[PATCH v3 05/10] arm64: mm: Introduce VA_BITS_ACTUAL
From: Steve Capper <hidden>
Date: 2019-06-12 17:29:07
Subsystem:
arm64 port (aarch64 architecture), kasan, kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Andrey Ryabinin, Marc Zyngier, Oliver Upton, Linus Torvalds
In order to support 52-bit kernel addresses detectable at boot time, one needs to know the actual VA_BITS detected. A new variable VA_BITS_ACTUAL is introduced in this commit and employed for the KVM hypervisor layout, KASAN, fault handling and phys-to/from-virt translation where there would normally be compile time constants. In order to maintain performance in phys_to_virt, another variable physvirt_offset is introduced. Signed-off-by: Steve Capper <redacted> --- arch/arm64/include/asm/kasan.h | 2 +- arch/arm64/include/asm/memory.h | 12 +++++++----- arch/arm64/include/asm/mmu_context.h | 2 +- arch/arm64/kernel/head.S | 5 +++++ arch/arm64/kvm/va_layout.c | 14 +++++++------- arch/arm64/mm/fault.c | 4 ++-- arch/arm64/mm/init.c | 7 ++++++- arch/arm64/mm/mmu.c | 3 +++ 8 files changed, 32 insertions(+), 17 deletions(-)
diff --git a/arch/arm64/include/asm/kasan.h b/arch/arm64/include/asm/kasan.h
index 10d2add842da..ff991dc86ae1 100644
--- a/arch/arm64/include/asm/kasan.h
+++ b/arch/arm64/include/asm/kasan.h@@ -31,7 +31,7 @@ * (1ULL << (64 - KASAN_SHADOW_SCALE_SHIFT)) */ #define _KASAN_SHADOW_START(va) (KASAN_SHADOW_END - (1UL << ((va) - KASAN_SHADOW_SCALE_SHIFT))) -#define KASAN_SHADOW_START _KASAN_SHADOW_START(VA_BITS) +#define KASAN_SHADOW_START _KASAN_SHADOW_START(VA_BITS_ACTUAL) void kasan_init(void); void kasan_copy_shadow(pgd_t *pgdir);
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 4814c8e77daf..1c37b2620bb4 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h@@ -48,8 +48,6 @@ * VA_START - the first kernel virtual address. */ #define VA_BITS (CONFIG_ARM64_VA_BITS) -#define VA_START (UL(0xffffffffffffffff) - \ - (UL(1) << (VA_BITS - 1)) + 1) #define PAGE_OFFSET (UL(0xffffffffffffffff) - \ (UL(1) << VA_BITS) + 1) #define KIMAGE_VADDR (MODULES_END)
@@ -177,10 +175,14 @@ #endif #ifndef __ASSEMBLY__ +extern u64 vabits_actual; +#define VA_BITS_ACTUAL ({vabits_actual;}) +#define VA_START (_VA_START(VA_BITS_ACTUAL)) #include <linux/bitops.h> #include <linux/mmdebug.h> +extern s64 physvirt_offset; extern s64 memstart_addr; /* PHYS_OFFSET - the physical address of the start of memory. */ #define PHYS_OFFSET ({ VM_BUG_ON(memstart_addr & 1); memstart_addr; })
@@ -247,9 +249,9 @@ extern u64 vabits_user; * space. Testing the top bit for the start of the region is a * sufficient check. */ -#define __is_lm_address(addr) (!((addr) & BIT(VA_BITS - 1))) +#define __is_lm_address(addr) (!((addr) & BIT(VA_BITS_ACTUAL - 1))) -#define __lm_to_phys(addr) (((addr) & ~PAGE_OFFSET) + PHYS_OFFSET) +#define __lm_to_phys(addr) (((addr) + physvirt_offset)) #define __kimg_to_phys(addr) ((addr) - kimage_voffset) #define __virt_to_phys_nodebug(x) ({ \
@@ -268,7 +270,7 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x); #define __phys_addr_symbol(x) __pa_symbol_nodebug(x) #endif -#define __phys_to_virt(x) ((unsigned long)((x) - PHYS_OFFSET) | PAGE_OFFSET) +#define __phys_to_virt(x) ((unsigned long)((x) - physvirt_offset)) #define __phys_to_kimg(x) ((unsigned long)((x) + kimage_voffset)) /*
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index 2da3e478fd8f..133ecb65b602 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h@@ -106,7 +106,7 @@ static inline void __cpu_set_tcr_t0sz(unsigned long t0sz) isb(); } -#define cpu_set_default_tcr_t0sz() __cpu_set_tcr_t0sz(TCR_T0SZ(VA_BITS)) +#define cpu_set_default_tcr_t0sz() __cpu_set_tcr_t0sz(TCR_T0SZ(VA_BITS_ACTUAL)) #define cpu_set_idmap_tcr_t0sz() __cpu_set_tcr_t0sz(idmap_t0sz) /*
