4.4-stable review patch. If anyone has any objections, please let me know.
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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, };
/* @@ -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