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Date:   Fri, 26 Feb 2021 13:17:30 +0200
From:   Mike Rapoport <rppt@linux.ibm.com>
To:     George Kennedy <george.kennedy@oracle.com>
Cc:     David Hildenbrand <david@redhat.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Konrad Rzeszutek Wilk <konrad@darnok.org>,
        Will Deacon <will.deacon@arm.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>,
        Peter Collingbourne <pcc@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Christoph Hellwig <hch@infradead.org>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Dhaval Giani <dhaval.giani@oracle.com>
Subject: Re: [PATCH] mm, kasan: don't poison boot memory
Message-ID: <20210226111730.GL1854360@linux.ibm.com>
References: <450a9895-a2b4-d11b-97ca-1bd33d5308d4@oracle.com>
 <20210224103754.GA1854360@linux.ibm.com>
 <9b7251d1-7b90-db4f-fa5e-80165e1cbb4b@oracle.com>
 <20210225085300.GB1854360@linux.ibm.com>
 <9973d0e2-e28b-3f8a-5f5d-9d142080d141@oracle.com>
 <20210225145700.GC1854360@linux.ibm.com>
 <bb444ddb-d60d-114f-c2fe-64e5fb34102d@oracle.com>
 <20210225160706.GD1854360@linux.ibm.com>
 <6000e7fd-bf8b-b9b0-066d-23661da8a51d@oracle.com>
 <dc5e007c-9223-b03b-1c58-28d2712ec352@oracle.com>
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Hi George,

