Get rid of superfluous ifdef and return explicit word size depending on
32-bit or 64-bit mode.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251208160352.1363040-5-jremus@linux.ibm.com
The unwind user framework in general requires an architecture-specific
implementation of unwind_user_word_size() to be present for any unwind
method, whether that is fp or a future other method, such as potentially
sframe.
Guard unwind_user_word_size() by the availability of the UNWIND_USER
framework instead of the specific HAVE_UNWIND_USER_FP method.
This facilitates to selectively disable HAVE_UNWIND_USER_FP on x86
(e.g. for test purposes) once a new unwind method is added to unwind
user.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251208160352.1363040-4-jremus@linux.ibm.com
This simplifies the code. unwind_user_next_fp() does not need to
return -EINVAL if config option HAVE_UNWIND_USER_FP is disabled, as
unwind_user_start() will then not select this unwind method and
unwind_user_next() will therefore not call it.
Provide (1) a dummy definition of ARCH_INIT_USER_FP_FRAME, if the unwind
user method HAVE_UNWIND_USER_FP is not enabled, (2) a common fallback
definition of unwind_user_at_function_start() which returns false, and
(3) a common dummy definition of ARCH_INIT_USER_FP_ENTRY_FRAME.
Note that enabling the config option HAVE_UNWIND_USER_FP without
defining ARCH_INIT_USER_FP_FRAME triggers a compile error, which is
helpful when implementing support for this unwind user method in an
architecture. Enabling the config option when providing an arch-
specific unwind_user_at_function_start() definition makes it necessary
to also provide an arch-specific ARCH_INIT_USER_FP_ENTRY_FRAME
definition.
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251208160352.1363040-3-jremus@linux.ibm.com
When userspace is interrupted at the start of a function, before we
get a chance to complete the frame, unwind will miss one caller.
X86 has a uprobe specific fixup for this, add bits to the generic
unwinder to support this.
Suggested-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251024145156.GM4068168@noisy.programming.kicks-ass.net
Use ARCH_INIT_USER_FP_FRAME to describe how frame pointers are unwound
on x86, and enable CONFIG_HAVE_UNWIND_USER_FP accordingly so the
unwind_user interfaces can be used.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20250827193828.347397433@kernel.org
