diff options
| -rw-r--r-- | arch/arm/kernel/setup.c | 29 | ||||
| -rw-r--r-- | arch/arm/kernel/swp_emulate.c | 4 | ||||
| -rw-r--r-- | arch/arm/mm/Kconfig | 2 |
3 files changed, 27 insertions, 8 deletions
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 8a16ee5d8a95..84db893dedc2 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -393,19 +393,34 @@ static void __init cpuid_init_hwcaps(void) elf_hwcap |= HWCAP_LPAE; } -static void __init feat_v6_fixup(void) +static void __init elf_hwcap_fixup(void) { - int id = read_cpuid_id(); - - if ((id & 0xff0f0000) != 0x41070000) - return; + unsigned id = read_cpuid_id(); + unsigned sync_prim; /* * HWCAP_TLS is available only on 1136 r1p0 and later, * see also kuser_get_tls_init. */ - if ((((id >> 4) & 0xfff) == 0xb36) && (((id >> 20) & 3) == 0)) + if (read_cpuid_part() == ARM_CPU_PART_ARM1136 && + ((id >> 20) & 3) == 0) { elf_hwcap &= ~HWCAP_TLS; + return; + } + + /* Verify if CPUID scheme is implemented */ + if ((id & 0x000f0000) != 0x000f0000) + return; + + /* + * If the CPU supports LDREX/STREX and LDREXB/STREXB, + * avoid advertising SWP; it may not be atomic with + * multiprocessing cores. + */ + sync_prim = ((read_cpuid_ext(CPUID_EXT_ISAR3) >> 8) & 0xf0) | + ((read_cpuid_ext(CPUID_EXT_ISAR4) >> 20) & 0x0f); + if (sync_prim >= 0x13) + elf_hwcap &= ~HWCAP_SWP; } /* @@ -609,7 +624,7 @@ static void __init setup_processor(void) #endif erratum_a15_798181_init(); - feat_v6_fixup(); + elf_hwcap_fixup(); cacheid_init(); cpu_init(); diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c index b1b89882b113..67ca8578c6d8 100644 --- a/arch/arm/kernel/swp_emulate.c +++ b/arch/arm/kernel/swp_emulate.c @@ -27,6 +27,7 @@ #include <linux/perf_event.h> #include <asm/opcodes.h> +#include <asm/system_info.h> #include <asm/traps.h> #include <asm/uaccess.h> @@ -266,6 +267,9 @@ static struct undef_hook swp_hook = { */ static int __init swp_emulation_init(void) { + if (cpu_architecture() < CPU_ARCH_ARMv7) + return 0; + #ifdef CONFIG_PROC_FS if (!proc_create("cpu/swp_emulation", S_IRUGO, NULL, &proc_status_fops)) return -ENOMEM; diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index df46620206af..577039a3f6e5 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -669,7 +669,7 @@ config ARM_VIRT_EXT details. config SWP_EMULATE - bool "Emulate SWP/SWPB instructions" + bool "Emulate SWP/SWPB instructions" if !SMP depends on CPU_V7 default y if SMP select HAVE_PROC_CPU if PROC_FS |