kernel/git/stable/linux.git/arch/arm64/Makefile, branch linux-5.7.y

ARM64: vdso32: Install vdso32 from vdso_install

2020-08-26T09:42:22+00:00

[ Upstream commit 8d75785a814241587802655cc33e384230744f0c ] Add the 32-bit vdso Makefile to the vdso_install rule so that 'make vdso_install' installs the 32-bit compat vdso when it is compiled. Fixes: a7f71a2c8903 ("arm64: compat: Add vDSO") Signed-off-by: Stephen Boyd Reviewed-by: Vincenzo Frascino Acked-by: Will Deacon Cc: Vincenzo Frascino Link: https://lore.kernel.org/r/20200818014950.42492-1-swboyd@chromium.org Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin

arm64: Always force a branch protection mode when the compiler has one

2020-04-01T20:23:40+00:00

Compilers with branch protection support can be configured to enable it by default, it is likely that distributions will do this as part of deploying branch protection system wide. As well as the slight overhead from having some extra NOPs for unused branch protection features this can cause more serious problems when the kernel is providing pointer authentication to userspace but not built for pointer authentication itself. In that case our switching of keys for userspace can affect the kernel unexpectedly, causing pointer authentication instructions in the kernel to corrupt addresses. To ensure that we get consistent and reliable behaviour always explicitly initialise the branch protection mode, ensuring that the kernel is built the same way regardless of the compiler defaults. Fixes: 7503197562567 (arm64: add basic pointer authentication support) Reported-by: Szabolcs Nagy Signed-off-by: Mark Brown Cc: stable@vger.kernel.org [catalin.marinas@arm.com: remove Kconfig option in favour of Makefile check] Signed-off-by: Catalin Marinas

arm64: compile the kernel with ptrauth return address signing

2020-03-18T09:50:21+00:00

Compile all functions with two ptrauth instructions: PACIASP in the prologue to sign the return address, and AUTIASP in the epilogue to authenticate the return address (from the stack). If authentication fails, the return will cause an instruction abort to be taken, followed by an oops and killing the task. This should help protect the kernel against attacks using return-oriented programming. As ptrauth protects the return address, it can also serve as a replacement for CONFIG_STACKPROTECTOR, although note that it does not protect other parts of the stack. The new instructions are in the HINT encoding space, so on a system without ptrauth they execute as NOPs. CONFIG_ARM64_PTR_AUTH now not only enables ptrauth for userspace and KVM guests, but also automatically builds the kernel with ptrauth instructions if the compiler supports it. If there is no compiler support, we do not warn that the kernel was built without ptrauth instructions. GCC 7 and 8 support the -msign-return-address option, while GCC 9 deprecates that option and replaces it with -mbranch-protection. Support both options. Clang uses an external assembler hence this patch makes sure that the correct parameters (-march=armv8.3-a) are passed down to help it recognize the ptrauth instructions. Ftrace function tracer works properly with Ptrauth only when patchable-function-entry feature is present and is ensured by the Kconfig dependency. Cc: Catalin Marinas Cc: Will Deacon Cc: Masahiro Yamada Reviewed-by: Kees Cook Reviewed-by: Vincenzo Frascino # not co-dev parts Co-developed-by: Vincenzo Frascino Signed-off-by: Vincenzo Frascino Signed-off-by: Kristina Martsenko [Amit: Cover leaf function, comments, Ftrace Kconfig] Signed-off-by: Amit Daniel Kachhap Signed-off-by: Catalin Marinas

arm64: Turn "broken gas inst" into real config option

2020-01-15T16:35:12+00:00

Use the new 'as-instr' Kconfig macro to define CONFIG_BROKEN_GAS_INST directly, making it available everywhere. Signed-off-by: Vladimir Murzin [will: Drop redundant 'y if' logic] Signed-off-by: Will Deacon

arm64: Move the LSE gas support detection to Kconfig

2020-01-15T12:50:48+00:00

As the Kconfig syntax gained support for $(as-instr) tests, move the LSE gas support detection from Makefile to the main arm64 Kconfig and remove the additional CONFIG_AS_LSE definition and check. Cc: Will Deacon Reviewed-by: Vladimir Murzin Tested-by: Vladimir Murzin Signed-off-by: Catalin Marinas Signed-off-by: Will Deacon

