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Message-ID: <20121001132850.GA22956@gmail.com>
Date: Mon, 1 Oct 2012 15:28:50 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/asm changes for v3.7
Linus,
Please pull the latest x86-asm-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-asm-for-linus
HEAD: c416ddf5b909736f5b57d348f5de159693e699ad x86: Unspaghettize do_trap()
The one change that stands out is the alternatives patching
change that prevents us from ever patching back instructions
from SMP to UP: this simplifies things and speeds up CPU
hotplug. Other than that it's smaller fixes, cleanups and
improvements.
out-of-topic modifications in x86-asm-for-linus:
------------------------------------------------
kernel/cpu.c # 816afe4: x86/smp: Don't ever patch back to
Thanks,
Ingo
------------------>
Frederic Weisbecker (1):
x86: Unspaghettize do_trap()
Ian Campbell (1):
x86: Drop unnecessary kernel_eflags variable on 64-bit
Jan Beulich (3):
x86/64: Adjust types of temporaries used by ffs()/fls()/fls64()
x86: Prefer TZCNT over BFS
x86: Use REP BSF unconditionally
Rusty Russell (1):
x86/smp: Don't ever patch back to UP if we unplug cpus
Tao Guo (1):
x86_64: Work around old GAS bug
Documentation/kernel-parameters.txt | 3 -
arch/x86/include/asm/alternative.h | 4 +-
arch/x86/include/asm/bitops.h | 14 ++---
arch/x86/include/asm/calling.h | 48 ++++++++--------
arch/x86/include/asm/processor.h | 1 -
arch/x86/kernel/alternative.c | 107 +++++++++---------------------------
arch/x86/kernel/cpu/common.c | 4 --
arch/x86/kernel/entry_64.S | 22 ++++----
arch/x86/kernel/smpboot.c | 20 +------
arch/x86/kernel/traps.c | 60 ++++++++++----------
arch/x86/xen/smp.c | 6 +-
kernel/cpu.c | 11 ----
12 files changed, 101 insertions(+), 199 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ad7e2e5..7aef334 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2638,9 +2638,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
smart2= [HW]
Format: <io1>[,<io2>[,...,<io8>]]
- smp-alt-once [X86-32,SMP] On a hotplug CPU system, only
- attempt to substitute SMP alternatives once at boot.
-
smsc-ircc2.nopnp [HW] Don't use PNP to discover SMC devices
smsc-ircc2.ircc_cfg= [HW] Device configuration I/O port
smsc-ircc2.ircc_sir= [HW] SIR base I/O port
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 7078068..444704c 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -60,7 +60,7 @@ extern void alternatives_smp_module_add(struct module *mod, char *name,
void *locks, void *locks_end,
void *text, void *text_end);
extern void alternatives_smp_module_del(struct module *mod);
-extern void alternatives_smp_switch(int smp);
+extern void alternatives_enable_smp(void);
extern int alternatives_text_reserved(void *start, void *end);
extern bool skip_smp_alternatives;
#else
@@ -68,7 +68,7 @@ static inline void alternatives_smp_module_add(struct module *mod, char *name,
void *locks, void *locks_end,
void *text, void *text_end) {}
static inline void alternatives_smp_module_del(struct module *mod) {}
-static inline void alternatives_smp_switch(int smp) {}
+static inline void alternatives_enable_smp(void) {}
static inline int alternatives_text_reserved(void *start, void *end)
{
return 0;
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 72f5009..6dfd019 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -355,7 +355,7 @@ static int test_bit(int nr, const volatile unsigned long *addr);
*/
static inline unsigned long __ffs(unsigned long word)
{
- asm("bsf %1,%0"
+ asm("rep; bsf %1,%0"
: "=r" (word)
: "rm" (word));
return word;
@@ -369,7 +369,7 @@ static inline unsigned long __ffs(unsigned long word)
*/
static inline unsigned long ffz(unsigned long word)
{
- asm("bsf %1,%0"
+ asm("rep; bsf %1,%0"
: "=r" (word)
: "r" (~word));
return word;
@@ -417,10 +417,9 @@ static inline int ffs(int x)
* We cannot do this on 32 bits because at the very least some
* 486 CPUs did not behave this way.
*/
- long tmp = -1;
asm("bsfl %1,%0"
: "=r" (r)
- : "rm" (x), "0" (tmp));
+ : "rm" (x), "0" (-1));
#elif defined(CONFIG_X86_CMOV)
asm("bsfl %1,%0\n\t"
"cmovzl %2,%0"
@@ -459,10 +458,9 @@ static inline int fls(int x)
* We cannot do this on 32 bits because at the very least some
* 486 CPUs did not behave this way.
