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powerpc/prom: Add CPU info to hardware description string later

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cur_cpu_spec->cpu_name is appended to ppc_hw_desc before cur_cpu_spec
has taken on its final value. This is illustrated on pseries by
comparing the CPU name as reported at boot ("POWER8E (raw)") to the
contents of /proc/cpuinfo ("POWER8 (architected)"):

  $ dmesg | grep Hardware
  Hardware name: IBM,8408-E8E POWER8E (raw) 0x4b0201 0xf000004 \
    of:IBM,FW860.50 (SV860_146) hv:phyp pSeries

  $ grep -m 1 ^cpu /proc/cpuinfo
  cpu             : POWER8 (architected), altivec supported

Some 44x models would appear to be affected as well; see
identical_pvr_fixup().

This results in incorrect CPU information in stack dumps --
ppc_hw_desc is an input to dump_stack_set_arch_desc().

Delay gathering the CPU name until after all potential calls to
identify_cpu().

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Fixes: bd649d40e0 ("powerpc: Add PVR & CPU name to hardware description")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240603-fix-cpu-hwdesc-v1-1-945f2850fcaa@linux.ibm.com
This commit is contained in:
Nathan Lynch 2024-06-03 07:36:55 -05:00 committed by Michael Ellerman
parent 0974d03eb4
commit 7bdd1c6c87
1 changed files with 8 additions and 4 deletions
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12
arch/powerpc/kernel/prom.c
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@ -331,6 +331,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
void *data)
{
const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
const __be32 *cpu_version = NULL;
const __be32 *prop;
const __be32 *intserv;
int i, nthreads;
@ -420,7 +421,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
prop = of_get_flat_dt_prop(node, "cpu-version", NULL);
if (prop && (be32_to_cpup(prop) & 0xff000000) == 0x0f000000) {
identify_cpu(0, be32_to_cpup(prop));
seq_buf_printf(&ppc_hw_desc, "0x%04x ", be32_to_cpup(prop));
cpu_version = prop;
}
check_cpu_feature_properties(node);
@ -431,6 +432,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
}
identical_pvr_fixup(node);
// We can now add the CPU name & PVR to the hardware description
seq_buf_printf(&ppc_hw_desc, "%s 0x%04lx ", cur_cpu_spec->cpu_name, mfspr(SPRN_PVR));
if (cpu_version)
seq_buf_printf(&ppc_hw_desc, "0x%04x ", be32_to_cpup(cpu_version));
init_mmu_slb_size(node);
#ifdef CONFIG_PPC64
@ -881,9 +888,6 @@ void __init early_init_devtree(void *params)
dt_cpu_ftrs_scan();
// We can now add the CPU name & PVR to the hardware description
seq_buf_printf(&ppc_hw_desc, "%s 0x%04lx ", cur_cpu_spec->cpu_name, mfspr(SPRN_PVR));
/* Retrieve CPU related informations from the flat tree
* (altivec support, boot CPU ID, ...)
*/