Hi Pingfan,
+ avail = intserv_node->avail;
+ nthreads = intserv_node->len / sizeof(int);
+ for (j = 0; j < nthreads && cpu < nr_cpu_ids; j++) {
set_cpu_present(cpu, avail);
set_cpu_possible(cpu, true);
- cpu_to_phys_id[cpu] = be32_to_cpu(intserv[j]);
+ cpu_to_phys_id[cpu] =
be32_to_cpu(intserv_node->intserv[j]);
+ DBG("thread %d -> cpu %d (hard id %d)\n",
+ j, cpu, be32_to_cpu(intserv[j]));
Intserv is not defined. Should "be32_to_cpu(intserv_node->intserv[j])?
cpu++;
}
+ }
-Original Message-
From: Pingfan Liu
Sent: Monday, September 25, 2023 2:54 AM
To: linuxppc-dev@lists.ozlabs.org
Cc: Pingfan Liu ; Michael Ellerman ;
Nicholas Piggin ; Christophe Leroy
; Mahesh Salgaonkar ; Wen
Xiong ; Baoquan He ; Ming Lei
; ke...@lists.infradead.org
Subject: [EXTERNAL] [PATCHv7 2/4] powerpc/setup: Loosen the mapping between cpu
logical id and its seq in dt
*** Idea ***
For kexec -p, the boot cpu can be not the cpu0, this causes the problem of
allocating memory for paca_ptrs[]. However, in theory, there is no requirement
to assign cpu's logical id as its present sequence in the device tree. But
there is something like cpu_first_thread_sibling(), which makes assumption on
the mapping inside a core. Hence partially loosening the mapping, i.e. unbind
the mapping of core while keep the mapping inside a core.
*** Implement ***
At this early stage, there are plenty of memory to utilize. Hence, this patch
allocates interim memory to link the cpu info on a list, then reorder cpus by
changing the list head. As a result, there is a rotate shift between the
sequence number in dt and the cpu logical number.
*** Result ***
After this patch, a boot-cpu's logical id will always be mapped into the range
[0,threads_per_core).
Besides this, at this phase, all threads in the boot core are forced to be
onlined. This restriction will be lifted in a later patch with extra effort.
Signed-off-by: Pingfan Liu
Cc: Michael Ellerman
Cc: Nicholas Piggin
Cc: Christophe Leroy
Cc: Mahesh Salgaonkar
Cc: Wen Xiong
Cc: Baoquan He
Cc: Ming Lei
Cc: ke...@lists.infradead.org
To: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/kernel/prom.c | 25 +
arch/powerpc/kernel/setup-common.c | 87 +++---
2 files changed, 85 insertions(+), 27 deletions(-)
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index
ec82f5bda908..87272a2d8c10 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -76,7 +76,9 @@ u64 ppc64_rma_size;
unsigned int boot_cpu_node_count __ro_after_init; #endif static phys_addr_t
first_memblock_size;
+#ifdef CONFIG_SMP
static int __initdata boot_cpu_count;
+#endif
static int __init early_parse_mem(char *p) { @@ -331,8 +333,7 @@ static int
__init early_init_dt_scan_cpus(unsigned long node,
const __be32 *intserv;
int i, nthreads;
int len;
- int found = -1;
- int found_thread = 0;
+ bool found = false;
/* We are scanning "cpu" nodes only */
if (type == NULL || strcmp(type, "cpu") != 0) @@ -355,8 +356,15 @@
static int __init early_init_dt_scan_cpus(unsigned long node,
for (i = 0; i < nthreads; i++) {
if (be32_to_cpu(intserv[i]) ==
fdt_boot_cpuid_phys(initial_boot_params)) {
- found = boot_cpu_count;
- found_thread = i;
+ /*
+* always map the boot-cpu logical id into the
+* range of [0, thread_per_core)
+*/
+ boot_cpuid = i;
+ found = true;
+ /* This works around the hole in paca_ptrs[]. */
+ if (nr_cpu_ids < nthreads)
+ set_nr_cpu_ids(nthreads);
}
#ifdef CONFIG_SMP
/* logical cpu id is always 0 on UP kernels */ @@ -365,14
+373,13 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
}
/* Not the boot CPU */
- if (found < 0)
+ if (!found)
return 0;
- DBG("boot cpu: logical %d physical %d\n", found,
- be32_to_cpu(intserv[found_thread]));
- boot_cpuid = found;
+ DBG("boot cpu: logical %d physical %d\n", boot_cpuid,
+ be32_to_cpu(intserv[boot_cpuid]));
- boot_cpu_hwid = be32_to_cpu(intserv[found_thread]);
+ boot_cpu_hwid = be32_to_cpu(intserv[boot_cpuid]);
/*
* PAPR defines "logical" PVR values for cpus that diff --git
a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kerne