*/
- long tmp = -1;
asm("bsrl %1,%0"
: "=r" (r)
- : "rm" (x), "0" (tmp));
+ : "rm" (x), "0" (-1));
#elif defined(CONFIG_X86_CMOV)
asm("bsrl %1,%0\n\t"
"cmovzl %2,%0"
@@ -490,13 +488,13 @@ static inline int fls(int x)
#ifdef CONFIG_X86_64
static __always_inline int fls64(__u64 x)
{
- long bitpos = -1;
+ int bitpos = -1;
/*
* AMD64 says BSRQ won't clobber the dest reg if x==0; Intel64 says the
* dest reg is undefined if x==0, but their CPU architect says its
* value is written to set it to the same as before.
*/
- asm("bsrq %1,%0"
+ asm("bsrq %1,%q0"
: "+r" (bitpos)
: "rm" (x));
return bitpos + 1;
diff --git a/arch/x86/include/asm/calling.h b/arch/x86/include/asm/calling.h
index a9e3a74..7f8422a 100644
--- a/arch/x86/include/asm/calling.h
+++ b/arch/x86/include/asm/calling.h
@@ -49,38 +49,36 @@ For 32-bit we have the following conventions - kernel is built with
#include "dwarf2.h"
/*
- * 64-bit system call stack frame layout defines and helpers, for
- * assembly code (note that the seemingly unnecessary parentheses
- * are to prevent cpp from inserting spaces in expressions that get
- * passed to macros):
+ * 64-bit system call stack frame layout defines and helpers,
+ * for assembly code:
*/
-#define R15 (0)
-#define R14 (8)
-#define R13 (16)
-#define R12 (24)
-#define RBP (32)
-#define RBX (40)
+#define R15 0
+#define R14 8
+#define R13 16
+#define R12 24
+#define RBP 32
+#define RBX 40
/* arguments: interrupts/non tracing syscalls only save up to here: */
-#define R11 (48)
-#define R10 (56)
-#define R9 (64)
-#define R8 (72)
-#define RAX (80)
-#define RCX (88)
-#define RDX (96)
-#define RSI (104)
-#define RDI (112)
-#define ORIG_RAX (120) /* + error_code */
+#define R11 48
+#define R10 56
+#define R9 64
+#define R8 72
+#define RAX 80
+#define RCX 88
+#define RDX 96
+#define RSI 104
+#define RDI 112
+#define ORIG_RAX 120 /* + error_code */
/* end of arguments */
/* cpu exception frame or undefined in case of fast syscall: */
-#define RIP (128)
-#define CS (136)
-#define EFLAGS (144)
-#define RSP (152)
-#define SS (160)
+#define RIP 128
+#define CS 136
+#define EFLAGS 144
+#define RSP 152
+#define SS 160
#define ARGOFFSET R11
#define SWFRAME ORIG_RAX
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index d048cad..9738b39 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -423,7 +423,6 @@ DECLARE_INIT_PER_CPU(irq_stack_union);
DECLARE_PER_CPU(char *, irq_stack_ptr);
DECLARE_PER_CPU(unsigned int, irq_count);
-extern unsigned long kernel_eflags;
extern asmlinkage void ignore_sysret(void);
#else /* X86_64 */
#ifdef CONFIG_CC_STACKPROTECTOR
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index afb7ff7..af1f326 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -23,19 +23,6 @@
#define MAX_PATCH_LEN (255-1)
-#ifdef CONFIG_HOTPLUG_CPU
-static int smp_alt_once;
-
-static int __init bootonly(char *str)
-{
- smp_alt_once = 1;
- return 1;
-}
-__setup("smp-alt-boot", bootonly);
-#else
-#define smp_alt_once 1
-#endif
-
static int __initdata_or_module debug_alternative;
static int __init debug_alt(char *str)
@@ -326,9 +313,6 @@ static void alternatives_smp_unlock(const s32 *start, const s32 *end,
{
const s32 *poff;
- if (noreplace_smp)
- return;
-
mutex_lock(&text_mutex);
for (poff = start; poff < end; poff++) {
u8 *ptr = (u8 *)poff + *poff;
@@ -359,7 +343,7 @@ struct smp_alt_module {
};
static LIST_HEAD(smp_alt_modules);
static DEFINE_MUTEX(smp_alt);
-static int smp_mode = 1; /* protected by smp_alt */
