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[92.145.124.62]) by smtp.gmail.com with ESMTPSA id 13-20020a05600c228d00b0040fb0c90da6sm7215696wmf.14.2024.02.02.04.47.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Feb 2024 04:47:12 -0800 (PST) From: Alexandre Ghiti To: Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Alexandre Ghiti Subject: [PATCH] riscv: Only flush the mm icache when setting an exec pte Date: Fri, 2 Feb 2024 13:47:11 +0100 Message-Id: <20240202124711.256146-1-alexghiti@rivosinc.com> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" We used to emit a flush_icache_all() whenever a dirty executable mapping is set in the page table but we can instead call flush_icache_mm() which will only send IPIs to cores that currently run this mm and add a deferred icache flush to the others. The number of calls to sbi_remote_fence_i() (tested without IPI support): With a simple buildroot rootfs: * Before: ~5k * After : 4 (!) Tested on HW, the boot to login is ~4.5% faster. With an ubuntu rootfs: * Before: ~24k * After : ~13k Signed-off-by: Alexandre Ghiti Reviewed-by: Charlie Jenkins --- arch/riscv/include/asm/pgtable.h | 14 +++++++------- arch/riscv/mm/cacheflush.c | 4 ++-- arch/riscv/mm/pgtable.c | 2 +- 3 files changed, 10 insertions(+), 10 deletions(-) diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgta= ble.h index 0c94260b5d0c..058cfa89dd29 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -513,12 +513,12 @@ static inline void set_pte(pte_t *ptep, pte_t pteval) WRITE_ONCE(*ptep, pteval); } =20 -void flush_icache_pte(pte_t pte); +void flush_icache_pte(struct mm_struct *mm, pte_t pte); =20 -static inline void __set_pte_at(pte_t *ptep, pte_t pteval) +static inline void __set_pte_at(struct mm_struct *mm, pte_t *ptep, pte_t p= teval) { if (pte_present(pteval) && pte_exec(pteval)) - flush_icache_pte(pteval); + flush_icache_pte(mm, pteval); =20 set_pte(ptep, pteval); } @@ -529,7 +529,7 @@ static inline void set_ptes(struct mm_struct *mm, unsig= ned long addr, page_table_check_ptes_set(mm, ptep, pteval, nr); =20 for (;;) { - __set_pte_at(ptep, pteval); + __set_pte_at(mm, ptep, pteval); if (--nr =3D=3D 0) break; ptep++; @@ -541,7 +541,7 @@ static inline void set_ptes(struct mm_struct *mm, unsig= ned long addr, static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - __set_pte_at(ptep, __pte(0)); + __set_pte_at(mm, ptep, __pte(0)); } =20 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS /* defined in mm/pgtable.c */ @@ -707,14 +707,14 @@ static inline void set_pmd_at(struct mm_struct *mm, u= nsigned long addr, pmd_t *pmdp, pmd_t pmd) { page_table_check_pmd_set(mm, pmdp, pmd); - return __set_pte_at((pte_t *)pmdp, pmd_pte(pmd)); + return __set_pte_at(mm, (pte_t *)pmdp, pmd_pte(pmd)); } =20 static inline void set_pud_at(struct mm_struct *mm, unsigned long addr, pud_t *pudp, pud_t pud) { page_table_check_pud_set(mm, pudp, pud); - return __set_pte_at((pte_t *)pudp, pud_pte(pud)); + return __set_pte_at(mm, (pte_t *)pudp, pud_pte(pud)); } =20 #ifdef CONFIG_PAGE_TABLE_CHECK diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c index b0774993c0f3..3e234e95d952 100644 --- a/arch/riscv/mm/cacheflush.c +++ b/arch/riscv/mm/cacheflush.c @@ -85,12 +85,12 @@ void flush_icache_mm(struct mm_struct *mm, bool local) #endif /* CONFIG_SMP */ =20 #ifdef CONFIG_MMU -void flush_icache_pte(pte_t pte) +void flush_icache_pte(struct mm_struct *mm, pte_t pte) { struct folio *folio =3D page_folio(pte_page(pte)); =20 if (!test_bit(PG_dcache_clean, &folio->flags)) { - flush_icache_all(); + flush_icache_mm(mm, false); set_bit(PG_dcache_clean, &folio->flags); } } diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c index ef887efcb679..533ec9055fa0 100644 --- a/arch/riscv/mm/pgtable.c +++ b/arch/riscv/mm/pgtable.c @@ -10,7 +10,7 @@ int ptep_set_access_flags(struct vm_area_struct *vma, pte_t entry, int dirty) { if (!pte_same(ptep_get(ptep), entry)) - __set_pte_at(ptep, entry); + __set_pte_at(vma->vm_mm, ptep, entry); /* * update_mmu_cache will unconditionally execute, handling both * the case that the PTE changed and the spurious fault case. --=20 2.39.2