On 02/05/2018 04:47 PM, André Przywara wrote:
> On 05/02/18 20:10, Andrew F. Davis wrote:
>> On 02/05/2018 11:11 AM, Andre Przywara wrote:
>>> Hi,
>>>
>>> thanks for picking this up!
>>>
>>> On 01/02/18 23:04, Andrew F. Davis (by way of Andre Przywara
>>> <andre@xxxxxxxxx>) wrote:
>>>> From: Benjamin Fair <b-fair@xxxxxx>
>
> ....
>
>>>> +
>>>> +int fdt_simple_addr_size(const void *fdt, int nodeoffset, int idx,
>>>> + uintptr_t *addrp, size_t *sizep)
>>>
>>> I believe this was mentioned in previous reviews:
>>> I don't think that those types are the right ones to use here.
>>> There is no correlation between the address size used in a DT and the
>>> (current) size of pointers or addressable memory.
>>> So you might end up in 32-bit code reading a DT with 64-bit addresses.
>>> MMIO addresses might be under 4GB underway, or you are running using
>>> LPAE, where physical addresses can be 40 bits long.
>
>> This function checks for these mismatches and returns an error. The
>> point of this helper is for the system about to use these pointers, if
>> you want to manipulate them on a different system or use them later then
>> this helper is not correct for you.
>
> Imagine you have a TI(!) Keystone SoC, the kernel DT tells me the
> address and size are 64 bit, though the A15 cores will always have
> uintptr_t and size_t at 32 bits. So you can never use this function
> there, even if you would have the MMU using long descriptors, and even
> if you just want to program the GIC to allow non-secure access in a
> small secure firmware shim using libfdt:
> compatible = "arm,gic-400", "arm,cortex-a15-gic";
> reg = <0x0 0x02561000 0x0 0x1000>, ....
> That would be perfectly accessible with the MMU off.
> Looking further into the .dtsi actually underlines Rob's point of not
> supporting translation being much less useful (though it would happen to
> work in this case, more or less by chance).
>
>>> So I think we should use uint64_t* here, this would also avoid the
>>> checks below.
>>>
>>
>> What will happen if I am on a 32-bit big-endian system, and I only want
>> to read in a 32-bit address, but the DT node is 64-bit? How will I know
>> that it read in 64-bits?
>
> if ((base_addr & (uintptr_t)~0) != base_addr)
> return -EFBIG;
>
>> How will I know where the MSB is?
>
> DT is always big endian. libfdt takes care of that.
>
>> Do we care about 128-bit?
>
> No. I am not aware of such a system, especially not one using DT.
> Keystones are real, though. DTs for ARMv8 systems running in AArch32 are
> real as well.
>
>> Etc.. I don't think this can be made generic for all the
>> combinations, and so for simplicity the address pointer and size must
>> match the system. For other more complex uses you will have to implement
>> your own handling.
>
> We don't need to be super generic, but at least should care about
> existing systems. I ran into this issue with 32 bit guests on an 64-bit
> hypervisor. The HV tooling generates the same DT and the guest needs to
> deal with that.
>
> Please note, I actually like this patch and am not asking for a complete
> rewrite: We just change the pointer types and drop the size check: done.
>
Fair enough, I think we just had different use-case intentions in mind
but I can adapt the returned values outside of this helper for my
specific use.
I'll post a v2 with the changes here shortly.
Thanks,
Andrew
> Or if a range-aware version isn't too far away, we use that.
>
> Cheers,
> Andre.
