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[92.145.124.62]) by smtp.gmail.com with ESMTPSA id h3-20020a5d4303000000b0033629538fa2sm5560888wrq.18.2023.12.13.12.31.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 Dec 2023 12:31:18 -0800 (PST) From: Alexandre Ghiti To: Russell King , Ryan Roberts , Alexander Potapenko , Marco Elver , Dmitry Vyukov , Paul Walmsley , Palmer Dabbelt , Albert Ou , Anup Patel , Atish Patra , Ard Biesheuvel , Andrey Ryabinin , Andrey Konovalov , Vincenzo Frascino , kasan-dev@googlegroups.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-efi@vger.kernel.org, linux-mm@kvack.org Cc: Alexandre Ghiti Subject: [PATCH v2 1/4] riscv: Use WRITE_ONCE() when setting page table entries Date: Wed, 13 Dec 2023 21:29:58 +0100 Message-Id: <20231213203001.179237-2-alexghiti@rivosinc.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231213203001.179237-1-alexghiti@rivosinc.com> References: <20231213203001.179237-1-alexghiti@rivosinc.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To avoid any compiler "weirdness" when accessing page table entries which are concurrently modified by the HW, let's use WRITE_ONCE() macro (commit 20a004e7b017 ("arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables") gives a great explanation with more details). Signed-off-by: Alexandre Ghiti --- arch/riscv/include/asm/pgtable-64.h | 6 +++--- arch/riscv/include/asm/pgtable.h | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h index 9a2c780a11e9..5d8431a390dd 100644 --- a/arch/riscv/include/asm/pgtable-64.h +++ b/arch/riscv/include/asm/pgtable-64.h @@ -202,7 +202,7 @@ static inline int pud_user(pud_t pud) static inline void set_pud(pud_t *pudp, pud_t pud) { - *pudp = pud; + WRITE_ONCE(*pudp, pud); } static inline void pud_clear(pud_t *pudp) @@ -278,7 +278,7 @@ static inline unsigned long _pmd_pfn(pmd_t pmd) static inline void set_p4d(p4d_t *p4dp, p4d_t p4d) { if (pgtable_l4_enabled) - *p4dp = p4d; + WRITE_ONCE(*p4dp, p4d); else set_pud((pud_t *)p4dp, (pud_t){ p4d_val(p4d) }); } @@ -351,7 +351,7 @@ static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address) static inline void set_pgd(pgd_t *pgdp, pgd_t pgd) { if (pgtable_l5_enabled) - *pgdp = pgd; + WRITE_ONCE(*pgdp, pgd); else set_p4d((p4d_t *)pgdp, (p4d_t){ pgd_val(pgd) }); } diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 294044429e8e..c9f4b250b4ee 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -248,7 +248,7 @@ static inline int pmd_leaf(pmd_t pmd) static inline void set_pmd(pmd_t *pmdp, pmd_t pmd) { - *pmdp = pmd; + WRITE_ONCE(*pmdp, pmd); } static inline void pmd_clear(pmd_t *pmdp) @@ -510,7 +510,7 @@ static inline int pte_same(pte_t pte_a, pte_t pte_b) */ static inline void set_pte(pte_t *ptep, pte_t pteval) { - *ptep = pteval; + WRITE_ONCE(*ptep, pteval); } void flush_icache_pte(pte_t pte);