x86 idle: remove 32-bit-only "no-hlt" parameter, hlt_works_ok flag
Remove 32-bit x86 a cmdline param "no-hlt",
and the cpuinfo_x86.hlt_works_ok that it sets.
If a user wants to avoid HLT, then "idle=poll"
is much more useful, as it avoids invocation of HLT
in idle, while "no-hlt" failed to do so.
Indeed, hlt_works_ok was consulted in only 3 places.
First, in /proc/cpuinfo where "hlt_bug yes"
would be printed if and only if the user booted
the system with "no-hlt" -- as there was no other code
to set that flag.
Second, check_hlt() would not invoke halt() if "no-hlt"
were on the cmdline.
Third, it was consulted in stop_this_cpu(), which is invoked
by native_machine_halt()/reboot_interrupt()/smp_stop_nmi_callback() --
all cases where the machine is being shutdown/reset.
The flag was not consulted in the more frequently invoked
play_dead()/hlt_play_dead() used in processor offline and suspend.
Since Linux-3.0 there has been a run-time notice upon "no-hlt" invocations
indicating that it would be removed in 2012.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: x86@kernel.org
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 3b0cd1e..109ee45 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1881,10 +1881,6 @@
wfi(ARM) instruction doesn't work correctly and not to
use it. This is also useful when using JTAG debugger.
- no-hlt [BUGS=X86-32] Tells the kernel that the hlt
- instruction doesn't work correctly and not to
- use it.
-
no_file_caps Tells the kernel not to honor file capabilities. The
only way then for a file to be executed with privilege
is to be setuid root or executed by root.
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 8a28fea..b9e7d27 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -89,7 +89,6 @@
char wp_works_ok; /* It doesn't on 386's */
/* Problems on some 486Dx4's and old 386's: */
- char hlt_works_ok;
char hard_math;
char rfu;
char fdiv_bug;
@@ -165,15 +164,6 @@
extern const struct seq_operations cpuinfo_op;
-static inline int hlt_works(int cpu)
-{
-#ifdef CONFIG_X86_32
- return cpu_data(cpu).hlt_works_ok;
-#else
- return 1;
-#endif
-}
-
#define cache_line_size() (boot_cpu_data.x86_cache_alignment)
extern void cpu_detect(struct cpuinfo_x86 *c);
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 92dfec9..af6455e 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -17,15 +17,6 @@
#include <asm/paravirt.h>
#include <asm/alternative.h>
-static int __init no_halt(char *s)
-{
- WARN_ONCE(1, "\"no-hlt\" is deprecated, please use \"idle=poll\"\n");
- boot_cpu_data.hlt_works_ok = 0;
- return 1;
-}
-
-__setup("no-hlt", no_halt);
-
static int __init no_387(char *s)
{
boot_cpu_data.hard_math = 0;
@@ -89,23 +80,6 @@
pr_warn("Hmm, FPU with FDIV bug\n");
}
-static void __init check_hlt(void)
-{
- if (boot_cpu_data.x86 >= 5 || paravirt_enabled())
- return;
-
- pr_info("Checking 'hlt' instruction... ");
- if (!boot_cpu_data.hlt_works_ok) {
- pr_cont("disabled\n");
- return;
- }
- halt();
- halt();
- halt();
- halt();
- pr_cont("OK\n");
-}
-
/*
* Check whether we are able to run this kernel safely on SMP.
*
@@ -129,7 +103,6 @@
print_cpu_info(&boot_cpu_data);
#endif
check_config();
- check_hlt();
init_utsname()->machine[1] =
'0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
alternative_instructions();
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 3286a92..e280253 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -28,7 +28,6 @@
{
seq_printf(m,
"fdiv_bug\t: %s\n"
- "hlt_bug\t\t: %s\n"
"f00f_bug\t: %s\n"
"coma_bug\t: %s\n"
"fpu\t\t: %s\n"
@@ -36,7 +35,6 @@
"cpuid level\t: %d\n"
"wp\t\t: %s\n",
c->fdiv_bug ? "yes" : "no",
- c->hlt_works_ok ? "no" : "yes",
c->f00f_bug ? "yes" : "no",
c->coma_bug ? "yes" : "no",
c->hard_math ? "yes" : "no",
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index cd5a4c9..aef852e 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -415,10 +415,8 @@
set_cpu_online(smp_processor_id(), false);
disable_local_APIC();
- for (;;) {
- if (hlt_works(smp_processor_id()))
- halt();
- }
+ for (;;)
+ halt();
}
/*
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 2b73b5c..94eac5c 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -556,9 +556,6 @@
COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
/* Set up idle, making sure it calls safe_halt() pvop */
-#ifdef CONFIG_X86_32
- boot_cpu_data.hlt_works_ok = 1;
-#endif
disable_cpuidle();
disable_cpufreq();
WARN_ON(xen_set_default_idle());
