Date: Mon, 10 Feb 2020 11:26:29 -0800 From: Mark Millard <marklmi@yahoo.com> To: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: RPi4's memreserve use in fdt not handled by aarch64 fdt_get_reserved_mem (called via its initarm) Message-ID: <EE1EC418-DD8D-4789-9924-7DA36A44464F@yahoo.com> In-Reply-To: <6F4936C9-34A1-4490-8F5A-D1C2B2CE6232@yahoo.com> References: <DF1349C0-ACFA-4FA9-9AC2-507BD0DBB0DE@yahoo.com> <6F4936C9-34A1-4490-8F5A-D1C2B2CE6232@yahoo.com>
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On 2020-Feb-9, at 22:00, Mark Millard <marklmi at yahoo.com> wrote: > On 2020-Feb-9, at 21:12, Mark Millard <marklmi at yahoo.com> wrote: > >> aarch64 seems to be ignoring the RPi4B's memreserve use. >> >> My hypothesis is that head -r356776 and later are >> allocating RAM areas that overlap with the >> memreserve area. >> >> 1st see separate submittals about the live dts text reported >> by fdt print in u-boot on the example RPi4B 4 GiByte machine: >> >> https://lists.freebsd.org/pipermail/freebsd-arm/2020-February/021207.html >> https://lists.freebsd.org/pipermail/freebsd-arm/2020-February/021205.html >> >> Then: >> >> aarch64's initarm uses fdt_get_reserved_mem and not >> fdt_get_reserved_regions. So, looking at what that >> implies: >> >> int >> fdt_get_reserved_mem(struct mem_region *reserved, int *mreserved) >> { >> pcell_t reg[FDT_REG_CELLS]; >> phandle_t child, root; >> int addr_cells, size_cells; >> int i, rv; >> >> root = OF_finddevice("/reserved-memory"); >> if (root == -1) { >> return (ENXIO); >> } >> . . . (I'll not list it all to show the lack of >> memreserve handling) . . . >> >> This does not check for and handle memreserve. >> >> By contrast armv7 and armv6 each have an initarm >> that uses fdt_get_reserved_regions and that in >> turn has: >> >> int >> fdt_get_reserved_regions(struct mem_region *mr, int *mrcnt) >> { >> pcell_t reserve[FDT_REG_CELLS * FDT_MEM_REGIONS]; >> pcell_t *reservep; >> phandle_t memory, root; >> int addr_cells, size_cells; >> int i, res_len, rv, tuple_size, tuples; >> >> root = OF_finddevice("/"); >> memory = OF_finddevice("/memory"); >> if (memory == -1) { >> rv = ENXIO; >> goto out; >> } >> >> if ((rv = fdt_addrsize_cells(OF_parent(memory), &addr_cells, >> &size_cells)) != 0) >> goto out; >> >> if (addr_cells > 2) { >> rv = ERANGE; >> goto out; >> } >> >> tuple_size = sizeof(pcell_t) * (addr_cells + size_cells); >> >> res_len = OF_getproplen(root, "memreserve"); >> if (res_len <= 0 || res_len > sizeof(reserve)) { >> rv = ERANGE; >> goto out; >> } >> >> if (OF_getprop(root, "memreserve", reserve, res_len) <= 0) { >> rv = ENXIO; >> goto out; >> } >> . . . >> >> So this handles memreserve but not /reserved-memory . >> >> It appears that for the RPi4B's the 32-bit "normal use" >> has lead to aarch64 having memreserve instead of >> /reserved-memory . >> > > I managed to make a quick test patch for head -r356529 > but it did not make the RPi4B boot attempt behave > differently. So, either I messed up or handling memreserve > is not sufficient. (Some alternate information might be > covering the address range already?) Example alternate information was: memory@0 { device_type = "memory"; reg = <0x00000000 0x00000000 0x3b400000 0x00000000 0x40000000 0xbc000000>; }; That looks like it avoids indicating anything from the memreserve region. (I've no clue if such is a requirement for memory@0, but it happens to be the case for the test context.) > I'm not familiar with the subject matter in the code, so > I may have messed up the test. I just used: > > # svnlite diff /usr/src/sys/dev/fdt/fdt_common.c > Index: /usr/src/sys/dev/fdt/fdt_common.c > =================================================================== > --- /usr/src/sys/dev/fdt/fdt_common.c (revision 357529) > +++ /usr/src/sys/dev/fdt/fdt_common.c (working copy) > @@ -512,6 +512,11 @@ > > root = OF_finddevice("/reserved-memory"); > if (root == -1) { > + // Fail over to checking for and handling memreserve, > + // such as for a RPi4B. > + if (0 == fdt_get_reserved_regions(reserved,mreserved)) > + return (0); > + > return (ENXIO); > } I do not know if such is appropriate code or not. For my specific test context, it makes no difference. === Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)home | help
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