arm64/mm: Fix ttbr0 values stored in struct thread_info for software-pan
[ Upstream commit 9163f01130304fab1f74683d7d44632da7bda637 ]
When using CONFIG_ARM64_SW_TTBR0_PAN, a task's thread_info::ttbr0 must be
the TTBR0_EL1 value used to run userspace. With 52-bit PAs, the PA must be
packed into the TTBR using phys_to_ttbr(), but we forget to do this in some
of the SW PAN code. Thus, if the value is installed into TTBR0_EL1 (as may
happen in the uaccess routines), this could result in UNPREDICTABLE
behaviour.
Since hardware with 52-bit PA support almost certainly has HW PAN, which
will be used in preference, this shouldn't be a practical issue, but let's
fix this for consistency.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Fixes: 529c4b05a3
("arm64: handle 52-bit addresses in TTBR")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/1623749578-11231-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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@ -184,9 +184,9 @@ static inline void update_saved_ttbr0(struct task_struct *tsk,
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return;
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if (mm == &init_mm)
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ttbr = __pa_symbol(reserved_pg_dir);
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ttbr = phys_to_ttbr(__pa_symbol(reserved_pg_dir));
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else
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ttbr = virt_to_phys(mm->pgd) | ASID(mm) << 48;
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ttbr = phys_to_ttbr(virt_to_phys(mm->pgd)) | ASID(mm) << 48;
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WRITE_ONCE(task_thread_info(tsk)->ttbr0, ttbr);
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}
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@ -356,7 +356,7 @@ void __init setup_arch(char **cmdline_p)
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* faults in case uaccess_enable() is inadvertently called by the init
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* thread.
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*/
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init_task.thread_info.ttbr0 = __pa_symbol(reserved_pg_dir);
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init_task.thread_info.ttbr0 = phys_to_ttbr(__pa_symbol(reserved_pg_dir));
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#endif
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#ifdef CONFIG_VT
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