From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B9B2115AD2 for ; Tue, 6 Jun 2023 11:40:06 +0000 (UTC) Received: from loongson.cn (unknown [10.180.13.185]) by gateway (Coremail) with SMTP id _____8AxHusIG39kkyIAAA--.681S3; Tue, 06 Jun 2023 19:39:52 +0800 (CST) Received: from [10.180.13.185] (unknown [10.180.13.185]) by localhost.localdomain (Coremail) with SMTP id AQAAf8DxluQFG39kWkkCAA--.9429S3; Tue, 06 Jun 2023 19:39:49 +0800 (CST) Subject: Re: [PATCH] LoongArch: let pmd_present return true when splitting pmd To: Huacai Chen , WANG Xuerui , Andrew Morton , Anshuman Khandual , David Hildenbrand , Mike Rapoport , Jiaxun Yang , Feiyang Chen , Qi Zheng Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, loongson-kernel@lists.loongnix.cn References: <20230524074132.10916-1-zhanghongchen@loongson.cn> From: Hongchen Zhang Message-ID: <46ce41a3-16bd-6d92-c8a8-764283859190@loongson.cn> Date: Tue, 6 Jun 2023 19:38:38 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 Precedence: bulk X-Mailing-List: loongarch@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20230524074132.10916-1-zhanghongchen@loongson.cn> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-CM-TRANSID:AQAAf8DxluQFG39kWkkCAA--.9429S3 X-CM-SenderInfo: x2kd0w5krqwupkhqwqxorr0wxvrqhubq/1tbiAQANB2R8fwAONwAGsT X-Coremail-Antispam: 1Uk129KBj93XoWxXrykur4kWw15Cr1DCr47WrX_yoW5Gr17p3 Z7CFykur45KFyIy343tF1fZry7ursrGFn2gryqgw1UAFy3X397Jrn8Kwn8ZFy8XayvyFW8 Wrn2g3W5Way3J3cCm3ZEXasCq-sJn29KB7ZKAUJUUUUx529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUPFb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Jr0_Gr1l84ACjcxK6I8E87Iv67AKxVWxJr0_GcWl84ACjcxK6I8E87Iv6xkF7I0E14v2 6F4UJVW0owAaw2AFwI0_JF0_Jw1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2xF0c Ia020Ex4CE44I27wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JF0_ Jw1lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvEwIxGrw CYjI0SjxkI62AI1cAE67vIY487MxkF7I0En4kS14v26r126r1DMxAIw28IcxkI7VAKI48J MxC20s026xCaFVCjc4AY6r1j6r4UMxCIbckI1I0E14v26r1Y6r17MI8I3I0E5I8CrVAFwI 0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y 0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxV WUJVW8JwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1l IxAIcVC2z280aVCY1x0267AKxVWUJVW8JbIYCTnIWIevJa73UjIFyTuYvjxUcbAwUUUUU Hi, Gentle ping. On 2023/5/24 pm 3:41, Hongchen Zhang wrote: > when we split a pmd into ptes, pmd_present() and pmd_trans_huge() should > return true,otherwise it would be treated as a swap pmd. > As arm64 does in > commit b65399f6111b ("arm64/mm: Change THP helpers to comply with generic MM semantics") > we add a _PAGE_PRESENT_INVALID bit for LoongArch. > > Signed-off-by: Hongchen Zhang > --- > arch/loongarch/include/asm/pgtable-bits.h | 2 ++ > arch/loongarch/include/asm/pgtable.h | 3 ++- > 2 files changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/loongarch/include/asm/pgtable-bits.h b/arch/loongarch/include/asm/pgtable-bits.h > index 8b98d22a145b..a7469d28d9d0 100644 > --- a/arch/loongarch/include/asm/pgtable-bits.h > +++ b/arch/loongarch/include/asm/pgtable-bits.h > @@ -22,12 +22,14 @@ > #define _PAGE_PFN_SHIFT 12 > #define _PAGE_SWP_EXCLUSIVE_SHIFT 23 > #define _PAGE_PFN_END_SHIFT 48 > +#define _PAGE_PRESENT_INVALID_SHIFT 60 > #define _PAGE_NO_READ_SHIFT 61 > #define _PAGE_NO_EXEC_SHIFT 62 > #define _PAGE_RPLV_SHIFT 63 > > /* Used by software */ > #define _PAGE_PRESENT (_ULCAST_(1) << _PAGE_PRESENT_SHIFT) > +#define _PAGE_PRESENT_INVALID (_ULCAST_(1) << _PAGE_PRESENT_INVALID_SHIFT) > #define _PAGE_WRITE (_ULCAST_(1) << _PAGE_WRITE_SHIFT) > #define _PAGE_ACCESSED (_ULCAST_(1) << _PAGE_ACCESSED_SHIFT) > #define _PAGE_MODIFIED (_ULCAST_(1) << _PAGE_MODIFIED_SHIFT) > diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h > index d28fb9dbec59..9a9f9ff9b709 100644 > --- a/arch/loongarch/include/asm/pgtable.h > +++ b/arch/loongarch/include/asm/pgtable.h > @@ -213,7 +213,7 @@ static inline int pmd_bad(pmd_t pmd) > static inline int pmd_present(pmd_t pmd) > { > if (unlikely(pmd_val(pmd) & _PAGE_HUGE)) > - return !!(pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROTNONE)); > + return !!(pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROTNONE | _PAGE_PRESENT_INVALID)); > > return pmd_val(pmd) != (unsigned long)invalid_pte_table; > } > @@ -558,6 +558,7 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) > > static inline pmd_t pmd_mkinvalid(pmd_t pmd) > { > + pmd_val(pmd) |= _PAGE_PRESENT_INVALID; > pmd_val(pmd) &= ~(_PAGE_PRESENT | _PAGE_VALID | _PAGE_DIRTY | _PAGE_PROTNONE); > > return pmd; > > base-commit: f1fcbaa18b28dec10281551dfe6ed3a3ed80e3d6 > Best Regards Hongchen Zhang