mirror of
git://sourceware.org/git/libabigail.git
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abg-elf-helpers: migrate ppc64 specific helpers
This migrates more helpers to abg-elf-helpers:
lookup_ppc64_elf_fn_entry_point_address with dependencies
read_uint64_from_array_of_bytes
read_int_from_array_of_bytes
address_is_in_opd_section with dependency
address_is_in_section
read_context::find_opd_section and read_context::opd_section_ are obsolete.
* src/abg-dwarf-reader.cc (read_context::opd_section_): Delete.
(read_context::find_opd_section): Delete.
(read_context::read_uint64_from_array_of_bytes): Delete.
(read_context::read_int_from_array_of_bytes): Delete.
(read_context::lookup_ppc64_elf_fn_entry_point_address): Delete.
(read_context::address_is_in_opd_section): Delete.
(read_context::address_is_in_section): Delete.
(read_context::load_symbol_maps_from_symtab_section): Adjust.
* src/abg-elf-helpers.cc (read_int_from_array_of_bytes): New.
(read_uint64_from_array_of_bytes): New.
(lookup_ppc64_elf_fn_entry_point_address): New.
(address_is_in_section): New.
(address_is_in_opd_section): New.
* src/abg-elf-helpers.h
(lookup_ppc64_elf_fn_entry_point_address): New declaration.
(address_is_in_opd_section): New declaration.
Reviewed-by: Giuliano Procida <gprocida@google.com>
Reviewed-by: Dodji Seketeli <dodji@seketeli.org>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Dodji Seketeli <dodji@redhat.com>
This commit is contained in:
Matthias Maennich
Dodji Seketeli
parent
9cd191b3c4
commit
e87f2672d9
@ -2146,10 +2146,6 @@ public:
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mutable Elf* elf_handle_;
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string elf_path_;
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mutable Elf_Scn* symtab_section_;
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// The "Official procedure descriptor section, aka .opd", used in
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// ppc64 elf v1 binaries. This section contains the procedure
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// descriptors on that platform.
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mutable Elf_Scn* opd_section_;
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Dwarf_Die* cur_tu_die_;
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mutable dwarf_expr_eval_context dwarf_expr_eval_context_;
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// A set of maps (one per kind of die source) that associates a decl
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@ -2330,7 +2326,6 @@ public:
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elf_handle_ = 0;
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elf_path_ = elf_path;
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symtab_section_ = 0;
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opd_section_ = 0;
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cur_tu_die_ = 0;
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exported_decls_builder_ = 0;
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@ -5323,19 +5318,6 @@ public:
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return symtab_section_;
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}
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/// Return the "Official Procedure descriptors section." This
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/// section is named .opd, and is usually present only on PPC64
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/// ELFv1 binaries.
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///
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/// @return the .opd section, if found. Return nil otherwise.
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Elf_Scn*
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find_opd_section() const
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{
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if (!opd_section_)
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opd_section_ = elf_helpers::find_opd_section(elf_handle());
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return opd_section_;
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}
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/// Lookup an elf symbol, referred to by its index, from the .symtab
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/// section.
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///
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@ -5447,152 +5429,6 @@ public:
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return sym;
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}
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/// Read 8 bytes and convert their value into an uint64_t.
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///
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/// @param bytes the array of bytes to read the next 8 bytes from.
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/// Note that this array must be at least 8 bytes long.
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///
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/// @param result where to store the resuting uint64_t that was read.
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///
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/// @param is_big_endian if true, read the 8 bytes in Big Endian
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/// mode, otherwise, read them in Little Endian.
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///
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/// @param true if the 8 bytes could be read, false otherwise.
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bool
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read_uint64_from_array_of_bytes(const uint8_t *bytes,
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bool is_big_endian,
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uint64_t &result) const
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{
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return read_int_from_array_of_bytes(bytes, 8, is_big_endian, result);
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}
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/// Read N bytes and convert their value into an integer type T.
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///
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/// Note that N cannot be bigger than 8 for now. The type passed needs to be
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/// at least of the size of number_of_bytes.
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///
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/// @param bytes the array of bytes to read the next 8 bytes from.
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/// Note that this array must be at least 8 bytes long.
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///
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/// @param number_of_bytes the number of bytes to read. This number
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/// cannot be bigger than 8.
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///
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/// @param is_big_endian if true, read the 8 bytes in Big Endian
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/// mode, otherwise, read them in Little Endian.
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///
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/// @param result where to store the resuting integer that was read.
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///
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///
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/// @param true if the 8 bytes could be read, false otherwise.
