forked from Minki/linux
arm64: unify idmap removal
We currently open-code the removal of the idmap and restoration of the current task's MMU state in a few places. Before introducing yet more copies of this sequence, unify these to call a new helper, cpu_uninstall_idmap. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Jeremy Linton <jeremy.linton@arm.com> Cc: Laura Abbott <labbott@fedoraproject.org> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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@ -27,6 +27,7 @@
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#include <asm-generic/mm_hooks.h>
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#include <asm/cputype.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#ifdef CONFIG_PID_IN_CONTEXTIDR
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static inline void contextidr_thread_switch(struct task_struct *next)
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@ -89,6 +90,30 @@ static inline void cpu_set_default_tcr_t0sz(void)
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: "r"(TCR_T0SZ(VA_BITS)), "I"(TCR_T0SZ_OFFSET), "I"(TCR_TxSZ_WIDTH));
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}
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/*
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* Remove the idmap from TTBR0_EL1 and install the pgd of the active mm.
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*
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* The idmap lives in the same VA range as userspace, but uses global entries
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* and may use a different TCR_EL1.T0SZ. To avoid issues resulting from
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* speculative TLB fetches, we must temporarily install the reserved page
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* tables while we invalidate the TLBs and set up the correct TCR_EL1.T0SZ.
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*
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* If current is a not a user task, the mm covers the TTBR1_EL1 page tables,
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* which should not be installed in TTBR0_EL1. In this case we can leave the
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* reserved page tables in place.
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*/
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static inline void cpu_uninstall_idmap(void)
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{
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struct mm_struct *mm = current->active_mm;
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cpu_set_reserved_ttbr0();
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local_flush_tlb_all();
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cpu_set_default_tcr_t0sz();
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if (mm != &init_mm)
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cpu_switch_mm(mm->pgd, mm);
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}
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/*
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* It would be nice to return ASIDs back to the allocator, but unfortunately
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* that introduces a race with a generation rollover where we could erroneously
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@ -62,6 +62,7 @@
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#include <asm/memblock.h>
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#include <asm/efi.h>
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#include <asm/xen/hypervisor.h>
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#include <asm/mmu_context.h>
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phys_addr_t __fdt_pointer __initdata;
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@ -149,9 +149,7 @@ asmlinkage void secondary_start_kernel(void)
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* TTBR0 is only used for the identity mapping at this stage. Make it
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* point to zero page to avoid speculatively fetching new entries.
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*/
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cpu_set_reserved_ttbr0();
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local_flush_tlb_all();
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cpu_set_default_tcr_t0sz();
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cpu_uninstall_idmap();
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preempt_disable();
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trace_hardirqs_off();
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@ -60,7 +60,6 @@ void __init cpu_suspend_set_dbg_restorer(void (*hw_bp_restore)(void *))
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*/
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int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
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{
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struct mm_struct *mm = current->active_mm;
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int ret;
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unsigned long flags;
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@ -87,22 +86,11 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
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ret = __cpu_suspend_enter(arg, fn);
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if (ret == 0) {
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/*
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* We are resuming from reset with TTBR0_EL1 set to the
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* idmap to enable the MMU; set the TTBR0 to the reserved
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* page tables to prevent speculative TLB allocations, flush
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* the local tlb and set the default tcr_el1.t0sz so that
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* the TTBR0 address space set-up is properly restored.
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* If the current active_mm != &init_mm we entered cpu_suspend
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* with mappings in TTBR0 that must be restored, so we switch
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* them back to complete the address space configuration
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* restoration before returning.
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* We are resuming from reset with the idmap active in TTBR0_EL1.
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* We must uninstall the idmap and restore the expected MMU
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* state before we can possibly return to userspace.
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*/
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cpu_set_reserved_ttbr0();
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local_flush_tlb_all();
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cpu_set_default_tcr_t0sz();
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if (mm != &init_mm)
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cpu_switch_mm(mm->pgd, mm);
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cpu_uninstall_idmap();
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/*
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* Restore per-cpu offset before any kernel
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@ -468,9 +468,7 @@ void __init paging_init(void)
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* TTBR0 is only used for the identity mapping at this stage. Make it
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* point to zero page to avoid speculatively fetching new entries.
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*/
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cpu_set_reserved_ttbr0();
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local_flush_tlb_all();
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cpu_set_default_tcr_t0sz();
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cpu_uninstall_idmap();
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}
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/*
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