From: Dave Hansen <[email protected]> There are effectively two ASID types: 1. The one stored in the mmu_context that goes from 0->5 2. The one programmed into the hardware that goes from 1->6
This consolidates the locations where converting beween the two (by doing +1) to a single place which gives us a nice place to comment. KAISER will also need to, given an ASID, know which hardware ASID to flush for the userspace mapping. Signed-off-by: Dave Hansen <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/include/asm/tlbflush.h | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 3101581c5da0..24b27eb5904c 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -88,21 +88,26 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm) */ #define MAX_ASID_AVAILABLE ((1<<CR3_AVAIL_ASID_BITS) - 2) -/* - * 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 u16 kern_asid(u16 asid) +{ + VM_WARN_ON_ONCE(asid > MAX_ASID_AVAILABLE); + /* + * 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. + */ + return asid + 1; +} + 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 > MAX_ASID_AVAILABLE); - return __sme_pa(pgd) | (asid + 1); + return __sme_pa(pgd) | kern_asid(asid); } else { VM_WARN_ON_ONCE(asid != 0); return __sme_pa(pgd); @@ -112,7 +117,8 @@ static inline unsigned long build_cr3(pgd_t *pgd, u16 asid) static inline unsigned long build_cr3_noflush(pgd_t *pgd, u16 asid) { VM_WARN_ON_ONCE(asid > MAX_ASID_AVAILABLE); - return __sme_pa(pgd) | (asid + 1) | CR3_NOFLUSH; + VM_WARN_ON_ONCE(!this_cpu_has(X86_FEATURE_PCID)); + return __sme_pa(pgd) | kern_asid(asid) | CR3_NOFLUSH; } #ifdef CONFIG_PARAVIRT -- 2.14.1
