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| author | Eduard Zingerman <eddyz87@gmail.com> | 2026-09-04 01:33:23 -0700 |
|---|---|---|
| committer | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2026-09-04 12:58:04 +0200 |
| commit | 836b2fe544a5e9b5ce116622cb36fba33838c6fd (patch) | |
| tree | 95e38e4aaa0a6a78e373148b3d0af4aa2ab3d371 /arch/powerpc/sysdev/dcr-low.S | |
| download | linux-stable-836b2fe544a5e9b5ce116622cb36fba33838c6fd.tar.gz linux-stable-836b2fe544a5e9b5ce116622cb36fba33838c6fd.zip | |
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 'arch/powerpc/sysdev/dcr-low.S')
| -rw-r--r-- | arch/powerpc/sysdev/dcr-low.S | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/dcr-low.S b/arch/powerpc/sysdev/dcr-low.S new file mode 100644 index 000000000..e8401b205 --- /dev/null +++ b/arch/powerpc/sysdev/dcr-low.S @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * "Indirect" DCR access + * + * Copyright (c) 2004 Eugene Surovegin <ebs@ebshome.net> + */ + +#include <linux/export.h> +#include <asm/ppc_asm.h> +#include <asm/processor.h> +#include <asm/bug.h> + +#define DCR_ACCESS_PROLOG(table) \ + cmplwi cr0,r3,1024; \ + rlwinm r3,r3,4,18,27; \ + lis r5,table@h; \ + ori r5,r5,table@l; \ + add r3,r3,r5; \ + bge- 1f; \ + mtctr r3; \ + bctr; \ +1: trap; \ + EMIT_BUG_ENTRY 1b,__FILE__,__LINE__,0; \ + blr + +_GLOBAL(__mfdcr) + DCR_ACCESS_PROLOG(__mfdcr_table) +EXPORT_SYMBOL(__mfdcr) + +_GLOBAL(__mtdcr) + DCR_ACCESS_PROLOG(__mtdcr_table) +EXPORT_SYMBOL(__mtdcr) + +__mfdcr_table: + mfdcr r3,0; blr +__mtdcr_table: + mtdcr 0,r4; blr + +dcr = 1 + .rept 1023 + mfdcr r3,dcr; blr + mtdcr dcr,r4; blr + dcr = dcr + 1 + .endr |