Basically this patch looks ok, just a couple of nitpicks/comments. Please change the subject to something more meaningful like
"x86, AMD: Make cpu_has_amd_erratum use currect cpuinfo descriptor" or so. On Tue, Jul 23, 2013 at 01:48:29PM +0200, Torsten Kaiser wrote: > cpu_has_amd_erratum() is buggy, because it uses the per-cpu cpu_info > before it is filled by smp_store_boot_cpu_info() / smp_store_cpu_info(). > > If early microcode loading is enabled its collect_cpu_info_amd_early() will > fill ->x86 and so the fallback to boot_cpu_data is not used. > But ->x86_vendor was not filled and is still 0 == X86_VENDOR_INTEL resulting > in > no errata fixes getting applied and my system hangs on boot. > > Using cpu_info in cpu_has_amd_erratum() is wrong anyway: Its only caller > init_amd() will have a struct cpuinfo_x86 as parameter and the set_cpu_bug() > that is controlled by cpu_has_amd_erratum() also only uses that struct. > > So pass the struct cpuinfo_x86 from init_amd() to cpu_has_amd_erratum() and > the broken fallback can be dropped. > > I also turned the vendor check into an BUG_ON() because init_amd() can only > be used by AMD CPUs and if the current failure hadn't been silent this bug > would have been much more obvious. BUG_ON is kinda heavy-handed here, a WARN_ON should be fine. Other than that, I like the commit message: it explains the whole deal in a very detailed manner and I'd wish more commit messages on lkml would be like that. Good job! > Signed-off-by: Torsten Kaiser <[email protected]> > > --- a/arch/x86/kernel/cpu/amd.c 2013-07-22 06:33:10.027931005 +0200 > +++ b/arch/x86/kernel/cpu/amd.c 2013-07-22 06:35:15.757931265 +0200 > @@ -512,7 +512,7 @@ static void early_init_amd(struct cpuinf > > static const int amd_erratum_383[]; > static const int amd_erratum_400[]; > -static bool cpu_has_amd_erratum(const int *erratum); > +static bool cpu_has_amd_erratum(struct cpuinfo_x86 *cpu, const int *erratum); > > static void init_amd(struct cpuinfo_x86 *c) > { > @@ -729,11 +729,11 @@ static void init_amd(struct cpuinfo_x86 > value &= ~(1ULL << 24); > wrmsrl_safe(MSR_AMD64_BU_CFG2, value); > > - if (cpu_has_amd_erratum(amd_erratum_383)) > + if (cpu_has_amd_erratum(c, amd_erratum_383)) > set_cpu_bug(c, X86_BUG_AMD_TLB_MMATCH); > } > > - if (cpu_has_amd_erratum(amd_erratum_400)) > + if (cpu_has_amd_erratum(c, amd_erratum_400)) > set_cpu_bug(c, X86_BUG_AMD_APIC_C1E); > > rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy); > @@ -878,22 +878,15 @@ static const int amd_erratum_400[] = > static const int amd_erratum_383[] = > AMD_OSVW_ERRATUM(3, AMD_MODEL_RANGE(0x10, 0, 0, 0xff, 0xf)); > > -static bool cpu_has_amd_erratum(const int *erratum) > + > +static bool cpu_has_amd_erratum(struct cpuinfo_x86 *cpu, const int *erratum) > { > - struct cpuinfo_x86 *cpu = __this_cpu_ptr(&cpu_info); > int osvw_id = *erratum++; > u32 range; > u32 ms; > > - /* > - * If called early enough that current_cpu_data hasn't been initialized > - * yet, fall back to boot_cpu_data. > - */ > - if (cpu->x86 == 0) > - cpu = &boot_cpu_data; > - > - if (cpu->x86_vendor != X86_VENDOR_AMD) > - return false; > + /* Should never be called on non-AMD-CPUs */ > + BUG_ON(cpu->x86_vendor != X86_VENDOR_AMD); > > if (osvw_id >= 0 && osvw_id < 65536 && > cpu_has(cpu, X86_FEATURE_OSVW)) { > -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
