[RFC PATCH v1 43/57] arm64: Clean up simple cases of CONFIG_ARM64_*K_PAGES

Ryan Roberts
2024-10-14T12:23:19Z

There are a number of places that define macros conditionally depending
on which of the CONFIG_ARM64_*K_PAGES macros are defined. But in
preparation for supporting boot-time page size selection, we will no
longer be able to make these decisions at compile time.

So let's refactor the code to check the size of PAGE_SIZE using the
ternary operator. This approach will still resolve to compile-time
constants when configured for a compile-time page size, but it will also
work when we turn PAGE_SIZE into a run-time value. Additionally,
IS_ENABLED(CONFIG_ARM64_*K_PAGES) instances are also converted to test
the size of PAGE_SIZE.

Additionally modify ARM64_HAS_VA52 capability detection to use a custom
match function, which chooses which feature register and field to check
based on PAGE_SIZE. The compiler will eliminate the other page sizes
when selecting a compile time page size, but will also now cope with
seting page size at boot time.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---

***NOTE***
Any confused maintainers may want to read the cover note here for context:
https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/

arch/arm64/include/asm/kvm_arm.h | 21 ++++-------
arch/arm64/include/asm/kvm_pgtable.h | 6 +---
arch/arm64/include/asm/memory.h | 7 ++--
arch/arm64/include/asm/processor.h | 10 +++---
arch/arm64/include/asm/sparsemem.h | 11 ++----
arch/arm64/include/asm/sysreg.h | 54 ++++++++++++++++++----------
arch/arm64/kernel/cpufeature.c | 43 +++++++++++++---------
arch/arm64/mm/fixmap.c | 2 +-
arch/arm64/mm/init.c | 20 +++++------
arch/arm64/mm/kasan_init.c | 8 ++---
arch/arm64/mm/mmu.c | 2 +-
drivers/irqchip/irq-gic-v3-its.c | 2 +-
12 files changed, 94 insertions(+), 92 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index d81cc746e0ebd..08155dc17ad17 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -189,22 +189,13 @@
* Entry_Level = 4 - Number_of_levels.
*
*/
-#ifdef CONFIG_ARM64_64K_PAGES
+#define VTCR_EL2_TGRAN \
+ (PAGE_SIZE == SZ_64K ? \
+ VTCR_EL2_TG0_64K : \
+ (PAGE_SIZE == SZ_16K ? VTCR_EL2_TG0_16K : VTCR_EL2_TG0_4K))

-#define VTCR_EL2_TGRAN VTCR_EL2_TG0_64K
-#define VTCR_EL2_TGRAN_SL0_BASE 3UL
-
-#elif defined(CONFIG_ARM64_16K_PAGES)
-
-#define VTCR_EL2_TGRAN VTCR_EL2_TG0_16K
-#define VTCR_EL2_TGRAN_SL0_BASE 3UL
-
-#else /* 4K */
-
-#define VTCR_EL2_TGRAN VTCR_EL2_TG0_4K
-#define VTCR_EL2_TGRAN_SL0_BASE 2UL
-
-#endif
+#define VTCR_EL2_TGRAN_SL0_BASE \
+ (PAGE_SIZE == SZ_64K ? 3UL : (PAGE_SIZE == SZ_16K ? 3UL : 2UL))

#define VTCR_EL2_LVLS_TO_SL0(levels) \
((VTCR_EL2_TGRAN_SL0_BASE - (4 - (levels))) << VTCR_EL2_SL0_SHIFT)
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 19278dfe79782..796614bf59e78 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -20,11 +20,7 @@
* - 16K (level 2): 32MB
* - 64K (level 2): 512MB
*/
-#ifdef CONFIG_ARM64_4K_PAGES
-#define KVM_PGTABLE_MIN_BLOCK_LEVEL 1
-#else
-#define KVM_PGTABLE_MIN_BLOCK_LEVEL 2
-#endif
+#define KVM_PGTABLE_MIN_BLOCK_LEVEL (PAGE_SIZE == SZ_4K ? 1 : 2)

