kernel.git/arch/arm64, branch linux-3.18.y

arm64: futex: Restore oldval initialization to work around buggy compilers

2019-04-27T07:30:31Z

commit ff8acf929014b7f87315588e0daf8597c8aa9d1c upstream. Commit 045afc24124d ("arm64: futex: Fix FUTEX_WAKE_OP atomic ops with non-zero result value") removed oldval's zero initialization in arch_futex_atomic_op_inuser because it is not necessary. Unfortunately, Android's arm64 GCC 4.9.4 [1] does not agree: ../kernel/futex.c: In function 'do_futex': ../kernel/futex.c:1658:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] return oldval == cmparg; ^ In file included from ../kernel/futex.c:73:0: ../arch/arm64/include/asm/futex.h:53:6: note: 'oldval' was declared here int oldval, ret, tmp; ^ GCC fails to follow that when ret is non-zero, futex_atomic_op_inuser returns right away, avoiding the uninitialized use that it claims. Restoring the zero initialization works around this issue. [1]: https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/ Cc: stable@vger.kernel.org Fixes: 045afc24124d ("arm64: futex: Fix FUTEX_WAKE_OP atomic ops with non-zero result value") Reviewed-by: Greg Kroah-Hartman Signed-off-by: Nathan Chancellor Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman

arm64: futex: Fix FUTEX_WAKE_OP atomic ops with non-zero result value

2019-04-27T07:30:26Z

commit 045afc24124d80c6998d9c770844c67912083506 upstream. Rather embarrassingly, our futex() FUTEX_WAKE_OP implementation doesn't explicitly set the return value on the non-faulting path and instead leaves it holding the result of the underlying atomic operation. This means that any FUTEX_WAKE_OP atomic operation which computes a non-zero value will be reported as having failed. Regrettably, I wrote the buggy code back in 2011 and it was upstreamed as part of the initial arm64 support in 2012. The reasons we appear to get away with this are: 1. FUTEX_WAKE_OP is rarely used and therefore doesn't appear to get exercised by futex() test applications 2. If the result of the atomic operation is zero, the system call behaves correctly 3. Prior to version 2.25, the only operation used by GLIBC set the futex to zero, and therefore worked as expected. From 2.25 onwards, FUTEX_WAKE_OP is not used by GLIBC at all. Fix the implementation by ensuring that the return value is either 0 to indicate that the atomic operation completed successfully, or -EFAULT if we encountered a fault when accessing the user mapping. Cc: Fixes: 6170a97460db ("arm64: Atomic operations") Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

arm64: support keyctl() system call in 32-bit mode

2019-04-03T04:22:15Z

[ Upstream commit 5c2a625937ba49bc691089370638223d310cda9a ] As is the case for a number of other architectures that have a 32-bit compat mode, enable KEYS_COMPAT if both COMPAT and KEYS are enabled. This allows AArch32 programs to use the keyctl() system call when running on an AArch64 kernel. Signed-off-by: Eric Biggers Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: kconfig: drop CONFIG_RTC_LIB dependency

2019-04-03T04:22:11Z

[ Upstream commit 99a507771fa57238dc7ffe674ae06090333d02c9 ] The rtc-lib dependency is not required, and seems it was just copy-pasted from ARM's Kconfig. If platform requires rtc-lib, they should select it individually. Reviewed-by: Arnd Bergmann Signed-off-by: Ezequiel Garcia Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: kernel: Include _AC definition in page.h

2019-04-03T04:22:10Z

[ Upstream commit 812264550dcba6cdbe84bfac2f27e7d23b5b8733 ] page.h uses '_AC' in the definition of PAGE_SIZE, but doesn't include linux/const.h where this is defined. This produces build warnings when only asm/page.h is included by asm code. Signed-off-by: James Morse Acked-by: Mark Rutland Acked-by: Catalin Marinas Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64/kernel: fix incorrect EL0 check in inv_entry macro

