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From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: ykaliuta@redhat.com, johan.almbladh@anyfinetworks.com,
	linuxppc-dev@lists.ozlabs.org, song@kernel.org,
	bpf@vger.kernel.org, Jiri Olsa <jolsa@redhat.com>,
	Hari Bathini <hbathini@linux.ibm.com>
Subject: [PATCH 05/13] powerpc/bpf: Skip branch range validation during first pass
Date: Thu,  6 Jan 2022 17:15:09 +0530	[thread overview]
Message-ID: <aeabfaa4651acd30edd0b99fdd13d598d91c9f5f.1641468127.git.naveen.n.rao@linux.vnet.ibm.com> (raw)
In-Reply-To: <cover.1641468127.git.naveen.n.rao@linux.vnet.ibm.com>

During the first pass, addrs[] is still being populated. So, all
branches to following instructions will appear to be going to the start
of the JIT program. Ignore branch range validation for such instructions
and assume those to be in range. Branch range validation will happen
during the second pass after addrs[] is setup properly.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
 arch/powerpc/net/bpf_jit.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index b20a2a83a6e75b..9cdd33d6be4cc0 100644
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -27,7 +27,7 @@
 #define PPC_JMP(dest)							      \
 	do {								      \
 		long offset = (long)(dest) - (ctx->idx * 4);		      \
-		if (!is_offset_in_branch_range(offset)) {		      \
+		if ((dest) != 0 && !is_offset_in_branch_range(offset)) {		      \
 			pr_err_ratelimited("Branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx);			\
 			return -ERANGE;					      \
 		}							      \
@@ -41,7 +41,7 @@
 #define PPC_BCC_SHORT(cond, dest)					      \
 	do {								      \
 		long offset = (long)(dest) - (ctx->idx * 4);		      \
-		if (!is_offset_in_cond_branch_range(offset)) {		      \
+		if ((dest) != 0 && !is_offset_in_cond_branch_range(offset)) {		      \
 			pr_err_ratelimited("Conditional branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx);		\
 			return -ERANGE;					      \
 		}							      \
-- 
2.34.1


  parent reply	other threads:[~2022-01-06 11:50 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-06 11:45 [PATCH 00/13] powerpc/bpf: Some fixes and updates Naveen N. Rao
2022-01-06 11:45 ` [PATCH 01/13] bpf: Guard against accessing NULL pt_regs in bpf_get_task_stack() Naveen N. Rao
2022-01-07 10:21   ` Daniel Borkmann
2022-01-10  8:57   ` Christophe Leroy
2022-01-10 10:36     ` Naveen N. Rao
2022-01-06 11:45 ` [PATCH 02/13] powerpc32/bpf: Fix codegen for bpf-to-bpf calls Naveen N. Rao
2022-01-10  9:06   ` Christophe Leroy
2022-01-10 10:52     ` Naveen N. Rao
2022-01-06 11:45 ` [PATCH 03/13] powerpc/bpf: Update ldimm64 instructions during extra pass Naveen N. Rao
2022-01-08 14:45   ` Jiri Olsa
2022-01-10  9:27   ` Christophe Leroy
2022-01-10 10:56     ` Naveen N. Rao
2022-01-06 11:45 ` [PATCH 04/13] tools/bpf: Rename 'struct event' to avoid naming conflict Naveen N. Rao
2022-01-07 10:21   ` Daniel Borkmann
2022-01-06 11:45 ` Naveen N. Rao [this message]
2022-01-06 11:45 ` [PATCH 06/13] powerpc/bpf: Emit a single branch instruction for known short branch ranges Naveen N. Rao
2022-01-06 11:45 ` [PATCH 07/13] powerpc/bpf: Handle large branch ranges with BPF_EXIT Naveen N. Rao
2022-01-06 11:45 ` [PATCH 08/13] powerpc64/bpf: Limit 'ldbrx' to processors compliant with ISA v2.06 Naveen N. Rao
2022-01-06 11:45 ` [PATCH 09/13] powerpc64/bpf: Do not save/restore LR on each call to bpf_stf_barrier() Naveen N. Rao
2022-01-06 11:45 ` [PATCH 10/13] powerpc64/bpf: Use r12 for constant blinding Naveen N. Rao
2022-01-06 11:45 ` [PATCH 11/13] powerpc64/bpf elfv2: Setup kernel TOC in r2 on entry Naveen N. Rao
2022-01-10  9:20   ` Christophe Leroy
2022-01-11 10:31     ` Naveen N. Rao
2022-01-11 14:35       ` Christophe Leroy
2022-01-11 14:43         ` Christophe Leroy
2022-01-14 11:17           ` Naveen N. Rao
2022-01-06 11:45 ` [PATCH 12/13] powerpc64/bpf elfv1: Do not load TOC before calling functions Naveen N. Rao
2022-01-06 11:45 ` [PATCH 13/13] powerpc64/bpf: Optimize instruction sequence used for function calls Naveen N. Rao
2022-01-06 21:46 ` [PATCH 00/13] powerpc/bpf: Some fixes and updates Daniel Borkmann
2022-01-07  7:36   ` Naveen N. Rao
2022-01-07 10:20     ` Daniel Borkmann
2022-01-10  3:47       ` Michael Ellerman
2022-01-16 10:41 ` Michael Ellerman

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