linux-dev/arch/arm/kernel/Makefile, branch linus/master

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2022-03-24T00:35:57Z

Pull ARM updates from Russell King: "Updates for IRQ stacks and virtually mapped stack support, and ftrace: - Support for IRQ and vmap'ed stacks This covers all the work related to implementing IRQ stacks and vmap'ed stacks for all 32-bit ARM systems that are currently supported by the Linux kernel, including RiscPC and Footbridge. It has been submitted for review in four different waves: - IRQ stacks support for v7 SMP systems [0] - vmap'ed stacks support for v7 SMP systems[1] - extending support for both IRQ stacks and vmap'ed stacks for all remaining configurations, including v6/v7 SMP multiplatform kernels and uniprocessor configurations including v7-M [2] - fixes and updates in [3] - ftrace fixes and cleanups Make all flavors of ftrace available on all builds, regardless of ISA choice, unwinder choice or compiler [4]: - use ADD not POP where possible - fix a couple of Thumb2 related issues - enable HAVE_FUNCTION_GRAPH_FP_TEST for robustness - enable the graph tracer with the EABI unwinder - avoid clobbering frame pointer registers to make Clang happy - Fixes for the above" [0] https://lore.kernel.org/linux-arm-kernel/20211115084732.3704393-1-ardb@kernel.org/ [1] https://lore.kernel.org/linux-arm-kernel/20211122092816.2865873-1-ardb@kernel.org/ [2] https://lore.kernel.org/linux-arm-kernel/20211206164659.1495084-1-ardb@kernel.org/ [3] https://lore.kernel.org/linux-arm-kernel/20220124174744.1054712-1-ardb@kernel.org/ [4] https://lore.kernel.org/linux-arm-kernel/20220203082204.1176734-1-ardb@kernel.org/ * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (62 commits) ARM: fix building NOMMU ARMv4/v5 kernels ARM: unwind: only permit stack switch when unwinding call_with_stack() ARM: Revert "unwind: dump exception stack from calling frame" ARM: entry: fix unwinder problems caused by IRQ stacks ARM: unwind: set frame.pc correctly for current-thread unwinding ARM: 9184/1: return_address: disable again for CONFIG_ARM_UNWIND=y ARM: 9183/1: unwind: avoid spurious warnings on bogus code addresses Revert "ARM: 9144/1: forbid ftrace with clang and thumb2_kernel" ARM: mach-bcm: disable ftrace in SMC invocation routines ARM: cacheflush: avoid clobbering the frame pointer ARM: kprobes: treat R7 as the frame pointer register in Thumb2 builds ARM: ftrace: enable the graph tracer with the EABI unwinder ARM: unwind: track location of LR value in stack frame ARM: ftrace: enable HAVE_FUNCTION_GRAPH_FP_TEST ARM: ftrace: avoid unnecessary literal loads ARM: ftrace: avoid redundant loads or clobbering IP ARM: ftrace: use trampolines to keep .init.text in branching range ARM: ftrace: use ADD not POP to counter PUSH at entry ARM: ftrace: ensure that ADR takes the Thumb bit into account ARM: make get_current() and __my_cpu_offset() __always_inline ...

ARM: 9184/1: return_address: disable again for CONFIG_ARM_UNWIND=y

2022-03-07T11:43:12Z

Commit 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI unwinder") removed the dummy version of return_address() that was provided for the CONFIG_ARM_UNWIND=y case, on the assumption that the removal of the kernel_text_address() call from unwind_frame() in the preceding patch made it safe to do so. However, this turns out not to be the case: Corentin reports warnings about suspicious RCU usage and other strange behavior that seems to originate in the stack unwinding that occurs in return_address(). Given that the function graph tracer (which is what these changes were enabling for CONFIG_ARM_UNWIND=y builds) does not appear to care about this distinction, let's revert return_address() to the old state. Cc: Corentin Labbe Fixes: 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI unwinder") Signed-off-by: Ard Biesheuvel Reported-by: Corentin Labbe Tested-by: Corentin Labbe Signed-off-by: Russell King (Oracle)

ARM: report Spectre v2 status through sysfs

2022-03-05T10:41:22Z

As per other architectures, add support for reporting the Spectre vulnerability status via sysfs CPU. Acked-by: Catalin Marinas Signed-off-by: Russell King (Oracle)

