc2b98eefd40cf90947ec 100644 (file)
--- a/arch/powerpc/include/asm/tlb.h
+++ b/arch/powerpc/include/asm/tlb.h
@@ -52,11 +52,23 @@ static inline int mm_is_core_local(struct mm_struct *mm)
        return cpumask_subset(mm_cpumask(mm),
                              topology_sibling_cpumask(smp_processor_id()));
 }
+
+static inline int mm_is_thread_local(struct mm_struct *mm)
+{
+       return cpumask_equal(mm_cpumask(mm),
+                             cpumask_of(smp_processor_id()));
+}
+
 #else
 static inline int mm_is_core_local(struct mm_struct *mm)
 {
        return 1;
 }
+
+static inline int mm_is_thread_local(struct mm_struct *mm)
+{
+       return 1;
+}
 #endif
 
 #endif /* __KERNEL__ */

diff --git a/arch/powerpc/mm/tlb-radix.c b/arch/powerpc/mm/tlb-radix.c
index 48df05ef523100e9aa67eb29fadf8b22cd116daf..d6960681939a82921ebb66d0c2f5914c333f7cf7 100644 (file)
--- a/arch/powerpc/mm/tlb-radix.c
+++ b/arch/powerpc/mm/tlb-radix.c
@@ -175,7 +175,7 @@ void radix__flush_tlb_mm(struct mm_struct *mm)
        if (unlikely(pid == MMU_NO_CONTEXT))
                goto no_context;
 
-       if (!mm_is_core_local(mm)) {
+       if (!mm_is_thread_local(mm)) {
                int lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
 
                if (lock_tlbie)
@@ -201,7 +201,7 @@ void radix__flush_tlb_pwc(struct mmu_gather *tlb, unsigned long addr)
        if (unlikely(pid == MMU_NO_CONTEXT))
                goto no_context;
 
-       if (!mm_is_core_local(mm)) {
+       if (!mm_is_thread_local(mm)) {
                int lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
 
                if (lock_tlbie)
@@ -226,7 +226,7 @@ void radix__flush_tlb_page_psize(struct mm_struct *mm, unsigned long vmaddr,
        pid = mm ? mm->context.id : 0;
        if (unlikely(pid == MMU_NO_CONTEXT))
                goto bail;
-       if (!mm_is_core_local(mm)) {
+       if (!mm_is_thread_local(mm)) {
                int lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
 
                if (lock_tlbie)
@@ -321,7 +321,7 @@ void radix__flush_tlb_range_psize(struct mm_struct *mm, unsigned long start,
 {
        unsigned long pid;
        unsigned long addr;
-       int local = mm_is_core_local(mm);
+       int local = mm_is_thread_local(mm);
        unsigned long ap = mmu_get_ap(psize);
        int lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
        unsigned long page_size = 1UL << mmu_psize_defs[psize].shift;