+static bool uniproc_patched = false; /* protected by smp_alt */
void __init_or_module alternatives_smp_module_add(struct module *mod,
char *name,
@@ -368,19 +352,18 @@ void __init_or_module alternatives_smp_module_add(struct module *mod,
{
struct smp_alt_module *smp;
- if (noreplace_smp)
- return;
+ mutex_lock(&smp_alt);
+ if (!uniproc_patched)
+ goto unlock;
- if (smp_alt_once) {
- if (boot_cpu_has(X86_FEATURE_UP))
- alternatives_smp_unlock(locks, locks_end,
- text, text_end);
- return;
- }
+ if (num_possible_cpus() == 1)
+ /* Don't bother remembering, we'll never have to undo it. */
+ goto smp_unlock;
smp = kzalloc(sizeof(*smp), GFP_KERNEL);
if (NULL == smp)
- return; /* we'll run the (safe but slow) SMP code then ... */
+ /* we'll run the (safe but slow) SMP code then ... */
+ goto unlock;
smp->mod = mod;
smp->name = name;
@@ -392,11 +375,10 @@ void __init_or_module alternatives_smp_module_add(struct module *mod,
__func__, smp->locks, smp->locks_end,
smp->text, smp->text_end, smp->name);
- mutex_lock(&smp_alt);
list_add_tail(&smp->next, &smp_alt_modules);
- if (boot_cpu_has(X86_FEATURE_UP))
- alternatives_smp_unlock(smp->locks, smp->locks_end,
- smp->text, smp->text_end);
+smp_unlock:
+ alternatives_smp_unlock(locks, locks_end, text, text_end);
+unlock:
mutex_unlock(&smp_alt);
}
@@ -404,24 +386,18 @@ void __init_or_module alternatives_smp_module_del(struct module *mod)
{
struct smp_alt_module *item;
- if (smp_alt_once || noreplace_smp)
- return;
-
mutex_lock(&smp_alt);
list_for_each_entry(item, &smp_alt_modules, next) {
if (mod != item->mod)
continue;
list_del(&item->next);
- mutex_unlock(&smp_alt);
- DPRINTK("%s: %s\n", __func__, item->name);
kfree(item);
- return;
+ break;
}
mutex_unlock(&smp_alt);
}
-bool skip_smp_alternatives;
-void alternatives_smp_switch(int smp)
+void alternatives_enable_smp(void)
{
struct smp_alt_module *mod;
@@ -436,34 +412,21 @@ void alternatives_smp_switch(int smp)
pr_info("lockdep: fixing up alternatives\n");
#endif
- if (noreplace_smp || smp_alt_once || skip_smp_alternatives)
- return;
- BUG_ON(!smp && (num_online_cpus() > 1));
+ /* Why bother if there are no other CPUs? */
+ BUG_ON(num_possible_cpus() == 1);
mutex_lock(&smp_alt);
- /*
- * Avoid unnecessary switches because it forces JIT based VMs to
- * throw away all cached translations, which can be quite costly.
- */
- if (smp == smp_mode) {
- /* nothing */
- } else if (smp) {
+ if (uniproc_patched) {
pr_info("switching to SMP code\n");
+ BUG_ON(num_online_cpus() != 1);
clear_cpu_cap(&boot_cpu_data, X86_FEATURE_UP);
clear_cpu_cap(&cpu_data(0), X86_FEATURE_UP);
list_for_each_entry(mod, &smp_alt_modules, next)
alternatives_smp_lock(mod->locks, mod->locks_end,
mod->text, mod->text_end);
- } else {
- pr_info("switching to UP code\n");
- set_cpu_cap(&boot_cpu_data, X86_FEATURE_UP);
- set_cpu_cap(&cpu_data(0), X86_FEATURE_UP);
- list_for_each_entry(mod, &smp_alt_modules, next)
- alternatives_smp_unlock(mod->locks, mod->locks_end,
- mod->text, mod->text_end);
+ uniproc_patched = false;
}
- smp_mode = smp;
mutex_unlock(&smp_alt);
}
@@ -540,40 +503,22 @@ void __init alternative_instructions(void)
apply_alternatives(__alt_instructions, __alt_instructions_end);
- /* switch to patch-once-at-boottime-only mode and free the
- * tables in case we know the number of CPUs will never ever
- * change */
-#ifdef CONFIG_HOTPLUG_CPU
- if (num_possible_cpus() < 2)
- smp_alt_once = 1;
-#endif
-
#ifdef CONFIG_SMP
