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Subject[PATCH 4.19 74/85] x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls
Date
4.19-stable review patch.  If anyone has any objections, please let me know.

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

From: Hedi Berriche <hedi.berriche@hpe.com>

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>

---
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,
};

/* 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 */
--- 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,

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_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
@@ -173,6 +173,13 @@ void efi_call_virt_check_flags(unsigned
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.
*

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