Commit 7212e37c authored by Hedi Berriche's avatar Hedi Berriche Committed by Greg Kroah-Hartman

x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls

commit f331e766c4be33f4338574f3c9f7f77e98ab4571 upstream.

Calls into UV firmware must be protected against concurrency, expose the
efi_runtime_lock to the UV platform, and use it to serialise UV BIOS
calls.
Signed-off-by: default avatarHedi Berriche <hedi.berriche@hpe.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: default avatarRuss Anderson <rja@hpe.com>
Reviewed-by: default avatarDimitri Sivanich <sivanich@hpe.com>
Reviewed-by: default avatarMike Travis <mike.travis@hpe.com>
Cc: Andy Shevchenko <andy@infradead.org>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-efi <linux-efi@vger.kernel.org>
Cc: platform-driver-x86@vger.kernel.org
Cc: stable@vger.kernel.org # v4.9+
Cc: Steve Wahl <steve.wahl@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190213193413.25560-5-hedi.berriche@hpe.comSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 137f4db1
......@@ -48,7 +48,8 @@ enum {
BIOS_STATUS_SUCCESS = 0,
BIOS_STATUS_UNIMPLEMENTED = -ENOSYS,
BIOS_STATUS_EINVAL = -EINVAL,
BIOS_STATUS_UNAVAIL = -EBUSY
BIOS_STATUS_UNAVAIL = -EBUSY,
BIOS_STATUS_ABORT = -EINTR,
};
/*
......@@ -111,4 +112,9 @@ extern long system_serial_number;
extern struct kobject *sgi_uv_kobj; /* /sys/firmware/sgi_uv */
/*
* EFI runtime lock; cf. firmware/efi/runtime-wrappers.c for details
*/
extern struct semaphore __efi_uv_runtime_lock;
#endif /* _ASM_X86_UV_BIOS_H */
......@@ -28,7 +28,8 @@
static struct uv_systab uv_systab;
s64 uv_bios_call(enum uv_bios_cmd which, u64 a1, u64 a2, u64 a3, u64 a4, u64 a5)
static s64 __uv_bios_call(enum uv_bios_cmd which, u64 a1, u64 a2, u64 a3,
u64 a4, u64 a5)
{
struct uv_systab *tab = &uv_systab;
s64 ret;
......@@ -43,6 +44,19 @@ s64 uv_bios_call(enum uv_bios_cmd which, u64 a1, u64 a2, u64 a3, u64 a4, u64 a5)
a1, a2, a3, a4, a5);
return ret;
}
s64 uv_bios_call(enum uv_bios_cmd which, u64 a1, u64 a2, u64 a3, u64 a4, u64 a5)
{
s64 ret;
if (down_interruptible(&__efi_uv_runtime_lock))
return BIOS_STATUS_ABORT;
ret = __uv_bios_call(which, a1, a2, a3, a4, a5);
up(&__efi_uv_runtime_lock);
return ret;
}
EXPORT_SYMBOL_GPL(uv_bios_call);
s64 uv_bios_call_irqsave(enum uv_bios_cmd which, u64 a1, u64 a2, u64 a3,
......@@ -51,10 +65,15 @@ s64 uv_bios_call_irqsave(enum uv_bios_cmd which, u64 a1, u64 a2, u64 a3,
unsigned long bios_flags;
s64 ret;
if (down_interruptible(&__efi_uv_runtime_lock))
return BIOS_STATUS_ABORT;
local_irq_save(bios_flags);
ret = uv_bios_call(which, a1, a2, a3, a4, a5);
ret = __uv_bios_call(which, a1, a2, a3, a4, a5);
local_irq_restore(bios_flags);
up(&__efi_uv_runtime_lock);
return ret;
}
......
......@@ -87,6 +87,13 @@ static DEFINE_SPINLOCK(efi_runtime_lock);
* context through efi_pstore_write().
*/
/*
* Expose the EFI runtime lock to the UV platform
*/
#ifdef CONFIG_X86_UV
extern struct semaphore __efi_uv_runtime_lock __alias(efi_runtime_lock);
#endif
/*
* As per commit ef68c8f87ed1 ("x86: Serialize EFI time accesses on rtc_lock"),
* the EFI specification requires that callers of the time related runtime
......
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