|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 6/7] xen/arm: Dissociate logical and hardware CPU ID
On 09/09/2013 02:38 PM, Ian Campbell wrote:
> t gOn Fri, 2013-08-30 at 14:30 +0100, Julien Grall wrote:
>> Introduce cpu_logical_map to associate a logical CPU ID to an hardware CPU
>> ID.
>> This map will be filled during Xen boot via the device tree. Each CPU node
>> contains a "reg" property which contains the hardware ID (ie MPIDR[0:23]).
>>
>> Also move /cpus parsing later so we can use the dt_* API.
>>
>> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
>> ---
>> xen/arch/arm/setup.c | 109
>> ++++++++++++++++++++++++++++++++++++++-
>> xen/arch/arm/smpboot.c | 4 ++
>> xen/common/device_tree.c | 48 -----------------
>> xen/include/asm-arm/processor.h | 4 ++
>> 4 files changed, 116 insertions(+), 49 deletions(-)
>>
>> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
>> index 137a65e..fabad91 100644
>> --- a/xen/arch/arm/setup.c
>> +++ b/xen/arch/arm/setup.c
>> @@ -496,6 +496,111 @@ void __init setup_cache(void)
>> cacheline_bytes = 1U << (4 + (ccsid & 0x7));
>> }
>>
>> +/* Parse the device tree and build the logical map array containing
>> + * MPIDR values related to logical cpus
>> + * Code base on Linux arch/arm/kernel/devtree.c
>> + */
>> +static void __init init_cpus_maps(void)
>> +{
>> + register_t mpidr;
>> + struct dt_device_node *cpus = dt_find_node_by_path("/cpus");
>> + struct dt_device_node *cpu;
>> + unsigned int i, j;
>> + unsigned int cpuidx = 1;
>> + u32 tmp_map[NR_CPUS] = { [0 ... NR_CPUS - 1] = MPIDR_INVALID };
>
> This is potentially a fair bit of data on the stack? If yes then it
> could be static init data?
Rigth. I will move to init data.
>
>> + bool_t bootcpu_valid = 0;
>> +
>> + mpidr = READ_SYSREG(MPIDR_EL1) & MPIDR_HWID_MASK;
>
> boot_cpu_mpidr would have saved me wondering why the current CPU was so
> special.
boot_cpu_mpidr is filled a bit after. I will move init_cpus_map later.
>> +
>> + if ( !cpus )
>> + {
>> + printk(XENLOG_WARNING "WARNING: Can't find /cpus in the device
>> tree.\n"
>> + "Using only 1 CPU\n");
>> + return;
>> + }
>> +
>> + for_each_child_node( cpus, cpu )
>> + {
>> + u32 hwid;
>> +
>> + if ( !dt_device_type_is_equal(cpu, "cpu") )
>> + continue;
>> +
>> + if ( !dt_property_read_u32(cpu, "reg", &hwid) )
>> + {
>> + printk(XENLOG_WARNING "cpu node `%s`: missing reg property\n",
>> + dt_node_full_name(cpu));
>> + continue;
>> + }
>> +
>> + /*
>> + * 8 MSBs must be set to 0 in the DT since the reg property
>> + * defines the MPIDR[23:0]
>> + */
>> + if ( hwid & ~MPIDR_HWID_MASK )
>> + {
>> + printk(XENLOG_WARNING "cpu node `%s`: invalid hwid value
>> (0x%x)\n",
>> + dt_node_full_name(cpu), hwid);
>> + continue;
>> + }
>> +
>> + /*
>> + * Duplicate MPIDRs are a recipe for disaster. Scan all initialized
>> + * entries and check for duplicates. If any found just skip the
>> node.
>> + * temp values values are initialized to MPIDR_INVALID to avoid
>> + * matching valid MPIDR[23:0] values.