- if (smp_alt_once) {
- if (1 == num_possible_cpus()) {
- pr_info("switching to UP code\n");
- set_cpu_cap(&boot_cpu_data, X86_FEATURE_UP);
- set_cpu_cap(&cpu_data(0), X86_FEATURE_UP);
-
- alternatives_smp_unlock(__smp_locks, __smp_locks_end,
- _text, _etext);
- }
- } else {
+ /* Patch to UP if other cpus not imminent. */
+ if (!noreplace_smp && (num_present_cpus() == 1 || setup_max_cpus <= 1)) {
+ uniproc_patched = true;
alternatives_smp_module_add(NULL, "core kernel",
__smp_locks, __smp_locks_end,
_text, _etext);
-
- /* Only switch to UP mode if we don't immediately boot others */
- if (num_present_cpus() == 1 || setup_max_cpus <= 1)
- alternatives_smp_switch(0);
}
-#endif
- apply_paravirt(__parainstructions, __parainstructions_end);
- if (smp_alt_once)
+ if (!uniproc_patched || num_possible_cpus() == 1)
free_init_pages("SMP alternatives",
(unsigned long)__smp_locks,
(unsigned long)__smp_locks_end);
+#endif
+
+ apply_paravirt(__parainstructions, __parainstructions_end);
restart_nmi();
}
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a5fbc3c..9961e2e 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1116,8 +1116,6 @@ void syscall_init(void)
X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF|X86_EFLAGS_IOPL);
}
-unsigned long kernel_eflags;
-
/*
* Copies of the original ist values from the tss are only accessed during
* debugging, no special alignment required.
@@ -1299,8 +1297,6 @@ void __cpuinit cpu_init(void)
fpu_init();
xsave_init();
- raw_local_save_flags(kernel_eflags);
-
if (is_uv_system())
uv_cpu_init();
}
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 69babd8..2c67061 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -342,15 +342,15 @@ ENDPROC(native_usergs_sysret64)
.macro SAVE_ARGS_IRQ
cld
/* start from rbp in pt_regs and jump over */
- movq_cfi rdi, RDI-RBP
- movq_cfi rsi, RSI-RBP
- movq_cfi rdx, RDX-RBP
- movq_cfi rcx, RCX-RBP
- movq_cfi rax, RAX-RBP
- movq_cfi r8, R8-RBP
- movq_cfi r9, R9-RBP
- movq_cfi r10, R10-RBP
- movq_cfi r11, R11-RBP
+ movq_cfi rdi, (RDI-RBP)
+ movq_cfi rsi, (RSI-RBP)
+ movq_cfi rdx, (RDX-RBP)
+ movq_cfi rcx, (RCX-RBP)
+ movq_cfi rax, (RAX-RBP)
+ movq_cfi r8, (R8-RBP)
+ movq_cfi r9, (R9-RBP)
+ movq_cfi r10, (R10-RBP)
+ movq_cfi r11, (R11-RBP)
/* Save rbp so that we can unwind from get_irq_regs() */
movq_cfi rbp, 0
@@ -384,7 +384,7 @@ ENDPROC(native_usergs_sysret64)
.endm
ENTRY(save_rest)
- PARTIAL_FRAME 1 REST_SKIP+8
+ PARTIAL_FRAME 1 (REST_SKIP+8)
movq 5*8+16(%rsp), %r11 /* save return address */
movq_cfi rbx, RBX+16
movq_cfi rbp, RBP+16
@@ -440,7 +440,7 @@ ENTRY(ret_from_fork)
LOCK ; btr $TIF_FORK,TI_flags(%r8)
- pushq_cfi kernel_eflags(%rip)
+ pushq_cfi $0x0002
popfq_cfi # reset kernel eflags
call schedule_tail # rdi: 'prev' task parameter
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 7c5a8c3..c80a33b 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -665,7 +665,8 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
unsigned long boot_error = 0;
int timeout;
- alternatives_smp_switch(1);
+ /* Just in case we booted with a single CPU. */
+ alternatives_enable_smp();
idle->thread.sp = (unsigned long) (((struct pt_regs *)
(THREAD_SIZE + task_stack_page(idle))) - 1);
@@ -1053,20 +1054,6 @@ out:
preempt_enable();
}
-void arch_disable_nonboot_cpus_begin(void)
-{
- /*
- * Avoid the smp alternatives switch during the disable_nonboot_cpus().
- * In the suspend path, we will be back in the SMP mode shortly anyways.
