[PATCH 1/2] ld/PE: no base relocs for section (relative) ones
Julian Waters
tanksherman27@gmail.com
Sun Sep 15 13:26:03 GMT 2024
Ah, how I wish I was a binutils reviewer so I could approve this
best regards,
Julian
On Thu, Sep 12, 2024 at 1:52 PM Jan Beulich <jbeulich@suse.com> wrote:
>
> Even more so than image relative (RVA) relocations, section relative
> ones as well as section ones should not have base relocations created in
> the final PE image. Reportedly section relative relocations will want
> using for TLS support in the (Windows) compiler.
>
> While there also correct the names for two of the "image base" relocs.
> ---
> "Unused" (sometimes "absolute") relocations may similarly need special
> casing. Except for Arm (and i386 according to coff/i386.h, albeit other
> information I have - without a reference to where that once came from -
> says 0 has the same meaning there, and even 1 and 2 also have meaning),
> where no such type exists, that's always the relocation numbered 0. So a
> simple boolean may do there, unless the case is handled elsewhere.
>
> I'm surprised pe_detail_list[] has no IA64, LoongArch64, MCore, and
> RISC-V entries.
>
> --- a/ld/pe-dll.c
> +++ b/ld/pe-dll.c
> @@ -185,6 +185,9 @@ typedef struct
> const char *target_name;
> const char *object_target;
> unsigned int imagebase_reloc;
> + unsigned int secrel_reloc_lo;
> + unsigned int secrel_reloc_hi;
> + unsigned int section_reloc;
> int pe_arch;
> int bfd_arch;
> bool underscored;
> @@ -257,11 +260,16 @@ static pe_details_type pe_detail_list[]
> #ifdef pe_use_plus
> "pei-x86-64",
> "pe-x86-64",
> - 3 /* R_IMAGEBASE */,
> + 3 /* R_AMD64_IMAGEBASE */,
> + 11 /* R_AMD64_SECREL32 */,
> + 12 /* R_AMD64_SECREL7 */,
> + 10 /* R_AMD64_SECTION */,
> #else
> "pei-i386",
> "pe-i386",
> 7 /* R_IMAGEBASE */,
> + 11, 11 /* R_SECREL32 */,
> + 10 /* R_SECTION */,
> #endif
> PE_ARCH_i386,
> bfd_arch_i386,
> @@ -276,7 +284,10 @@ static pe_details_type pe_detail_list[]
> {
> "pei-x86-64",
> "pe-bigobj-x86-64",
> - 3 /* R_IMAGEBASE */,
> + 3 /* R_AMD64_IMAGEBASE */,
> + 11 /* R_AMD64_SECREL32 */,
> + 12 /* R_AMD64_SECREL7 */,
> + 10 /* R_AMD64_SECTION */,
> PE_ARCH_i386,
> bfd_arch_i386,
> false,
> @@ -287,6 +298,8 @@ static pe_details_type pe_detail_list[]
> "pei-i386",
> "pe-bigobj-i386",
> 7 /* R_IMAGEBASE */,
> + 11, 11 /* R_SECREL32 */,
> + 10 /* R_SECTION */,
> PE_ARCH_i386,
> bfd_arch_i386,
> true,
> @@ -297,6 +310,7 @@ static pe_details_type pe_detail_list[]
> "pei-shl",
> "pe-shl",
> 16 /* R_SH_IMAGEBASE */,
> + ~0, 0, ~0, /* none */
> PE_ARCH_sh,
> bfd_arch_sh,
> true,
> @@ -306,6 +320,7 @@ static pe_details_type pe_detail_list[]
> "pei-mips",
> "pe-mips",
> 34 /* MIPS_R_RVA */,
> + ~0, 0, ~0, /* none */
> PE_ARCH_mips,
> bfd_arch_mips,
> false,
> @@ -315,6 +330,7 @@ static pe_details_type pe_detail_list[]
> "pei-arm-little",
> "pe-arm-little",
> 11 /* ARM_RVA32 */,
> + ~0, 0, ~0, /* none */
> PE_ARCH_arm,
> bfd_arch_arm,
> true,
> @@ -324,6 +340,8 @@ static pe_details_type pe_detail_list[]
> "pei-arm-wince-little",
> "pe-arm-wince-little",
> 2, /* ARM_RVA32 on Windows CE, see bfd/coff-arm.c. */
> + 15, 15, /* ARM_SECREL (dito) */
> + 14, /* ARM_SECTION (dito) */
> PE_ARCH_arm_wince,
> bfd_arch_arm,
> false,
> @@ -332,13 +350,16 @@ static pe_details_type pe_detail_list[]
> {
> "pei-aarch64-little",
> "pe-aarch64-little",
> - 2, /* ARM64_RVA32 */
> + 2, /* IMAGE_REL_ARM64_ADDR32NB */
> + 8, /* IMAGE_REL_ARM64_SECREL */
> + 11, /* IMAGE_REL_ARM64_SECREL_LOW12L */
