From: Mike Rapoport <rppt@linux.ibm.com> To: "Russell King (Oracle)" <linux@armlinux.org.uk> Cc: Mike Rapoport <rppt@kernel.org>, linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, Catalin Marinas <catalin.marinas@arm.com>, Christian Borntraeger <borntraeger@de.ibm.com>, David Hildenbrand <david@redhat.com>, Heiko Carstens <hca@linux.ibm.com>, Thomas Bogendoerfer <tsbogend@alpha.franken.de>, Vasily Gorbik <gor@linux.ibm.com>, Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org Subject: Re: [RFC/RFT PATCH 2/5] memblock: introduce generic memblock_setup_resources() Date: Wed, 2 Jun 2021 16:54:17 +0300 [thread overview] Message-ID: <YLeNiUkIw+aFpMcz@linux.ibm.com> (raw) In-Reply-To: <20210602101521.GD30436@shell.armlinux.org.uk> On Wed, Jun 02, 2021 at 11:15:21AM +0100, Russell King (Oracle) wrote: > On Wed, Jun 02, 2021 at 11:33:10AM +0300, Mike Rapoport wrote: > > On Tue, Jun 01, 2021 at 02:54:15PM +0100, Russell King (Oracle) wrote: > > > On Mon, May 31, 2021 at 03:29:56PM +0300, Mike Rapoport wrote: > > > > + code_resource.start = __pa_symbol(_text); > > > > + code_resource.end = __pa_symbol(_etext)-1; > > > > + rodata_resource.start = __pa_symbol(__start_rodata); > > > > + rodata_resource.end = __pa_symbol(__end_rodata)-1; > > > > + data_resource.start = __pa_symbol(_sdata); > > > > + data_resource.end = __pa_symbol(_edata)-1; > > > > + bss_resource.start = __pa_symbol(__bss_start); > > > > + bss_resource.end = __pa_symbol(__bss_stop)-1; > > > > > > This falls short on 32-bit ARM. The old code was: > > > > > > - kernel_code.start = virt_to_phys(_text); > > > - kernel_code.end = virt_to_phys(__init_begin - 1); > > > - kernel_data.start = virt_to_phys(_sdata); > > > - kernel_data.end = virt_to_phys(_end - 1); > > > > > > If I look at one of my kernels: > > > > > > c0008000 T _text > > > c0b5b000 R __end_rodata > > > ... exception and unwind tables live here ... > > > c0c00000 T __init_begin > > > c0e00000 D _sdata > > > c0e68870 D _edata > > > c0e68870 B __bss_start > > > c0e995d4 B __bss_stop > > > c0e995d4 B _end > > > > > > So the original covers _text..__init_begin-1 which includes the > > > exception and unwind tables. Your version above omits these, which > > > leaves them exposed. > > > > Right, this needs to be fixed. Is there any reason the exception and unwind > > tables cannot be placed between _sdata and _edata? > > > > It seems to me that they were left outside for purely historical reasons. > > Commit ee951c630c5c ("ARM: 7568/1: Sort exception table at compile time") > > moved the exception tables out of .data section before _sdata existed. > > Commit 14c4a533e099 ("ARM: 8583/1: mm: fix location of _etext") moved > > _etext before the unwind tables and didn't bother to put them into data or > > rodata areas. > > You can not assume that all sections will be between these symbols. This > isn't specific to 32-bit ARM. If you look at x86's vmlinux.lds.in, you > will see that BUG_TABLE and ORC_UNWIND_TABLE are after _edata, along > with many other undiscarded sections before __bss_start. But if you look at x86's setup_arch() all these never make it to the resource tree. So there are holes in /proc/iomem between the kernel resources. > So it seems your assumptions in trying to clean this up are somewhat > false. My assumption was that there is complete lack of consistency between what is reserved memory and how it is reported in /proc/iomem or /sys/firmware/memmap for that matter. I'm not trying to clean this up, I'm trying to make different views of the physical memory consistent. Consolidating several similar per-arch implementations is the first step in this direction. -- Sincerely yours, Mike.
