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path: root/arch/arm/kernel/return_address.c
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2022-10-04ARM: 9234/1: stacktrace: Avoid duplicate saving of exception PC valueLi Huafei1-0/+1
Because an exception stack frame is not created in the exception entry, save_trace() does special handling for the exception PC, but this is only needed when CONFIG_FRAME_POINTER_UNWIND=y. When CONFIG_ARM_UNWIND=y, unwind annotations have been added to the exception entry and save_trace() will repeatedly save the exception PC: [0x7f000090] hrtimer_hander+0x8/0x10 [hrtimer] [0x8019ec50] __hrtimer_run_queues+0x18c/0x394 [0x8019f760] hrtimer_run_queues+0xbc/0xd0 [0x8019def0] update_process_times+0x34/0x80 [0x801ad2a4] tick_periodic+0x48/0xd0 [0x801ad3dc] tick_handle_periodic+0x1c/0x7c [0x8010f2e0] twd_handler+0x30/0x40 [0x80177620] handle_percpu_devid_irq+0xa0/0x23c [0x801718d0] generic_handle_domain_irq+0x24/0x34 [0x80502d28] gic_handle_irq+0x74/0x88 [0x8085817c] generic_handle_arch_irq+0x58/0x78 [0x80100ba8] __irq_svc+0x88/0xc8 [0x80108114] arch_cpu_idle+0x38/0x3c [0x80108114] arch_cpu_idle+0x38/0x3c <==== duplicate saved exception PC [0x80861bf8] default_idle_call+0x38/0x130 [0x8015d5cc] do_idle+0x150/0x214 [0x8015d978] cpu_startup_entry+0x18/0x1c [0x808589c0] rest_init+0xd8/0xdc [0x80c00a44] arch_post_acpi_subsys_init+0x0/0x8 We can move the special handling of the exception PC in save_trace() to the unwind_frame() of the frame pointer unwinder. Signed-off-by: Li Huafei <lihuafei1@huawei.com> Reviewed-by: Linus Waleij <linus.walleij@linaro.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2022-03-11ARM: unwind: set frame.pc correctly for current-thread unwindingRussell King (Oracle)1-1/+2
When e.g. a WARN_ON() is encountered, we attempt to unwind the current thread. To do this, we set frame.pc to unwind_backtrace, which means it points at the beginning of the function. However, the rest of the state is initialised from within the function, which means the function prologue has already been run. This can be confusing, and with a recent patch from Ard, can result in the unwinder misbehaving if we want to be strict about the PC value. If we correctly initialise the state so it is self-consistent (in other words, set frame.pc to the location we are initialising it) then we eliminate this confusion, and avoid possible future issues. Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2021-10-22ARM: Recover kretprobe modified return address in stacktraceMasami Hiramatsu1-0/+4
Since the kretprobe replaces the function return address with the kretprobe_trampoline on the stack, arm unwinder shows it instead of the correct return address. This finds the correct return address from the per-task kretprobe_instances list and verify it is in between the caller fp and callee fp. Note that this supports both GCC and clang if CONFIG_FRAME_POINTER=y and CONFIG_ARM_UNWIND=n. For the ARM unwinder, this is still not working correctly. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-11-15ARM: 8918/2: only build return_address() if neededBen Dooks1-4/+0
The system currently warns if the config conditions for building return_address in arch/arm/kernel/return_address.c are not met, leaving just an EXPORT_SYMBOL_GPL(return_address) of a function defined to be 'static linline'. This is a result of aeea3592a13b ("ARM: 8158/1: LLVMLinux: use static inline in ARM ftrace.h"). Since we're not going to build anything other than an exported symbol for something that is already being defined to be an inline-able return of NULL, just avoid building the code to remove the following warning: Fixes: aeea3592a13b ("ARM: 8158/1: LLVMLinux: use static inline in ARM ftrace.h") Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner1-4/+1
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-28ARM: 8328/1: remove empty preprocessor #else branchUwe Kleine-König1-3/+1
When the patch for e16343c47e42 (ARM: 8160/1: drop warning about return_address not using unwind tables) was created there was still more code in said branch. Probably this simplification was just missed during conflict resolution when the patch was applied. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-13ARM: 8171/1: Use current_stack_pointer for return_addressBehan Webster1-2/+1
