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authorEduard Zingerman <eddyz87@gmail.com>2026-09-04 01:33:23 -0700
committerKumar Kartikeya Dwivedi <memxor@gmail.com>2026-09-04 12:58:04 +0200
commit836b2fe544a5e9b5ce116622cb36fba33838c6fd (patch)
tree95e38e4aaa0a6a78e373148b3d0af4aa2ab3d371 /tools/include/asm/alternative.h
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selftests/bpf: Check that JMP32 pointer vs zero jumps are not predictedgrafted
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 <npc@anthropic.com> Suggested-by: Nicholas Carlini <npc@anthropic.com> Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Diffstat (limited to 'tools/include/asm/alternative.h')
-rw-r--r--tools/include/asm/alternative.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/tools/include/asm/alternative.h b/tools/include/asm/alternative.h
new file mode 100644
index 000000000..8e548ac8f
--- /dev/null
+++ b/tools/include/asm/alternative.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TOOLS_ASM_ALTERNATIVE_ASM_H
+#define _TOOLS_ASM_ALTERNATIVE_ASM_H
+
+#if defined(__s390x__)
+#ifdef __ASSEMBLY__
+.macro ALTERNATIVE oldinstr, newinstr, feature
+ \oldinstr
+.endm
+#endif
+#else
+
+/* Just disable it so we can build arch/x86/lib/memcpy_64.S for perf bench: */
+
+#define ALTERNATIVE #
+
+#endif
+
+#endif