>
>>>
>>>> +{
>>>> + int parent;
>>>> + int ac, sc, reg_stride;
>>>> + int res;
>>>> + const fdt32_t *reg;
>>>> +
>>>> + reg = fdt_getprop(fdt, nodeoffset, "reg", &res);
>>>> + if (res < 0)
>>>> + return res;
>>>> +
>>>> + parent = fdt_parent_offset(fdt, nodeoffset);
>>>> + if (parent == -FDT_ERR_NOTFOUND) /* an node without a parent does
>>>> + * not have _any_ number of cells */
>>>> + return -FDT_ERR_BADNCELLS;
>>>> + if (parent < 0)
>>>> + return parent;
>>>> +
>>>> + ac = fdt_address_cells(fdt, parent);
>>>> + if (ac < 0)
>>>> + return ac;
>>>> + if (ac * sizeof(fdt32_t) > sizeof(*addrp))
>>>> + return -FDT_ERR_BADNCELLS;
>>>> +
>>>> + sc = fdt_size_cells(fdt, parent);
>>>> + if (sc < 0)
>>>> + return sc;
>>>> + if (sc * sizeof(fdt32_t) > sizeof(*sizep))
>>>> + return -FDT_ERR_BADNCELLS;
>>>> +
>>>> + reg_stride = ac + sc;
>>>> +
>>>> + /* res is the number of bytes read and must be an even multiple of the
>>>> + * sum of address cells and size cells */
>>>> + if ((res % (reg_stride * sizeof(*reg))) != 0)
>>>> + return -FDT_ERR_BADVALUE;
>>>> +
>>>> + if (addrp) {
>>>> + *addrp = (uintptr_t) _fdt_read_cells(®[reg_stride * idx], ac, &res);
>>>> + if (res < 0)
>>>> + return res;
>>>> + }
>>>> + if (sizep) {
>>>> + *sizep = (size_t) _fdt_read_cells(®[ac + reg_stride * idx], sc, &res);
>>>> + if (res < 0)
>>>> + return res;
>>>> + }
>>>> +
>>>> + return 0;
>>>> +}
>>>> diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
>>>> index c8c00fa..73f2fea 100644
>>>> --- a/libfdt/libfdt.h
>>>> +++ b/libfdt/libfdt.h
>>>> @@ -1101,6 +1101,39 @@ int fdt_address_cells(const void *fdt, int nodeoffset);
>>>> */
>>>> int fdt_size_cells(const void *fdt, int nodeoffset);
>>>>
>>>> +/**
>>>> + *
>>>> + * fdt_simple_addr_size - read address and/or size from the reg property of a
>>>> + * device node.
>>>> + * @fdt: pointer to the device tree blob
>>>> + * @nodeoffset: offset of the node to find the address and/or size from
>>>> + * @idx: which address/size pair to read
>>>> + * @addrp: pointer to where address will be stored (will be overwritten) or NULL
>>>> + * @sizep: pointer to where size will be stored (will be overwritten) or NULL
>>>> + *
>>>> + * When the node has a valid reg property, returns the address and/or size
>>>> + * values stored there. It does not perform any type of translation based on
>>>> + * the parent bus(es).
>>>> + *
>>>> + * NOTE: This function is expensive, as it must scan the device tree
>>>> + * structure from the start to nodeoffset, *twice*, with fdt_parent_offset.
>>>> + *
>>>> + * returns:
>>>> + * 0, on success
>>>> + * -FDT_ERR_BADVALUE, if there is an unexpected number of entries in the
>>>> + * reg property
>>>> + * -FDT_ERR_NOTFOUND, if the node does not have a reg property
>>>> + * -FDT_ERR_BADNCELLS, if the number of address or size cells is invalid
>>>> + * or greater than 2 (which is the maximum currently supported)
>>>> + * -FDT_ERR_BADMAGIC,
>>>> + * -FDT_ERR_BADSTATE,
>>>> + * -FDT_ERR_BADSTRUCTURE,
>>>> + * -FDT_ERR_BADVERSION,
>>>> + * -FDT_ERR_TRUNCATED, standard meanings
>>>> + */
>>>> +
>>>> +int fdt_simple_addr_size(const void *fdt, int nodeoffset, int idx,
>>>> + uintptr_t *addrp, size_t *sizep);
>>>>
>>>> /**********************************************************************/
>>>> /* Write-in-place functions */
>>>> diff --git a/libfdt/version.lds b/libfdt/version.lds
>>>> index 18fb69f..1f19341 100644
>>>> --- a/libfdt/version.lds
>>>> +++ b/libfdt/version.lds
>>>> @@ -59,6 +59,7 @@ LIBFDT_1.2 {
>>>> fdt_next_subnode;
>>>> fdt_address_cells;
>>>> fdt_size_cells;
>>>> + fdt_simple_addr_size;
>>>> fdt_stringlist_contains;
>>>> fdt_stringlist_count;
>>>> fdt_stringlist_search;
>>>> diff --git a/tests/.gitignore b/tests/.gitignore
>>>> index 9e209d5..acb9335 100644
>>>> --- a/tests/.gitignore
>>>> +++ b/tests/.gitignore
>>>> @@ -43,6 +43,7 @@ tmp.*
>>>> /path_offset
>>>> /path_offset_aliases
>>>> /phandle_format
>>>> +/addr_size
>>>> /property_iterate
>>>> /propname_escapes
>>>> /references
>>>> diff --git a/tests/Makefile.tests b/tests/Makefile.tests
>>>> index 262944a..1e326ea 100644
>>>> --- a/tests/Makefile.tests
>>>> +++ b/tests/Makefile.tests
>>>> @@ -8,7 +8,7 @@ LIB_TESTS_L = get_mem_rsv \
>>>> char_literal \
>>>> sized_cells \
>>>> notfound \
>>>> - addr_size_cells \
>>>> + addr_size_cells addr_size \
>>>> stringlist \
>>>> setprop_inplace nop_property nop_node \
>>>> sw_tree1 \
>>>> diff --git a/tests/addr_size.c b/tests/addr_size.c
>>>> new file mode 100644
>>>> index 0000000..10275f4
>>>> --- /dev/null
>>>> +++ b/tests/addr_size.c
>>>> @@ -0,0 +1,93 @@
>>>> +/*
>>>> + * libfdt - Flat Device Tree manipulation
>>>> + * Testcase for address and size handling
>>>> + * Copyright (C) 2016-2018 Texas Instruments Incorporated - http://www.ti.com/
>>>> + *
>>>> + * Based on addr_size_cells.c by David Gibson, <david@xxxxxxxxxxxxxxxxxxxxx>
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or modify it
>>>> + * under the terms of the GNU Lesser General Public License as published by
>>>> + * the Free Software Foundation; either version 2.1 of the License, or (at
>>>> + * your option) any later version.
>>>> + *
>>>> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
>>>> + * whether express or implied; without even the implied warranty of
>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>>>> + * Lesser General Public License for more details.
>>>> + */
>>>> +
>>>> +#include <stdlib.h>
>>>> +#include <stdio.h>
>>>> +#include <string.h>
>>>> +#include <stdint.h>
>>>> +
>>>> +#include <libfdt.h>
>>>> +
>>>> +#include "tests.h"
>>>> +#include "testdata.h"
>>>> +
>>>> +static void check_node(const void *fdt, const char *path, int err,
>>>> + int idx, uintptr_t addr, size_t size)
>>>> +{
>>>> + int offset, res;
>>>> + uintptr_t xaddr;
>>>> + size_t xsize;
>>>> +
>>>> + offset = fdt_path_offset(fdt, path);
>>>> + if (offset < 0)
>>>> + FAIL("Couldn't find path %s", path);
>>>> +
>>>> + res = fdt_simple_addr_size(fdt, offset, idx, &xaddr, &xsize);
>>>> + if (res != err)
>>>> + FAIL("fdt_simple_addr_size returned %s instead of %s",
>>>> + fdt_strerror(res), fdt_strerror(err));