> + 13, /* IMAGE_REL_ARM64_SECTION */
> PE_ARCH_aarch64,
> bfd_arch_aarch64,
> false,
> autofilter_symbollist_generic
> },
> - { NULL, NULL, 0, 0, 0, false, NULL }
> + { NULL, NULL, 0, 0, 0, 0, 0, 0, false, NULL }
> };
>
> static const pe_details_type *pe_details;
> @@ -1596,7 +1617,10 @@ generate_reloc (bfd *abfd, struct bfd_li
> printf ("rel: %s\n", sym->name);
> }
> if (!relocs[i]->howto->pc_relative
> - && relocs[i]->howto->type != pe_details->imagebase_reloc)
> + && relocs[i]->howto->type != pe_details->imagebase_reloc
> + && (relocs[i]->howto->type < pe_details->secrel_reloc_lo
> + || relocs[i]->howto->type > pe_details->secrel_reloc_hi)
> + && relocs[i]->howto->type != pe_details->section_reloc)
> {
> struct bfd_symbol *sym = *relocs[i]->sym_ptr_ptr;
> const struct bfd_link_hash_entry *blhe
> --- a/ld/testsuite/ld-pe/pe.exp
> +++ b/ld/testsuite/ld-pe/pe.exp
> @@ -37,6 +37,10 @@ if {[istarget i*86-*-cygwin*]
> {{objdump -s secrel_64.d}} "secrel.x"}
> {".secidx" "--disable-reloc-section" "" "" {secidx1.s secidx2.s}
> {{objdump -s secidx_64.d}} "secidx.x"}
> + {".secrel32 w/ relocs" "--enable-reloc-section" "" "" {secrel1.s secrel2.s}
> + {{objdump -p secrel-reloc.d}} "secrel.x"}
> + {".secidx w/ relocs" "--enable-reloc-section" "" "" {secidx1.s secidx2.s}
> + {{objdump -p secidx-reloc.d}} "secidx.x"}
> {"Empty export table" "" "" "" "exports.s"
> {{objdump -p exports64.d}} "exports.dll"}
> {"TLS directory entry" "" "" "" "tlssec.s"
> @@ -48,6 +52,10 @@ if {[istarget i*86-*-cygwin*]
> {{objdump -s secrel.d}} "secrel.x"}
> {".secidx" "--disable-auto-import --disable-reloc-section" "" "" {secidx1.s secidx2.s}
> {{objdump -s secidx.d}} "secidx.x"}
> + {".secrel32 w/ relocs" "--disable-auto-import --enable-reloc-section" "" "" {secrel1.s secrel2.s}
> + {{objdump -p secrel-reloc.d}} "secrel-reloc.x"}
> + {".secidx w/ relocs" "--disable-auto-import --enable-reloc-section" "" "" {secidx1.s secidx2.s}
> + {{objdump -p secidx-reloc.d}} "secidx-reloc.x"}
> {"Empty export table" "" "" "" "exports.s"
> {{objdump -p exports.d}} "exports.dll"}
> {"TLS directory entry" "" "" "" "tlssec.s"
> @@ -57,6 +65,8 @@ if {[istarget i*86-*-cygwin*]
> set pe_tests {
> {".secrel32" "--disable-reloc-section" "" "" {secrel1.s secrel2.s}
> {{objdump -s secrel.d}} "secrel.x"}
> + {".secrel32 w/ relocs" "" "" "" {secrel1.s secrel2.s}
> + {{objdump -p secrel-reloc.d}} "secrel-reloc.x"}
> {"Empty export table" "" "" "" "exports.s"
> {{objdump -p exports.d}} "exports.dll"}
> {"TLS directory entry" "" "" "" "tlssec.s"
> @@ -68,6 +78,10 @@ if {[istarget i*86-*-cygwin*]
> {{objdump -s secrel.d}} "secrel.x"}
> {".secidx" "--disable-reloc-section" "" "" {secidx1.s secidx2.s}
> {{objdump -s secidx.d}} "secidx.x"}
> + {".secrel32 w/ relocs" " --enable-reloc-section" "" "" {secrel1.s secrel2.s}
> + {{objdump -p secrel-reloc.d}} "secrel-reloc.x"}
> + {".secidx w/ relocs" " --enable-reloc-section" "" "" {secidx1.s secidx2.s}
> + {{objdump -p secidx-reloc.d}} "secidx-reloc.x"}
> {"Empty export table" "" "" "" "exports.s"
> {{objdump -p exports.d}} "exports.dll"}
> {"TLS directory entry" "" "" "" "tlssec.s"
> --- /dev/null
> +++ b/ld/testsuite/ld-pe/secidx-reloc.d
> @@ -0,0 +1,5 @@
> +#...
> +The Data Directory
> +#...
> +Entry 5 0+ 0+ Base Relocation Directory \[\.reloc\]
> +#...
> --- /dev/null
> +++ b/ld/testsuite/ld-pe/secrel-reloc.d
> @@ -0,0 +1,5 @@
> +#...
> +The Data Directory
> +#...
> +Entry 5 0+ 0+ Base Relocation Directory \[\.reloc\]
> +#...
>
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