- */
- skip_smp_alternatives = true;
-}
-
-void arch_disable_nonboot_cpus_end(void)
-{
- skip_smp_alternatives = false;
-}
-
void arch_enable_nonboot_cpus_begin(void)
{
set_mtrr_aps_delayed_init();
@@ -1256,9 +1243,6 @@ void native_cpu_die(unsigned int cpu)
if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
if (system_state == SYSTEM_RUNNING)
pr_info("CPU %u is now offline\n", cpu);
-
- if (1 == num_online_cpus())
- alternatives_smp_switch(0);
return;
}
msleep(100);
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index b481341..6ff7715 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -107,30 +107,45 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
dec_preempt_count();
}
-static void __kprobes
-do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
- long error_code, siginfo_t *info)
+static int __kprobes
+do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
+ struct pt_regs *regs, long error_code)
{
- struct task_struct *tsk = current;
-
#ifdef CONFIG_X86_32
if (regs->flags & X86_VM_MASK) {
/*
- * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
+ * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
* On nmi (interrupt 2), do_trap should not be called.
*/
- if (trapnr < X86_TRAP_UD)
- goto vm86_trap;
- goto trap_signal;
+ if (trapnr < X86_TRAP_UD) {
+ if (!handle_vm86_trap((struct kernel_vm86_regs *) regs,
+ error_code, trapnr))
+ return 0;
+ }
+ return -1;
}
#endif
+ if (!user_mode(regs)) {
+ if (!fixup_exception(regs)) {
+ tsk->thread.error_code = error_code;
+ tsk->thread.trap_nr = trapnr;
+ die(str, regs, error_code);
+ }
+ return 0;
+ }
- if (!user_mode(regs))
- goto kernel_trap;
+ return -1;
+}
-#ifdef CONFIG_X86_32
-trap_signal:
-#endif
+static void __kprobes
+do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
+ long error_code, siginfo_t *info)
+{
+ struct task_struct *tsk = current;
+
+
+ if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))
+ return;
/*
* We want error_code and trap_nr set for userspace faults and
* kernelspace faults which result in die(), but not
@@ -158,23 +173,6 @@ trap_signal:
force_sig_info(signr, info, tsk);
else
force_sig(signr, tsk);
- return;
-
-kernel_trap:
- if (!fixup_exception(regs)) {
- tsk->thread.error_code = error_code;
- tsk->thread.trap_nr = trapnr;
- die(str, regs, error_code);
- }
- return;
-
-#ifdef CONFIG_X86_32
-vm86_trap:
- if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
- error_code, trapnr))
- goto trap_signal;
- return;
-#endif
}
#define DO_ERROR(trapnr, signr, str, name) \
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index f58dca7..353c50f 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -377,7 +377,8 @@ static int __cpuinit xen_cpu_up(unsigned int cpu, struct task_struct *idle)
return rc;
if (num_online_cpus() == 1)
- alternatives_smp_switch(1);
+ /* Just in case we booted with a single CPU. */
+ alternatives_enable_smp();
rc = xen_smp_intr_init(cpu);
if (rc)
@@ -424,9 +425,6 @@ static void xen_cpu_die(unsigned int cpu)
unbind_from_irqhandler(per_cpu(xen_irq_work, cpu), NULL);
xen_uninit_lock_cpu(cpu);
xen_teardown_timer(cpu);
-
- if (num_online_cpus() == 1)
- alternatives_smp_switch(0);
}
static void __cpuinit xen_play_dead(void) /* used only with HOTPLUG_CPU */
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 14d3258..f6bfe3e 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -439,14 +439,6 @@ EXPORT_SYMBOL_GPL(cpu_up);
#ifdef CONFIG_PM_SLEEP_SMP
static cpumask_var_t frozen_cpus;
-void __weak arch_disable_nonboot_cpus_begin(void)
-{
-}
-
-void __weak arch_disable_nonboot_cpus_end(void)
-{
-}
-
int disable_nonboot_cpus(void)
{
int cpu, first_cpu, error = 0;
@@ -458,7 +450,6 @@ int disable_nonboot_cpus(void)
* with the userspace trying to use the CPU hotplug at the same time
*/
cpumask_clear(frozen_cpus);
- arch_disable_nonboot_cpus_begin();
printk("Disabling non-boot CPUs ...\n");
for_each_online_cpu(cpu) {
@@ -474,8 +465,6 @@ int disable_nonboot_cpus(void)
}
}
- arch_disable_nonboot_cpus_end();
-
if (!error) {
BUG_ON(num_online_cpus() > 1);
/* Make sure the CPUs won't be enabled by someone else */
--
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