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index ab68c3fe7a19..b3335e639b6d 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S@@ -332,6 +332,11 @@ __create_page_tables: dmb sy dc ivac, x6 // Invalidate potentially stale cache line + adr_l x6, vabits_actual + str x5, [x6] + dmb sy + dc ivac, x6 // Invalidate potentially stale cache line + /* * VA_BITS may be too small to allow for an ID mapping to be created * that covers system RAM if that is located sufficiently high in the
diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c
index c712a7376bc1..c9a1debb45bd 100644
--- a/arch/arm64/kvm/va_layout.c
+++ b/arch/arm64/kvm/va_layout.c@@ -40,25 +40,25 @@ static void compute_layout(void) int kva_msb; /* Where is my RAM region? */ - hyp_va_msb = idmap_addr & BIT(VA_BITS - 1); - hyp_va_msb ^= BIT(VA_BITS - 1); + hyp_va_msb = idmap_addr & BIT(VA_BITS_ACTUAL - 1); + hyp_va_msb ^= BIT(VA_BITS_ACTUAL - 1); kva_msb = fls64((u64)phys_to_virt(memblock_start_of_DRAM()) ^ (u64)(high_memory - 1)); - if (kva_msb == (VA_BITS - 1)) { + if (kva_msb == (VA_BITS_ACTUAL - 1)) { /* * No space in the address, let's compute the mask so - * that it covers (VA_BITS - 1) bits, and the region + * that it covers (VA_BITS_ACTUAL - 1) bits, and the region * bit. The tag stays set to zero. */ - va_mask = BIT(VA_BITS - 1) - 1; + va_mask = BIT(VA_BITS_ACTUAL - 1) - 1; va_mask |= hyp_va_msb; } else { /* * We do have some free bits to insert a random tag. * Hyp VAs are now created from kernel linear map VAs - * using the following formula (with V == VA_BITS): + * using the following formula (with V == VA_BITS_ACTUAL): * * 63 ... V | V-1 | V-2 .. tag_lsb | tag_lsb - 1 .. 0 * ---------------------------------------------------------
@@ -66,7 +66,7 @@ static void compute_layout(void) */ tag_lsb = kva_msb; va_mask = GENMASK_ULL(tag_lsb - 1, 0); - tag_val = get_random_long() & GENMASK_ULL(VA_BITS - 2, tag_lsb); + tag_val = get_random_long() & GENMASK_ULL(VA_BITS_ACTUAL - 2, tag_lsb); tag_val |= hyp_va_msb; tag_val >>= tag_lsb; }
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index a30818ed9c60..a17aa822a81c 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c@@ -171,9 +171,9 @@ static void show_pte(unsigned long addr) return; } - pr_alert("%s pgtable: %luk pages, %u-bit VAs, pgdp=%016lx\n", + pr_alert("%s pgtable: %luk pages, %llu-bit VAs, pgdp=%016lx\n", mm == &init_mm ? "swapper" : "user", PAGE_SIZE / SZ_1K, - mm == &init_mm ? VA_BITS : (int)vabits_user, + mm == &init_mm ? VA_BITS_ACTUAL : (int)vabits_user, (unsigned long)virt_to_phys(mm->pgd)); pgdp = pgd_offset(mm, addr); pgd = READ_ONCE(*pgdp);
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 574ed1d4be19..d89341df2d0e 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c@@ -61,6 +61,9 @@ s64 memstart_addr __ro_after_init = -1; EXPORT_SYMBOL(memstart_addr); +s64 physvirt_offset __ro_after_init; +EXPORT_SYMBOL(physvirt_offset); + phys_addr_t arm64_dma_phys_limit __ro_after_init; #ifdef CONFIG_KEXEC_CORE
@@ -311,7 +314,7 @@ static void __init fdt_enforce_memory_region(void) void __init arm64_memblock_init(void) { - const s64 linear_region_size = BIT(VA_BITS - 1); + const s64 linear_region_size = BIT(VA_BITS_ACTUAL - 1); /* Handle linux,usable-memory-range property */ fdt_enforce_memory_region();
@@ -325,6 +328,8 @@ void __init arm64_memblock_init(void) memstart_addr = round_down(memblock_start_of_DRAM(), ARM64_MEMSTART_ALIGN); + physvirt_offset = PHYS_OFFSET - PAGE_OFFSET; + /* * Remove the memory that we will not be able to cover with the * linear mapping. Take care not to clip the kernel which may be
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 16063ff10c6d..dcbb6593dd90 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c@@ -54,6 +54,9 @@ u64 idmap_ptrs_per_pgd = PTRS_PER_PGD; u64 vabits_user __ro_after_init; EXPORT_SYMBOL(vabits_user); +u64 __section(".mmuoff.data.write") vabits_actual; +EXPORT_SYMBOL(vabits_actual); + u64 kimage_voffset __ro_after_init; EXPORT_SYMBOL(kimage_voffset);
--
2.20.1
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