#define kvm_lpa2_is_enabled() system_supports_lpa2()

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 54fb014eba058..6aa97fa22dc30 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -188,11 +188,8 @@
#define MT_S2_FWB_NORMAL_NC 5
#define MT_S2_FWB_DEVICE_nGnRE 1

-#ifdef CONFIG_ARM64_4K_PAGES
-#define IOREMAP_MAX_ORDER (PUD_SHIFT)
-#else
-#define IOREMAP_MAX_ORDER (PMD_SHIFT)
-#endif
+#define IOREMAP_MAX_ORDER \
+ (PAGE_SIZE == SZ_4K ? PUD_SHIFT : PMD_SHIFT)

/*
* Open-coded (swapper_pg_dir - reserved_pg_dir) as this cannot be calculated
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index f77371232d8c6..444694a4e6733 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -55,15 +55,15 @@
#define TASK_SIZE_MAX (UL(1) << VA_BITS)

#ifdef CONFIG_COMPAT
-#if defined(CONFIG_ARM64_64K_PAGES) && defined(CONFIG_KUSER_HELPERS)
+#if defined(CONFIG_KUSER_HELPERS)
/*
- * With CONFIG_ARM64_64K_PAGES enabled, the last page is occupied
- * by the compat vectors page.
+ * With 64K pages in use, the last page is occupied by the compat vectors page.
*/
-#define TASK_SIZE_32 UL(0x100000000)
+#define TASK_SIZE_32 \
+ (PAGE_SIZE == SZ_64K ? UL(0x100000000) : (UL(0x100000000) - PAGE_SIZE))
#else
#define TASK_SIZE_32 (UL(0x100000000) - PAGE_SIZE)
-#endif /* CONFIG_ARM64_64K_PAGES */
+#endif /* CONFIG_KUSER_HELPERS */
#define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \
TASK_SIZE_32 : TASK_SIZE_64)
#define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
diff --git a/arch/arm64/include/asm/sparsemem.h b/arch/arm64/include/asm/sparsemem.h
index 8a8acc220371c..a05fdd54014f7 100644
--- a/arch/arm64/include/asm/sparsemem.h
+++ b/arch/arm64/include/asm/sparsemem.h
@@ -11,19 +11,12 @@
* Section size must be at least 512MB for 64K base
* page size config. Otherwise it will be less than
* MAX_PAGE_ORDER and the build process will fail.
- */
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SECTION_SIZE_BITS 29
-
-#else
-
-/*
+ *
* Section size must be at least 128MB for 4K base
* page size config. Otherwise PMD based huge page
* entries could not be created for vmemmap mappings.
* 16K follows 4K for simplicity.
*/
-#define SECTION_SIZE_BITS 27
-#endif /* CONFIG_ARM64_64K_PAGES */
+#define SECTION_SIZE_BITS (PAGE_SIZE == SZ_64K ? 29 : 27)

#endif
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 4a9ea103817e8..cbcf861bbf2a6 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -10,10 +10,12 @@
#define __ASM_SYSREG_H

#include <linux/bits.h>
+#include <linux/sizes.h>
#include <linux/stringify.h>
#include <linux/kasan-tags.h>

#include <asm/gpr-num.h>
+#include <asm/page-def.h>

/*
* ARMv8 ARM reserves the following encoding for system registers:
@@ -913,24 +915,40 @@
#define ID_AA64MMFR0_EL1_PARANGE_MAX ID_AA64MMFR0_EL1_PARANGE_48
#endif

