From: Will Deacon will.deacon@arm.com
commit 7655abb95386 upstream.
In preparation for mapping kernelspace and userspace with different ASIDs, move the ASID to TTBR1 and update switch_mm to context-switch TTBR0 via an invalid mapping (the zero page).
Reviewed-by: Mark Rutland mark.rutland@arm.com Tested-by: Laura Abbott labbott@redhat.com Tested-by: Shanker Donthineni shankerd@codeaurora.org Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Alex Shi alex.shi@linaro.org [v4.9 backport] Signed-off-by: Mark Rutland mark.rutland@arm.com [v4.9 backport] --- arch/arm64/include/asm/mmu_context.h | 7 +++++++ arch/arm64/include/asm/pgtable-hwdef.h | 1 + arch/arm64/include/asm/proc-fns.h | 6 ------ arch/arm64/mm/proc.S | 9 ++++++--- 4 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index a50185375f09..b96c4799f881 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -50,6 +50,13 @@ static inline void cpu_set_reserved_ttbr0(void) isb(); }
+static inline void cpu_switch_mm(pgd_t *pgd, struct mm_struct *mm) +{ + BUG_ON(pgd == swapper_pg_dir); + cpu_set_reserved_ttbr0(); + cpu_do_switch_mm(virt_to_phys(pgd),mm); +} + /* * TCR.T0SZ value to use when the ID map is active. Usually equals * TCR_T0SZ(VA_BITS), unless system RAM is positioned very high in diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h index eb0c2bd90de9..8df4cb6ac6f7 100644 --- a/arch/arm64/include/asm/pgtable-hwdef.h +++ b/arch/arm64/include/asm/pgtable-hwdef.h @@ -272,6 +272,7 @@ #define TCR_TG1_4K (UL(2) << TCR_TG1_SHIFT) #define TCR_TG1_64K (UL(3) << TCR_TG1_SHIFT)
+#define TCR_A1 (UL(1) << 22) #define TCR_ASID16 (UL(1) << 36) #define TCR_TBI0 (UL(1) << 37) #define TCR_HA (UL(1) << 39) diff --git a/arch/arm64/include/asm/proc-fns.h b/arch/arm64/include/asm/proc-fns.h index 14ad6e4e87d1..16cef2e8449e 100644 --- a/arch/arm64/include/asm/proc-fns.h +++ b/arch/arm64/include/asm/proc-fns.h @@ -35,12 +35,6 @@ extern u64 cpu_do_resume(phys_addr_t ptr, u64 idmap_ttbr);
#include <asm/memory.h>
-#define cpu_switch_mm(pgd,mm) \ -do { \ - BUG_ON(pgd == swapper_pg_dir); \ - cpu_do_switch_mm(virt_to_phys(pgd),mm); \ -} while (0) - #endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */ #endif /* __ASM_PROCFNS_H */ diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 352c73b6a59e..3378f3e21224 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -132,9 +132,12 @@ ENDPROC(cpu_do_resume) * - pgd_phys - physical address of new TTB */ ENTRY(cpu_do_switch_mm) + mrs x2, ttbr1_el1 mmid x1, x1 // get mm->context.id - bfi x0, x1, #48, #16 // set the ASID - msr ttbr0_el1, x0 // set TTBR0 + bfi x2, x1, #48, #16 // set the ASID + msr ttbr1_el1, x2 // in TTBR1 (since TCR.A1 is set) + isb + msr ttbr0_el1, x0 // now update TTBR0 isb alternative_if ARM64_WORKAROUND_CAVIUM_27456 ic iallu @@ -222,7 +225,7 @@ ENTRY(__cpu_setup) * both user and kernel. */ ldr x10, =TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \ - TCR_TG_FLAGS | TCR_ASID16 | TCR_TBI0 + TCR_TG_FLAGS | TCR_ASID16 | TCR_TBI0 | TCR_A1 tcr_set_idmap_t0sz x10, x9
/*