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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Pasha Tatashin , Russell King , Catalin Marinas , Will Deacon , Ryan Roberts , linux-arm-kernel@lists.infradead.org, Huacai Chen , loongarch@lists.linux.dev, "James E.J. Bottomley" , Helge Deller , linux-parisc@vger.kernel.org, Madhavan Srinivasan , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Gerald Schaefer , linux-s390@vger.kernel.org, "David S. Miller" , Andreas Larsson , sparclinux@vger.kernel.org, Richard Weinberger , Anton Ivanov , Johannes Berg , linux-um@lists.infradead.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Ning Sun , x86@kernel.org, tboot-devel@lists.sourceforge.net, Ard Biesheuvel , Ilias Apalodimas , linux-efi@vger.kernel.org, Vishal Moola , Alistair Popple , "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1784037902; l=2504; i=kevin.brodsky@arm.com; s=20260427; h=from:subject:message-id; bh=FInc2gTxhVQc4LYtwtKoJPw43dSvFTnMs+LPVQ5s9u0=; b=LLyApQy3cCX+sEK7+yEv+wdSQwFfqhZ/PtGYmJI+JJbZMoulhtvHZSYrG2onhzlRcBnCeJhTe oQ14mia3FhGBEfCDsSpVX5EPWBdyUPXpBCd8WmZOxEP54NLEVWz9CaD X-Developer-Key: i=kevin.brodsky@arm.com; a=ed25519; pk=N2QG+eJKrvkNovwhhwJhnJ4+ScVfsGCHldmqLfcMTFs= X-Rspamd-Queue-Id: 577FD14000C X-Rspam-User: X-Stat-Signature: 6j8sstbw8t9z1ct5pdwj5m3ersqcpuip X-Rspamd-Server: rspam03 X-HE-Tag: 1784037934-421760 X-HE-Meta: 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 49XCTMON snGVTuCC5jD/MFBAndAsYk3nrfoWzxJa2nGQPedgj7oF6Rkjs8ZpD22GZ2p4liERgRONh2KlklFFKwYi+bv6ZFRQLiuyQySg1nnDvBTxcnuXN13ZTOSiFBvf/QbLeoqVCROgrOR/cFYYIL7MwAymehh4eWxCjmWXEA2mHk6WYtT+eMm69YLS4BldOnsXrBGSonclcHjxgJCa0R2+PQI76augvlHh8Ckvji+Vy2Ab4Nk5prosy3+NeXwRakH/j3Hwqda3W/Bj+FwBp3kTMHZpHR2SFnmE9bBYh5hP5KDugytMgX3Acuq9q6yz6PcyFy0h0jV9XE+oMbvz1nLOps+2J8ljJwqiWKaK8QjlcoWyw4YaZzch8BDv4q++96g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: mm code often needs to know whether some mm represents a kernel or user address space. This is currently done by comparing the mm pointer with &init_mm; besides not being particularly elegant, this ignores the fact that other mm's (e.g. efi_mm) may also represent parts of the kernel address space. Introduce a new mm flag MMF_KERNEL and set it for init_mm. Subsequent patches will use this flag to replace comparisons with &init_mm. No functional change is introduced for now. Assisted-by: Codex:GPT-5.5 Signed-off-by: Kevin Brodsky --- include/linux/mm_types.h | 10 ++++++++++ mm/init-mm.c | 1 + 2 files changed, 11 insertions(+) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index a2e0dc5892ff..7838ea3aac00 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -1414,6 +1414,8 @@ struct mm_struct { char flexible_array[] __aligned(__alignof__(unsigned long)); }; +#define MM_FLAGS_INIT(flags) { .__mm_flags = { BITMAP_FROM_U64(flags) } } + static inline bool mm_flags_test(int flag, const struct mm_struct *mm) { return test_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags)); @@ -2001,6 +2003,9 @@ enum { #define MMF_TOPDOWN 31 /* mm searches top down by default */ #define MMF_TOPDOWN_MASK BIT(MMF_TOPDOWN) +#define MMF_KERNEL 32 /* mm belongs to the kernel */ +#define MMF_KERNEL_MASK BIT_ULL(MMF_KERNEL) + #define MMF_INIT_LEGACY_MASK (MMF_DUMP_FILTER_MASK |\ MMF_DISABLE_THP_MASK | MMF_HAS_MDWE_MASK |\ MMF_VM_MERGE_ANY_MASK | MMF_TOPDOWN_MASK) @@ -2008,6 +2013,11 @@ enum { /* Legacy flags must fit within 32 bits. */ static_assert((u64)MMF_INIT_LEGACY_MASK <= (u64)UINT_MAX); +static inline bool mm_is_kernel(const struct mm_struct *mm) +{ + return mm && mm_flags_test(MMF_KERNEL, mm); +} + /* * Initialise legacy flags according to masks, propagating selected flags on * fork. Further flag manipulation can be performed by the caller. diff --git a/mm/init-mm.c b/mm/init-mm.c index 3e792aad7626..93773269bf87 100644 --- a/mm/init-mm.c +++ b/mm/init-mm.c @@ -34,6 +34,7 @@ struct mm_struct init_mm = { .pgd = swapper_pg_dir, .mm_users = ATOMIC_INIT(2), .mm_count = ATOMIC_INIT(1), + .flags = MM_FLAGS_INIT(MMF_KERNEL_MASK), .write_protect_seq = SEQCNT_ZERO(init_mm.write_protect_seq), MMAP_LOCK_INITIALIZER(init_mm) .page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock), -- 2.51.2