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Message-Id: <200903111631.29787.rusty@rustcorp.com.au>
Date: Wed, 11 Mar 2009 16:31:29 +1030
From: Rusty Russell <rusty@...tcorp.com.au>
To: Stephen Rothwell <sfr@...b.auug.org.au>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org, linux-laptop@...r.kernel.org,
Ingo Molnar <mingo@...e.hu>
Subject: [PATCH] cpumask: update 32-bit APM not to mug current->cpus_allowed.
Impact: cleanup, avoid cpumask games.
The APM code wants to run on CPU 0: we create an "on_cpu0" wrapper
which uses work_on_cpu() if we're not already on cpu 0.
This introduces a new failure mode: -ENOMEM, so we add an explicit err
arg and handle Linux-style errnos in apm_err().
Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
To: Stephen Rothwell <sfr@...b.auug.org.au>
Cc: linux-laptop@...r.kernel.org
---
arch/x86/kernel/apm_32.c | 276 +++++++++++++++++++++++++++--------------------
1 file changed, 159 insertions(+), 117 deletions(-)
diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -466,7 +466,7 @@ static const lookup_t error_table[] = {
* @err: APM BIOS return code
*
* Write a meaningful log entry to the kernel log in the event of
- * an APM error.
+ * an APM error. Note that this also handles (negative) kernel errors.
*/
static void apm_error(char *str, int err)
@@ -478,41 +478,12 @@ static void apm_error(char *str, int err
break;
if (i < ERROR_COUNT)
printk(KERN_NOTICE "apm: %s: %s\n", str, error_table[i].msg);
+ else if (err < 0)
+ printk(KERN_NOTICE "apm: %s: linux error code %i\n", str, err);
else
printk(KERN_NOTICE "apm: %s: unknown error code %#2.2x\n",
str, err);
}
-
-/*
- * Lock APM functionality to physical CPU 0
- */
-
-#ifdef CONFIG_SMP
-
-static cpumask_t apm_save_cpus(void)
-{
- cpumask_t x = current->cpus_allowed;
- /* Some bioses don't like being called from CPU != 0 */
- set_cpus_allowed(current, cpumask_of_cpu(0));
- BUG_ON(smp_processor_id() != 0);
- return x;
-}
-
-static inline void apm_restore_cpus(cpumask_t mask)
-{
- set_cpus_allowed(current, mask);
-}
-
-#else
-
-/*
- * No CPU lockdown needed on a uniprocessor
- */
-
-#define apm_save_cpus() (current->cpus_allowed)
-#define apm_restore_cpus(x) (void)(x)
-
-#endif
/*
* These are the actual BIOS calls. Depending on APM_ZERO_SEGS and
@@ -568,16 +539,23 @@ static inline void apm_irq_restore(unsig
# define APM_DO_RESTORE_SEGS
#endif
+struct apm_bios_call {
+ u32 func;
+ /* In and out */
+ u32 ebx;
+ u32 ecx;
+ /* Out only */
+ u32 eax;
+ u32 edx;
+ u32 esi;
+
+ /* Error: -ENOMEM, or bits 8-15 of eax */
+ int err;
+};
+
/**
- * apm_bios_call - Make an APM BIOS 32bit call
- * @func: APM function to execute
- * @ebx_in: EBX register for call entry
- * @ecx_in: ECX register for call entry
- * @eax: EAX register return
- * @ebx: EBX register return
- * @ecx: ECX register return
- * @edx: EDX register return
- * @esi: ESI register return
+ * __apm_bios_call - Make an APM BIOS 32bit call
+ * @_call: pointer to struct apm_bios_call.
*
* Make an APM call using the 32bit protected mode interface. The
* caller is responsible for knowing if APM BIOS is configured and
@@ -586,35 +564,109 @@ static inline void apm_irq_restore(unsig
* flag is loaded into AL. If there is an error, then the error
* code is returned in AH (bits 8-15 of eax) and this function
* returns non-zero.
+ *
+ * Note: this makes the call on the current CPU.