>>>> + if (res < 0)
>>>> + return;
>>>> +
>>>> + if (xaddr != addr)
>>>> + FAIL("Physical address for %s is %p instead of %p\n",
>>>> + path, (void *) xaddr, (void *) addr);
>>>> +
>>>> + if (xsize != size)
>>>> + FAIL("Size for %s is %zx instead of %zx\n",
>>>> + path, xsize, size);
>>>> +}
>>>> +
>>>> +int main(int argc, char *argv[])
>>>> +{
>>>> + void *fdt;
>>>> +
>>>> + if (argc != 2)
>>>> + CONFIG("Usage: %s <dtb file>\n", argv[0]);
>>>> +
>>>> + test_init(argc, argv);
>>>> + fdt = load_blob(argv[1]);
>>>> +
>>>> + if (sizeof(uintptr_t) == 4 && sizeof(size_t) == 4) {
>>>> + /* 32-bit address , 32-bit size */
>>>> + check_node(fdt, "/identity-bus@0/id-device@400",
>>>> + -FDT_ERR_BADNCELLS, 0, 0x0, 0x0);
>>>> + check_node(fdt, "/simple-bus@1000000/sb-device@8000000800",
>>>> + -FDT_ERR_BADNCELLS, 0, 0x0, 0x0);
>>>> + }
>>>> + else if (sizeof(uintptr_t) == 8 && sizeof(size_t) == 8) {
>>>> + /* 64-bit uintptr_t , 64-bit size_t */
>>>> + check_node(fdt, "/identity-bus@0/id-device@400",
>>>> + 0, 0,0x400, 0x100);
>>>> + check_node(fdt, "/simple-bus@1000000/sb-device@8000000800",
>>>> + 0, 0, 0x8000000800, 0x200);
>>>> + check_node(fdt, "/identity-bus@0/id-device@400",
>>>> + 0, 1, 0x400000000, 0x100000030);
>>>> + check_node(fdt, "/simple-bus@1000000/sb-device@8000000800",
>>>> + 0, 1, 0x70000000, 0x700);
>>>> + check_node(fdt, "/simple-bus@1000000/sb-device@8000000800",
>>>> + 0, 2, 0x1050000000, 0x20);
>>>> + }
>>>> +
>>>> + check_node(fdt, "/identity-bus@0",
>>>> + -FDT_ERR_NOTFOUND, 0, 0x0, 0x0);
>>>> + check_node(fdt, "/narrow-bus@2000000/sb-device@80000000",
>>>> + 0, 0, 0x00000800, 0x200);
>>>> +
>>>> + PASS();
>>>> +}
>>>> diff --git a/tests/addresses.dts b/tests/addresses.dts
>>>> index a2faaf5..747c291 100644
>>>> --- a/tests/addresses.dts
>>>> +++ b/tests/addresses.dts
>>>> @@ -6,10 +6,30 @@
>>>> #size-cells = <2>;
>>>>
>>>> identity-bus@0 {
>>>> + #address-cells = <2>;
>>>> + #size-cells = <2>;
>>>> + id-device@400 {
>>>> + reg = <0x0 0x00000400 0x0 0x00000100>,
>>>> + <0x4 0x00000000 0x1 0x00000030>;
>>>> + };
>>>> };
>>>>
>>>> simple-bus@1000000 {
>>>> #address-cells = <2>;
>>>> #size-cells = <1>;
>>>> + sb-device@8000000800 {
>>>> + reg = <0x80 0x00000800 0x200>,
>>>> + <0x00 0x70000000 0x700>,
>>>> + <0x10 0x50000000 0x020>;
>>>> + };
>>>> + };
>>>> +
>>>> + narrow-bus@2000000 {
>>>> + #address-cells = <1>;
>>>> + #size-cells = <1>;
>>>> + sb-device@80000000 {
>>>> + reg = <0x00000800 0x200>,
>>>> + <0x50000000 0x020>;
>>>> + };
>>>> };
>>>> };
>>>> diff --git a/tests/run_tests.sh b/tests/run_tests.sh
>>>> index 0d30edf..c195d0d 100755
>>>> --- a/tests/run_tests.sh
>>>> +++ b/tests/run_tests.sh
>>>> @@ -311,6 +311,7 @@ libfdt_tests () {
>>>>
>>>> run_dtc_test -I dts -O dtb -o addresses.test.dtb addresses.dts
>>>> run_test addr_size_cells addresses.test.dtb
>>>> + run_test addr_size addresses.test.dtb
>>>>
>>>> run_dtc_test -I dts -O dtb -o stringlist.test.dtb stringlist.dts
>>>> run_test stringlist stringlist.test.dtb
>>>>
>
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