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[bpf-next,v3,07/11] libbpf: Fix accessing the first syscall argument on arm64

Message ID 20220204145018.1983773-8-iii@linux.ibm.com (mailing list archive)
State Accepted
Commit 8b9b06ad47268006922d574dce4bbb29788e636e
Delegated to: BPF
Headers show
Series libbpf: Fix accessing syscall arguments | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 7 maintainers not CCed: andrii@kernel.org kpsingh@kernel.org john.fastabend@gmail.com kafai@fb.com songliubraving@fb.com yhs@fb.com netdev@vger.kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 7 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next success VM_Test

Commit Message

Ilya Leoshkevich Feb. 4, 2022, 2:50 p.m. UTC
On arm64, the first syscall argument should be accessed via orig_x0
(see arch/arm64/include/asm/syscall.h). Currently regs[0] is used
instead, leading to bpf_syscall_macro test failure.

Reported-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 tools/lib/bpf/bpf_tracing.h | 1 +
 1 file changed, 1 insertion(+)
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Patch

diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index 08d2990c006f..317bee0fd8e4 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -145,6 +145,7 @@ 
 /* arm64 provides struct user_pt_regs instead of struct pt_regs to userspace */
 #define __PT_REGS_CAST(x) ((const struct user_pt_regs *)(x))
 #define __PT_PARM1_REG regs[0]
+#define __PT_PARM1_REG_SYSCALL orig_x0
 #define __PT_PARM2_REG regs[1]
 #define __PT_PARM3_REG regs[2]
 #define __PT_PARM4_REG regs[3]