On Fri, 17 May 2013, Lorenzo Pieralisi wrote: > DT cpu map parsing code must be made compliant with the latest cpus/cpu > nodes bindings updates, hence this patch updates the arm_dt_init_cpu_maps() > function with checks and additional parsing rules. > > Uniprocessor systems predating v7 do not parse the cpus node at all > since the reg property is meaningless on those systems. > > Device trees for 64-bit systems can be taken as device tree input also > for 64-bit CPUs running in 32-bit mode. The code checks that the reg entries > are zeroed as required in the respective fields and detects automatically > the cpus node #address-cells value so that device tree written for > 64-bit ARM platforms (that can have cpus node #address-cells == 2) can still > be taken as input. The correct device tree entries are to be set up by the > boot loader, kernel code just checks that device tree entries in the cpus > node are as expected for a 32-bit CPU (reg[63:24] == 0). > > cpu node entries with invalid reg property or containing duplicates are > ignored and the device tree parsing is not stopped anymore when such > entries are encountered, the device tree cpu node entry is just skipped. > > A device tree with cpu nodes missing the boot CPU MPIDR is considered > an error and the kernel flags this up as such to trigger firmware updates. > > Signed-off-by: Lorenzo Pieralisi <[email protected]>
Acked-by: Nicolas Pitre <[email protected]> > --- > arch/arm/kernel/devtree.c | 146 > ++++++++++++++++++++++++++++------------------ > 1 file changed, 88 insertions(+), 58 deletions(-) > > diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > index 0905502..80d6cf24 100644 > --- a/arch/arm/kernel/devtree.c > +++ b/arch/arm/kernel/devtree.c > @@ -23,6 +23,7 @@ > #include <asm/setup.h> > #include <asm/page.h> > #include <asm/smp_plat.h> > +#include <asm/system_info.h> > #include <asm/mach/arch.h> > #include <asm/mach-types.h> > > @@ -72,100 +73,129 @@ void __init arm_dt_memblock_reserve(void) > */ > void __init arm_dt_init_cpu_maps(void) > { > - /* > - * Temp logical map is initialized with UINT_MAX values that are > - * considered invalid logical map entries since the logical map must > - * contain a list of MPIDR[23:0] values where MPIDR[31:24] must > - * read as 0. > - */ > struct device_node *cpu, *cpus; > - u32 i, j, cpuidx = 1; > + u32 i, ac, cpuidx = 1; > + int len; > u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0; > > - u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID }; > bool bootcpu_valid = false; > cpus = of_find_node_by_path("/cpus"); > > - if (!cpus) > + if (!cpus || ((cpu_architecture() < CPU_ARCH_ARMv7) && !is_smp())) > return; > > + if (of_property_read_u32(cpus, "#address-cells", &ac)) { > + pr_warn("%s invalid #address-cells\n", cpus->full_name); > + ac = of_n_addr_cells(cpus); > + } > + /* > + * The boot CPU knows its MPIDR and initialize it > + * to allow DT boot CPU detection. > + */ > + cpu_logical_map(0) = mpidr; > + > for_each_child_of_node(cpus, cpu) { > - u32 hwid; > + u64 hwid64; > + u32 hwid32; > + const __be32 *prop; > > if (of_node_cmp(cpu->type, "cpu")) > continue; > > pr_debug(" * %s...\n", cpu->full_name); > /* > - * A device tree containing CPU nodes with missing "reg" > - * properties is considered invalid to build the > - * cpu_logical_map. > + * A CPU node with missing or wrong "reg" property is > + * considered invalid to build a cpu_logical_map entry. > */ > - if (of_property_read_u32(cpu, "reg", &hwid)) { > - pr_debug(" * %s missing reg property\n", > - cpu->full_name); > - return; > + prop = of_get_property(cpu, "reg", &len); > + if (!prop || len < (ac * sizeof(*prop))) { > + pr_warn(" * %s node missing/wrong reg property, > skipped\n", > + cpu->full_name); > + goto next; > } > > /* > - * 8 MSBs must be set to 0 in the DT since the reg property > - * defines the MPIDR[23:0]. > + * Always read reg as u64 value. > + * For dts with #address-cells == 1 hwid64[63:32] > + * will be set to 0 by of_read_number. > + * Toss away the top 32 bits and