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

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

diff --git a/arch/x86/include/asm/uv/bios.h b/arch/x86/include/asm/uv/bios.h
index e652a7cc61863667fad8ff2baa0a7242485600df..3f697a9e3f59b37e4fa37cf0f672114a2d84312b 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,
 };
 
 /* Address map parameters */
@@ -167,4 +168,9 @@ 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 4a6a5a26c58295e4245b09be21a658c3ddae86a2..eb33432f2f241db7475e32e651ae2bc9ca526361 100644 (file)
--- a/arch/x86/platform/uv/bios_uv.c
+++ b/arch/x86/platform/uv/bios_uv.c
@@ -29,7 +29,8 @@
 
 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;
@@ -51,6 +52,19 @@ s64 uv_bios_call(enum uv_bios_cmd which, u64 a1, u64 a2, u64 a3, u64 a4, u64 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,
@@ -59,10 +73,15 @@ 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 8903b9ccfc2b8da6cdc5341fef8619744d904c88..e2abfdb5cee6a2339e73ba6ec753dce1f83b2dbd 100644 (file)
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -146,6 +146,13 @@ void efi_call_virt_check_flags(unsigned long flags, const char *call)
  */
 static DEFINE_SEMAPHORE(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
+
 /*
  * Calls the appropriate efi_runtime_service() with the appropriate
  * arguments.