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Shutemov" Cc: Andi Kleen , Andrey Konovalov , Dave Hansen , Dmitriy Vyukov , "H.J. Lu" , Kostya Serebryany , LKML , Linux Memory Management List , Andy Lutomirski , Peter Zijlstra , Rick Edgecombe , Andrey Ryabinin , Taras Madan , "the arch/x86 maintainers" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=HVU5PUix; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf19.hostedemail.com: domain of glider@google.com designates 209.85.128.175 as permitted sender) smtp.mailfrom=glider@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1658409239; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=otORvzl7/EquxrHIAFf6clZzYDIdRdFY2L1POt7+dtE=; b=ireAIYJtVcKoATXkON8n5Y2RWu0SAsIIC6YtdT0kRWRQDHZSl9L+Yw2Kmfy4P1iOwJeOyN 3L+HrTFwIxshEmvpoqG+9O8zdIKKnz4ZD7UgnUg7GeKuN7gTlEL94Vivu9rbuW5NDXxV/t W2zD86MXmejeWgTDJ1Hms7ppXfN315w= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1658409239; a=rsa-sha256; cv=none; b=sIdGqOaSZJ0HmXpE2uhTDVeJ964VPXOUhPCojafSHP/0MRQwAS8tmkXbYIlz2m7Q6urzPD AIZ3reHoCmC9beccjloLznqAhu+O+FPH/9D8wC9TOaJbtCv4AAZZDFp2JdHDvD7w0tXqaC ECNAEi6TcuZPOycJut6HLj5FXqT8/GY= X-Stat-Signature: zuhob8wsriogpjwegn78beazw3knz84q X-Rspamd-Queue-Id: 5282D1A0029 X-Rspam-User: Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=HVU5PUix; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf19.hostedemail.com: domain of glider@google.com designates 209.85.128.175 as permitted sender) smtp.mailfrom=glider@google.com X-Rspamd-Server: rspam11 X-HE-Tag: 1658409239-378251 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jul 13, 2022 at 5:02 PM Kirill A. Shutemov wrote: > > Linear Address Masking mode for userspace pointers encoded in CR3 bits. > The mode is selected per-thread. Add new thread features indicate that th= e > thread has Linear Address Masking enabled. > > switch_mm_irqs_off() now respects these flags and constructs CR3 > accordingly. > > The active LAM mode gets recorded in the tlb_state. > > Signed-off-by: Kirill A. Shutemov Tested-by: Alexander Potapenko > --- > v5.1: > - Fix build issue with CONFIG_MODULE=3Dy > --- > arch/x86/include/asm/mmu.h | 3 +++ > arch/x86/include/asm/mmu_context.h | 24 +++++++++++++++++ > arch/x86/include/asm/tlbflush.h | 35 +++++++++++++++++++++++++ > arch/x86/mm/tlb.c | 42 +++++++++++++++++++----------- > 4 files changed, 89 insertions(+), 15 deletions(-) > > diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h > index 5d7494631ea9..002889ca8978 100644 > --- a/arch/x86/include/asm/mmu.h > +++ b/arch/x86/include/asm/mmu.h > @@ -40,6 +40,9 @@ typedef struct { > > #ifdef CONFIG_X86_64 > unsigned short flags; > + > + /* Active LAM mode: X86_CR3_LAM_U48 or X86_CR3_LAM_U57 or 0 (dis= abled) */ > + unsigned long lam_cr3_mask; > #endif > > struct mutex lock; > diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mm= u_context.h > index b8d40ddeab00..69c943b2ae90 100644 > --- a/arch/x86/include/asm/mmu_context.h > +++ b/arch/x86/include/asm/mmu_context.h > @@ -91,6 +91,29 @@ static inline void switch_ldt(struct mm_struct *prev, = struct mm_struct *next) > } > #endif > > +#ifdef CONFIG_X86_64 > +static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) > +{ > + return mm->context.lam_cr3_mask; > +} > + > +static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm= ) > +{ > + mm->context.lam_cr3_mask =3D oldmm->context.lam_cr3_mask; > +} > + > +#else > + > +static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) > +{ > + return 0; > +} > + > +static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm= ) > +{ > +} > +#endif > + > #define enter_lazy_tlb enter_lazy_tlb > extern void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk= ); > > @@ -168,6 +191,7 @@ static inline int arch_dup_mmap(struct mm_struct *old= mm, struct mm_struct *mm) > { > arch_dup_pkeys(oldmm, mm); > paravirt_arch_dup_mmap(oldmm, mm); > + dup_lam(oldmm, mm); > return ldt_dup_context(oldmm, mm); > } > > diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbfl= ush.h > index 4af5579c7ef7..efe83d33327f 100644 > --- a/arch/x86/include/asm/tlbflush.h > +++ b/arch/x86/include/asm/tlbflush.h > @@ -100,6 +100,16 @@ struct tlb_state { > */ > bool invalidate_other; > > +#ifdef CONFIG_X86_64 > + /* > + * Active LAM mode. > + * > + * X86_CR3_LAM_U57/U48 shifted right by X86_CR3_LAM_U57_BIT or 0 = if LAM > + * disabled. > + */ > + u8 lam; > +#endif > + > /* > * Mask that contains TLB_NR_DYN_ASIDS+1 bits to indicate > * the corresponding user PCID needs a flush next time we > @@ -356,6 +366,30 @@ static inline bool huge_pmd_needs_flush(pmd_t oldpmd= , pmd_t newpmd) > } > #define huge_pmd_needs_flush huge_pmd_needs_flush > > +#ifdef CONFIG_X86_64 > +static inline unsigned long tlbstate_lam_cr3_mask(void) > +{ > + unsigned long lam =3D this_cpu_read(cpu_tlbstate.lam); > + > + return lam << X86_CR3_LAM_U57_BIT; > +} > + > +static inline void set_tlbstate_cr3_lam_mask(unsigned long mask) > +{ > + this_cpu_write(cpu_tlbstate.lam, mask >> X86_CR3_LAM_U57_BIT); > +} > + > +#else > + > +static inline unsigned long tlbstate_lam_cr3_mask(void) > +{ > + return 0; > +} > + > +static inline void set_tlbstate_cr3_lam_mask(u64 mask) > +{ > +} > +#endif > #endif /* !MODULE */ > > static inline void __native_tlb_flush_global(unsigned long cr4) > @@ -363,4 +397,5 @@ static inline void __native_tlb_flush_global(unsigned= long cr4) > native_write_cr4(cr4 ^ X86_CR4_PGE); > native_write_cr4(cr4); > } > + > #endif /* _ASM_X86_TLBFLUSH_H */ > diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c > index d400b6d9d246..4c93f87a8928 100644 > --- a/arch/x86/mm/tlb.c > +++ b/arch/x86/mm/tlb.c > @@ -154,17 +154,18 @@ static inline u16 user_pcid(u16 asid) > return ret; > } > > -static inline unsigned long build_cr3(pgd_t *pgd, u16 asid) > +static inline unsigned long build_cr3(pgd_t *pgd, u16 asid, unsigned lon= g lam) > { > if (static_cpu_has(X86_FEATURE_PCID)) { > - return __sme_pa(pgd) | kern_pcid(asid); > + return __sme_pa(pgd) | kern_pcid(asid) | lam; > } else { > VM_WARN_ON_ONCE(asid !=3D 0); > - return __sme_pa(pgd); > + return __sme_pa(pgd) | lam; > } > } > > -static inline unsigned long build_cr3_noflush(pgd_t *pgd, u16 asid) > +static inline unsigned long build_cr3_noflush(pgd_t *pgd, u16 asid, > + unsigned long lam) > { > VM_WARN_ON_ONCE(asid > MAX_ASID_AVAILABLE); > /* > @@ -173,7 +174,7 @@ static inline unsigned long build_cr3_noflush(pgd_t *= pgd, u16 asid) > * boot because all CPU's the have same capabilities: > */ > VM_WARN_ON_ONCE(!boot_cpu_has(X86_FEATURE_PCID)); > - return __sme_pa(pgd) | kern_pcid(asid) | CR3_NOFLUSH; > + return __sme_pa(pgd) | kern_pcid(asid) | lam | CR3_NOFLUSH; > } > > /* > @@ -274,15 +275,16 @@ static inline void invalidate_user_asid(u16 asid) > (unsigned long *)this_cpu_ptr(&cpu_tlbstate.user_pcid_f= lush_mask)); > } > > -static void load_new_mm_cr3(pgd_t *pgdir, u16 new_asid, bool need_flush) > +static void load_new_mm_cr3(pgd_t *pgdir, u16 new_asid, unsigned long la= m, > + bool need_flush) > { > unsigned long new_mm_cr3; > > if (need_flush) { > invalidate_user_asid(new_asid); > - new_mm_cr3 =3D build_cr3(pgdir, new_asid); > + new_mm_cr3 =3D build_cr3(pgdir, new_asid, lam); > } else { > - new_mm_cr3 =3D build_cr3_noflush(pgdir, new_asid); > + new_mm_cr3 =3D build_cr3_noflush(pgdir, new_asid, lam); > } > > /* > @@ -491,6 +493,8 @@ void switch_mm_irqs_off(struct mm_struct *prev, struc= t mm_struct *next, > { > struct mm_struct *real_prev =3D this_cpu_read(cpu_tlbstate.loaded= _mm); > u16 prev_asid =3D this_cpu_read(cpu_tlbstate.loaded_mm_asid); > + unsigned long prev_lam =3D tlbstate_lam_cr3_mask(); > + unsigned long new_lam =3D mm_lam_cr3_mask(next); > bool was_lazy =3D this_cpu_read(cpu_tlbstate_shared.is_lazy); > unsigned cpu =3D smp_processor_id(); > u64 next_tlb_gen; > @@ -520,7 +524,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struc= t mm_struct *next, > * isn't free. > */ > #ifdef CONFIG_DEBUG_VM > - if (WARN_ON_ONCE(__read_cr3() !=3D build_cr3(real_prev->pgd, prev= _asid))) { > + if (WARN_ON_ONCE(__read_cr3() !=3D build_cr3(real_prev->pgd, prev= _asid, prev_lam))) { > /* > * 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. > @@ -622,15 +626,16 @@ void switch_mm_irqs_off(struct mm_struct *prev, str= uct mm_struct *next, > barrier(); > } > > + set_tlbstate_cr3_lam_mask(new_lam); > 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); > - load_new_mm_cr3(next->pgd, new_asid, true); > + load_new_mm_cr3(next->pgd, new_asid, new_lam, true); > > trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); > } else { > /* The new ASID is already up to date. */ > - load_new_mm_cr3(next->pgd, new_asid, false); > + load_new_mm_cr3(next->pgd, new_asid, new_lam, false); > > trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, 0); > } > @@ -691,6 +696,10 @@ void initialize_tlbstate_and_flush(void) > /* Assert that CR3 already references the right mm. */ > WARN_ON((cr3 & CR3_ADDR_MASK) !=3D __pa(mm->pgd)); > > + /* LAM expected to be disabled in CR3 and init_mm */ > + WARN_ON(cr3 & (X86_CR3_LAM_U48 | X86_CR3_LAM_U57)); > + WARN_ON(mm_lam_cr3_mask(&init_mm)); > + > /* > * Assert that CR4.PCIDE is set if needed. (CR4.PCIDE initializa= tion > * doesn't work like other CR4 bits because it can only be set fr= om > @@ -699,8 +708,8 @@ void initialize_tlbstate_and_flush(void) > WARN_ON(boot_cpu_has(X86_FEATURE_PCID) && > !(cr4_read_shadow() & X86_CR4_PCIDE)); > > - /* Force ASID 0 and force a TLB flush. */ > - write_cr3(build_cr3(mm->pgd, 0)); > + /* Disable LAM, force ASID 0 and force a TLB flush. */ > + write_cr3(build_cr3(mm->pgd, 0, 0)); > > /* Reinitialize tlbstate. */ > this_cpu_write(cpu_tlbstate.last_user_mm_spec, LAST_USER_MM_INIT)= ; > @@ -708,6 +717,7 @@ void initialize_tlbstate_and_flush(void) > this_cpu_write(cpu_tlbstate.next_asid, 1); > this_cpu_write(cpu_tlbstate.ctxs[0].ctx_id, mm->context.ctx_id); > this_cpu_write(cpu_tlbstate.ctxs[0].tlb_gen, tlb_gen); > + set_tlbstate_cr3_lam_mask(0); > > for (i =3D 1; i < TLB_NR_DYN_ASIDS; i++) > this_cpu_write(cpu_tlbstate.ctxs[i].ctx_id, 0); > @@ -1047,8 +1057,10 @@ void flush_tlb_kernel_range(unsigned long start, u= nsigned long end) > */ > unsigned long __get_current_cr3_fast(void) > { > - unsigned long cr3 =3D build_cr3(this_cpu_read(cpu_tlbstate.loaded= _mm)->pgd, > - this_cpu_read(cpu_tlbstate.loaded_mm_asid)); > + unsigned long cr3 =3D > + build_cr3(this_cpu_read(cpu_tlbstate.loaded_mm)->pgd, > + this_cpu_read(cpu_tlbstate.loaded_mm_asid), > + tlbstate_lam_cr3_mask()); > > /* For now, be very restrictive about when this can be called. */ > VM_WARN_ON(in_nmi() || preemptible()); > -- > 2.35.1 > --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Liana Sebastian Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg