Juni 2009 - Vax-linux

[LV] Now for some more noise , ok any noise ...
by Mr. James W. Laferriere 04 Sep '09

04 Sep '09

Hello All , My Micro Vax 4000 (QBUS) just arrived in town . So hopefully at least someone (me) will be putting a biot more noise onto the list over the next few months . Before I do tho , Is there any Good or Bad news to share ? Twys , JimL -- +------------------------------------------------------------------+ | James W. Laferriere | System Techniques | Give me VMS | | Network&System Engineer | 2133 McCullam Ave | Give me Linux | | babydr(a)baby-dragons.com | Fairbanks, AK. 99701 | only on AXP | +------------------------------------------------------------------+ _______________________________________________ Linux-Vax mailing list Linux-Vax(a)pergamentum.com http://www.pergamentum.com/mailman/listinfo/linux-vax

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[LV] [ping] libgcc: Add __udivsi3 and __umodsi3 for vax-*-linux*
by Maciej W. Rozycki 27 Jun '09

27 Jun '09

Hi, Could anyone please have a look and review this patch: http://gcc.gnu.org/ml/gcc-patches/2009-06/msg00805.html Thanks, Maciej _______________________________________________ Linux-Vax mailing list Linux-Vax(a)mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax

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[LV] [PATCH] VAX/ELF: PLT disassembly support
by Maciej W. Rozycki 19 Jun '09

