Merge branch 'bpf-support-new-insns-from-cpu-v4'

Yonghong Song says:

====================
bpf: Support new insns from cpu v4

In previous discussion ([1]), it is agreed that we should introduce
cpu version 4 (llvm flag -mcpu=v4) which contains some instructions
which can simplify code, make code easier to understand, fix the
existing problem, or simply for feature completeness. More specifically,
the following new insns are proposed:
  . sign extended load
  . sign extended mov
  . bswap
  . signed div/mod
  . ja with 32-bit offset

This patch set added kernel support for insns proposed in [1] except
BPF_ST which already has full kernel support. Beside the above proposed
insns, LLVM will generate BPF_ST insn as well under -mcpu=v4.
The llvm patch ([2]) has been merged into llvm-project 'main' branch.

The patchset implements interpreter, jit and verifier support for these new
insns.

For this patch set, I tested cpu v2/v3/v4 and the selftests are all passed.
I also tested selftests introduced in this patch set with additional changes
beside normal jit testing (bpf_jit_enable = 1 and bpf_jit_harden = 0)
  - bpf_jit_enable = 0
  - bpf_jit_enable = 1 and bpf_jit_harden = 1
and both testing passed.

  [1] https://lore.kernel.org/bpf/4bfe98be-5333-1c7e-2f6d-42486c8ec039@meta.com/
  [2] https://reviews.llvm.org/D144829

Changelogs:
  v4 -> v5:
   . for v4, patch 8/17 missed in mailing list and patchwork, so resend.
   . rebase on top of master
  v3 -> v4:
   . some minor asm syntax adjustment based on llvm change.
   . add clang version and target arch guard for new tests
     so they can still compile with old llvm compilers.
   . some changes to the bpf doc.
  v2 -> v3:
   . add missed disasm change from v2.
   . handle signed load of ctx fields properly.
   . fix some interpreter sdiv/smod error when bpf_jit_enable = 0.
   . fix some verifier range bounding errors.
   . add more C tests.
  RFCv1 -> v2:
   . add more verifier supports for signed extend load and mov insns.
   . rename some insn names to be more consistent with intel practice.
   . add cpuv4 test runner for test progs.
   . add more unit and C tests.
   . add documentation.
====================

Link: https://lore.kernel.org/r/20230728011143.3710005-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2 files changed, 14 insertions, 4 deletions

diff --git a/include/linux/filter.h b/include/linux/filter.h
index f69114083ec7..f5eabe3fa5e8 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -69,6 +69,9 @@ struct ctl_table_header;
 /* unused opcode to mark special load instruction. Same as BPF_ABS */
 #define BPF_PROBE_MEM	0x20
 
+/* unused opcode to mark special ldsx instruction. Same as BPF_IND */
+#define BPF_PROBE_MEMSX	0x40
+
 /* unused opcode to mark call to interpreter with arguments */
 #define BPF_CALL_ARGS	0xe0
 
@@ -90,22 +93,28 @@ struct ctl_table_header;
 
 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
 
-#define BPF_ALU64_REG(OP, DST, SRC)				\
+#define BPF_ALU64_REG_OFF(OP, DST, SRC, OFF)			\
 	((struct bpf_insn) {					\
 		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,	\
 		.dst_reg = DST,					\
 		.src_reg = SRC,					\
-		.off   = 0,					\
+		.off   = OFF,					\
 		.imm   = 0 })
 
-#define BPF_ALU32_REG(OP, DST, SRC)				\
+#define BPF_ALU64_REG(OP, DST, SRC)				\
+	BPF_ALU64_REG_OFF(OP, DST, SRC, 0)
+
+#define BPF_ALU32_REG_OFF(OP, DST, SRC, OFF)			\
 	((struct bpf_insn) {					\
 		.code  = BPF_ALU | BPF_OP(OP) | BPF_X,		\
 		.dst_reg = DST,					\
 		.src_reg = SRC,					\
-		.off   = 0,					\
+		.off   = OFF,					\
 		.imm   = 0 })
 
+#define BPF_ALU32_REG(OP, DST, SRC)				\
+	BPF_ALU32_REG_OFF(OP, DST, SRC, 0)
+
 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
 
 #define BPF_ALU64_IMM(OP, DST, IMM)				\
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 7fc98f4b63e9..14fd26b09e4b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -19,6 +19,7 @@
 
 /* ld/ldx fields */
 #define BPF_DW		0x18	/* double word (64-bit) */
+#define BPF_MEMSX	0x80	/* load with sign extension */
 #define BPF_ATOMIC	0xc0	/* atomic memory ops - op type in immediate */
 #define BPF_XADD	0xc0	/* exclusive add - legacy name */