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: Hedi Berriche <hedi.berriche@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Russ Anderson <rja@hpe.com>
Reviewed-by: Dimitri Sivanich <sivanich@hpe.com>
Reviewed-by: Mike 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.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/include/asm/uv/bios.h b/arch/x86/include/asm/uv/bios.h
index 71605c7d5c5c52989d64a3c9305f58b091cd15eb..8b7594f2d48f31719f4b25d7cfec3242d87bd0dc 100644 (file)
--- 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 */

diff --git a/arch/x86/platform/uv/bios_uv.c b/arch/x86/platform/uv/bios_uv.c
index 1584cbed0dce25eab259cdaf00ad49724cd09bac..a45a1c5aabeadf98b403ed0552319107f6ac5f54 100644 (file)
--- 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, 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;
 }
 

diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
index 228bbf91046137de619a4f8f89825e8ccc34b5ab..906d0224f50dd88b19cd694a0221a7a064c1445d 100644 (file)
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -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