bpf: add variants of -mcpu=# and support for additional jmp insns
-mcpu=# will support:
. generic: the default insn set
. v1: insn set version 1, the same as generic
. v2: insn set version 2, version 1 + additional jmp insns
. probe: the compiler will probe the underlying kernel to
decide proper version of insn set.
We did not not use -mcpu=native since llc/llvm will interpret -mcpu=native
as the underlying hardware architecture regardless of -march value.
Currently, only x86_64 supports -mcpu=probe. Other architecture will
silently revert to "generic".
Also added -mcpu=help to print available cpu parameters.
llvm will print out the information only if there are at least one
cpu and at least one feature. Add an unused dummy feature to
enable the printout.
Examples for usage:
$ llc -march=bpf -mcpu=v1 -filetype=asm t.ll
$ llc -march=bpf -mcpu=v2 -filetype=asm t.ll
$ llc -march=bpf -mcpu=generic -filetype=asm t.ll
$ llc -march=bpf -mcpu=probe -filetype=asm t.ll
$ llc -march=bpf -mcpu=v3 -filetype=asm t.ll
'v3' is not a recognized processor for this target (ignoring processor)
...
$ llc -march=bpf -mcpu=help -filetype=asm t.ll
Available CPUs for this target:
generic - Select the generic processor.
probe - Select the probe processor.
v1 - Select the v1 processor.
v2 - Select the v2 processor.
Available features for this target:
dummy - unused feature.
Use +feature to enable a feature, or -feature to disable it.
For example, llc -mcpu=mycpu -mattr=+feature1,-feature2
...
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 311522
diff --git a/llvm/lib/Support/Host.cpp b/llvm/lib/Support/Host.cpp
index ac2af7b..aa1c4ae 100644
--- a/llvm/lib/Support/Host.cpp
+++ b/llvm/lib/Support/Host.cpp
@@ -267,6 +267,43 @@
return "generic";
}
+StringRef sys::detail::getHostCPUNameForBPF() {
+#if !defined(__linux__) || !defined(__x86_64__)
+ return "generic";
+#else
+ uint8_t insns[40] __attribute__ ((aligned (8))) =
+ /* BPF_MOV64_IMM(BPF_REG_0, 0) */
+ { 0xb7, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
+ /* BPF_MOV64_IMM(BPF_REG_2, 1) */
+ 0xb7, 0x2, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0,
+ /* BPF_JMP_REG(BPF_JLT, BPF_REG_0, BPF_REG_2, 1) */
+ 0xad, 0x20, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0,
+ /* BPF_MOV64_IMM(BPF_REG_0, 1) */
+ 0xb7, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0,
+ /* BPF_EXIT_INSN() */
+ 0x95, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };
+
+ struct bpf_prog_load_attr {
+ uint32_t prog_type;
+ uint32_t insn_cnt;
+ uint64_t insns;
+ uint64_t license;
+ uint32_t log_level;
+ uint32_t log_size;
+ uint64_t log_buf;
+ uint32_t kern_version;
+ uint32_t prog_flags;
+ } attr = {};
+ attr.prog_type = 1; /* BPF_PROG_TYPE_SOCKET_FILTER */
+ attr.insn_cnt = 5;
+ attr.insns = (uint64_t)insns;
+ attr.license = (uint64_t)"DUMMY";
+
+ int fd = syscall(321 /* __NR_bpf */, 5 /* BPF_PROG_LOAD */, &attr, sizeof(attr));
+ return (fd > 0) ? "v2" : "v1";
+#endif
+}
+
#if defined(__i386__) || defined(_M_IX86) || \
defined(__x86_64__) || defined(_M_X64)
@@ -1420,7 +1457,7 @@
Features["prefetchwt1"] = HasLeaf7 && (ECX & 1);
Features["avx512vbmi"] = HasLeaf7 && ((ECX >> 1) & 1) && HasAVX512Save;
- Features["avx512vpopcntdq"] = HasLeaf7 && ((ECX >> 14) & 1) && HasAVX512Save;
+ Features["avx512vpopcntdq"] = HasLeaf7 && ((ECX >> 14) & 1) && HasAVX512Save;
// Enable protection keys
Features["pku"] = HasLeaf7 && ((ECX >> 4) & 1);