-#if defined(CONFIG_ARM64_4K_PAGES)
-#define ID_AA64MMFR0_EL1_TGRAN_SHIFT ID_AA64MMFR0_EL1_TGRAN4_SHIFT
-#define ID_AA64MMFR0_EL1_TGRAN_LPA2 ID_AA64MMFR0_EL1_TGRAN4_52_BIT
-#define ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN ID_AA64MMFR0_EL1_TGRAN4_SUPPORTED_MIN
-#define ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX ID_AA64MMFR0_EL1_TGRAN4_SUPPORTED_MAX
-#define ID_AA64MMFR0_EL1_TGRAN_2_SHIFT ID_AA64MMFR0_EL1_TGRAN4_2_SHIFT
-#elif defined(CONFIG_ARM64_16K_PAGES)
-#define ID_AA64MMFR0_EL1_TGRAN_SHIFT ID_AA64MMFR0_EL1_TGRAN16_SHIFT
-#define ID_AA64MMFR0_EL1_TGRAN_LPA2 ID_AA64MMFR0_EL1_TGRAN16_52_BIT
-#define ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN ID_AA64MMFR0_EL1_TGRAN16_SUPPORTED_MIN
-#define ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX ID_AA64MMFR0_EL1_TGRAN16_SUPPORTED_MAX
-#define ID_AA64MMFR0_EL1_TGRAN_2_SHIFT ID_AA64MMFR0_EL1_TGRAN16_2_SHIFT
-#elif defined(CONFIG_ARM64_64K_PAGES)
-#define ID_AA64MMFR0_EL1_TGRAN_SHIFT ID_AA64MMFR0_EL1_TGRAN64_SHIFT
-#define ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN ID_AA64MMFR0_EL1_TGRAN64_SUPPORTED_MIN
-#define ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX ID_AA64MMFR0_EL1_TGRAN64_SUPPORTED_MAX
-#define ID_AA64MMFR0_EL1_TGRAN_2_SHIFT ID_AA64MMFR0_EL1_TGRAN64_2_SHIFT
-#endif
+#define ID_AA64MMFR0_EL1_TGRAN_SHIFT \
+ (PAGE_SIZE == SZ_4K ? \
+ ID_AA64MMFR0_EL1_TGRAN4_SHIFT : \
+ (PAGE_SIZE == SZ_16K ? \
+ ID_AA64MMFR0_EL1_TGRAN16_SHIFT : \
+ ID_AA64MMFR0_EL1_TGRAN64_SHIFT))
+
+#define ID_AA64MMFR0_EL1_TGRAN_LPA2 \
+ (PAGE_SIZE == SZ_4K ? \
+ ID_AA64MMFR0_EL1_TGRAN4_52_BIT : \
+ (PAGE_SIZE == SZ_16K ? \
+ ID_AA64MMFR0_EL1_TGRAN16_52_BIT : \
+ -1))
+
+#define ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN \
+ (PAGE_SIZE == SZ_4K ? \
+ ID_AA64MMFR0_EL1_TGRAN4_SUPPORTED_MIN : \
+ (PAGE_SIZE == SZ_16K ? \
+ ID_AA64MMFR0_EL1_TGRAN16_SUPPORTED_MIN : \
+ ID_AA64MMFR0_EL1_TGRAN64_SUPPORTED_MIN))
+
+#define ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX \
+ (PAGE_SIZE == SZ_4K ? \
+ ID_AA64MMFR0_EL1_TGRAN4_SUPPORTED_MAX : \
+ (PAGE_SIZE == SZ_16K ? \
+ ID_AA64MMFR0_EL1_TGRAN16_SUPPORTED_MAX : \
+ ID_AA64MMFR0_EL1_TGRAN64_SUPPORTED_MAX))
+
+#define ID_AA64MMFR0_EL1_TGRAN_2_SHIFT \
+ (PAGE_SIZE == SZ_4K ? \
+ ID_AA64MMFR0_EL1_TGRAN4_2_SHIFT : \
+ (PAGE_SIZE == SZ_16K ? \
+ ID_AA64MMFR0_EL1_TGRAN16_2_SHIFT : \
+ ID_AA64MMFR0_EL1_TGRAN64_2_SHIFT))

