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

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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>
This commit is contained in:
Dave Hansen 2017-12-04 15:07:54 +01:00 committed by Ingo Molnar
parent 3f67af51e5
commit 50fb83a62c
3 changed files with 31 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
arch/x86/include/asm/mmu_context.h
View File

@ -290,33 +290,6 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
return __pkru_allows_pkey(vma_pkey(vma), write);
}
/*
* 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. */

26
arch/x86/include/asm/tlbflush.h
View File

@ -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

8
arch/x86/mm/tlb.c
View File

@ -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);