From 6458de97fc15530b54477c4e2b70af653e8ac3d9 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 30 Mar 2020 20:30:45 +0200 Subject: [PATCH] x86/mce/amd: Straighten CPU hotplug path mce_threshold_create_device() hotplug callback runs on the plugged in CPU so: - use this_cpu_read() which is faster - pass in struct threshold_bank **bp to threshold_create_bank() and instead of doing per-CPU accesses - Use rdmsr_safe() instead of rdmsr_safe_on_cpu() which avoids an IPI. No functional changes. Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200403161943.1458-6-bp@alien8.de --- arch/x86/kernel/cpu/mce/amd.c | 32 +++++++++++++++----------------- 1 file changed, 15 insertions(+), 17 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c index d3c416b..a33d9a1 100644 --- a/arch/x86/kernel/cpu/mce/amd.c +++ b/arch/x86/kernel/cpu/mce/amd.c @@ -1223,10 +1223,10 @@ static int allocate_threshold_blocks(unsigned int cpu, struct threshold_bank *tb u32 low, high; int err; - if ((bank >= per_cpu(mce_num_banks, cpu)) || (block >= NR_BLOCKS)) + if ((bank >= this_cpu_read(mce_num_banks)) || (block >= NR_BLOCKS)) return 0; - if (rdmsr_safe_on_cpu(cpu, address, &low, &high)) + if (rdmsr_safe(address, &low, &high)) return 0; if (!(high & MASK_VALID_HI)) { @@ -1316,9 +1316,10 @@ static int __threshold_add_blocks(struct threshold_bank *b) return err; } -static int threshold_create_bank(unsigned int cpu, unsigned int bank) +static int threshold_create_bank(struct threshold_bank **bp, unsigned int cpu, + unsigned int bank) { - struct device *dev = per_cpu(mce_device, cpu); + struct device *dev = this_cpu_read(mce_device); struct amd_northbridge *nb = NULL; struct threshold_bank *b = NULL; const char *name = get_name(bank, NULL); @@ -1338,7 +1339,7 @@ static int threshold_create_bank(unsigned int cpu, unsigned int bank) if (err) goto out; - per_cpu(threshold_banks, cpu)[bank] = b; + bp[bank] = b; refcount_inc(&b->cpus); err = __threshold_add_blocks(b); @@ -1374,8 +1375,7 @@ static int threshold_create_bank(unsigned int cpu, unsigned int bank) if (err) goto out_kobj; - per_cpu(threshold_banks, cpu)[bank] = b; - + bp[bank] = b; return 0; out_kobj: @@ -1487,35 +1487,33 @@ int mce_threshold_remove_device(unsigned int cpu) */ int mce_threshold_create_device(unsigned int cpu) { - unsigned int bank; + unsigned int numbanks, bank; struct threshold_bank **bp; int err; if (!mce_flags.amd_threshold) return 0; - bp = per_cpu(threshold_banks, cpu); + bp = this_cpu_read(threshold_banks); if (bp) return 0; - bp = kcalloc(per_cpu(mce_num_banks, cpu), sizeof(struct threshold_bank *), - GFP_KERNEL); + numbanks = this_cpu_read(mce_num_banks); + bp = kcalloc(numbanks, sizeof(*bp), GFP_KERNEL); if (!bp) return -ENOMEM; - per_cpu(threshold_banks, cpu) = bp; - - for (bank = 0; bank < per_cpu(mce_num_banks, cpu); ++bank) { - if (!(per_cpu(bank_map, cpu) & (1 << bank))) + for (bank = 0; bank < numbanks; ++bank) { + if (!(this_cpu_read(bank_map) & (1 << bank))) continue; - err = threshold_create_bank(cpu, bank); + err = threshold_create_bank(bp, cpu, bank); if (err) goto out_err; } + this_cpu_write(threshold_banks, bp); if (thresholding_irq_en) mce_threshold_vector = amd_threshold_interrupt; - return 0; out_err: mce_threshold_remove_device(cpu); -- 2.7.4