Re: [PATCH 2/2] arm64/ptdump: Replace u64 with pteval_t

From: Anshuman Khandual
Date: Tue Mar 18 2025 - 00:38:18 EST

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In reply to: Ryan Roberts: "Re: [PATCH 2/2] arm64/ptdump: Replace u64 with pteval_t"
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On 3/17/25 14:58, Ryan Roberts wrote:
> On 17/03/2025 06:18, Anshuman Khandual wrote:
>> Page table entry's value, mask and protection are represented with pteval_t
>> data type format not u64 that has been assumed while dumping the page table
>> entries. Replace all such u64 instances with pteval_t instead as required.
>>
>> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
>> Cc: Will Deacon <will@xxxxxxxxxx>
>> Cc: Marc Zyngier <maz@xxxxxxxxxx>
>> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>> Cc: linux-kernel@xxxxxxxxxxxxxxx
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
>> ---
>> arch/arm64/include/asm/ptdump.h | 8 ++++----
>> arch/arm64/mm/ptdump.c | 2 +-
>> 2 files changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
>> index e5da9ce8a515..476a870489b9 100644
>> --- a/arch/arm64/include/asm/ptdump.h
>> +++ b/arch/arm64/include/asm/ptdump.h
>> @@ -24,8 +24,8 @@ struct ptdump_info {
>> };
>>
>> struct ptdump_prot_bits {
>> - u64 mask;
>> - u64 val;
>> + pteval_t mask;
>> + pteval_t val;
>
> Given Ard's suggestion of using "ptdesc" as a generic term for PTDESC_SHIFT (or
> PTDESC_ORDER, or whatever we ended up calling it), I wonder if it would be
> cleaner to do the same with the types? We could have a ptdesc_t, which is
> typedef'ed as u64 (or u128), then pteval_t, pmdval_t, ..., could all be
> typedef'ed as ptdesc_t. Then for code that just wants a generic pgtable
> descriptor value, we can use that type to indicate that it can be at any level.

Something like the following ? Will cross check again if this might have
missed something which could be converted as ptdesc_t as well.

diff --git a/arch/arm64/include/asm/pgtable-types.h b/arch/arm64/include/asm/pgtable-types.h
index 6d6d4065b0cb..686541e986e3 100644
--- a/arch/arm64/include/asm/pgtable-types.h
+++ b/arch/arm64/include/asm/pgtable-types.h
@@ -11,11 +11,13 @@

#include <asm/types.h>

-typedef u64 pteval_t;
-typedef u64 pmdval_t;
-typedef u64 pudval_t;
-typedef u64 p4dval_t;
-typedef u64 pgdval_t;
+typedef u64 ptdesc_t;
+
+typedef ptdesc_t pteval_t;
+typedef ptdesc_t pmdval_t;
+typedef ptdesc_t pudval_t;
+typedef ptdesc_t p4dval_t;
+typedef ptdesc_t pgdval_t;

/*
* These are used to make use of C type-checking..
@@ -46,7 +48,7 @@ typedef struct { pgdval_t pgd; } pgd_t;
#define pgd_val(x) ((x).pgd)
#define __pgd(x) ((pgd_t) { (x) } )

-typedef struct { pteval_t pgprot; } pgprot_t;
+typedef struct { ptdesc_t pgprot; } pgprot_t;
#define pgprot_val(x) ((x).pgprot)
#define __pgprot(x) ((pgprot_t) { (x) } )

diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
index e5da9ce8a515..9548813bc877 100644
--- a/arch/arm64/include/asm/ptdump.h
+++ b/arch/arm64/include/asm/ptdump.h
@@ -24,8 +24,8 @@ struct ptdump_info {
};

struct ptdump_prot_bits {
- u64 mask;
- u64 val;
+ ptdesc_t mask;
+ ptdesc_t val;
const char *set;
const char *clear;
};
@@ -34,7 +34,7 @@ struct ptdump_pg_level {
const struct ptdump_prot_bits *bits;
char name[4];
int num;
- u64 mask;
+ ptdesc_t mask;
};

/*
@@ -51,7 +51,7 @@ struct ptdump_pg_state {
const struct mm_struct *mm;
unsigned long start_address;
int level;
- u64 current_prot;
+ ptdesc_t current_prot;
bool check_wx;
unsigned long wx_pages;
unsigned long uxn_pages;
diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 1d25d8899dbf..42e281c07c2f 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -29,7 +29,7 @@ static bool region_is_misaligned(const efi_memory_desc_t *md)
* executable, everything else can be mapped with the XN bits
* set. Also take the new (optional) RO/XP bits into account.
*/
-static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)
+static __init ptdesc_t create_mapping_protection(efi_memory_desc_t *md)
{
u64 attr = md->attribute;
u32 type = md->type;
@@ -83,7 +83,7 @@ static __init pteval_t create_mapping_protection(efi_memory_desc_t *md)

int __init efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md)
{
- pteval_t prot_val = create_mapping_protection(md);
+ ptdesc_t prot_val = create_mapping_protection(md);
bool page_mappings_only = (md->type == EFI_RUNTIME_SERVICES_CODE ||
md->type == EFI_RUNTIME_SERVICES_DATA);

diff --git a/arch/arm64/kernel/pi/map_kernel.c b/arch/arm64/kernel/pi/map_kernel.c
index e57b043f324b..a00f57c73d81 100644
--- a/arch/arm64/kernel/pi/map_kernel.c
+++ b/arch/arm64/kernel/pi/map_kernel.c
@@ -159,7 +159,7 @@ static void noinline __section(".idmap.text") set_ttbr0_for_lpa2(u64 ttbr)
static void __init remap_idmap_for_lpa2(void)
{
/* clear the bits that change meaning once LPA2 is turned on */
- pteval_t mask = PTE_SHARED;
+ ptdesc_t mask = PTE_SHARED;