2019-04-03T04:22:10Z

[ Upstream commit b660950c60a7278f9d8deb7c32a162031207c758 ] The implementation of macro inv_entry refers to its 'el' argument without the required leading backslash, which results in an undefined symbol 'el' to be passed into the kernel_entry macro rather than the index of the exception level as intended. This undefined symbol strangely enough does not result in build failures, although it is visible in vmlinux: $ nm -n vmlinux |head U el 0000000000000000 A _kernel_flags_le_hi32 0000000000000000 A _kernel_offset_le_hi32 0000000000000000 A _kernel_size_le_hi32 000000000000000a A _kernel_flags_le_lo32 ..... However, it does result in incorrect code being generated for invalid exceptions taken from EL0, since the argument check in kernel_entry assumes EL1 if its argument does not equal '0'. Signed-off-by: Ard Biesheuvel Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin

arm64: fix COMPAT_SHMLBA definition for large pages

2019-04-03T04:22:09Z

[ Upstream commit b9b7aebb42d1b1392f3111de61136bb6cf3aae3f ] ARM glibc uses (4 * __getpagesize()) for SHMLBA, which is correct for 4KB pages and works fine for 64KB pages, but the kernel uses a hardcoded 16KB that is too small for 64KB page based kernels. This changes the definition to what user space sees when using 64KB pages. Acked-by: Arnd Bergmann Signed-off-by: Yury Norov Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: Relax GIC version check during early boot

2019-03-23T07:19:00Z

[ Upstream commit 74698f6971f25d045301139413578865fc2bd8f9 ] Updates to the GIC architecture allow ID_AA64PFR0_EL1.GIC to have values other than 0 or 1. At the moment, Linux is quite strict in the way it handles this field at early boot stage (cpufeature is fine) and will refuse to use the system register CPU interface if it doesn't find the value 1. Fixes: 021f653791ad17e03f98aaa7fb933816ae16f161 ("irqchip: gic-v3: Initial support for GICv3") Reported-by: Chase Conklin Reviewed-by: Marc Zyngier Signed-off-by: Vladimir Murzin Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: ftrace: don't adjust the LR value

2019-02-20T09:08:58Z

[ Upstream commit 6e803e2e6e367db9a0d6ecae1bd24bb5752011bd ] The core ftrace code requires that when it is handed the PC of an instrumented function, this PC is the address of the instrumented instruction. This is necessary so that the core ftrace code can identify the specific instrumentation site. Since the instrumented function will be a BL, the address of the instrumented function is LR - 4 at entry to the ftrace code. This fixup is applied in the mcount_get_pc and mcount_get_pc0 helpers, which acquire the PC of the instrumented function. The mcount_get_lr helper is used to acquire the LR of the instrumented function, whose value does not require this adjustment, and cannot be adjusted to anything meaningful. No adjustment of this value is made on other architectures, including arm. However, arm64 adjusts this value by 4. This patch brings arm64 in line with other architectures and removes the adjustment of the LR value. Signed-off-by: Mark Rutland Cc: AKASHI Takahiro Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: Torsten Duwe Cc: Will Deacon Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

arm64: remove no-op -p linker flag

2018-12-01T08:48:00Z

(commit 1a381d4a0a9a0f999a13faaba22bf6b3fc80dcb9 upstream) Linking the ARM64 defconfig kernel with LLVM lld fails with the error: ld.lld: error: unknown argument: -p Makefile:1015: recipe for target 'vmlinux' failed Without this flag, the ARM64 defconfig kernel successfully links with lld and boots on Dragonboard 410c. After digging through binutils source and changelogs, it turns out that -p is only relevant to ancient binutils installations targeting 32-bit ARM. binutils accepts -p for AArch64 too, but it's always been undocumented and silently ignored. A comment in ld/emultempl/aarch64elf.em explains that it's "Only here for backwards compatibility". Since this flag is a no-op on ARM64, we can safely drop it. Acked-by: Will Deacon Reviewed-by: Nick Desaulniers Signed-off-by: Greg Hackmann Signed-off-by: Catalin Marinas Signed-off-by: Nick Desaulniers Signed-off-by: Sasha Levin