Author: markj Date: Sun Dec 29 21:46:50 2019 New Revision: 356187 URL: https://svnweb.freebsd.org/changeset/base/356187
Log: Add libdtrace support for arm64 USDT probes. arm64 is still lacking a fasttrap implementation, which is required to actually enable userland probes, but this at least allows USDT probes to be linked into userland applications. Submitted by: Klaus Küchemann <macipho...@googlemail.com> (original) MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D22360 Modified: head/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c Modified: head/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c ============================================================================== --- head/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c Sun Dec 29 21:46:00 2019 (r356186) +++ head/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c Sun Dec 29 21:46:50 2019 (r356187) @@ -229,9 +229,10 @@ prepare_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, for (j = 0; j < nrel; j++) { #if defined(__aarch64__) -/* XXX */ - printf("%s:%s(%d): aarch64 not implemented\n", - __FUNCTION__, __FILE__, __LINE__); + rel->r_offset = s->dofs_offset + + dofr[j].dofr_offset; + rel->r_info = ELF32_R_INFO(count + dep->de_global, + R_ARM_REL32); #elif defined(__arm__) /* XXX */ printf("%s:%s(%d): arm not implemented\n", @@ -425,7 +426,10 @@ prepare_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, for (j = 0; j < nrel; j++) { #if defined(__aarch64__) -/* XXX */ + rel->r_offset = s->dofs_offset + + dofr[j].dofr_offset; + rel->r_info = ELF64_R_INFO(count + dep->de_global, + R_AARCH64_PREL64); #elif defined(__arm__) /* XXX */ #elif defined(__mips__) @@ -541,6 +545,8 @@ dump_elf32(dtrace_hdl_t *dtp, const dof_hdr_t *dof, in elf_file.ehdr.e_machine = EM_SPARC; #elif defined(__i386) || defined(__amd64) elf_file.ehdr.e_machine = EM_386; +#elif defined(__aarch64__) + elf_file.ehdr.e_machine = EM_AARCH64; #endif elf_file.ehdr.e_version = EV_CURRENT; elf_file.ehdr.e_shoff = sizeof (Elf32_Ehdr); @@ -687,6 +693,8 @@ dump_elf64(dtrace_hdl_t *dtp, const dof_hdr_t *dof, in elf_file.ehdr.e_machine = EM_SPARCV9; #elif defined(__i386) || defined(__amd64) elf_file.ehdr.e_machine = EM_AMD64; +#elif defined(__aarch64__) + elf_file.ehdr.e_machine = EM_AARCH64; #endif elf_file.ehdr.e_version = EV_CURRENT; elf_file.ehdr.e_shoff = sizeof (Elf64_Ehdr); @@ -802,14 +810,66 @@ dt_symtab_lookup(Elf_Data *data_sym, int start, int en } #if defined(__aarch64__) -/* XXX */ +#define DT_OP_NOP 0xd503201f +#define DT_OP_RET 0xd65f03c0 +#define DT_OP_CALL26 0x94000000 +#define DT_OP_JUMP26 0x14000000 + static int dt_modtext(dtrace_hdl_t *dtp, char *p, int isenabled, GElf_Rela *rela, uint32_t *off) { - printf("%s:%s(%d): aarch64 not implemented\n", __FUNCTION__, __FILE__, - __LINE__); - return (-1); + uint32_t *ip; + + /* + * Ensure that the offset is aligned on an instruction boundary. + */ + if ((rela->r_offset & (sizeof (uint32_t) - 1)) != 0) + return (-1); + + /* + * We only know about some specific relocation types. + * We also recognize relocation type NONE, since that gets used for + * relocations of USDT probes, and we might be re-processing a file. + */ + if (GELF_R_TYPE(rela->r_info) != R_AARCH64_CALL26 && + GELF_R_TYPE(rela->r_info) != R_AARCH64_JUMP26 && + GELF_R_TYPE(rela->r_info) != R_AARCH64_NONE) + return (-1); + + ip = (uint32_t *)(p + rela->r_offset); + + /* + * We may have already processed this object file in an earlier linker + * invocation. Check to see if the present instruction sequence matches + * the one we would install below. + */ + if (ip[0] == DT_OP_NOP || ip[0] == DT_OP_RET) + return (0); + + /* + * We only expect call instructions with a displacement of 0, or a jump + * instruction acting as a tail call. + */ + if (ip[0] != DT_OP_CALL26 && ip[0] != DT_OP_JUMP26) { + dt_dprintf("found %x instead of a call or jmp instruction at " + "%llx\n", ip[0], (u_longlong_t)rela->r_offset); + return (-1); + } + + /* + * On arm64, we do not have to differentiate between regular probes and + * is-enabled probes. Both cases are encoded as a regular branch for + * non-tail call locations, and a jump for tail call locations. Calls + * are to be converted into a no-op whereas jumps should become a + * return. + */ + if (ip[0] == DT_OP_CALL26) + ip[0] = DT_OP_NOP; + else + ip[0] = DT_OP_RET; + + return (0); } #elif defined(__arm__) /* XXX */ @@ -1254,6 +1314,8 @@ process_obj(dtrace_hdl_t *dtp, const char *obj, int *e emachine1 = emachine2 = EM_SPARCV9; #elif defined(__i386) || defined(__amd64) emachine1 = emachine2 = EM_AMD64; +#elif defined(__aarch64__) + emachine1 = emachine2 = EM_AARCH64; #endif symsize = sizeof (Elf64_Sym); } else { _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
