diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/boot/boot.h | 1 | ||||
| -rw-r--r-- | arch/x86/boot/cpu.c | 2 | ||||
| -rw-r--r-- | arch/x86/boot/cpucheck.c | 33 | ||||
| -rw-r--r-- | arch/x86/boot/cpuflags.c | 1 | ||||
| -rw-r--r-- | arch/x86/boot/cpuflags.h | 1 |
5 files changed, 38 insertions, 0 deletions
diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h index 9011a88353de..a5ce666a2423 100644 --- a/arch/x86/boot/boot.h +++ b/arch/x86/boot/boot.h @@ -294,6 +294,7 @@ static inline int cmdline_find_option_bool(const char *option) /* cpu.c, cpucheck.c */ int check_cpu(int *cpu_level_ptr, int *req_level_ptr, u32 **err_flags_ptr); +int check_knl_erratum(void); int validate_cpu(void); /* early_serial_console.c */ diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c index 29207f69ae8c..26240dde081e 100644 --- a/arch/x86/boot/cpu.c +++ b/arch/x86/boot/cpu.c @@ -93,6 +93,8 @@ int validate_cpu(void) show_cap_strs(err_flags); putchar('\n'); return -1; + } else if (check_knl_erratum()) { + return -1; } else { return 0; } diff --git a/arch/x86/boot/cpucheck.c b/arch/x86/boot/cpucheck.c index 1fd7d575092e..4ad7d70e8739 100644 --- a/arch/x86/boot/cpucheck.c +++ b/arch/x86/boot/cpucheck.c @@ -24,6 +24,7 @@ # include "boot.h" #endif #include <linux/types.h> +#include <asm/intel-family.h> #include <asm/processor-flags.h> #include <asm/required-features.h> #include <asm/msr-index.h> @@ -175,6 +176,8 @@ int check_cpu(int *cpu_level_ptr, int *req_level_ptr, u32 **err_flags_ptr) puts("WARNING: PAE disabled. Use parameter 'forcepae' to enable at your own risk!\n"); } } + if (!err) + err = check_knl_erratum(); if (err_flags_ptr) *err_flags_ptr = err ? err_flags : NULL; @@ -185,3 +188,33 @@ int check_cpu(int *cpu_level_ptr, int *req_level_ptr, u32 **err_flags_ptr) return (cpu.level < req_level || err) ? -1 : 0; } + +int check_knl_erratum(void) +{ + /* + * First check for the affected model/family: + */ + if (!is_intel() || + cpu.family != 6 || + cpu.model != INTEL_FAM6_XEON_PHI_KNL) + return 0; + + /* + * This erratum affects the Accessed/Dirty bits, and can + * cause stray bits to be set in !Present PTEs. We have + * enough bits in our 64-bit PTEs (which we have on real + * 64-bit mode or PAE) to avoid using these troublesome + * bits. But, we do not have enough space in our 32-bit + * PTEs. So, refuse to run on 32-bit non-PAE kernels. + */ + if (IS_ENABLED(CONFIG_X86_64) || IS_ENABLED(CONFIG_X86_PAE)) + return 0; + + puts("This 32-bit kernel can not run on this Xeon Phi x200\n" + "processor due to a processor erratum. Use a 64-bit\n" + "kernel, or enable PAE in this 32-bit kernel.\n\n"); + + return -1; +} + + diff --git a/arch/x86/boot/cpuflags.c b/arch/x86/boot/cpuflags.c index 431fa5f84537..6687ab953257 100644 --- a/arch/x86/boot/cpuflags.c +++ b/arch/x86/boot/cpuflags.c @@ -102,6 +102,7 @@ void get_cpuflags(void) cpuid(0x1, &tfms, &ignored, &cpu.flags[4], &cpu.flags[0]); cpu.level = (tfms >> 8) & 15; + cpu.family = cpu.level; cpu.model = (tfms >> 4) & 15; if (cpu.level >= 6) cpu.model += ((tfms >> 16) & 0xf) << 4; diff --git a/arch/x86/boot/cpuflags.h b/arch/x86/boot/cpuflags.h index 4cb404fd45ce..15ad56a3f905 100644 --- a/arch/x86/boot/cpuflags.h +++ b/arch/x86/boot/cpuflags.h @@ -6,6 +6,7 @@ struct cpu_features { int level; /* Family, or 64 for x86-64 */ + int family; /* Family, always */ int model; u32 flags[NCAPINTS]; }; |