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6f31bb737e
Since the leafloop test program was moved into the main Perf binary as a workload, it inherited the same compiler options as Perf. In this case the -fstack-protector option broke the assumption that simple leaf frames don't have a stack frame on Arm. This causes test_arm_callgraph_fp.sh to pass even if the stack isn't augmented with the link register, making the test useless. Fix it by rewriting the leaf function in assembly seeing as it's so simple. Adding -fno-stack-protector would also work, but wouldn't be robust against other future compiler option additions. The local variables and 'a' variable were never needed so remove them to simplify. Reviewed-by: Ian Rogers <irogers@google.com> Assisted-by: GitHub-Copilot:GPT-5.5 Signed-off-by: James Clark <james.clark@linaro.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
69 lines
1.2 KiB
C
69 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#include <signal.h>
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#include <stdlib.h>
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#include <linux/compiler.h>
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#include <unistd.h>
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#include "../tests.h"
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/* We want to check these symbols in perf script */
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noinline void leaf(void);
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noinline void parent(void);
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static volatile sig_atomic_t done asm("leafloop_done");
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static void sighandler(int sig __maybe_unused)
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{
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done = 1;
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}
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#if defined(__aarch64__)
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/*
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* Write leaf() in assembly so it stays as a minimal leaf function with no
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* stack frame and won't get silently broken in the future by any Perf wide
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* compilation options like -fstack-protector-all.
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*/
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asm(
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".pushsection .text,\"ax\",%progbits\n"
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".global leaf\n"
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".type leaf, %function\n"
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"leaf:\n"
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" adrp x1, leafloop_done\n"
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" ldr w2, [x1, #:lo12:leafloop_done]\n"
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" cbz w2, leaf\n"
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" ret\n"
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".size leaf, .-leaf\n"
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".popsection\n"
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);
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#else
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noinline void leaf(void)
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{
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while (!done)
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;
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}
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#endif
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noinline void parent(void)
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{
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leaf();
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}
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static int leafloop(int argc, const char **argv)
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{
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int sec = 1;
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if (argc > 0)
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sec = atoi(argv[0]);
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signal(SIGINT, sighandler);
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signal(SIGALRM, sighandler);
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alarm(sec);
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parent();
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return 0;
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}
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DEFINE_WORKLOAD(leafloop);
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