From 7212e37cbdf99f48e4a6c689a42f4bda1ae69001 Mon Sep 17 00:00:00 2001 From: Hedi Berriche Date: Wed, 13 Feb 2019 19:34:13 +0000 Subject: [PATCH] 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 Signed-off-by: Borislav Petkov Reviewed-by: Ard Biesheuvel Reviewed-by: Russ Anderson Reviewed-by: Dimitri Sivanich Reviewed-by: Mike Travis Cc: Andy Shevchenko Cc: Bhupesh Sharma Cc: Darren Hart Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: linux-efi Cc: platform-driver-x86@vger.kernel.org Cc: stable@vger.kernel.org # v4.9+ Cc: Steve Wahl Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20190213193413.25560-5-hedi.berriche@hpe.com Signed-off-by: Greg Kroah-Hartman --- 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(-) diff --git a/arch/x86/include/asm/uv/bios.h b/arch/x86/include/asm/uv/bios.h index 71605c7d5c5c..8b7594f2d48f 100644 --- 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 1584cbed0dce..a45a1c5aabea 100644 --- 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 228bbf910461..906d0224f50d 100644 --- 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