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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: hH+RNZS3loZTceiyZ9QODzURDgqk4bazTl0Yry5JU0EQnwRxrWRvOiQrfHyaWnipCUF9yAAZZPdT2LGzwlQhtxTR1zraRwWMWphSe01l62eajAxrCYa33bQ4GRSWBE7j8OCNPLQPpjhumcpqWx2ADEvSRpVNAA7MUFy5E/X9ZjU/s3gXD1v9Xm3+1FW0/J5bI2N5Gb+aBeSnVx493m4F1QAHlPcqQzPuCAFSSTa2yoD5zG453McyfH0dTRlcsHKkbVGeUzMxify/MYu9plWKkvYcRycBsG9mahM1B0xr2jBmRp7yTADhi5QPF64eTgllZvhBG/vzgVAZNyMMp/dhiksXrQwxnGo5xo7Um+RLFnI5ITIs+yA5QRqWTY/kzwMavBPbMy+5pCefKsafyz9KHN1SGWL0KI1wPVgbSyScJi/BqMzVs11xOGvlNGXfkIHy X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Sep 2026 08:50:23.5936 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 422790ac-64b3-4742-e01c-08df17bd6003 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[4.158.2.129];Helo=[outbound-uk1.az.dlp.m.darktrace.com] X-MS-Exchange-CrossTenant-AuthSource: DB5PEPF00014B97.eurprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB4PR08MB8078 On 18/09/2026 4:55 pm, Ryan Roberts wrote: > On 14/09/2026 14:51, Muhammad Usama Anjum wrote: >> Add hw_pte_val() to preserve an lvalue for the HW PTE bits, so atomic >> updates can take their address. pte_val() expects a SW PTE value and >> cannot operate directly on a distinct hw_pte_t. >> >> With ARCH_HAS_HW_PTE_T, use pte_val() on the wrapper's __pte member; >> otherwise, use pte_val() directly. >> >> The atomic operations and their ordering are unchanged. >> >> Signed-off-by: Muhammad Usama Anjum >> --- >> arch/arm64/include/asm/pgtable.h | 10 +++++----- >> arch/arm64/mm/fault.c | 6 +++--- >> include/linux/pgtable_types.h | 4 ++++ >> 3 files changed, 12 insertions(+), 8 deletions(-) >> >> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h >> index 652ce413be389..4768ec59de555 100644 >> --- a/arch/arm64/include/asm/pgtable.h >> +++ b/arch/arm64/include/asm/pgtable.h >> @@ -1303,7 +1303,7 @@ static inline bool __ptep_test_and_clear_young(struct vm_area_struct *vma, >> do { >> old_pte = pte; >> pte = pte_mkold(pte); >> - pte_val(pte) = cmpxchg_relaxed(&pte_val(*ptep), >> + pte_val(pte) = cmpxchg_relaxed(&hw_pte_val(*ptep), >> pte_val(old_pte), pte_val(pte)); >> } while (pte_val(pte) != pte_val(old_pte)); >> >> @@ -1346,7 +1346,7 @@ static inline pte_t __ptep_get_and_clear_anysz(struct mm_struct *mm, >> hw_pte_t *ptep, >> unsigned long pgsize) >> { >> - pte_t pte = __pte(xchg_relaxed(&pte_val(*ptep), 0)); >> + pte_t pte = __pte(xchg_relaxed(&hw_pte_val(*ptep), 0)); >> >> switch (pgsize) { >> case PAGE_SIZE: >> @@ -1422,7 +1422,7 @@ static inline void ___ptep_set_wrprotect(struct mm_struct *mm, >> do { >> old_pte = pte; >> pte = pte_wrprotect(pte); >> - pte_val(pte) = cmpxchg_relaxed(&pte_val(*ptep), >> + pte_val(pte) = cmpxchg_relaxed(&hw_pte_val(*ptep), >> pte_val(old_pte), pte_val(pte)); >> } while (pte_val(pte) != pte_val(old_pte)); >> } >> @@ -1460,7 +1460,7 @@ static inline void __clear_young_dirty_pte(struct vm_area_struct *vma, >> if (flags & CYDP_CLEAR_DIRTY) >> pte = pte_mkclean(pte); >> >> - pte_val(pte) = cmpxchg_relaxed(&pte_val(*ptep), >> + pte_val(pte) = cmpxchg_relaxed(&hw_pte_val(*ptep), >> pte_val(old_pte), pte_val(pte)); >> } while (pte_val(pte) != pte_val(old_pte)); >> } >> @@ -1830,7 +1830,7 @@ static inline bool ptep_try_set(hw_pte_t *ptep, pte_t new_pte) >> { >> pteval_t old = 0; >> >> - if (!try_cmpxchg(&pte_val(*ptep), &old, pte_val(new_pte))) >> + if (!try_cmpxchg(&hw_pte_val(*ptep), &old, pte_val(new_pte))) >> return false; >> >> /* >> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c >> index b77f4be88e3ea..7d6c30f27214e 100644 >> --- a/arch/arm64/mm/fault.c >> +++ b/arch/arm64/mm/fault.c >> @@ -225,8 +225,8 @@ int __ptep_set_access_flags_anysz(struct vm_area_struct *vma, >> /* >> * Setting the flags must be done atomically to avoid racing with the >> * hardware update of the access/dirty state. The PTE_RDONLY bit must >> - * be set to the most permissive (lowest value) of *ptep and entry >> - * (calculated as: a & b == ~(~a | ~b)). >> + * be set to the most permissive (lowest value) of the current PTE and >> + * entry (calculated as: a & b == ~(~a | ~b)). > > This seems like an unrelated and unecessary comment change? I'm trying to replace *ptep with current PTE for consistency. I'll drop this change. > >> */ >> pte_val(entry) ^= PTE_RDONLY; >> pteval = pte_val(pte); >> @@ -235,7 +235,7 @@ int __ptep_set_access_flags_anysz(struct vm_area_struct *vma, >> pteval ^= PTE_RDONLY; >> pteval |= pte_val(entry); >> pteval ^= PTE_RDONLY; >> - pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval); >> + pteval = cmpxchg_relaxed(&hw_pte_val(*ptep), old_pteval, pteval); >> } while (pteval != old_pteval); >> >> /* >> diff --git a/include/linux/pgtable_types.h b/include/linux/pgtable_types.h >> index d6c5a7548550b..ee4eace5c3e1c 100644 >> --- a/include/linux/pgtable_types.h >> +++ b/include/linux/pgtable_types.h >> @@ -9,9 +9,13 @@ >> #ifdef CONFIG_ARCH_HAS_HW_PTE_T >> typedef struct __hw_pte_t { pte_t __pte; } hw_pte_t; >> #define __pte_from_hw(pte) ((pte).__pte) >> + > > nit: why the newline here (and equivalent below)? I'll drop the newlines. > >> +#define hw_pte_val(x) pte_val((x).__pte) > > Wouldn't it be better to add these as part of the generic series? I know we > prefer to add an api along with its first user, but in this case it seems odd, > because you're effectively requiring that arm64 is the first merged arch to > support this? You could also use the same argument to say that none of this > should be merged until the commit where an arch turns on ARCH_HAS_HW_PTE_T. Agreed. Thanks for explaining. I'll move the definition to the generic series. > > Thanks, > Ryan > > >> #else >> #define hw_pte_t pte_t >> #define __pte_from_hw(pte) (pte) >> + >> +#define hw_pte_val(x) pte_val(x) >> #endif >> >> #endif /* !__ASSEMBLY__ */ >> > -- Thanks, Usama