>> + */
>> + for ( j = 0; j < cpuidx; j++ )
>> + {
>> + if ( tmp_map[j] == hwid )
>> + {
>> + printk(XENLOG_WARNING "cpu node `%s`: duplicate /cpu reg
>> properties in the DT\n",
>> + dt_node_full_name(cpu));
>> + continue;
>> + }
>> + }
>> +
>> + /*
>> + * 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 and so that the logical map build from DT is
>> + * validated and can be used to set the map.
>> + */
>> + if ( hwid == mpidr )
>> + {
>> + i = 0;
>> + bootcpu_valid = 1;
>> + }
>> + else
>> + i = cpuidx++;
>> +
>> + if ( cpuidx > NR_CPUS )
>> + {
>> + printk(XENLOG_WARNING "DT /cpu %u node greater than max cores
>> %u, capping them\n",
>> + cpuidx, NR_CPUS);
>> + cpuidx = NR_CPUS;
>> + break;
>> + }
>> +
>> + tmp_map[i] = hwid;
>> + }
>> +
>> + if ( !bootcpu_valid )
>> + {
>> + printk(XENLOG_WARNING "DT missing boot CPU MPIDR[23:0]\n"
>> + "Using only 1 CPU\n");
>> + return;
>> + }
>> +
>> + for ( i = 0; i < cpuidx; i++ )
>> + {
>> + cpumask_set_cpu(i, &cpu_possible_map);
>> + cpu_logical_map(i) = tmp_map[i];
>
> For i == 0 this happens in smp_clear_cpu_maps too. You may as well start
> from 1.
Ok.
>> + }
>> +}
>> +
>> /* C entry point for boot CPU */
>> void __init start_xen(unsigned long boot_phys_offset,
>> unsigned long fdt_paddr,
>> @@ -515,7 +620,6 @@ void __init start_xen(unsigned long boot_phys_offset,
>> + (fdt_paddr & ((1 << SECOND_SHIFT) - 1));
>> fdt_size = device_tree_early_init(device_tree_flattened);
>>
>> - cpus = smp_get_max_cpus();
>> cmdline_parse(device_tree_bootargs(device_tree_flattened));
>>
>> setup_pagetables(boot_phys_offset, get_xen_paddr());
>> @@ -528,6 +632,9 @@ void __init start_xen(unsigned long boot_phys_offset,
>> dt_uart_init();
>> console_init_preirq();
>>
>> + init_cpus_maps();
>> + cpus = smp_get_max_cpus();
>
> It seems like anything which was previously using this should by now be
> using some sort of for_each_foo() helper over the apropriate bitmasks?
Yes. I will send a patch for that.
>> +
>> system_state = SYS_STATE_boot;
>>
>> processor_id();
>> diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
>> index b6aea63..c0d25de 100644
>> --- a/xen/arch/arm/smpboot.c
>> +++ b/xen/arch/arm/smpboot.c
>> @@ -39,6 +39,9 @@ EXPORT_SYMBOL(cpu_possible_map);
>>
>> struct cpuinfo_arm cpu_data[NR_CPUS];
>>
>> +/* CPU logical map: map xen cpuid to an MPIDR */
>> +u32 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = MPIDR_INVALID };
>> +
>> /* Fake one node for now. See also include/asm-arm/numa.h */
>> nodemask_t __read_mostly node_online_map = { { [0] = 1UL } };
>>
>> @@ -82,6 +85,7 @@ smp_clear_cpu_maps (void)
>> cpumask_clear(&cpu_online_map);
>> cpumask_set_cpu(0, &cpu_online_map);
>> cpumask_set_cpu(0, &cpu_possible_map);
>> + cpu_logical_map(0) = READ_SYSREG(MPIDR_EL1) & MPIDR_HWID_MASK;
>> }
>>
>> int __init
>> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
>> index 5620b23..cc519af 100644
>> --- a/xen/common/device_tree.c
>> +++ b/xen/common/device_tree.c
