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From: 潘庆霖 <panqinglin2020@iscas.ac.cn>
To: "Anup Patel" <apatel@ventanamicro.com>
Cc: "Palmer Dabbelt" <palmer@dabbelt.com>,
	 "Paul Walmsley" <paul.walmsley@sifive.com>,
	 "Alexandre Ghiti" <alexandre.ghiti@canonical.com>,
	 "Atish Patra" <atishp@atishpatra.org>,
	 "Alistair Francis" <Alistair.Francis@wdc.com>,
	 "Anup Patel" <anup@brainfault.org>,
	linux-riscv@lists.infradead.org,  linux-kernel@vger.kernel.org,
	 "Mayuresh Chitale" <mchitale@ventanamicro.com>
Subject: Re: [PATCH] RISC-V: mm: Fix set_satp_mode() for platform not having Sv57
Date: Fri, 15 Apr 2022 12:47:22 +0800 (GMT+08:00)	[thread overview]
Message-ID: <4c4c7a.17284.1802b8c14cc.Coremail.panqinglin2020@iscas.ac.cn> (raw)
In-Reply-To: <20220412033335.1384230-1-apatel@ventanamicro.com>

Hi Anup,

&gt; 
&gt; When Sv57 is not available the satp.MODE test in set_satp_mode() will
&gt; fail and lead to pgdir re-programming for Sv48. The pgdir re-programming
&gt; will fail as well due to pre-existing pgdir entry used for Sv57 and as
&gt; a result kernel fails to boot on RISC-V platform not having Sv57.
&gt; 
&gt; To fix above issue, we should clear the pgdir memory in set_satp_mode()
&gt; before re-programming.
&gt; 
&gt; Fixes: 011f09d12052 ("riscv: mm: Set sv57 on defaultly")
&gt; Reported-by: Mayuresh Chitale <mchitale@ventanamicro.com>
&gt; Signed-off-by: Anup Patel <apatel@ventanamicro.com>
&gt; ---
&gt;  arch/riscv/mm/init.c | 1 +
&gt;  1 file changed, 1 insertion(+)
&gt; 
&gt; diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
&gt; index 9535bea8688c..b0793dc0c291 100644
&gt; --- a/arch/riscv/mm/init.c
&gt; +++ b/arch/riscv/mm/init.c
&gt; @@ -718,6 +718,7 @@ static __init void set_satp_mode(void)
&gt;  		if (!check_l4) {
&gt;  			disable_pgtable_l5();
&gt;  			check_l4 = true;
&gt; +			memset(early_pg_dir, 0, PAGE_SIZE);
&gt;  			goto retry;
&gt;  		}
&gt;  		disable_pgtable_l4();
&gt; -- 


I find it that the set_satp_mode function is in .init.text section which begins at 0x80800000.
And its pgd_index in both Sv48 and Sv57 will be 0. So it may not be necessary to clear the 
early_pg_dir when the kernel find Sv57 is not supported? And may I get the steps of reproduction
from you?
 
Yours,
Qinglin
</apatel@ventanamicro.com></mchitale@ventanamicro.com>
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WARNING: multiple messages have this Message-ID (diff)
From: 潘庆霖 <panqinglin2020@iscas.ac.cn>
To: "Anup Patel" <apatel@ventanamicro.com>
Cc: "Palmer Dabbelt" <palmer@dabbelt.com>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Alexandre Ghiti" <alexandre.ghiti@canonical.com>,
	"Atish Patra" <atishp@atishpatra.org>,
	"Alistair Francis" <Alistair.Francis@wdc.com>,
	"Anup Patel" <anup@brainfault.org>,
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	"Mayuresh Chitale" <mchitale@ventanamicro.com>
Subject: Re: [PATCH] RISC-V: mm: Fix set_satp_mode() for platform not having Sv57
Date: Fri, 15 Apr 2022 12:47:22 +0800 (GMT+08:00)	[thread overview]
Message-ID: <4c4c7a.17284.1802b8c14cc.Coremail.panqinglin2020@iscas.ac.cn> (raw)
In-Reply-To: <20220412033335.1384230-1-apatel@ventanamicro.com>

Hi Anup,

&gt; 
&gt; When Sv57 is not available the satp.MODE test in set_satp_mode() will
&gt; fail and lead to pgdir re-programming for Sv48. The pgdir re-programming
&gt; will fail as well due to pre-existing pgdir entry used for Sv57 and as
&gt; a result kernel fails to boot on RISC-V platform not having Sv57.
&gt; 
&gt; To fix above issue, we should clear the pgdir memory in set_satp_mode()
&gt; before re-programming.
&gt; 
&gt; Fixes: 011f09d12052 ("riscv: mm: Set sv57 on defaultly")
&gt; Reported-by: Mayuresh Chitale <mchitale@ventanamicro.com>
&gt; Signed-off-by: Anup Patel <apatel@ventanamicro.com>
&gt; ---
&gt;  arch/riscv/mm/init.c | 1 +
&gt;  1 file changed, 1 insertion(+)
&gt; 
&gt; diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
&gt; index 9535bea8688c..b0793dc0c291 100644
&gt; --- a/arch/riscv/mm/init.c
&gt; +++ b/arch/riscv/mm/init.c
&gt; @@ -718,6 +718,7 @@ static __init void set_satp_mode(void)
&gt;  		if (!check_l4) {
&gt;  			disable_pgtable_l5();
&gt;  			check_l4 = true;
&gt; +			memset(early_pg_dir, 0, PAGE_SIZE);
&gt;  			goto retry;
&gt;  		}
&gt;  		disable_pgtable_l4();
&gt; -- 


I find it that the set_satp_mode function is in .init.text section which begins at 0x80800000.
And its pgd_index in both Sv48 and Sv57 will be 0. So it may not be necessary to clear the 
early_pg_dir when the kernel find Sv57 is not supported? And may I get the steps of reproduction
from you?
 
Yours,
Qinglin
</apatel@ventanamicro.com></mchitale@ventanamicro.com>

  reply	other threads:[~2022-04-15  4:48 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-12  3:33 [PATCH] RISC-V: mm: Fix set_satp_mode() for platform not having Sv57 Anup Patel
2022-04-12  3:33 ` Anup Patel
2022-04-15  4:47 ` 潘庆霖 [this message]
2022-04-15  4:47   ` 潘庆霖
2022-04-15  4:53   ` Anup Patel
2022-04-15  4:53     ` Anup Patel
2022-04-15  5:10     ` 潘庆霖
2022-04-15  5:10       ` 潘庆霖
2022-04-15  5:47 ` Atish Patra
2022-04-15  5:47   ` Atish Patra
2022-04-21  9:30 ` Anup Patel
2022-04-21  9:30   ` Anup Patel
2022-04-21 21:12   ` Palmer Dabbelt
2022-04-21 21:12     ` Palmer Dabbelt

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