6.1-stable review patch. If anyone has any objections, please let me know.
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From: Nathan Lynch nathanl@linux.ibm.com
[ Upstream commit 7bdd1c6c87de758750d419eedab7285b95b66417 ]
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: bd649d40e0f2 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/prom.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index 9531ab90feb8a..e5b90d67cd536 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -324,6 +324,7 @@ 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; @@ -404,7 +405,7 @@ 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); @@ -415,6 +416,12 @@ 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 @@ -852,9 +859,6 @@ 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, ...) */