*/
-
-static u8 apm_bios_call(u32 func, u32 ebx_in, u32 ecx_in,
- u32 *eax, u32 *ebx, u32 *ecx, u32 *edx, u32 *esi)
+static long __apm_bios_call(void *_call)
{
APM_DECL_SEGS
unsigned long flags;
- cpumask_t cpus;
int cpu;
struct desc_struct save_desc_40;
struct desc_struct *gdt;
-
- cpus = apm_save_cpus();
+ struct apm_bios_call *call = _call;
cpu = get_cpu();
+ BUG_ON(cpu != 0);
gdt = get_cpu_gdt_table(cpu);
save_desc_40 = gdt[0x40 / 8];
gdt[0x40 / 8] = bad_bios_desc;
apm_irq_save(flags);
APM_DO_SAVE_SEGS;
- apm_bios_call_asm(func, ebx_in, ecx_in, eax, ebx, ecx, edx, esi);
+ apm_bios_call_asm(call->func, call->ebx, call->ecx,
+ &call->eax, &call->ebx, &call->ecx, &call->edx,
+ &call->esi);
APM_DO_RESTORE_SEGS;
apm_irq_restore(flags);
gdt[0x40 / 8] = save_desc_40;
put_cpu();
- apm_restore_cpus(cpus);
- return *eax & 0xff;
+ return call->eax & 0xff;
+}
+
+/* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
+static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
+{
+ int ret;
+
+ /* Don't bother with work_on_cpu in the common case, so we don't
+ * have to worry about OOM or overhead. */
+ if (get_cpu() == 0) {
+ ret = fn(call);
+ put_cpu();
+ } else {
+ put_cpu();
+ ret = work_on_cpu(0, fn, call);
+ }
+
+ /* work_on_cpu can fail with -ENOMEM */
+ if (ret < 0)
+ call->err = ret;
+ else
+ call->err = (call->eax >> 8) & 0xff;
+
+ return ret;
+}
+
+/**
+ * apm_bios_call - Make an APM BIOS 32bit call (on CPU 0)
+ * @call: the apm_bios_call registers.
+ *
+ * If there is an error, it is returned in @call.err.
+ */
+static int apm_bios_call(struct apm_bios_call *call)
+{
+ return on_cpu0(__apm_bios_call, call);
+}
+
+/**
+ * __apm_bios_call_simple - Make an APM BIOS 32bit call (on CPU 0)
+ * @_call: pointer to struct apm_bios_call.
+ *
+ * Make a BIOS call that returns one value only, or just status.
+ * If there is an error, then the error code is returned in AH
+ * (bits 8-15 of eax) and this function returns non-zero (it can
+ * also return -ENOMEM). This is used for simpler BIOS operations.
+ * This call may hold interrupts off for a long time on some laptops.
+ *
+ * Note: this makes the call on the current CPU.
+ */
+static long __apm_bios_call_simple(void *_call)
+{
+ u8 error;
+ APM_DECL_SEGS
+ unsigned long flags;
+ int cpu;
+ struct desc_struct save_desc_40;
+ struct desc_struct *gdt;
+ struct apm_bios_call *call = _call;
+
+ cpu = get_cpu();
+ BUG_ON(cpu != 0);
+ gdt = get_cpu_gdt_table(cpu);
+ save_desc_40 = gdt[0x40 / 8];
+ gdt[0x40 / 8] = bad_bios_desc;
+
+ apm_irq_save(flags);
+ APM_DO_SAVE_SEGS;
+ error = apm_bios_call_simple_asm(call->func, call->ebx, call->ecx,
+ &call->eax);
+ APM_DO_RESTORE_SEGS;
+ apm_irq_restore(flags);
+ gdt[0x40 / 8] = save_desc_40;
+ put_cpu();
+ return error;
}
/**
@@ -623,40 +675,28 @@ static u8 apm_bios_call(u32 func, u32 eb
* @ebx_in: EBX register value for BIOS call
* @ecx_in: ECX register value for BIOS call
* @eax: EAX register on return from the BIOS call
+ * @err: bits
*
* Make a BIOS call that returns one value only, or just status.
- * If there is an error, then the error code is returned in AH
- * (bits 8-15 of eax) and this function returns non-zero. This is
- * used for simpler BIOS operations. This call may hold interrupts
- * off for a long time on some laptops.
+ * If there is an error, then the error code is returned in @err
+ * and this function returns non-zero. This is used for simpler
+ * BIOS operations. This call may hold interrupts off for a long
+ * time on some laptops.
*/
+static int apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax,
+ int *err)
+{
+ struct apm_bios_call call;
+ int ret;
-static u8 apm_bios_call_simple(u32 func, u32 ebx_in, u32 ecx_in, u32 *eax)
-{
- u8 error;
- APM_DECL_SEGS
- unsigned long flags;
- cpumask_t cpus;
- int cpu;
- struct desc_struct save_desc_40;
- struct desc_struct *gdt;
+ call.func = func;
+ call.ebx = ebx_in;
+ call.ecx = ecx_in;
- cpus = apm_save_cpus();
-
- cpu = get_cpu();
- gdt = get_cpu_gdt_table(cpu);
- save_desc_40 = gdt[0x40 / 8];
- gdt[0x40 / 8] = bad_bios_desc;
-
- apm_irq_save(flags);
- APM_DO_SAVE_SEGS;
- error = apm_bios_call_simple_asm(func, ebx_in, ecx_in, eax);
- APM_DO_RESTORE_SEGS;
- apm_irq_restore(flags);
- gdt[0x40 / 8] = save_desc_40;
- put_cpu();
- apm_restore_cpus(cpus);
- return error;
+ ret = on_cpu0(__apm_bios_call_simple, &call);
+ *eax = call.eax;
+ *err = call.err;
+ return ret;
}
/**
@@ -678,9 +718,10 @@ static int apm_driver_version(u_short *v
static int apm_driver_version(u_short *val)
{
u32 eax;
+ int err;
- if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax))
- return (eax >> 8) & 0xff;
+ if (apm_bios_call_simple(APM_FUNC_VERSION, 0, *val, &eax, &err))
+ return err;
*val = eax;
return APM_SUCCESS;
}
@@ -701,22 +742,21 @@ static int apm_driver_version(u_short *v
* that APM 1.2 is in use. If no messges are pending the value 0x80
* is returned (No power management events pending).
*/
-
static int apm_get_event(apm_event_t *event, apm_eventinfo_t *info)
{
- u32 eax;
- u32 ebx;
- u32 ecx;
- u32 dummy;
+ struct apm_bios_call call;
- if (apm_bios_call(APM_FUNC_GET_EVENT, 0, 0, &eax, &ebx, &ecx,
- &dummy, &dummy))
- return (eax >> 8) & 0xff;
- *event = ebx;
+ call.func = APM_FUNC_GET_EVENT;
+ call.ebx = call.ecx = 0;
+
+ if (apm_bios_call(&call))
+ return call.err;
+
+ *event = call.ebx;
if (apm_info.connection_version < 0x0102)
*info = ~0; /* indicate info not valid */
else
- *info = ecx;
+ *info = call.ecx;
return APM_SUCCESS;
}
@@ -737,9 +777,10 @@ static int set_power_state(u_short what,
static int set_power_state(u_short what, u_short state)
{
u32 eax;
+ int err;
- if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax))
- return (eax >> 8) & 0xff;
+ if (apm_bios_call_simple(APM_FUNC_SET_STATE, what, state, &eax, &err))
+ return err;
return APM_SUCCESS;
}
@@ -770,6 +811,7 @@ static int apm_do_idle(void)
u8 ret = 0;
int idled = 0;
int polling;
+ int err;
polling = !!(current_thread_info()->status & TS_POLLING);
if (polling) {
@@ -782,7 +824,7 @@ static int apm_do_idle(void)
}
if (!need_resched()) {
idled = 1;
- ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax);
+ ret = apm_bios_call_simple(APM_FUNC_IDLE, 0, 0, &eax, &err);
}
if (polling)
current_thread_info()->status |= TS_POLLING;
@@ -797,8 +839,7 @@ static int apm_do_idle(void)
* Only report the failure the first 5 times.
*/
if (++t < 5) {
- printk(KERN_DEBUG "apm_do_idle failed (%d)\n",
- (eax >> 8) & 0xff);
+ printk(KERN_DEBUG "apm_do_idle failed (%d)\n", err);
t = jiffies;
}
return -1;
@@ -816,9 +857,10 @@ static void apm_do_busy(void)
static void apm_do_busy(void)
{
u32 dummy;
+ int err;
if (clock_slowed || ALWAYS_CALL_BUSY) {
- (void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy);
+ (void)apm_bios_call_simple(APM_FUNC_BUSY, 0, 0, &dummy, &err);
clock_slowed = 0;
}
}
@@ -937,7 +979,7 @@ static void apm_power_off(void)
/* Some bioses don't like being called from CPU != 0 */
if (apm_info.realmode_power_off) {
- (void)apm_save_cpus();
+ set_cpus_allowed_ptr(current, cpumask_of(0));
machine_real_restart(po_bios_call, sizeof(po_bios_call));
} else {
(void)set_system_power_state(APM_STATE_OFF);
@@ -956,12 +998,13 @@ static int apm_enable_power_management(i
static int apm_enable_power_management(int enable)
{
u32 eax;
+ int err;
if ((enable == 0) && (apm_info.bios.flags & APM_BIOS_DISENGAGED))
return APM_NOT_ENGAGED;
if (apm_bios_call_simple(APM_FUNC_ENABLE_PM, APM_DEVICE_BALL,
- enable, &eax))
- return (eax >> 8) & 0xff;
+ enable, &eax, &err))
+ return err;
if (enable)
apm_info.bios.flags &= ~APM_BIOS_DISABLED;
else
@@ -986,24 +1029,23 @@ static int apm_enable_power_management(i
static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
{
- u32 eax;
- u32 ebx;
- u32 ecx;
- u32 edx;
- u32 dummy;
+ struct apm_bios_call call;
+
+ call.func = APM_FUNC_GET_STATUS;
+ call.ebx = APM_DEVICE_ALL;
+ call.ecx = 0;
if (apm_info.get_power_status_broken)
return APM_32_UNSUPPORTED;
- if (apm_bios_call(APM_FUNC_GET_STATUS, APM_DEVICE_ALL, 0,
- &eax, &ebx, &ecx, &edx, &dummy))
- return (eax >> 8) & 0xff;
- *status = ebx;
- *bat = ecx;
+ if (apm_bios_call(&call))
+ return call.err;
+ *status = call.ebx;
+ *bat = call.ecx;
if (apm_info.get_power_status_swabinminutes) {
- *life = swab16((u16)edx);
+ *life = swab16((u16)call.edx);
*life |= 0x8000;
} else
- *life = edx;
+ *life = call.edx;
return APM_SUCCESS;
}
@@ -1048,12 +1090,14 @@ static int apm_engage_power_management(u
static int apm_engage_power_management(u_short device, int enable)
{
u32 eax;
+ int err;
if ((enable == 0) && (device == APM_DEVICE_ALL)
&& (apm_info.bios.flags & APM_BIOS_DISABLED))
return APM_DISABLED;
- if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable, &eax))
- return (eax >> 8) & 0xff;
+ if (apm_bios_call_simple(APM_FUNC_ENGAGE_PM, device, enable,
+ &eax, &err))
+ return err;
if (device == APM_DEVICE_ALL) {
if (enable)
apm_info.bios.flags &= ~APM_BIOS_DISENGAGED;
@@ -1678,16 +1722,14 @@ static int apm(void *unused)
char *power_stat;
char *bat_stat;
-#ifdef CONFIG_SMP
/* 2002/08/01 - WT
* This is to avoid random crashes at boot time during initialization
* on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
* Some bioses don't like being called from CPU != 0.
* Method suggested by Ingo Molnar.
*/
- set_cpus_allowed(current, cpumask_of_cpu(0));
+ set_cpus_allowed_ptr(current, cpumask_of(0));
BUG_ON(smp_processor_id() != 0);
-#endif
if (apm_info.connection_version == 0) {
apm_info.connection_version = apm_info.bios.version;
--
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