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ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()

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Different function signatures means they needs to be different
functions; otherwise CFI gets upset.

As triggered by the ftrace boot tests:

  [] CFI failure at ftrace_return_to_handler+0xac/0x16c (target: ftrace_stub+0x0/0x14; expected type: 0x0a5d5347)

Fixes: 3c516f89e1 ("x86: Add support for CONFIG_CFI_CLANG")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/Y06dg4e1xF6JTdQq@hirez.programming.kicks-ass.net
This commit is contained in:
Peter Zijlstra
2022-10-18 13:49:21 +02:00
parent b5f1fc3184
commit 883bbbffa5
3 changed files with 27 additions and 15 deletions
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18
include/asm-generic/vmlinux.lds.h
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@@ -162,6 +162,16 @@
#define PATCHABLE_DISCARDS *(__patchable_function_entries)
#endif
#ifndef CONFIG_ARCH_SUPPORTS_CFI_CLANG
/*
* Simply points to ftrace_stub, but with the proper protocol.
* Defined by the linker script in linux/vmlinux.lds.h
*/
#define FTRACE_STUB_HACK ftrace_stub_graph = ftrace_stub;
#else
#define FTRACE_STUB_HACK
#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
/*
* The ftrace call sites are logged to a section whose name depends on the
@@ -169,10 +179,6 @@
* FTRACE_CALLSITE_SECTION. We capture all of them here to avoid header
* dependencies for FTRACE_CALLSITE_SECTION's definition.
*
* Need to also make ftrace_stub_graph point to ftrace_stub
* so that the same stub location may have different protocols
* and not mess up with C verifiers.
*
* ftrace_ops_list_func will be defined as arch_ftrace_ops_list_func
* as some archs will have a different prototype for that function
* but ftrace_ops_list_func() will have a single prototype.
@@ -182,11 +188,11 @@
KEEP(*(__mcount_loc)) \
KEEP_PATCHABLE \
__stop_mcount_loc = .; \
ftrace_stub_graph = ftrace_stub; \
FTRACE_STUB_HACK \
ftrace_ops_list_func = arch_ftrace_ops_list_func;
#else
# ifdef CONFIG_FUNCTION_TRACER
# define MCOUNT_REC() ftrace_stub_graph = ftrace_stub; \
# define MCOUNT_REC() FTRACE_STUB_HACK \
ftrace_ops_list_func = arch_ftrace_ops_list_func;
# else
# define MCOUNT_REC()