/*
* We have to clear bits [9:8] in all block or page descriptors in the
diff --git a/arch/arm64/kernel/pi/map_range.c b/arch/arm64/kernel/pi/map_range.c
index 2b69e3beeef8..30c6bc50844f 100644
--- a/arch/arm64/kernel/pi/map_range.c
+++ b/arch/arm64/kernel/pi/map_range.c
@@ -30,7 +30,7 @@ void __init map_range(u64 *pte, u64 start, u64 end, u64 pa, pgprot_t prot,
int level, pte_t *tbl, bool may_use_cont, u64 va_offset)
{
u64 cmask = (level == 3) ? CONT_PTE_SIZE - 1 : U64_MAX;
- pteval_t protval = pgprot_val(prot) & ~PTE_TYPE_MASK;
+ ptdesc_t protval = pgprot_val(prot) & ~PTE_TYPE_MASK;
int lshift = (3 - level) * (PAGE_SHIFT - 3);
u64 lmask = (PAGE_SIZE << lshift) - 1;

@@ -87,7 +87,7 @@ void __init map_range(u64 *pte, u64 start, u64 end, u64 pa, pgprot_t prot,
}
}

-asmlinkage u64 __init create_init_idmap(pgd_t *pg_dir, pteval_t clrmask)
+asmlinkage u64 __init create_init_idmap(pgd_t *pg_dir, ptdesc_t clrmask)
{
u64 ptep = (u64)pg_dir + PAGE_SIZE;
pgprot_t text_prot = PAGE_KERNEL_ROX;
diff --git a/arch/arm64/kernel/pi/pi.h b/arch/arm64/kernel/pi/pi.h
index c91e5e965cd3..91dcb5b6bbd1 100644
--- a/arch/arm64/kernel/pi/pi.h
+++ b/arch/arm64/kernel/pi/pi.h
@@ -33,4 +33,4 @@ void map_range(u64 *pgd, u64 start, u64 end, u64 pa, pgprot_t prot,

asmlinkage void early_map_kernel(u64 boot_status, void *fdt);

-asmlinkage u64 create_init_idmap(pgd_t *pgd, pteval_t clrmask);
+asmlinkage u64 create_init_idmap(pgd_t *pgd, ptdesc_t clrmask);
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index 07aeab8a7606..c86c348857c4 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -83,7 +83,7 @@ arch_initcall(adjust_protection_map);

pgprot_t vm_get_page_prot(unsigned long vm_flags)
{
- pteval_t prot;
+ ptdesc_t prot;

/* Short circuit GCS to avoid bloating the table. */
if (system_supports_gcs() && (vm_flags & VM_SHADOW_STACK)) {
diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
index fd1610b4fd15..280e850f1688 100644
--- a/arch/arm64/mm/ptdump.c
+++ b/arch/arm64/mm/ptdump.c
@@ -194,7 +194,7 @@ void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump);
struct ptdump_pg_level *pg_level = st->pg_level;
static const char units[] = "KMGTPE";
- u64 prot = 0;
+ ptdesc_t prot = 0;

/* check if the current level has been folded dynamically */
if (st->mm && ((level == 1 && mm_p4d_folded(st->mm)) ||
--
2.25.1

>
> Thanks,
> Ryan
>
>> const char *set;
>> const char *clear;
>> };
>> @@ -34,7 +34,7 @@ struct ptdump_pg_level {
>> const struct ptdump_prot_bits *bits;
>> char name[4];
>> int num;
>> - u64 mask;
>> + pteval_t mask;
>> };
>>
>> /*
>> @@ -51,7 +51,7 @@ struct ptdump_pg_state {
>> const struct mm_struct *mm;
>> unsigned long start_address;
>> int level;
>> - u64 current_prot;
>> + pteval_t current_prot;
>> bool check_wx;
>> unsigned long wx_pages;
>> unsigned long uxn_pages;
>> diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
>> index fd1610b4fd15..a5651be95868 100644
>> --- a/arch/arm64/mm/ptdump.c
>> +++ b/arch/arm64/mm/ptdump.c
>> @@ -194,7 +194,7 @@ void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
>> struct ptdump_pg_state *st = container_of(pt_st, struct ptdump_pg_state, ptdump);
>> struct ptdump_pg_level *pg_level = st->pg_level;
>> static const char units[] = "KMGTPE";
>> - u64 prot = 0;
>> + pteval_t prot = 0;
>>
>> /* check if the current level has been folded dynamically */
>> if (st->mm && ((level == 1 && mm_p4d_folded(st->mm)) ||
>

Next message: Marcelo Schmitt: "Re: [PATCH v2] iio: frequency: ad9832: Use FIELD_PREP macro to set bit fields"
Previous message: Zhang Yi: "Re: [PATCH] jbd2: add a missing data flush during file and fs synchronization"
In reply to: Ryan Roberts: "Re: [PATCH 2/2] arm64/ptdump: Replace u64 with pteval_t"
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