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Merge branch 'swp' (early part) into for-next

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This commit is contained in:
Russell King 2014-08-05 10:27:17 +01:00
commit c89c3a6acb
3 changed files with 27 additions and 8 deletions
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29
arch/arm/kernel/setup.c
View File

@ -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();

4
arch/arm/kernel/swp_emulate.c
View File

@ -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;

2
arch/arm/mm/Kconfig
View File

@ -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