ARM: ftrace: enable the graph tracer with the EABI unwinder

2022-02-09T08:13:59Z

Enable the function graph tracer in combination with the EABI unwinder, so that Thumb2 builds or Clang ARM builds can make use of it. This involves using the unwinder to locate the return address of an instrumented function on the stack, so that it can be overridden and made to refer to the ftrace handling routines that need to be called at function return. Given that for these builds, it is not guaranteed that the value of the link register is stored on the stack, fall back to the stack slot that will be used by the ftrace exit code to restore LR in the instrumented function's execution context. Signed-off-by: Ard Biesheuvel Reviewed-by: Steven Rostedt (Google)

ARM: unwind: track location of LR value in stack frame

2022-02-09T08:13:43Z

The ftrace graph tracer needs to override the return address of an instrumented function, in order to install a hook that gets invoked when the function returns again. Currently, we only support this when building for ARM using GCC with frame pointers, as in this case, it is guaranteed that the function will reload LR from [FP, #-4] in all cases, and we can simply pass that address to the ftrace code. In order to support this for configurations that rely on the EABI unwinder, such as Thumb2 builds, make the unwinder keep track of the address from which LR was unwound, permitting ftrace to make use of this in a subsequent patch. Drop the call to is_kernel_text_address(), which is problematic in terms of ftrace recursion, given that it may be instrumented itself. The call is redundant anyway, as no unwind directives will be found unless the PC points to memory that is known to contain executable code. Signed-off-by: Ard Biesheuvel Reviewed-by: Nick Desaulniers

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux

2020-12-22T21:34:27Z

Pull ARM updates from Russell King: - Rework phys/virt translation - Add KASan support - Move DT out of linear map region - Use more PC-relative addressing in assembly - Remove FP emulation handling while in kernel mode - Link with '-z norelro' - remove old check for GCC <= 4.2 in ARM unwinder code - disable big endian if using clang's linker * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (46 commits) ARM: 9027/1: head.S: explicitly map DT even if it lives in the first physical section ARM: 9038/1: Link with '-z norelro' ARM: 9037/1: uncompress: Add OF_DT_MAGIC macro ARM: 9036/1: uncompress: Fix dbgadtb size parameter name ARM: 9035/1: uncompress: Add be32tocpu macro ARM: 9033/1: arm/smp: Drop the macro S(x,s) ARM: 9032/1: arm/mm: Convert PUD level pgtable helper macros into functions ARM: 9031/1: hyp-stub: remove unused .L__boot_cpu_mode_offset symbol ARM: 9044/1: vfp: use undef hook for VFP support detection ARM: 9034/1: __div64_32(): straighten up inline asm constraints ARM: 9030/1: entry: omit FP emulation for UND exceptions taken in kernel mode ARM: 9029/1: Make iwmmxt.S support Clang's integrated assembler ARM: 9028/1: disable KASAN in call stack capturing routines ARM: 9026/1: unwind: remove old check for GCC <= 4.2 ARM: 9025/1: Kconfig: CPU_BIG_ENDIAN depends on !LD_IS_LLD ARM: 9024/1: Drop useless cast of "u64" to "long long" ARM: 9023/1: Spelling s/mmeory/memory/ ARM: 9022/1: Change arch/arm/lib/mem*.S to use WEAK instead of .weak ARM: kvm: replace open coded VA->PA calculations with adr_l call ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET ...

Merge branch 'devel-stable' into for-next

2020-12-21T11:19:26Z

ARM: 9028/1: disable KASAN in call stack capturing routines

2020-12-08T10:14:57Z

KASAN uses the routines in stacktrace.c to capture the call stack each time memory gets allocated or freed. Some of these routines are also used to log CPU and memory context when exceptions are taken, and so in some cases, memory accesses may be made that are not strictly in line with the KASAN constraints, and may therefore trigger false KASAN positives. So follow the example set by other architectures, and simply disable KASAN instrumentation for these routines. Reviewed-by: Linus Walleij Signed-off-by: Ard Biesheuvel Signed-off-by: Russell King

ARM: remove ebsa110 platform

2020-10-30T20:57:03Z

Russell said that he is no longer using this machine, and it seems that nobody else has in a long time, so it's time to say goodbye to it. As this is the last platform using CONFIG_ARCH_USES_GETTIMEOFFSET, there are some follow-up patches to remove that as well. Acked-by: Russell King Signed-off-by: Arnd Bergmann

ARM: p2v: move patching code to separate assembler source file

2020-10-28T15:59:43Z

Move the phys2virt patching code into a separate .S file before doing some work on it. Suggested-by: Nicolas Pitre Reviewed-by: Linus Walleij Signed-off-by: Ard Biesheuvel