Re: [PATCH v2] of/fdt: Rework early_init_dt_scan_memory() to call directly
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2021-12-13 12:47:04
Also in:
linux-devicetree, linux-mips, lkml
Rob Herring [off-list ref] writes:
Use of the of_scan_flat_dt() function predates libfdt and is discouraged as libfdt provides a nicer set of APIs. Rework early_init_dt_scan_memory() to be called directly and use libfdt.
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quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index 6e1a106f02eb..63762a3b75e8 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c@@ -532,19 +532,19 @@ static int __init early_init_drmem_lmb(struct drmem_lmb *lmb, } #endif /* CONFIG_PPC_PSERIES */ -static int __init early_init_dt_scan_memory_ppc(unsigned long node, - const char *uname, - int depth, void *data) +static int __init early_init_dt_scan_memory_ppc(void) { #ifdef CONFIG_PPC_PSERIES - if (depth == 1 && - strcmp(uname, "ibm,dynamic-reconfiguration-memory") == 0) { + const void *fdt = initial_boot_params; + int node = fdt_path_offset(fdt, "/ibm,dynamic-reconfiguration-memory"); + + if (node > 0) { walk_drmem_lmbs_early(node, NULL, early_init_drmem_lmb); return 0; } #endif - return early_init_dt_scan_memory(node, uname, depth, data); + return early_init_dt_scan_memory(); } /*@@ -749,7 +749,7 @@ void __init early_init_devtree(void *params) /* Scan memory nodes and rebuild MEMBLOCKs */ early_init_dt_scan_root(); - of_scan_flat_dt(early_init_dt_scan_memory_ppc, NULL); + early_init_dt_scan_memory_ppc(); parse_early_param();@@ -858,7 +858,7 @@ void __init early_get_first_memblock_info(void *params, phys_addr_t *size) */ add_mem_to_memblock = 0; early_init_dt_scan_root(); - of_scan_flat_dt(early_init_dt_scan_memory_ppc, NULL); + early_init_dt_scan_memory_ppc(); add_mem_to_memblock = 1; if (size)
This blows up one of my machines with: [ 0.000000][ T0] printk: bootconsole [udbg0] enabled -> early_setup(), dt_ptr: 0x1ec90000 [ 0.000000][ T0] ------------[ cut here ]------------ [ 0.000000][ T0] kernel BUG at arch/powerpc/mm/book3s64/hash_utils.c:2117! [ 0.000000][ T0] Oops: Exception in kernel mode, sig: 5 [#1] [ 0.000000][ T0] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA [ 0.000000][ T0] Modules linked in: [ 0.000000][ T0] CPU: 0 PID: 0 Comm: swapper Not tainted 5.16.0-rc4-00073-g81291383ffde-dirty #69 [ 0.000000][ T0] NIP: c0000000000924d8 LR: c000000002009764 CTR: c0000000000924d0 [ 0.000000][ T0] REGS: c000000002833bc0 TRAP: 0700 Not tainted (5.16.0-rc4-00073-g81291383ffde-dirty) [ 0.000000][ T0] MSR: 8000000000021003 <SF,ME,RI,LE> CR: 24000244 XER: 20000001 [ 0.000000][ T0] CFAR: 0000000000000730 IRQMASK: 1 [ 0.000000][ T0] GPR00: c000000002009764 c000000002833e60 c000000002834100 ffffffffffffffff [ 0.000000][ T0] GPR04: 0000000000000000 c000000002080866 0000000000000000 0000000000000000 [ 0.000000][ T0] GPR08: c000000002080864 0000000000000001 c0000000028d4100 c000000000ffe598 [ 0.000000][ T0] GPR12: c0000000000924d0 c000000002082200 0000000000000000 0000000000000000 [ 0.000000][ T0] GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 0.000000][ T0] GPR20: 0000000000000001 0000000010004604 0000000000000000 0000000010004bfc [ 0.000000][ T0] GPR24: 0000000000000000 c000000000000000 0000000002970000 c00000000008a480 [ 0.000000][ T0] GPR28: c0000000028e19f8 c00000001ec90000 c000000002865af8 000000001ec90000 [ 0.000000][ T0] NIP [c0000000000924d8] hash__setup_initial_memory_limit+0x18/0x110 [ 0.000000][ T0] LR [c000000002009764] early_init_devtree+0x13c/0x4ec [ 0.000000][ T0] Call Trace: [ 0.000000][ T0] [c000000002833e60] [c0000000020096fc] early_init_devtree+0xd4/0x4ec (unreliable) [ 0.000000][ T0] [c000000002833f10] [c00000000200b008] early_setup+0xc8/0x22c [ 0.000000][ T0] [c000000002833f90] [000000000000d368] 0xd368 [ 0.000000][ T0] Instruction dump: [ 0.000000][ T0] 4bffff0c eaa10028 4bffff44 60000000 60000000 60420000 3c4c027a 38421c40 [ 0.000000][ T0] 7c0802a6 4bfe2e5d 3123ffff 7d291910 <0b090000> 3d220003 392919f8 e9290000 [ 0.000000][ T0] random: get_random_bytes called from oops_exit+0x54/0xa0 with crng_init=0 [ 0.000000][ T0] ---[ end trace 0000000000000000 ]--- It's complaining about memstart_addr being 0, which implies early_init_dt_add_memory_arch() was never called. Will try and get some more debug tomorrow. cheers