From: Jean-Philippe Brucker jean-philippe@linaro.org
[ Upstream commit 702eddc77a905782083b14ccd05b23840675fd18 ]
When building Arm NEON (SIMD) code from lib/raid6/neon.uc, GCC emits DWARF information using a base type "__Poly8_t", which is internal to GCC and not recognized by Clang. This causes build failures when building with Clang a vmlinux.h generated from an arm64 kernel that was built with GCC.
vmlinux.h:47284:9: error: unknown type name '__Poly8_t' typedef __Poly8_t poly8x16_t[16]; ^~~~~~~~~
The polyX_t types are defined as unsigned integers in the "Arm C Language Extension" document (101028_Q220_00_en). Emit typedefs based on standard integer types for the GCC internal types, similar to those emitted by Clang.
Including linux/kernel.h to use ARRAY_SIZE() incidentally redefined max(), causing a build bug due to different types, hence the seemingly unrelated change.
Reported-by: Jakov Petrina jakov.petrina@sartura.hr Signed-off-by: Jean-Philippe Brucker jean-philippe@linaro.org Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: Andrii Nakryiko andriin@fb.com Link: https://lore.kernel.org/bpf/20200812143909.3293280-1-jean-philippe@linaro.or... Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/btf_dump.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index bbb4303172606..4edf76c5a7101 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -13,6 +13,7 @@ #include <errno.h> #include <linux/err.h> #include <linux/btf.h> +#include <linux/kernel.h> #include "btf.h" #include "hashmap.h" #include "libbpf.h" @@ -548,6 +549,9 @@ static int btf_dump_order_type(struct btf_dump *d, __u32 id, bool through_ptr) } }
+static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id, + const struct btf_type *t); + static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id, const struct btf_type *t); static void btf_dump_emit_struct_def(struct btf_dump *d, __u32 id, @@ -670,6 +674,9 @@ static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
switch (kind) { case BTF_KIND_INT: + /* Emit type alias definitions if necessary */ + btf_dump_emit_missing_aliases(d, id, t); + tstate->emit_state = EMITTED; break; case BTF_KIND_ENUM: @@ -869,7 +876,7 @@ static void btf_dump_emit_struct_def(struct btf_dump *d, btf_dump_printf(d, ": %d", m_sz); off = m_off + m_sz; } else { - m_sz = max(0, btf__resolve_size(d->btf, m->type)); + m_sz = max(0LL, btf__resolve_size(d->btf, m->type)); off = m_off + m_sz * 8; } btf_dump_printf(d, ";"); @@ -889,6 +896,32 @@ static void btf_dump_emit_struct_def(struct btf_dump *d, btf_dump_printf(d, " __attribute__((packed))"); }
+static const char *missing_base_types[][2] = { + /* + * GCC emits typedefs to its internal __PolyX_t types when compiling Arm + * SIMD intrinsics. Alias them to standard base types. + */ + { "__Poly8_t", "unsigned char" }, + { "__Poly16_t", "unsigned short" }, + { "__Poly64_t", "unsigned long long" }, + { "__Poly128_t", "unsigned __int128" }, +}; + +static void btf_dump_emit_missing_aliases(struct btf_dump *d, __u32 id, + const struct btf_type *t) +{ + const char *name = btf_dump_type_name(d, id); + int i; + + for (i = 0; i < ARRAY_SIZE(missing_base_types); i++) { + if (strcmp(name, missing_base_types[i][0]) == 0) { + btf_dump_printf(d, "typedef %s %s;\n\n", + missing_base_types[i][1], name); + break; + } + } +} + static void btf_dump_emit_enum_fwd(struct btf_dump *d, __u32 id, const struct btf_type *t) {