Use the global current_stack_pointer to get the value of the stack pointer. This change supports being able to compile the kernel with both gcc and Clang. Signed-off-by: Behan Webster <behanw@converseincode.com> Reviewed-by: Mark Charlebois <charlebm@gmail.com> Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-09-26ARM: 8160/1: drop warning about return_address not using unwind tablesUwe Kleine-König1-4/+0
The warning was introduced in 2009 (commit 4bf1fa5a34aa ([ARM] 5613/1: implement CALLER_ADDRESSx)). The only "problem" here is that CALLER_ADDRESSx for x > 1 returns NULL which doesn't do much harm. The drawback of implementing a fix (i.e. use unwind tables to implement CALLER_ADDRESSx) is that much of the unwinder code would need to be marked as not traceable. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-09-26ARM: 8158/1: LLVMLinux: use static inline in ARM ftrace.hBehan Webster1-5/+0
With compilers which follow the C99 standard (like modern versions of gcc and clang), "extern inline" does the wrong thing (emits code for an externally linkable version of the inline function). In this case using static inline and removing the NULL version of return_address in return_address.c does the right thing. Signed-off-by: Behan Webster <behanw@converseincode.com> Reviewed-by: Mark Charlebois <charlebm@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-03-19ARM: 7676/1: fix a wrong value returned from CALLER_ADDRnKeun-O Park1-2/+3
This makes return_address() return a correct value for CALLER_ADDRn. To have a correct value from CALLER_ADDRn, we need to fix three points. * The unwind_frame() does not update frame->lr but frame->pc for backtrace. So frame->pc is meaningful for backtrace. * data.level should be adjusted by adding 2 additional iteration levels. With the current +1 level adjustment, the result of CALLER_ADDR1 will be the same return address with CALLER_ADDR0. * The initialization of data.addr to NULL is needed. When unwind_fame() fails right after data.level reaches zero, the routine returns data.addr which has uninitialized garbage value. Signed-off-by: Sahara <keun-o.park@windriver.com> Reviewed-by: Dave Martin <dave.martin@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-10-31arm: convert core files from module.h to export.hPaul Gortmaker1-1/+1
Many of the core ARM kernel files are not modules, but just including module.h for exporting symbols. Now these files can use the lighter footprint export.h for this role. There are probably lots more, but ARM files of mach-* and plat-* don't get coverage via a simple yesconfig build. They will have to be cleaned up and tested via using their respective configs. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-02-23ARM: fix some sparse errors in generic ARM codeRussell King1-0/+1
arch/arm/kernel/return_address.c:37:6: warning: symbol 'return_address' was not declared. Should it be static? arch/arm/kernel/setup.c:76:14: warning: symbol 'processor_id' was not declared. Should it be static? arch/arm/kernel/traps.c:259:1: warning: symbol 'die_lock' was not declared. Should it be static? arch/arm/vfp/vfpmodule.c:156:6: warning: symbol 'vfp_raise_sigfpe' was not declared. Should it be static? Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-07-21[ARM] 5613/1: implement CALLER_ADDRESSxUwe Kleine-König1-0/+71
From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> As __builtin_return_address(n) doesn't work for ARM with n > 0, the kernel needs its own implementation. This fixes many warnings saying: warning: unsupported argument to '__builtin_return_address' The new methods and walk_stackframe must not be instrumented because CALLER_ADDRESSx is used in the various tracers and tracing the tracer is a bad idea. What's currently missing is an implementation using unwind tables. This is not fatal though, it's just that the tracers don't get enough information to be really useful. Note that if both ARM_UNWIND and FRAME_POINTER are enabled, walk_stackframe uses unwind information. So in this case the same implementation is used as when FRAME_POINTER is disabled. Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>