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782f46cbce
Function tracer on powerpc can only work with vmlinux having a .text size of up to ~64MB due to powerpc branch instruction having a limited relative branch range of 32MB. Today, this is only detected on kernel boot when ftrace is init'ed. Add a post-link script to check the size of .text so that we can detect this at build time, and break the build if necessary. We add a dependency on !COMPILE_TEST for CONFIG_HAVE_FUNCTION_TRACER so that allyesconfig and other test builds can continue to work without enabling ftrace. Signed-off-by: Naveen N Rao <naveen@kernel.org> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://patch.msgid.link/20241030070850.1361304-11-hbathini@linux.ibm.com
50 lines
1.6 KiB
Bash
Executable file
50 lines
1.6 KiB
Bash
Executable file
#!/bin/bash
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# SPDX-License-Identifier: GPL-2.0-or-later
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#
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# This script checks vmlinux to ensure that all functions can call ftrace_caller() either directly,
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# or through the stub, ftrace_tramp_text, at the end of kernel text.
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# Error out if any command fails
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set -e
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# Allow for verbose output
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if [ "$V" = "1" ]; then
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set -x
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fi
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if [ $# -lt 2 ]; then
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echo "$0 [path to nm] [path to vmlinux]" 1>&2
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exit 1
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fi
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# Have Kbuild supply the path to nm so we handle cross compilation.
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nm="$1"
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vmlinux="$2"
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stext_addr=$($nm "$vmlinux" | grep -e " [TA] _stext$" | \
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cut -d' ' -f1 | tr '[:lower:]' '[:upper:]')
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ftrace_caller_addr=$($nm "$vmlinux" | grep -e " T ftrace_caller$" | \
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cut -d' ' -f1 | tr '[:lower:]' '[:upper:]')
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ftrace_tramp_addr=$($nm "$vmlinux" | grep -e " T ftrace_tramp_text$" | \
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cut -d' ' -f1 | tr '[:lower:]' '[:upper:]')
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ftrace_caller_offset=$(echo "ibase=16;$ftrace_caller_addr - $stext_addr" | bc)
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ftrace_tramp_offset=$(echo "ibase=16;$ftrace_tramp_addr - $ftrace_caller_addr" | bc)
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sz_32m=$(printf "%d" 0x2000000)
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sz_64m=$(printf "%d" 0x4000000)
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# ftrace_caller - _stext < 32M
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if [ "$ftrace_caller_offset" -ge "$sz_32m" ]; then
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echo "ERROR: ftrace_caller (0x$ftrace_caller_addr) is beyond 32MiB of _stext" 1>&2
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echo "ERROR: consider disabling CONFIG_FUNCTION_TRACER, or reducing the size \
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of kernel text" 1>&2
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exit 1
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fi
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# ftrace_tramp_text - ftrace_caller < 64M
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if [ "$ftrace_tramp_offset" -ge "$sz_64m" ]; then
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echo "ERROR: kernel text extends beyond 64MiB from ftrace_caller" 1>&2
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echo "ERROR: consider disabling CONFIG_FUNCTION_TRACER, or reducing the size \
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of kernel text" 1>&2
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exit 1
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fi
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