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template<typename T>
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bool
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read_int_from_array_of_bytes(const uint8_t *bytes,
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unsigned char number_of_bytes,
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bool is_big_endian,
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T &result) const
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{
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if (!bytes)
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return false;
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ABG_ASSERT(number_of_bytes <= 8);
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ABG_ASSERT(number_of_bytes <= sizeof(T));
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T res = 0;
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const uint8_t *cur = bytes;
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if (is_big_endian)
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{
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// In Big Endian, the most significant byte is at the lowest
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// address.
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const uint8_t* msb = cur;
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res = *msb;
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// Now read the remaining least significant bytes.
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for (uint i = 1; i < number_of_bytes; ++i)
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res = (res << 8) | ((T)msb[i]);
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}
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else
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{
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// In Little Endian, the least significant byte is at the
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// lowest address.
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const uint8_t* lsb = cur;
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res = *lsb;
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// Now read the remaining most significant bytes.
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for (uint i = 1; i < number_of_bytes; ++i)
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res = res | (((T)lsb[i]) << i * 8);
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}
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result = res;
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return true;
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}
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/// Lookup the address of the function entry point that corresponds
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/// to the address of a given function descriptor.
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///
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/// On PPC64, a function pointer is the address of a function
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/// descriptor. Function descriptors are located in the .opd
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/// section. Each function descriptor is a triplet of three
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/// addresses, each one on 64 bits. Among those three address only
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/// the first one is of any interest to us: the address of the entry
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/// point of the function.
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///
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/// This function returns the address of the entry point of the
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/// function whose descriptor's address is given.
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///
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/// http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#FUNC-DES
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///
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/// https://www.ibm.com/developerworks/community/blogs/5894415f-be62-4bc0-81c5-3956e82276f3/entry/deeply_understand_64_bit_powerpc_elf_abi_function_descriptors?lang=en
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///
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/// @param fn_desc_address the address of the function descriptor to
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/// consider.
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///
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/// @return the address of the entry point of the function whose
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/// descriptor has the address @p fn_desc_address. If there is no
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/// .opd section (e.g because we are not on ppc64) or more generally
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/// if the function descriptor could not be found then this function
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/// just returns the address of the fuction descriptor.
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GElf_Addr
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lookup_ppc64_elf_fn_entry_point_address(GElf_Addr fn_desc_address) const
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{
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if (!elf_handle())
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return fn_desc_address;
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if (!architecture_is_ppc64(elf_handle()))
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return fn_desc_address;
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bool is_big_endian = architecture_is_big_endian(elf_handle());
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Elf_Scn *opd_section = find_opd_section();
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if (!opd_section)
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return fn_desc_address;
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GElf_Shdr header_mem;
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// The section header of the .opd section.
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GElf_Shdr *opd_sheader = gelf_getshdr(opd_section, &header_mem);
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// The offset of the function descriptor entry, in the .opd
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// section.
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size_t fn_desc_offset = fn_desc_address - opd_sheader->sh_addr;
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Elf_Data *elf_data = elf_rawdata(opd_section, 0);
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// Ensure that the opd_section has at least 8 bytes, starting from
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// the offset we want read the data from.
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if (elf_data->d_size <= fn_desc_offset + 8)
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return fn_desc_address;
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// A pointer to the data of the .opd section, that we can actually
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// do something with.
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uint8_t * bytes = (uint8_t*) elf_data->d_buf;
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// The resulting address we are looking for is going to be formed
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// in this variable.
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GElf_Addr result = 0;
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ABG_ASSERT(read_uint64_from_array_of_bytes(bytes + fn_desc_offset,
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is_big_endian, result));
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return result;
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}
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/// Test if a given function symbol has been exported.
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///
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/// @param symbol_address the address of the symbol we are looking
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@ -5911,13 +5747,15 @@ public:
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// symbol that are in the .opd section.
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GElf_Addr fn_desc_addr = sym->st_value;
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GElf_Addr fn_entry_point_addr =
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lookup_ppc64_elf_fn_entry_point_address(fn_desc_addr);
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lookup_ppc64_elf_fn_entry_point_address(elf_handle(),
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fn_desc_addr);
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addr_elf_symbol_sptr_map_type::const_iterator it2 =
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fun_entry_addr_sym_map().find(fn_entry_point_addr);
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if (it2 == fun_entry_addr_sym_map().end())
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fun_entry_addr_sym_map()[fn_entry_point_addr] = symbol;
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else if (address_is_in_opd_section(fn_desc_addr))
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else if (address_is_in_opd_section(elf_handle(),
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fn_desc_addr))
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{
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// Either
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//
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@ -6080,24 +5918,6 @@ public:
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return true;
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}
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/// Return true if an address is in the ".opd" section that is
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/// present on the ppc64 platform.
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///
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/// @param addr the address to consider.
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///
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/// @return true iff @p addr is designates a word that is in the
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/// ".opd" section.
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bool
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address_is_in_opd_section(Dwarf_Addr addr)
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{
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Elf_Scn * opd_section = find_opd_section();
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if (!opd_section)
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return false;
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if (address_is_in_section(addr, opd_section))
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return true;
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return false;
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}
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/// Load the symbol maps if necessary.
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///
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/// @return true iff the symbol maps has been loaded by this
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@ -6248,26 +6068,6 @@ public:
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return addr;
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}
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/// Test if a given address is in a given section.
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///
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/// @param addr the address to consider.
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///
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/// @param section the section to consider.
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bool
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address_is_in_section(Dwarf_Addr addr, Elf_Scn* section) const
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{
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if (!section)
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return false;
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GElf_Shdr sheader_mem;
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GElf_Shdr* sheader = gelf_getshdr(section, &sheader_mem);
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if (sheader->sh_addr <= addr && addr <= sheader->sh_addr + sheader->sh_size)
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return true;
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return false;
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}
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/// For a relocatable (*.o) elf file, this function expects an
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/// absolute address, representing a global variable symbol. It
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/// then extracts the address of the {.data,.data1,.rodata,.bss}
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@ -861,6 +861,153 @@ architecture_is_big_endian(Elf* elf_handle)
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return is_big_endian;
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}
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/// Read N bytes and convert their value into an integer type T.
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///
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/// Note that N cannot be bigger than 8 for now. The type passed needs to be at
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/// least of the size of number_of_bytes.
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///
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/// @param bytes the array of bytes to read the next 8 bytes from.
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/// Note that this array must be at least 8 bytes long.
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///
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/// @param number_of_bytes the number of bytes to read. This number
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/// cannot be bigger than 8.
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///
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/// @param is_big_endian if true, read the 8 bytes in Big Endian
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/// mode, otherwise, read them in Little Endian.
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///
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/// @param result where to store the resuting integer that was read.
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///
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///
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/// @param true if the 8 bytes could be read, false otherwise.
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template <typename T>
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bool
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read_int_from_array_of_bytes(const uint8_t* bytes,
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unsigned char number_of_bytes,
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bool is_big_endian,
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T& result)
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{
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if (!bytes)
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return false;
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ABG_ASSERT(number_of_bytes <= 8);
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ABG_ASSERT(number_of_bytes <= sizeof(T));
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T res = 0;
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const uint8_t* cur = bytes;
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if (is_big_endian)
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{
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// In Big Endian, the most significant byte is at the lowest
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// address.
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const uint8_t* msb = cur;
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res = *msb;
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// Now read the remaining least significant bytes.
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for (uint i = 1; i < number_of_bytes; ++i)
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res = (res << 8) | ((T)msb[i]);
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}
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else
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{
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// In Little Endian, the least significant byte is at the
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// lowest address.
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const uint8_t* lsb = cur;
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res = *lsb;
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// Now read the remaining most significant bytes.
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for (uint i = 1; i < number_of_bytes; ++i)
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res = res | (((T)lsb[i]) << i * 8);
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}
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result = res;
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return true;
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}
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/// Read 8 bytes and convert their value into an uint64_t.
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///
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/// @param bytes the array of bytes to read the next 8 bytes from.
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/// Note that this array must be at least 8 bytes long.
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///
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/// @param result where to store the resuting uint64_t that was read.
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///
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/// @param is_big_endian if true, read the 8 bytes in Big Endian
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/// mode, otherwise, read them in Little Endian.
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///
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/// @param true if the 8 bytes could be read, false otherwise.
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bool
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read_uint64_from_array_of_bytes(const uint8_t* bytes,
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bool is_big_endian,
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uint64_t& result)
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{
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return read_int_from_array_of_bytes(bytes, 8, is_big_endian, result);
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}
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/// Lookup the address of the function entry point that corresponds
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/// to the address of a given function descriptor.
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///
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/// On PPC64, a function pointer is the address of a function
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/// descriptor. Function descriptors are located in the .opd
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/// section. Each function descriptor is a triplet of three
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/// addresses, each one on 64 bits. Among those three address only
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/// the first one is of any interest to us: the address of the entry
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/// point of the function.
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///
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/// This function returns the address of the entry point of the
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/// function whose descriptor's address is given.
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///
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/// http://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#FUNC-DES
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///
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/// https://www.ibm.com/developerworks/community/blogs/5894415f-be62-4bc0-81c5-3956e82276f3/entry/deeply_understand_64_bit_powerpc_elf_abi_function_descriptors?lang=en
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///
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/// @param fn_desc_address the address of the function descriptor to
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/// consider.