>> @@ -118,18 +118,6 @@ static bool_t __init device_tree_node_matches(const
>> void *fdt, int node,
>> && (name[match_len] == '@' || name[match_len] == '\0');
>> }
>>
>> -static bool_t __init device_tree_type_matches(const void *fdt, int node,
>> - const char *match)
>> -{
>> - const void *prop;
>> -
>> - prop = fdt_getprop(fdt, node, "device_type", NULL);
>> - if ( prop == NULL )
>> - return 0;
>> -
>> - return !dt_node_cmp(prop, match);
>> -}
>> -
>> static bool_t __init device_tree_node_compatible(const void *fdt, int node,
>> const char *match)
>> {
>> @@ -348,40 +336,6 @@ static void __init process_memory_node(const void *fdt,
>> int node,
>> }
>> }
>>
>> -static void __init process_cpu_node(const void *fdt, int node,
>> - const char *name,
>> - u32 address_cells, u32 size_cells)
>> -{
>> - const struct fdt_property *prop;
>> - u32 cpuid;
>> - int len;
>> -
>> - prop = fdt_get_property(fdt, node, "reg", &len);
>> - if ( !prop )
>> - {
>> - early_printk("fdt: node `%s': missing `reg' property\n", name);
>> - return;
>> - }
>> -
>> - if ( len < sizeof (cpuid) )
>> - {
>> - dt_printk("fdt: node `%s': `reg` property length is too short\n",
>> - name);
>> - return;
>> - }
>> -
>> - cpuid = dt_read_number((const __be32 *)prop->data, 1);
>> -
>> - /* TODO: handle non-contiguous CPU ID */
>> - if ( cpuid >= NR_CPUS )
>> - {
>> - dt_printk("fdt: node `%s': reg(0x%x) >= NR_CPUS(%d)\n",
>> - name, cpuid, NR_CPUS);
>> - return;
>> - }
>> - cpumask_set_cpu(cpuid, &cpu_possible_map);
>> -}
>> -
>> static void __init process_multiboot_node(const void *fdt, int node,
>> const char *name,
>> u32 address_cells, u32 size_cells)
>> @@ -435,8 +389,6 @@ static int __init early_scan_node(const void *fdt,
>> {
>> if ( device_tree_node_matches(fdt, node, "memory") )
>> process_memory_node(fdt, node, name, address_cells, size_cells);
>> - else if ( device_tree_type_matches(fdt, node, "cpu") )
>> - process_cpu_node(fdt, node, name, address_cells, size_cells);
>> else if ( device_tree_node_compatible(fdt, node, "xen,multiboot-module"
>> ) )
>> process_multiboot_node(fdt, node, name, address_cells, size_cells);
>>
>> diff --git a/xen/include/asm-arm/processor.h
>> b/xen/include/asm-arm/processor.h
>> index b884354..5bc7259 100644
>> --- a/xen/include/asm-arm/processor.h
>> +++ b/xen/include/asm-arm/processor.h
>> @@ -13,6 +13,7 @@
>> #define MPIDR_AFF0_SHIFT (0)
>> #define MPIDR_AFF0_MASK (0xff << MPIDR_AFF0_SHIFT)
>> #define MPIDR_HWID_MASK 0xffffff
>> +#define MPIDR_INVALID (~MPIDR_HWID_MASK)
>>
>> /* TTBCR Translation Table Base Control Register */
>> #define TTBCR_EAE 0x80000000
>> @@ -234,6 +235,9 @@ extern void identify_cpu(struct cpuinfo_arm *);
>> extern struct cpuinfo_arm cpu_data[];
>> #define current_cpu_data cpu_data[smp_processor_id()]
>>
>> +extern u32 __cpu_logical_map[];
>> +#define cpu_logical_map(cpu) __cpu_logical_map[cpu]
>> +
>> union hsr {
>> uint32_t bits;
>> struct {
>
>
--
Julien Grall
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |