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authorJan Beulich <JBeulich@novell.com>2011-07-19 11:53:07 +0100
committerIngo Molnar <mingo@elte.hu>2011-07-21 09:21:00 +0200
commitef68c8f87ed13f65df867dddf36c0e185b27b942 (patch)
tree5caf15b1d46697bda2201fd1625d498e64df9f01
parentac619f4eba45da10053fc991f8a5d47b3be79fa3 (diff)
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x86: Serialize EFI time accesses on rtc_lock
The EFI specification requires that callers of the time related runtime functions serialize with other CMOS accesses in the kernel, as the EFI time functions may choose to also use the legacy CMOS RTC. Besides fixing a latent bug, this is a prerequisite to safely enable the rtc-efi driver for x86, which ought to be preferred over rtc-cmos on all EFI platforms. Signed-off-by: Jan Beulich <jbeulich@novell.com> Acked-by: Matthew Garrett <mjg59@srcf.ucam.org> Cc: <mjg@redhat.com> Link: http://lkml.kernel.org/r/4E257E33020000780004E319@nat28.tlf.novell.com Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Matthew Garrett <mjg@redhat.com>
-rw-r--r--arch/x86/platform/efi/efi.c39
1 files changed, 33 insertions, 6 deletions
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 474356b98ed..b8823d5a011 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -79,26 +79,50 @@ early_param("add_efi_memmap", setup_add_efi_memmap);
static efi_status_t virt_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc)
{
- return efi_call_virt2(get_time, tm, tc);
+ unsigned long flags;
+ efi_status_t status;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+ status = efi_call_virt2(get_time, tm, tc);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ return status;
}
static efi_status_t virt_efi_set_time(efi_time_t *tm)
{
- return efi_call_virt1(set_time, tm);
+ unsigned long flags;
+ efi_status_t status;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+ status = efi_call_virt1(set_time, tm);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ return status;
}
static efi_status_t virt_efi_get_wakeup_time(efi_bool_t *enabled,
efi_bool_t *pending,
efi_time_t *tm)
{
- return efi_call_virt3(get_wakeup_time,
- enabled, pending, tm);
+ unsigned long flags;
+ efi_status_t status;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+ status = efi_call_virt3(get_wakeup_time,
+ enabled, pending, tm);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ return status;
}
static efi_status_t virt_efi_set_wakeup_time(efi_bool_t enabled, efi_time_t *tm)
{
- return efi_call_virt2(set_wakeup_time,
- enabled, tm);
+ unsigned long flags;
+ efi_status_t status;
+
+ spin_lock_irqsave(&rtc_lock, flags);
+ status = efi_call_virt2(set_wakeup_time,
+ enabled, tm);
+ spin_unlock_irqrestore(&rtc_lock, flags);
+ return status;
}
static efi_status_t virt_efi_get_variable(efi_char16_t *name,
@@ -164,11 +188,14 @@ static efi_status_t __init phys_efi_set_virtual_address_map(
static efi_status_t __init phys_efi_get_time(efi_time_t *tm,
efi_time_cap_t *tc)
{
+ unsigned long flags;
efi_status_t status;
+ spin_lock_irqsave(&rtc_lock, flags);
efi_call_phys_prelog();
status = efi_call_phys2(efi_phys.get_time, tm, tc);
efi_call_phys_epilog();
+ spin_unlock_irqrestore(&rtc_lock, flags);
return status;
}