#define CPACR_EL1_FPEN_EL1EN (BIT(20)) /* enable EL1 access */
#define CPACR_EL1_FPEN_EL0EN (BIT(21)) /* enable EL0 access, if EL1EN set */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 646ecd3069fdd..7705c9c0e7142 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1831,11 +1831,13 @@ static bool has_nv1(const struct arm64_cpu_capabilities *entry, int scope)
is_midr_in_range_list(read_cpuid_id(), nv1_ni_list)));
}

-#if defined(ID_AA64MMFR0_EL1_TGRAN_LPA2) && defined(ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_LPA2)
static bool has_lpa2_at_stage1(u64 mmfr0)
{
unsigned int tgran;

+ if (PAGE_SIZE == SZ_64K)
+ return false;
+
tgran = cpuid_feature_extract_unsigned_field(mmfr0,
ID_AA64MMFR0_EL1_TGRAN_SHIFT);
return tgran == ID_AA64MMFR0_EL1_TGRAN_LPA2;
@@ -1845,6 +1847,9 @@ static bool has_lpa2_at_stage2(u64 mmfr0)
{
unsigned int tgran;

+ if (PAGE_SIZE == SZ_64K)
+ return false;
+
tgran = cpuid_feature_extract_unsigned_field(mmfr0,
ID_AA64MMFR0_EL1_TGRAN_2_SHIFT);
return tgran == ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_LPA2;
@@ -1857,10 +1862,26 @@ static bool has_lpa2(const struct arm64_cpu_capabilities *entry, int scope)
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
return has_lpa2_at_stage1(mmfr0) && has_lpa2_at_stage2(mmfr0);
}
-#else
-static bool has_lpa2(const struct arm64_cpu_capabilities *entry, int scope)
+
+#ifdef CONFIG_ARM64_VA_BITS_52
+static bool has_va52(const struct arm64_cpu_capabilities *entry, int scope)
{
- return false;
+ const struct arm64_cpu_capabilities entry_64k = {
+ ARM64_CPUID_FIELDS(ID_AA64MMFR2_EL1, VARange, 52)
+ };
+ const struct arm64_cpu_capabilities entry_16k = {
+ ARM64_CPUID_FIELDS(ID_AA64MMFR0_EL1, TGRAN16, 52_BIT)
+ };
+ const struct arm64_cpu_capabilities entry_4k = {
+ ARM64_CPUID_FIELDS(ID_AA64MMFR0_EL1, TGRAN4, 52_BIT)
+ };
+
+ if (PAGE_SIZE == SZ_64K)
+ return has_cpuid_feature(&entry_64k, scope);
+ else if (PAGE_SIZE == SZ_16K)
+ return has_cpuid_feature(&entry_16k, scope);
+ else
+ return has_cpuid_feature(&entry_4k, scope);
}
#endif

@@ -2847,20 +2868,10 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
},
#ifdef CONFIG_ARM64_VA_BITS_52
{
+ .desc = "52-bit Virtual Addressing",
.capability = ARM64_HAS_VA52,
.type = ARM64_CPUCAP_BOOT_CPU_FEATURE,
- .matches = has_cpuid_feature,
-#ifdef CONFIG_ARM64_64K_PAGES
- .desc = "52-bit Virtual Addressing (LVA)",
- ARM64_CPUID_FIELDS(ID_AA64MMFR2_EL1, VARange, 52)
-#else
- .desc = "52-bit Virtual Addressing (LPA2)",
-#ifdef CONFIG_ARM64_4K_PAGES
- ARM64_CPUID_FIELDS(ID_AA64MMFR0_EL1, TGRAN4, 52_BIT)
-#else
- ARM64_CPUID_FIELDS(ID_AA64MMFR0_EL1, TGRAN16, 52_BIT)
-#endif
-#endif
+ .matches = has_va52,
},
#endif
{
diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c
index de1e09d986ad2..15ce3253ad359 100644
--- a/arch/arm64/mm/fixmap.c
+++ b/arch/arm64/mm/fixmap.c
@@ -82,7 +82,7 @@ static void __init early_fixmap_init_pud(p4d_t *p4dp, unsigned long addr,
* share the top level pgd entry, which should only happen on
* 16k/4 levels configurations.
*/
- BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
+ BUG_ON(PAGE_SIZE != SZ_16K);
}