19 Jun '09

Hello, The VAX/ELF backend lacks a platform-specific PLT disassembly helper. The result is the table is messed up in the dump. Here's an example: $ vax-linux-objdump -d -j .plt ld.so.1 ld.so.1: file format elf32-vax Disassembly of section .plt: 000005c8 <.plt>: 5c8: dd ef 7e 42 pushl 1484c <_GLOBAL_OFFSET_TABLE_+0x4> 5cc: 01 00 5ce: 17 ff 7c 42 jmp *14850 <_GLOBAL_OFFSET_TABLE_+0x8> 5d2: 01 00 5d4: fc xfc 5d5: 0f 16 ef ec remque $0x16,5c8 <GLIBC_2.0+0x5c8> 5d9: ff ff ff 5dc: 00 halt 5dd: 00 halt 5de: 00 halt 5df: 00 halt 5e0: fc xfc 5e1: 0f 16 ef e0 remque $0x16,5c8 <GLIBC_2.0+0x5c8> 5e5: ff ff ff 5e8: 0c 00 00 00 prober $0x0,$0x0,$0x0 5ec: fc xfc 5ed: 0f 16 ef d4 remque $0x16,5c8 <GLIBC_2.0+0x5c8> 5f1: ff ff ff 5f4: 18 00 bgeq 5f6 <GLIBC_2.0+0x5f6> 5f6: 00 halt 5f7: 00 halt 5f8: fc xfc 5f9: 0f 16 ef c8 remque $0x16,5c8 <GLIBC_2.0+0x5c8> 5fd: ff ff ff 600: 24 00 00 00 cvtpt $0x0,$0x0,$0x0,*0xbcef160f(ap),*31060d <_end+0x2fb511> 604: fc 0f 16 ef 608: bc ff ff ff 60c: 30 00 ... The patch below implements the helper needed. There is a small issue with weak symbols which do not have the BSF_FUNCTION flag set and therefore do not match the usual logic to trigger entry mask decoding. To solve this problem, I have made use of an observation that the BSF_SYNTHETIC flag is only set for PLT symbols for the VAX target. If this ever changes in the future code will have to be adjusted accordingly. Here's a dump of the same PLT as above obtained with the patch applied: $ vax-linux-objdump -d -j .plt ld.so.1 ld.so.1: file format elf32-vax Disassembly of section .plt: 000005c8 <__libc_memalign@plt-0xc>: 5c8: dd ef 7e 42 pushl 1484c <_GLOBAL_OFFSET_TABLE_+0x4> 5cc: 01 00 5ce: 17 ff 7c 42 jmp *14850 <_GLOBAL_OFFSET_TABLE_+0x8> 5d2: 01 00 000005d4 <__libc_memalign@plt>: 5d4: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 5d6: 16 ef ec ff jsb 5c8 <GLIBC_2.0+0x5c8> 5da: ff ff 5dc: 00 00 00 00 .long 0x00000000 000005e0 <malloc@plt>: 5e0: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 5e2: 16 ef e0 ff jsb 5c8 <GLIBC_2.0+0x5c8> 5e6: ff ff 5e8: 0c 00 00 00 .long 0x0000000c 000005ec <calloc@plt>: 5ec: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 5ee: 16 ef d4 ff jsb 5c8 <GLIBC_2.0+0x5c8> 5f2: ff ff 5f4: 18 00 00 00 .long 0x00000018 000005f8 <realloc@plt>: 5f8: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 5fa: 16 ef c8 ff jsb 5c8 <GLIBC_2.0+0x5c8> 5fe: ff ff 600: 24 00 00 00 .long 0x00000024 00000604 <free@plt>: 604: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 606: 16 ef bc ff jsb 5c8 <GLIBC_2.0+0x5c8> 60a: ff ff 60c: 30 00 00 00 .long 0x00000030 bfd/ 2009-06-04 Maciej W. Rozycki <macro(a)linux-mips.org> * elf32-vax.c (elf_vax_plt_sym_val): New function. (elf_backend_plt_sym_val): Define. opcodes/ 2009-06-04 Maciej W. Rozycki <macro(a)linux-mips.org> * vax-dis.c (is_function_entry): Return success for synthetic symbols too. (is_plt_tail): New function. (print_insn_vax): Decode PLT entry offset longword. OK to apply? Maciej binutils-2.19.1-vax-plt-sym.patch diff -up --recursive --new-file binutils-2.19.1.macro/bfd/elf32-vax.c binutils-2.19.1/bfd/elf32-vax.c --- binutils-2.19.1.macro/bfd/elf32-vax.c 2008-01-11 09:07:03.000000000 +0000 +++ binutils-2.19.1/bfd/elf32-vax.c 2009-05-15 22:46:54.000000000 +0000 @@ -47,6 +47,8 @@ static bfd_boolean elf_vax_finish_dynami Elf_Internal_Sym *); static bfd_boolean elf_vax_finish_dynamic_sections (bfd *, struct bfd_link_info *); +static bfd_vma elf_vax_plt_sym_val (bfd_vma, const asection *, + const arelent *); static bfd_boolean elf32_vax_set_private_flags (bfd *, flagword); static bfd_boolean elf32_vax_merge_private_bfd_data (bfd *, bfd *); @@ -2068,6 +2070,13 @@ elf_vax_finish_dynamic_sections (bfd *ou return TRUE; } +static bfd_vma +elf_vax_plt_sym_val (bfd_vma i, const asection *plt, + const arelent *rel ATTRIBUTE_UNUSED) +{ + return plt->vma + (i + 1) * PLT_ENTRY_SIZE; +} + #define TARGET_LITTLE_SYM bfd_elf32_vax_vec #define TARGET_LITTLE_NAME "elf32-vax" #define ELF_MACHINE_CODE EM_VAX @@ -2092,6 +2101,7 @@ elf_vax_finish_dynamic_sections (bfd *ou elf_vax_finish_dynamic_sections #define elf_backend_gc_mark_hook elf_vax_gc_mark_hook #define elf_backend_gc_sweep_hook elf_vax_gc_sweep_hook +#define elf_backend_plt_sym_val elf_vax_plt_sym_val #define bfd_elf32_bfd_merge_private_bfd_data \ elf32_vax_merge_private_bfd_data #define bfd_elf32_bfd_set_private_flags \ diff -up --recursive --new-file binutils-2.19.1.macro/opcodes/vax-dis.c binutils-2.19.1/opcodes/vax-dis.c --- binutils-2.19.1.macro/opcodes/vax-dis.c 2007-07-05 09:49:02.000000000 +0000 +++ binutils-2.19.1/opcodes/vax-dis.c 2009-05-15 23:52:10.000000000 +0000 @@ -171,21 +171,24 @@ free_entry_array (void) } } #endif -/* Check if the given address is a known function entry. Either there must - be a symbol of function type at this address, or the address must be - a forced entry point. The later helps in disassembling ROM images, because - there's no symbol table at all. Forced entry points can be given by - supplying several -M options to objdump: -M entry:0xffbb7730. */ +/* Check if the given address is a known function entry point. This is + the case if there is a symbol of the function type at this address. + We also check for synthetic symbols as these are used for PLT entries + (weak undefined symbols may not have the function type set). Finally + the address may have been forced to be treated as an entry point. The + latter helps in disassembling ROM images, because there's no symbol + table at all. Forced entry points can be given by supplying several + -M options to objdump: -M entry:0xffbb7730. */ static bfd_boolean is_function_entry (struct disassemble_info *info, bfd_vma addr) { unsigned int i; - /* Check if there's a BSF_FUNCTION symbol at our address. */ + /* Check if there's a function or PLT symbol at our address. */ if (info->symbols && info->symbols[0] - && (info->symbols[0]->flags & BSF_FUNCTION) + && (info->symbols[0]->flags & (BSF_FUNCTION | BSF_SYNTHETIC)) && addr == bfd_asymbol_value (info->symbols[0])) return TRUE; @@ -197,6 +200,22 @@ is_function_entry (struct disassemble_in return FALSE; } +/* Check if the given address is the last longword of a PLT entry. + This longword is data and depending on the value it may interfere + with disassembly of further PLT entries. We make use of the fact + PLT symbols are marked BSF_SYNTHETIC. */ +static bfd_boolean +is_plt_tail (struct disassemble_info *info, bfd_vma addr) +{ + if (info->symbols + && info->symbols[0] + && (info->symbols[0]->flags & BSF_SYNTHETIC) + && addr == bfd_asymbol_value (info->symbols[0]) + 8) + return TRUE; + + return FALSE; +} + static int print_insn_mode (const char *d, int size, @@ -412,6 +431,18 @@ print_insn_vax (bfd_vma memaddr, disasse return 2; } + /* Decode PLT entry offset longword. */ + if (is_plt_tail (info, memaddr)) + { + int offset; + + FETCH_DATA (info, buffer + 4); + offset = buffer[3] << 24 | buffer[2] << 16 | buffer[1] << 8 | buffer[0]; + (*info->fprintf_func) (info->stream, ".long 0x%08x", offset); + + return 4; + } + for (votp = &votstrs[0]; votp->name[0]; votp++) { vax_opcodeT opcode = votp->detail.code; _______________________________________________ Linux-Vax mailing list Linux-Vax(a)mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax

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[LV] [PATCH] VAX/ELF: Store all call-saved registers upon PLT stub entry
by Maciej W. Rozycki 16 Jun '09

16 Jun '09

Hello, For the VAX processor the list of registers to be preserved across procedure calls is specified by the 16-bit word at the entry point, called the entry mask. That word is interpreted by the procedure call instruction and the registers requested are stored on the stack together with a copy of the entry mask before control is transferred. Later on, this data is used by the return instruction to restore the registers previously saved. This poses a problem with PLT stubs used for lazy run-time resolving. The stubs are called as if they were actual procedures, so they have to provide information about which registers to store. That information is not available at the static link time as PLT entries are normally only created for global symbol references to shared objects and such symbols, even if available from the same binary, are subject to preemption. Therefore this information has to be orchestrated somehow. I could see two possible solutions: 1. Either to create a fake mask to include the call-saved registers the lazy resolver actually clobbers. This approach has a potential advantage of not requiring unnecessary stack transfers. Unfortunately the advantage is quickly flushed down the drain as the piece of code called by the PLT stub has to recreate the stack frame manually by retrieving the mask from the address to be called once it has been resolved, determining which registers have to be saved, copying part of the stack frame already created down the stack, inserting the extra registers and updating the mask stored on the stack. 2. Always save all the call-saved registers. This has a potential performance disadvantage, but I believe it to be negligible as the area near the stack pointer is typically hot in the cache and the lazy resolver is only called at most once per function per program execution. The advantage is simplicity. All the stores are done by the call instruction, which has been designed (and undoubtedly optimised) for this kind of operation. There is no need to do fragile fiddling with the stack in the lazy resolver and on average the actual performance may not be worse at all. The difference is going to be lost in the lazy resolver's overhead anyway. The current approach in BFD seems to be #1 above and I would like to get it changed to the #2. Given the issues with the VAX/ELF backend I'm not sure if the PLT stubs have already been used in actual software, raising binary compatibility concerns. If so, I would limit this change to Linux (regrettably creating an incompatible ELF flavour), otherwise I suggest it to be applied universally. While the standard VAX ABI only defines <R11:R6> as call-saved, the mask I chose includes <R5:R2> too due to the -fcall-saved-REG GCC option -- the information about which registers are consider call-saved is not carried along binaries. OTOH, <R1:R0> are skipped as they are result registers and must never be saved across calls. bfd/ 2009-06-04 Maciej W. Rozycki <macro(a)linux-mips.org> * elf32-vax.c (elf_vax_plt_entry): Set the entry mask to include <R11:R2>. Comments? Maciej binutils-2.19.1-vax-plt-mask.patch diff -up --recursive --new-file binutils-2.19.1.macro/bfd/elf32-vax.c binutils-2.19.1/bfd/elf32-vax.c --- binutils-2.19.1.macro/bfd/elf32-vax.c 2008-01-11 09:07:03.000000000 +0000 +++ binutils-2.19.1/bfd/elf32-vax.c 2009-04-20 20:11:20.000000000 +0000 @@ -368,7 +368,7 @@ static const bfd_byte elf_vax_plt0_entry static const bfd_byte elf_vax_plt_entry[PLT_ENTRY_SIZE] = { - 0x40, 0x00, /* .word ^M<r6> */ + 0xfc, 0x0f, /* .word ^M<r11:r2> */ 0x16, 0xef, /* jsb L^(pc) */ 0, 0, 0, 0, /* replaced with offset to start of .plt */ 0, 0, 0, 0, /* index into .rela.plt */ _______________________________________________ Linux-Vax mailing list Linux-Vax(a)mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax

