From c812026c54cfaec23fa1d78cdbfd0e56e787470a Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Wed, 7 Aug 2019 16:55:19 +0100 Subject: [PATCH] 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/include/asm/assembler.h | 12 ++++++++++-- arch/arm64/kernel/head.S | 2 +- arch/arm64/kernel/hibernate-asm.S | 8 ++++---- arch/arm64/mm/proc.S | 6 +++--- 4 files changed, 18 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index e3a15c751b13..ede368bafa2c 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -538,9 +538,17 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU * In future this may be nop'ed out when dealing with 52-bit kernel VAs. * ttbr: Value of ttbr to set, modified. */ - .macro offset_ttbr1, ttbr + .macro offset_ttbr1, ttbr, tmp #ifdef CONFIG_ARM64_USER_VA_BITS_52 orr \ttbr, \ttbr, #TTBR1_BADDR_4852_OFFSET +#endif + +#ifdef CONFIG_ARM64_VA_BITS_52 + mrs_s \tmp, SYS_ID_AA64MMFR2_EL1 + and \tmp, \tmp, #(0xf << ID_AA64MMFR2_LVA_SHIFT) + cbnz \tmp, .Lskipoffs_\@ + orr \ttbr, \ttbr, #TTBR1_BADDR_4852_OFFSET +.Lskipoffs_\@ : #endif .endm @@ -550,7 +558,7 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU * to be nop'ed out when dealing with 52-bit kernel VAs. */ .macro restore_ttbr1, ttbr -#ifdef CONFIG_ARM64_USER_VA_BITS_52 +#if defined(CONFIG_ARM64_USER_VA_BITS_52) || defined(CONFIG_ARM64_VA_BITS_52) bic \ttbr, \ttbr, #TTBR1_BADDR_4852_OFFSET #endif .endm 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 diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S index 7dbf2be470f6..8d289ff7584d 100644 --- a/arch/arm64/mm/proc.S +++ b/arch/arm64/mm/proc.S @@ -168,7 +168,7 @@ ENDPROC(cpu_do_switch_mm) .macro __idmap_cpu_set_reserved_ttbr1, tmp1, tmp2 adrp \tmp1, empty_zero_page phys_to_ttbr \tmp2, \tmp1 - offset_ttbr1 \tmp2 + offset_ttbr1 \tmp2, \tmp1 msr ttbr1_el1, \tmp2 isb tlbi vmalle1 @@ -187,7 +187,7 @@ ENTRY(idmap_cpu_replace_ttbr1) __idmap_cpu_set_reserved_ttbr1 x1, x3 - offset_ttbr1 x0 + offset_ttbr1 x0, x3 msr ttbr1_el1, x0 isb @@ -362,7 +362,7 @@ __idmap_kpti_secondary: cbnz w18, 1b /* All done, act like nothing happened */ - offset_ttbr1 swapper_ttb + offset_ttbr1 swapper_ttb, x18 msr ttbr1_el1, swapper_ttb isb ret