On Thu, Feb 25, 2021 at 08:19:18PM -0500, George Kennedy wrote:
> 
> Mike,
> 
> To get rid of the 0x00000000BE453000 hardcoding, I added the following patch
> to your above patch to get the iBFT table "address" to use with
> memblock_reserve():
> 
> diff --git a/drivers/acpi/acpica/tbfind.c b/drivers/acpi/acpica/tbfind.c
> index 56d81e4..4bc7bf3 100644
> --- a/drivers/acpi/acpica/tbfind.c
> +++ b/drivers/acpi/acpica/tbfind.c
> @@ -120,3 +120,34 @@
> ???? (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
> ???? return_ACPI_STATUS(status);
> ?}
> +
> +acpi_physical_address
> +acpi_tb_find_table_address(char *signature)
> +{
> +??? acpi_physical_address address = 0;
> +??? struct acpi_table_desc *table_desc;
> +??? int i;
> +
> +??? ACPI_FUNCTION_TRACE(tb_find_table_address);
> +
> +printk(KERN_ERR "XXX acpi_tb_find_table_address: signature=%s\n",
> signature);
> +
> +??? (void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
> +??? for (i = 0; i < acpi_gbl_root_table_list.current_table_count; ++i) {
> +??? ??? if (memcmp(&(acpi_gbl_root_table_list.tables[i].signature),
> +??? ??? ??? ?? signature, ACPI_NAMESEG_SIZE)) {
> +
> +??? ??? ??? /* Not the requested table */
> +
> +??? ??? ??? continue;
> +??? ??? }
> +
> +??? ??? /* Table with matching signature has been found */
> +??? ??? table_desc = &acpi_gbl_root_table_list.tables[i];
> +??? ??? address = table_desc->address;
> +??? }
> +
> +??? (void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
> +printk(KERN_ERR "XXX acpi_tb_find_table_address(EXIT): address=%llx\n",
> address);
> +??? return address;
> +}
> diff --git a/drivers/firmware/iscsi_ibft_find.c
> b/drivers/firmware/iscsi_ibft_find.c
> index 95fc1a6..0de70b4 100644
> --- a/drivers/firmware/iscsi_ibft_find.c
> +++ b/drivers/firmware/iscsi_ibft_find.c
> @@ -28,6 +28,8 @@
> 
> ?#include <asm/mmzone.h>
> 
> +extern acpi_physical_address acpi_tb_find_table_address(char *signature);
> +
> ?/*
> ? * Physical location of iSCSI Boot Format Table.
> ? */
> @@ -116,24 +118,32 @@ void __init reserve_ibft_region(void)
> ?{
> ???? struct acpi_table_ibft *table;
> ???? unsigned long size;
> +??? acpi_physical_address address;
> 
> ???? table = find_ibft();
> ???? if (!table)
> ???? ??? return;
> 
> ???? size = PAGE_ALIGN(table->header.length);
> +??? address = acpi_tb_find_table_address(table->header.signature);
> ?#if 0
> ?printk(KERN_ERR "XXX reserve_ibft_region: table=%llx,
> virt_to_phys(table)=%llx, size=%lx\n",
> ???? (u64)table, virt_to_phys(table), size);
> ???? memblock_reserve(virt_to_phys(table), size);
> ?#else
> -printk(KERN_ERR "XXX reserve_ibft_region: table=%llx, 0x00000000BE453000,
> size=%lx\n",
> -??? (u64)table, size);
> -??? memblock_reserve(0x00000000BE453000, size);
> +printk(KERN_ERR "XXX reserve_ibft_region: table=%llx, address=%llx,
> size=%lx\n",
> +??? (u64)table, address, size);
> +??? if (address)
> +??? ??? memblock_reserve(address, size);
> +??? else
> +??? ??? printk(KERN_ERR "%s: Can't find table address\n", __func__);
> ?#endif
> 
> -??? if (efi_enabled(EFI_BOOT))
> +??? if (efi_enabled(EFI_BOOT)) {
> +printk(KERN_ERR "XXX reserve_ibft_region: calling acpi_put_table(%llx)\n",
> (u64)&table->header);
> ???? ??? acpi_put_table(&table->header);
> -??? else
> +??? } else {
> ???? ??? ibft_addr = table;
> +printk(KERN_ERR "XXX reserve_ibft_region: ibft_addr=%llx\n",
> (u64)ibft_addr);
> +??? }
> ?}
> 
> Debug from the above:
> [??? 0.050646] ACPI: Early table checksum verification disabled
> [??? 0.051778] ACPI: RSDP 0x00000000BFBFA014 000024 (v02 BOCHS )
> [??? 0.052922] ACPI: XSDT 0x00000000BFBF90E8 00004C (v01 BOCHS BXPCFACP
> 00000001????? 01000013)
> [??? 0.054623] ACPI: FACP 0x00000000BFBF5000 000074 (v01 BOCHS BXPCFACP
> 00000001 BXPC 00000001)
> [??? 0.056326] ACPI: DSDT 0x00000000BFBF6000 00238D (v01 BOCHS BXPCDSDT
> 00000001 BXPC 00000001)
> [??? 0.058016] ACPI: FACS 0x00000000BFBFD000 000040
> [??? 0.058940] ACPI: APIC 0x00000000BFBF4000 000090 (v01 BOCHS BXPCAPIC
> 00000001 BXPC 00000001)
> [??? 0.060627] ACPI: HPET 0x00000000BFBF3000 000038 (v01 BOCHS BXPCHPET
> 00000001 BXPC 00000001)
> [??? 0.062304] ACPI: BGRT 0x00000000BE49B000 000038 (v01 INTEL EDK2????
> 00000002????? 01000013)
> [??? 0.063987] ACPI: iBFT 0x00000000BE453000 000800 (v01 BOCHS BXPCFACP
> 00000000????? 00000000)
> [??? 0.065683] XXX acpi_tb_find_table_address: signature=iBFT
> [??? 0.066754] XXX acpi_tb_find_table_address(EXIT): address=be453000
> [??? 0.067959] XXX reserve_ibft_region: table=ffffffffff240000,
> address=be453000, size=1000
> [??? 0.069534] XXX reserve_ibft_region: calling
> acpi_put_table(ffffffffff240000)
> 
> Not sure if it's the right thing to do, but added
> "acpi_tb_find_table_address()" to return the physical address of a table to
> use with memblock_reserve().
> 
> virt_to_phys(table) does not seem to return the physical address for the
> iBFT table (it would be nice if struct acpi_table_header also had a
> "address" element for the physical address of the table).

virt_to_phys() does not work that early because then it is mapped with
early_memremap()  which uses different virtual to physical scheme.

I'd say that acpi_tb_find_table_address() makes sense if we'd like to
reserve ACPI tables outside of drivers/acpi. 

But probably we should simply reserve all the tables during
acpi_table_init() so that any table that firmware put in the normal memory
will be surely reserved.
 
> Ran 10 successful boots with the above without failure.

That's good news indeed :)

> George
> > 
> > 

-- 
Sincerely yours,
Mike.