x86/mm: Move the CR3 construction functions to tlbflush.h

For flushing the TLB, the ASID which has been programmed into the hardware
must be known.  That differs from what is in 'cpu_tlbstate'.

Add functions to transform the 'cpu_tlbstate' values into to the one
programmed into the hardware (CR3).

It's not easy to include mmu_context.h into tlbflush.h, so just move the
CR3 building over to tlbflush.h.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 5e25423..5ede7ca 100644 (file)
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -291,33 +291,6 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
 }
 
 /*
- * If PCID is on, ASID-aware code paths put the ASID+1 into the PCID
- * bits.  This serves two purposes.  It prevents a nasty situation in
- * which PCID-unaware code saves CR3, loads some other value (with PCID
- * == 0), and then restores CR3, thus corrupting the TLB for ASID 0 if
- * the saved ASID was nonzero.  It also means that any bugs involving
- * loading a PCID-enabled CR3 with CR4.PCIDE off will trigger
- * deterministically.
- */
-
-static inline unsigned long build_cr3(struct mm_struct *mm, u16 asid)
-{
-       if (static_cpu_has(X86_FEATURE_PCID)) {
-               VM_WARN_ON_ONCE(asid > 4094);
-               return __sme_pa(mm->pgd) | (asid + 1);
-       } else {
-               VM_WARN_ON_ONCE(asid != 0);
-               return __sme_pa(mm->pgd);
-       }
-}
-
-static inline unsigned long build_cr3_noflush(struct mm_struct *mm, u16 asid)
-{
-       VM_WARN_ON_ONCE(asid > 4094);
-       return __sme_pa(mm->pgd) | (asid + 1) | CR3_NOFLUSH;
-}
-
-/*
  * This can be used from process context to figure out what the value of
  * CR3 is without needing to do a (slow) __read_cr3().
  *
@@ -326,7 +299,7 @@ static inline unsigned long build_cr3_noflush(struct mm_struct *mm, u16 asid)
  */
 static inline unsigned long __get_current_cr3_fast(void)
 {
-       unsigned long cr3 = build_cr3(this_cpu_read(cpu_tlbstate.loaded_mm),
+       unsigned long cr3 = build_cr3(this_cpu_read(cpu_tlbstate.loaded_mm)->pgd,
                this_cpu_read(cpu_tlbstate.loaded_mm_asid));
 
        /* For now, be very restrictive about when this can be called. */

diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 552d581..ee7925a 100644 (file)
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -69,6 +69,32 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm)
        return atomic64_inc_return(&mm->context.tlb_gen);
 }
 
+/*
+ * If PCID is on, ASID-aware code paths put the ASID+1 into the PCID bits.
+ * This serves two purposes.  It prevents a nasty situation in which
+ * PCID-unaware code saves CR3, loads some other value (with PCID == 0),
+ * and then restores CR3, thus corrupting the TLB for ASID 0 if the saved
+ * ASID was nonzero.  It also means that any bugs involving loading a
+ * PCID-enabled CR3 with CR4.PCIDE off will trigger deterministically.
+ */
+struct pgd_t;
+static inline unsigned long build_cr3(pgd_t *pgd, u16 asid)
+{
+       if (static_cpu_has(X86_FEATURE_PCID)) {
+               VM_WARN_ON_ONCE(asid > 4094);
+               return __sme_pa(pgd) | (asid + 1);
+       } else {
+               VM_WARN_ON_ONCE(asid != 0);
+               return __sme_pa(pgd);
+       }
+}
+
+static inline unsigned long build_cr3_noflush(pgd_t *pgd, u16 asid)
+{
+       VM_WARN_ON_ONCE(asid > 4094);
+       return __sme_pa(pgd) | (asid + 1) | CR3_NOFLUSH;
+}
+
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
 #else

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 0569987..0a1be3a 100644 (file)
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -128,7 +128,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
         * isn't free.
         */
 #ifdef CONFIG_DEBUG_VM
-       if (WARN_ON_ONCE(__read_cr3() != build_cr3(real_prev, prev_asid))) {
+       if (WARN_ON_ONCE(__read_cr3() != build_cr3(real_prev->pgd, prev_asid))) {
                /*
                 * If we were to BUG here, we'd be very likely to kill
                 * the system so hard that we don't see the call trace.
@@ -195,7 +195,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
                if (need_flush) {
                        this_cpu_write(cpu_tlbstate.ctxs[new_asid].ctx_id, next->context.ctx_id);
                        this_cpu_write(cpu_tlbstate.ctxs[new_asid].tlb_gen, next_tlb_gen);
-                       write_cr3(build_cr3(next, new_asid));
+                       write_cr3(build_cr3(next->pgd, new_asid));
 
                        /*
                         * NB: This gets called via leave_mm() in the idle path
@@ -208,7 +208,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
                        trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL);
                } else {
                        /* The new ASID is already up to date. */
-                       write_cr3(build_cr3_noflush(next, new_asid));
+                       write_cr3(build_cr3_noflush(next->pgd, new_asid));
 
                        /* See above wrt _rcuidle. */
                        trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, 0);
@@ -288,7 +288,7 @@ void initialize_tlbstate_and_flush(void)
                !(cr4_read_shadow() & X86_CR4_PCIDE));
 
        /* Force ASID 0 and force a TLB flush. */
-       write_cr3(build_cr3(mm, 0));
+       write_cr3(build_cr3(mm->pgd, 0));
 
        /* Reinitialize tlbstate. */
        this_cpu_write(cpu_tlbstate.loaded_mm_asid, 0);