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///
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/// @return the address of the entry point of the function whose
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/// descriptor has the address @p fn_desc_address. If there is no
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/// .opd section (e.g because we are not on ppc64) or more generally
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/// if the function descriptor could not be found then this function
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/// just returns the address of the fuction descriptor.
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GElf_Addr
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lookup_ppc64_elf_fn_entry_point_address(Elf* elf_handle, GElf_Addr fn_desc_address)
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{
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if (!elf_handle)
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return fn_desc_address;
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if (!architecture_is_ppc64(elf_handle))
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return fn_desc_address;
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bool is_big_endian = architecture_is_big_endian(elf_handle);
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Elf_Scn* opd_section = find_opd_section(elf_handle);
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if (!opd_section)
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return fn_desc_address;
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GElf_Shdr header_mem;
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// The section header of the .opd section.
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GElf_Shdr* opd_sheader = gelf_getshdr(opd_section, &header_mem);
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// The offset of the function descriptor entry, in the .opd
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// section.
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size_t fn_desc_offset = fn_desc_address - opd_sheader->sh_addr;
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Elf_Data* elf_data = elf_rawdata(opd_section, 0);
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// Ensure that the opd_section has at least 8 bytes, starting from
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// the offset we want read the data from.
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if (elf_data->d_size <= fn_desc_offset + 8)
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return fn_desc_address;
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// A pointer to the data of the .opd section, that we can actually
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// do something with.
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uint8_t* bytes = (uint8_t*)elf_data->d_buf;
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// The resulting address we are looking for is going to be formed
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// in this variable.
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GElf_Addr result = 0;
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ABG_ASSERT(read_uint64_from_array_of_bytes(bytes + fn_desc_offset,
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is_big_endian, result));
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return result;
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}
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/// Test if the ELF binary denoted by a given ELF handle is a Linux
|
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/// Kernel Module.
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///
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@ -1025,5 +1172,46 @@ maybe_adjust_et_rel_sym_addr_to_abs_addr(Elf* elf_handle, GElf_Sym* sym)
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return addr + section_header.sh_addr;
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}
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/// Test if a given address is in a given section.
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///
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/// @param addr the address to consider.
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///
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/// @param section the section to consider.
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///
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||||
/// @return true iff @p addr is in section @p section.
|
||||
bool
|
||||
address_is_in_section(Dwarf_Addr addr, Elf_Scn* section)
|
||||
{
|
||||
if (!section)
|
||||
return false;
|
||||
|
||||
GElf_Shdr sheader_mem;
|
||||
GElf_Shdr* sheader = gelf_getshdr(section, &sheader_mem);
|
||||
|
||||
if (sheader->sh_addr <= addr && addr <= sheader->sh_addr + sheader->sh_size)
|
||||
return true;
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
/// Return true if an address is in the ".opd" section that is
|
||||
/// present on the ppc64 platform.
|
||||
///
|
||||
/// @param addr the address to consider.
|
||||
///
|
||||
/// @return true iff @p addr designates a word that is in the ".opd"
|
||||
/// section.
|
||||
bool
|
||||
address_is_in_opd_section(Elf* elf_handle, Dwarf_Addr addr)
|
||||
{
|
||||
Elf_Scn * opd_section = find_opd_section(elf_handle);
|
||||
if (!opd_section)
|
||||
return false;
|
||||
if (address_is_in_section(addr, opd_section))
|
||||
return true;
|
||||
return false;
|
||||
}
|
||||
|
||||
|
||||
} // end namespace elf_helpers
|
||||
} // end namespace abigail
|
||||
|
||||
@ -12,6 +12,7 @@
|
||||
|
||||
#include "config.h"
|
||||
|
||||
#include <elfutils/libdwfl.h>
|
||||
#include <gelf.h>
|
||||
#include <string>
|
||||
|
||||
@ -136,6 +137,10 @@ architecture_is_arm32(Elf* elf_handle);
|
||||
bool
|
||||
architecture_is_big_endian(Elf* elf_handle);
|
||||
|
||||
GElf_Addr
|
||||
lookup_ppc64_elf_fn_entry_point_address(Elf* elf_handle,
|
||||
GElf_Addr fn_desc_address);
|
||||
|
||||
//
|
||||
// Helpers for Linux Kernel Binaries
|
||||
//
|
||||
@ -165,6 +170,9 @@ is_dso(Elf* elf_handle);
|
||||
GElf_Addr
|
||||
maybe_adjust_et_rel_sym_addr_to_abs_addr(Elf* elf_handle, GElf_Sym* sym);
|
||||
|
||||
bool
|
||||
address_is_in_opd_section(Elf* elf_handle, Dwarf_Addr addr);
|
||||
|
||||
} // end namespace elf_helpers
|
||||
} // end namespace abigail
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user