Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 163/348] arm64/mm: Fix ttbr0 values stored in struct thread_info for software-pan | Date | Mon, 12 Jul 2021 08:09:07 +0200 |
| |
From: Anshuman Khandual <anshuman.khandual@arm.com>
[ 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: 529c4b05a3cb ("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> --- arch/arm64/include/asm/mmu_context.h | 4 ++-- arch/arm64/kernel/setup.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index 1355205e5da5..fb564de90aa7 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -184,9 +184,9 @@ static inline void update_saved_ttbr0(struct task_struct *tsk, return; if (mm == &init_mm) - ttbr = __pa_symbol(reserved_pg_dir); + ttbr = phys_to_ttbr(__pa_symbol(reserved_pg_dir)); else - ttbr = virt_to_phys(mm->pgd) | ASID(mm) << 48; + ttbr = phys_to_ttbr(virt_to_phys(mm->pgd)) | ASID(mm) << 48; WRITE_ONCE(task_thread_info(tsk)->ttbr0, ttbr); } diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 203a0c31f260..f55f4a15a905 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -356,7 +356,7 @@ void __init setup_arch(char **cmdline_p) * faults in case uaccess_enable() is inadvertently called by the init * thread. */ - init_task.thread_info.ttbr0 = __pa_symbol(reserved_pg_dir); + init_task.thread_info.ttbr0 = phys_to_ttbr(__pa_symbol(reserved_pg_dir)); #endif #ifdef CONFIG_VT -- 2.30.2
| |