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 AD0F87C for ; Wed, 7 Jun 2023 02:57:30 +0000 (UTC) Received: from loongson.cn (unknown [10.20.42.170]) by gateway (Coremail) with SMTP id _____8CxPusX8n9kCwEAAA--.41S3; Wed, 07 Jun 2023 10:57:27 +0800 (CST) Received: from [10.20.42.170] (unknown [10.20.42.170]) by localhost.localdomain (Coremail) with SMTP id AQAAf8DxluQU8n9knq8DAA--.13597S3; Wed, 07 Jun 2023 10:57:24 +0800 (CST) Message-ID: Date: Wed, 7 Jun 2023 10:57:24 +0800 Precedence: bulk X-Mailing-List: loongarch@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH] LoongArch: let pmd_present return true when splitting pmd Content-Language: en-US From: "bibo, mao" To: zhanghongchen@loongson.cn Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, loongson-kernel@lists.loongnix.cn, Huacai Chen , WANG Xuerui , Andrew Morton , Anshuman Khandual , David Hildenbrand , Mike Rapoport , Jiaxun Yang , Feiyang Chen , Qi Zheng References: <20230524074132.10916-1-zhanghongchen@loongson.cn> <46ce41a3-16bd-6d92-c8a8-764283859190@loongson.cn> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CM-TRANSID:AQAAf8DxluQU8n9knq8DAA--.13597S3 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBj93XoWxCrW5ur47WrWxKrykuF18tFc_yoWrGryDpw n7CFy8CrW5KFn7C34YqFy3XryUArsrG3Wqqr98GF18AFW7X3s2qrn8Wr909ry8Xan5tFy8 Xr45Ww15uFy3JwbCm3ZEXasCq-sJn29KB7ZKAUJUUUU7529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUPIb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_JFI_Gr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6r4UJVWxJr1ln4kS14v26r1Y6r17M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12 xvs2x26I8E6xACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r12 6r1DMcIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IY64vIr4 1lc7I2V7IY0VAS07AlzVAYIcxG8wCY1x0262kKe7AKxVWUAVWUtwCF04k20xvY0x0EwIxG rwCFx2IqxVCFs4IE7xkEbVWUJVW8JwCFI7km07C267AKxVWUXVWUAwC20s026c02F40E14 v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkG c2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI 0_Jr0_Gr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4U MIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07j7BMNUUU UU= I suggest to using bit12-bit20 since high weight bits such 63-61 are hw bits, it may expand for future hw use, or you had better negotiate with hw guys. >>> +#define _PAGE_PRESENT_INVALID_SHIFT 60 >>> #define _PAGE_NO_READ_SHIFT 61 >>> #define _PAGE_NO_EXEC_SHIFT 62 >>> #define _PAGE_RPLV_SHIFT 63 Regards Bibo, Mao 在 2023/6/6 21:49, bibo, mao 写道: > I do not object to adding sw bit for _PAGE_PRESENT_INVALID, only that can it use > bit12--bit20 since it is for pmd entry only? > > Regards > Bibo, Mao > > 在 2023/6/6 19:38, Hongchen Zhang 写道: >> 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 >> >> _______________________________________________ >> Loongson-kernel mailing list -- loongson-kernel@lists.loongnix.cn >> To unsubscribe send an email to loongson-kernel-leave@lists.loongnix.cn