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
