From c812026c54cfaec23fa1d78cdbfd0e56e787470a Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Wed, 7 Aug 2019 16:55:19 +0100 Subject: arm64: mm: Logic to make offset_ttbr1 conditional When running with a 52-bit userspace VA and a 48-bit kernel VA we offset ttbr1_el1 to allow the kernel pagetables with a 52-bit PTRS_PER_PGD to be used for both userspace and kernel. Moving on to a 52-bit kernel VA we no longer require this offset to ttbr1_el1 should we be running on a system with HW support for 52-bit VAs. This patch introduces conditional logic to offset_ttbr1 to query SYS_ID_AA64MMFR2_EL1 whenever 52-bit VAs are selected. If there is HW support for 52-bit VAs then the ttbr1 offset is skipped. We choose to read a system register rather than vabits_actual because offset_ttbr1 can be called in places where the kernel data is not actually mapped. Calls to offset_ttbr1 appear to be made from rarely called code paths so this extra logic is not expected to adversely affect performance. Signed-off-by: Steve Capper Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon --- arch/arm64/kernel/head.S | 2 +- arch/arm64/kernel/hibernate-asm.S | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'arch/arm64/kernel') diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 6dc7349868d9..a96dc4386c7c 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -777,7 +777,7 @@ ENTRY(__enable_mmu) phys_to_ttbr x1, x1 phys_to_ttbr x2, x2 msr ttbr0_el1, x2 // load TTBR0 - offset_ttbr1 x1 + offset_ttbr1 x1, x3 msr ttbr1_el1, x1 // load TTBR1 isb msr sctlr_el1, x0 diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S index 2f4a2ce7264b..38bcd4d4e43b 100644 --- a/arch/arm64/kernel/hibernate-asm.S +++ b/arch/arm64/kernel/hibernate-asm.S @@ -22,14 +22,14 @@ * Even switching to our copied tables will cause a changed output address at * each stage of the walk. */ -.macro break_before_make_ttbr_switch zero_page, page_table, tmp +.macro break_before_make_ttbr_switch zero_page, page_table, tmp, tmp2 phys_to_ttbr \tmp, \zero_page msr ttbr1_el1, \tmp isb tlbi vmalle1 dsb nsh phys_to_ttbr \tmp, \page_table - offset_ttbr1 \tmp + offset_ttbr1 \tmp, \tmp2 msr ttbr1_el1, \tmp isb .endm @@ -70,7 +70,7 @@ ENTRY(swsusp_arch_suspend_exit) * We execute from ttbr0, change ttbr1 to our copied linear map tables * with a break-before-make via the zero page */ - break_before_make_ttbr_switch x5, x0, x6 + break_before_make_ttbr_switch x5, x0, x6, x8 mov x21, x1 mov x30, x2 @@ -101,7 +101,7 @@ ENTRY(swsusp_arch_suspend_exit) dsb ish /* wait for PoU cleaning to finish */ /* switch to the restored kernels page tables */ - break_before_make_ttbr_switch x25, x21, x6 + break_before_make_ttbr_switch x25, x21, x6, x8 ic ialluis dsb ish -- cgit v1.2.3