arm64: implement ftrace with regs

2019-11-06T14:17:35+00:00

This patch implements FTRACE_WITH_REGS for arm64, which allows a traced function's arguments (and some other registers) to be captured into a struct pt_regs, allowing these to be inspected and/or modified. This is a building block for live-patching, where a function's arguments may be forwarded to another function. This is also necessary to enable ftrace and in-kernel pointer authentication at the same time, as it allows the LR value to be captured and adjusted prior to signing. Using GCC's -fpatchable-function-entry=N option, we can have the compiler insert a configurable number of NOPs between the function entry point and the usual prologue. This also ensures functions are AAPCS compliant (e.g. disabling inter-procedural register allocation). For example, with -fpatchable-function-entry=2, GCC 8.1.0 compiles the following: | unsigned long bar(void); | | unsigned long foo(void) | { | return bar() + 1; | } ... to: | : | nop | nop | stp x29, x30, [sp, #-16]! | mov x29, sp | bl 0 | add x0, x0, #0x1 | ldp x29, x30, [sp], #16 | ret This patch builds the kernel with -fpatchable-function-entry=2, prefixing each function with two NOPs. To trace a function, we replace these NOPs with a sequence that saves the LR into a GPR, then calls an ftrace entry assembly function which saves this and other relevant registers: | mov x9, x30 | bl Since patchable functions are AAPCS compliant (and the kernel does not use x18 as a platform register), x9-x18 can be safely clobbered in the patched sequence and the ftrace entry code. There are now two ftrace entry functions, ftrace_regs_entry (which saves all GPRs), and ftrace_entry (which saves the bare minimum). A PLT is allocated for each within modules. Signed-off-by: Torsten Duwe [Mark: rework asm, comments, PLTs, initialization, commit message] Signed-off-by: Mark Rutland Reviewed-by: Amit Daniel Kachhap Reviewed-by: Ard Biesheuvel Reviewed-by: Torsten Duwe Tested-by: Amit Daniel Kachhap Tested-by: Torsten Duwe Cc: AKASHI Takahiro Cc: Catalin Marinas Cc: Josh Poimboeuf Cc: Julien Thierry Cc: Will Deacon

arm64: Kconfig: Make CONFIG_COMPAT_VDSO a proper Kconfig option

2019-10-07T12:32:15+00:00

CONFIG_COMPAT_VDSO is defined by passing '-DCONFIG_COMPAT_VDSO' to the compiler when the generic compat vDSO code is in use. It's much cleaner and simpler to expose this as a proper Kconfig option (like x86 does), so do that and remove the bodge. Acked-by: Catalin Marinas Signed-off-by: Will Deacon

arm64: vdso32: Move definition of COMPATCC into vdso32/Makefile

2019-10-07T12:32:02+00:00

There's no need to export COMPATCC, so just define it locally in the vdso32/Makefile, which is the only place where it is used. Acked-by: Catalin Marinas Signed-off-by: Will Deacon

arm64: Default to building compat vDSO with clang when CONFIG_CC_IS_CLANG

2019-10-07T12:31:45+00:00

Rather than force the use of GCC for the compat cross-compiler, instead extract the target from CROSS_COMPILE_COMPAT and pass it to clang if the main compiler is clang. Acked-by: Catalin Marinas Signed-off-by: Will Deacon

arm64: vdso32: Fix broken compat vDSO build warnings

2019-10-07T10:07:16+00:00

The .config file and the generated include/config/auto.conf can end up out of sync after a set of commands since CONFIG_CROSS_COMPILE_COMPAT_VDSO is not updated correctly. The sequence can be reproduced as follows: $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig [...] $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig [set CONFIG_CROSS_COMPILE_COMPAT_VDSO="arm-linux-gnueabihf-"] $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- Which results in: arch/arm64/Makefile:62: CROSS_COMPILE_COMPAT not defined or empty, the compat vDSO will not be built even though the compat vDSO has been built: $ file arch/arm64/kernel/vdso32/vdso.so arch/arm64/kernel/vdso32/vdso.so: ELF 32-bit LSB pie executable, ARM, EABI5 version 1 (SYSV), dynamically linked, BuildID[sha1]=c67f6c786f2d2d6f86c71f708595594aa25247f6, stripped A similar case that involves changing the configuration parameter multiple times can be reconducted to the same family of problems. Remove the use of CONFIG_CROSS_COMPILE_COMPAT_VDSO altogether and instead rely on the cross-compiler prefix coming from the environment via CROSS_COMPILE_COMPAT, much like we do for the rest of the kernel. Cc: Will Deacon Cc: Catalin Marinas Reported-by: Will Deacon Signed-off-by: Vincenzo Frascino Signed-off-by: Will Deacon