WARNING: multiple messages have this Message-ID (diff)
From: Mike Rapoport <rppt@linux.ibm.com> To: "Russell King (Oracle)" <linux@armlinux.org.uk> Cc: Mike Rapoport <rppt@kernel.org>, linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, Catalin Marinas <catalin.marinas@arm.com>, Christian Borntraeger <borntraeger@de.ibm.com>, David Hildenbrand <david@redhat.com>, Heiko Carstens <hca@linux.ibm.com>, Thomas Bogendoerfer <tsbogend@alpha.franken.de>, Vasily Gorbik <gor@linux.ibm.com>, Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org Subject: Re: [RFC/RFT PATCH 2/5] memblock: introduce generic memblock_setup_resources() Date: Wed, 2 Jun 2021 16:54:17 +0300 [thread overview] Message-ID: <YLeNiUkIw+aFpMcz@linux.ibm.com> (raw) In-Reply-To: <20210602101521.GD30436@shell.armlinux.org.uk> On Wed, Jun 02, 2021 at 11:15:21AM +0100, Russell King (Oracle) wrote: > On Wed, Jun 02, 2021 at 11:33:10AM +0300, Mike Rapoport wrote: > > On Tue, Jun 01, 2021 at 02:54:15PM +0100, Russell King (Oracle) wrote: > > > On Mon, May 31, 2021 at 03:29:56PM +0300, Mike Rapoport wrote: > > > > + code_resource.start = __pa_symbol(_text); > > > > + code_resource.end = __pa_symbol(_etext)-1; > > > > + rodata_resource.start = __pa_symbol(__start_rodata); > > > > + rodata_resource.end = __pa_symbol(__end_rodata)-1; > > > > + data_resource.start = __pa_symbol(_sdata); > > > > + data_resource.end = __pa_symbol(_edata)-1; > > > > + bss_resource.start = __pa_symbol(__bss_start); > > > > + bss_resource.end = __pa_symbol(__bss_stop)-1; > > > > > > This falls short on 32-bit ARM. The old code was: > > > > > > - kernel_code.start = virt_to_phys(_text); > > > - kernel_code.end = virt_to_phys(__init_begin - 1); > > > - kernel_data.start = virt_to_phys(_sdata); > > > - kernel_data.end = virt_to_phys(_end - 1); > > > > > > If I look at one of my kernels: > > > > > > c0008000 T _text > > > c0b5b000 R __end_rodata > > > ... exception and unwind tables live here ... > > > c0c00000 T __init_begin > > > c0e00000 D _sdata > > > c0e68870 D _edata > > > c0e68870 B __bss_start > > > c0e995d4 B __bss_stop > > > c0e995d4 B _end > > > > > > So the original covers _text..__init_begin-1 which includes the > > > exception and unwind tables. Your version above omits these, which > > > leaves them exposed. > > > > Right, this needs to be fixed. Is there any reason the exception and unwind > > tables cannot be placed between _sdata and _edata? > > > > It seems to me that they were left outside for purely historical reasons. > > Commit ee951c630c5c ("ARM: 7568/1: Sort exception table at compile time") > > moved the exception tables out of .data section before _sdata existed. > > Commit 14c4a533e099 ("ARM: 8583/1: mm: fix location of _etext") moved > > _etext before the unwind tables and didn't bother to put them into data or > > rodata areas. > > You can not assume that all sections will be between these symbols. This > isn't specific to 32-bit ARM. If you look at x86's vmlinux.lds.in, you > will see that BUG_TABLE and ORC_UNWIND_TABLE are after _edata, along > with many other undiscarded sections before __bss_start. But if you look at x86's setup_arch() all these never make it to the resource tree. So there are holes in /proc/iomem between the kernel resources. > So it seems your assumptions in trying to clean this up are somewhat > false. My assumption was that there is complete lack of consistency between what is reserved memory and how it is reported in /proc/iomem or /sys/firmware/memmap for that matter. I'm not trying to clean this up, I'm trying to make different views of the physical memory consistent. Consolidating several similar per-arch implementations is the first step in this direction. -- Sincerely yours, Mike. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-06-02 13:55 UTC|newest] Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-31 12:29 [RFC/RFT PATCH 0/5] consolidate "System RAM" resources setup Mike Rapoport 2021-05-31 12:29 ` Mike Rapoport 2021-05-31 12:29 ` [RFC/RFT PATCH 1/5] s390: make crashk_res resource a child of "System RAM" Mike Rapoport 2021-05-31 12:29 ` Mike Rapoport 2021-06-01 8:45 ` David Hildenbrand 2021-06-01 8:45 ` David Hildenbrand 2021-06-01 9:02 ` David Hildenbrand 2021-06-01 9:02 ` David Hildenbrand 2021-06-02 6:25 ` Mike Rapoport 2021-06-02 6:25 ` Mike Rapoport 2021-06-01 13:18 ` Gerald Schaefer 2021-06-01 13:18 ` Gerald Schaefer 2021-06-02 6:54 ` Mike Rapoport 2021-06-02 6:54 ` Mike Rapoport 2021-05-31 12:29 ` [RFC/RFT PATCH 2/5] memblock: introduce generic memblock_setup_resources() Mike Rapoport 2021-05-31 12:29 ` Mike Rapoport 2021-06-01 13:54 ` Russell King (Oracle) 2021-06-01 13:54 ` Russell King (Oracle) 2021-06-02 8:33 ` Mike Rapoport 2021-06-02 8:33 ` Mike Rapoport 2021-06-02 10:15 ` Russell King (Oracle) 2021-06-02 10:15 ` Russell King (Oracle) 2021-06-02 13:54 ` Mike Rapoport [this message] 2021-06-02 13:54 ` Mike Rapoport 2021-06-02 15:51 ` Russell King (Oracle) 2021-06-02 15:51 ` Russell King (Oracle) 2021-06-02 18:43 ` Mike Rapoport 2021-06-02 18:43 ` Mike Rapoport 2021-06-02 20:15 ` Russell King (Oracle) 2021-06-02 20:15 ` Russell King (Oracle) 2021-06-03 10:32 ` Mike Rapoport 2021-06-03 10:32 ` Mike Rapoport 2021-05-31 12:29 ` [RFC/RFT PATCH 3/5] arm: switch to " Mike Rapoport 2021-05-31 12:29 ` Mike Rapoport 2021-05-31 12:29 ` [RFC/RFT PATCH 4/5] MIPS: switch to generic memblock_setup_resources Mike Rapoport 2021-05-31 12:29 ` Mike Rapoport 2021-05-31 12:29 ` [RFC/RFT PATCH 5/5] arm64: switch to generic memblock_setup_resources() Mike Rapoport 2021-05-31 12:29 ` Mike Rapoport 2021-06-01 13:44 ` [RFC/RFT PATCH 0/5] consolidate "System RAM" resources setup Russell King (Oracle) 2021-06-01 13:44 ` Russell King (Oracle) 2021-06-02 7:05 ` Mike Rapoport 2021-06-02 7:05 ` Mike Rapoport 2021-06-01 1:39 [RFC/RFT PATCH 2/5] memblock: introduce generic memblock_setup_resources() kernel test robot
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