store value in hwid32. > */ > - if (hwid & ~MPIDR_HWID_BITMASK) > - return; > - > + hwid32 = hwid64 = of_read_number(prop, ac); > + /* > + * hwid64[63:24] must be always be 0 since the reg > + * property defines the MPIDR[23:0] bits regardless > + * of the cpus node #address-cells value. > + */ > + if (hwid64 & ~MPIDR_HWID_BITMASK) { > + pr_warn(" * %s node reg[63:24] must be 0 on 32-bit dts, > got %#016llx, skipped\n", > + cpu->full_name, hwid64); > + goto next; > + } > /* > * Duplicate MPIDRs are a recipe for disaster. > * Scan all initialized entries and check for > - * duplicates. If any is found just bail out. > - * temp values were initialized to UINT_MAX > - * to avoid matching valid MPIDR[23:0] values. > + * duplicates. If any is found just ignore the CPU. > + * Boot CPU at logical index 0 is not checked to > + * allow self contained boot CPU detection logic. > */ > - for (j = 0; j < cpuidx; j++) > - if (WARN(tmp_map[j] == hwid, "Duplicate /cpu reg " > - "properties in the DT\n")) > - return; > + for (i = 1; i < cpuidx; i++) > + if (cpu_logical_map(i) == hwid32) { > + pr_warn(" * %s node duplicate cpu reg property, > skipped\n", > + cpu->full_name); > + goto next; > + } > > /* > - * Build a stashed array of MPIDR values. Numbering scheme > - * requires that if detected the boot CPU must be assigned > - * logical id 0. Other CPUs get sequential indexes starting > - * from 1. If a CPU node with a reg property matching the > - * boot CPU MPIDR is detected, this is recorded so that the > - * logical map built from DT is validated and can be used > - * to override the map created in smp_setup_processor_id(). > + * If a CPU node with a reg property matching the > + * cpu_logical_map(0) is detected, this is recorded so > + * that the bootcpu_valid condition can be checked when > + * DT scanning is completed. Duplicate boot cpu entries > + * are flagged up if detected. > */ > - if (hwid == mpidr) { > - i = 0; > - bootcpu_valid = true; > - } else { > - i = cpuidx++; > + if (hwid32 == cpu_logical_map(0)) { > + if (bootcpu_valid) { > + pr_warn(" * %s node duplicate boot cpu reg > property, skipped\n", > + cpu->full_name); > + } else { > + bootcpu_valid = true; > + } > + goto next; > } > + /* > + * Build cpu_logical_map array. Numbering scheme > + * requires that boot CPU is assigned logical id 0. > + * Other CPUs get sequential indexes starting from 1. > + */ > + i = cpuidx++; > > - if (WARN(cpuidx > nr_cpu_ids, "DT /cpu %u nodes greater than " > - "max cores %u, capping them\n", > - cpuidx, nr_cpu_ids)) { > + if (cpuidx > nr_cpu_ids) { > + pr_warn_once("DT cpu %u nodes greater than max cores > %u, capping them\n", > + cpuidx, nr_cpu_ids); > cpuidx = nr_cpu_ids; > - break; > + goto next; > } > > - tmp_map[i] = hwid; > + cpu_logical_map(i) = hwid32; > + set_cpu_possible(i, true); > + pr_debug("cpu_logical_map(%u) 0x%x\n", i, cpu_logical_map(i)); > +next: ; > } > - > - if (WARN(!bootcpu_valid, "DT missing boot CPU MPIDR[23:0], " > - "fall back to default cpu_logical_map\n")) > - return; > + /* > + * A DT missing the boot CPU MPIDR is a really bad omen > + * Flag it up as such. > + */ > + if (!bootcpu_valid) > + pr_warn("DT missing boot cpu node\n"); > > /* > - * Since the boot CPU node contains proper data, and all nodes have > - * a reg property, the DT CPU list can be considered valid and the > - * logical map created in smp_setup_processor_id() can be overridden > + * Since the DT might contain fewer entries than NR_CPUS, > + * cpu_logical_map entries initialized in smp_setup_processor_id() > + * but not found in the DT must be overriden with MPIDR_INVALID > + * values to make sure the cpu_logical_map does not contain stale > + * MPIDR values. > */ > - for (i = 0; i < cpuidx; i++) { > - set_cpu_possible(i, true); > - cpu_logical_map(i) = tmp_map[i]; > - pr_debug("cpu logical map 0x%x\n", cpu_logical_map(i)); > - } > + for (i = cpuidx; i < nr_cpu_ids; i++) > + cpu_logical_map(i) = MPIDR_INVALID; > } > > /** > -- > 1.8.2.2 > > _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
