[PATCH 4.4 135/143] x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls

From: Greg Kroah-Hartman
Date: Mon Feb 18 2019 - 09:20:46 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hedi Berriche <hedi.berriche@xxxxxxx>

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: Hedi Berriche <hedi.berriche@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Reviewed-by: Russ Anderson <rja@xxxxxxx>
Reviewed-by: Dimitri Sivanich <sivanich@xxxxxxx>
Reviewed-by: Mike Travis <mike.travis@xxxxxxx>
Cc: Andy Shevchenko <andy@xxxxxxxxxxxxx>
Cc: Bhupesh Sharma <bhsharma@xxxxxxxxxx>
Cc: Darren Hart <dvhart@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: linux-efi <linux-efi@xxxxxxxxxxxxxxx>
Cc: platform-driver-x86@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx # v4.9+
Cc: Steve Wahl <steve.wahl@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20190213193413.25560-5-hedi.berriche@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/x86/include/asm/uv/bios.h | 8 +++++++-
arch/x86/platform/uv/bios_uv.c | 23 +++++++++++++++++++++--
drivers/firmware/efi/runtime-wrappers.c | 7 +++++++
3 files changed, 35 insertions(+), 3 deletions(-)

--- a/arch/x86/include/asm/uv/bios.h
+++ b/arch/x86/include/asm/uv/bios.h
@@ -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 */
--- a/arch/x86/platform/uv/bios_uv.c
+++ b/arch/x86/platform/uv/bios_uv.c
@@ -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,
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_cm
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;
}

--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -88,6 +88,13 @@ static DEFINE_SPINLOCK(efi_runtime_lock)
*/

/*
+ * 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
* functions serialize with other CMOS accesses in the kernel, as the EFI time