if (p4d_none(p4d))
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 9b5ab6818f7f3..42eb246949072 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -73,13 +73,10 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit;
* (64k granule), or a multiple that can be mapped using contiguous bits
* in the page tables: 32 * PMD_SIZE (16k granule)
*/
-#if defined(CONFIG_ARM64_4K_PAGES)
-#define ARM64_MEMSTART_SHIFT PUD_SHIFT
-#elif defined(CONFIG_ARM64_16K_PAGES)
-#define ARM64_MEMSTART_SHIFT CONT_PMD_SHIFT
-#else
-#define ARM64_MEMSTART_SHIFT PMD_SHIFT
-#endif
+#define ARM64_MEMSTART_SHIFT \
+ (PAGE_SIZE == SZ_4K ? \
+ PUD_SHIFT : \
+ (PAGE_SIZE == SZ_16K ? CONT_PMD_SHIFT : PMD_SHIFT))

/*
* sparsemem vmemmap imposes an additional requirement on the alignment of
@@ -87,11 +84,10 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit;
* has a direct correspondence, and needs to appear sufficiently aligned
* in the virtual address space.
*/
-#if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS
-#define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS)
-#else
-#define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT)
-#endif
+#define ARM64_MEMSTART_ALIGN \
+ (ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS ? \
+ (1UL << SECTION_SIZE_BITS) : \
+ (1UL << ARM64_MEMSTART_SHIFT))

static void __init arch_reserve_crashkernel(void)
{
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index b65a29440a0c9..9af897fb3c432 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -178,10 +178,10 @@ static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
} while (pgdp++, addr = next, addr != end);
}

-#if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS > 4
+#if CONFIG_PGTABLE_LEVELS > 4
#define SHADOW_ALIGN P4D_SIZE
#else
-#define SHADOW_ALIGN PUD_SIZE
+#define SHADOW_ALIGN (PAGE_SIZE == SZ_64K ? P4D_SIZE : PUD_SIZE)
#endif

/*
@@ -243,8 +243,8 @@ static int __init root_level_idx(u64 addr)
* not implemented. This means we need to index the table as usual,
* instead of masking off bits based on vabits_actual.
*/
- u64 vabits = IS_ENABLED(CONFIG_ARM64_64K_PAGES) ? VA_BITS
- : vabits_actual;
+ u64 vabits = PAGE_SIZE == SZ_64K ? VA_BITS
+ : vabits_actual;
int shift = (ARM64_HW_PGTABLE_LEVELS(vabits) - 1) * (PAGE_SHIFT - 3);

return (addr & ~_PAGE_OFFSET(vabits)) >> (shift + PAGE_SHIFT);
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index d4d30eaefb4cd..a528787c1e550 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1179,7 +1179,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
{
WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));

- if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES))
+ if (PAGE_SIZE != SZ_4K)
return vmemmap_populate_basepages(start, end, node, altmap);
else
return vmemmap_populate_hugepages(start, end, node, altmap);
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index fdec478ba5e70..b745579b4b9f3 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -2323,7 +2323,7 @@ static int its_setup_baser(struct its_node *its, struct its_baser *baser,
baser_phys = virt_to_phys(base);

/* Check if the physical address of the memory is above 48bits */
- if (IS_ENABLED(CONFIG_ARM64_64K_PAGES) && (baser_phys >> 48)) {
+ if (PAGE_SIZE == SZ_64K && (baser_phys >> 48)) {

/* 52bit PA is supported only when PageSize=64K */
if (psz != SZ_64K) {
--
2.43.0