From 836b2fe544a5e9b5ce116622cb36fba33838c6fd Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 01:33:23 -0700 Subject: selftests/bpf: Check that JMP32 pointer vs zero jumps are not predicted Add jmp32_ptr_vs_zero_jne: the fall-through of the 32-bit compare, which the verifier used to skip, contains an out of bounds map value access, hence w/o the previous patch the program is accepted. See previous patch for detailed description. Reported-by: Nicholas Carlini Suggested-by: Nicholas Carlini Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- .../tools/check-fpatchable-function-entry.sh | 25 ++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100755 arch/powerpc/tools/check-fpatchable-function-entry.sh (limited to 'arch/powerpc/tools/check-fpatchable-function-entry.sh') diff --git a/arch/powerpc/tools/check-fpatchable-function-entry.sh b/arch/powerpc/tools/check-fpatchable-function-entry.sh new file mode 100755 index 000000000..baed467a0 --- /dev/null +++ b/arch/powerpc/tools/check-fpatchable-function-entry.sh @@ -0,0 +1,25 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +set -e + +# To debug, uncomment the following line +# set -x + +# Output from -fpatchable-function-entry can only vary on ppc64 elfv2, so this +# should not be invoked for other targets. Therefore we can pass in -m64 and +# -mabi explicitly, to take care of toolchains defaulting to other targets. + +# Test whether the compile option -fpatchable-function-entry exists and +# generates appropriate code +echo "int func() { return 0; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -fpatchable-function-entry=2 - -o - 2> /dev/null | \ + grep -q "__patchable_function_entries" + +# Test whether nops are generated after the local entry point +echo "int x; int func() { return x; }" | \ + $* -m64 -mabi=elfv2 -S -x c -O2 -fpatchable-function-entry=2 - -o - 2> /dev/null | \ + awk 'BEGIN { RS = ";" } /\.localentry.*nop.*\n[[:space:]]*nop/ { print $0 }' | \ + grep -q "func:" + +exit 0 -- cgit v1.3.1