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[LV] [PATCH] VAX/ELF: Provide correct relocation classes
by Maciej W. Rozycki 15 Jun '09

15 Jun '09

Hello, Class annotation for VAX relocations is missing. Here's an obvious fix. Regression-tested successfully with the vax-linux target. 2009-06-04 Maciej W. Rozycki <macro(a)linux-mips.org> * elf32-vax.c (elf_vax_reloc_type_class): New function. (elf_backend_reloc_type_class): Define. OK to apply? Maciej binutils-2.19.1-vax-reloc-class.patch diff -up --recursive --new-file binutils-2.19.1.macro/bfd/elf32-vax.c binutils-2.19.1/bfd/elf32-vax.c --- binutils-2.19.1.macro/bfd/elf32-vax.c 2008-01-11 09:07:03.000000000 +0000 +++ binutils-2.19.1/bfd/elf32-vax.c 2009-05-05 05:35:06.000000000 +0000 @@ -2068,6 +2068,22 @@ elf_vax_finish_dynamic_sections (bfd *ou return TRUE; } +static enum elf_reloc_type_class +elf_vax_reloc_type_class (const Elf_Internal_Rela *rela) +{ + switch ((int) ELF32_R_TYPE (rela->r_info)) + { + case R_VAX_RELATIVE: + return reloc_class_relative; + case R_VAX_JMP_SLOT: + return reloc_class_plt; + case R_VAX_COPY: + return reloc_class_copy; + default: + return reloc_class_normal; + } +} + #define TARGET_LITTLE_SYM bfd_elf32_vax_vec #define TARGET_LITTLE_NAME "elf32-vax" #define ELF_MACHINE_CODE EM_VAX @@ -2090,6 +2106,7 @@ elf_vax_finish_dynamic_sections (bfd *ou elf_vax_finish_dynamic_symbol #define elf_backend_finish_dynamic_sections \ elf_vax_finish_dynamic_sections +#define elf_backend_reloc_type_class elf_vax_reloc_type_class #define elf_backend_gc_mark_hook elf_vax_gc_mark_hook #define elf_backend_gc_sweep_hook elf_vax_gc_sweep_hook #define bfd_elf32_bfd_merge_private_bfd_data \ _______________________________________________ Linux-Vax mailing list Linux-Vax(a)mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax

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[LV] [PATCH] VAX/ELF: Correctly handle R_VAX_PC32 relocs in executables
by Maciej W. Rozycki 15 Jun '09

15 Jun '09

Hello, Non-PIC executables still need to create PLT entries if the static link determines the function called comes from a shared library. In this case the associated R_VAX_PC32 relocation has to be treated as if it was a R_VAX_PLT32 one. This is similar to how other platforms handle the scenario. Regression-tested successfully with the vax-linux target; running dynamically-linked `bash' on the target system (about the best native testing possible atm) revealed no problems either. bfd/ 2009-06-04 Maciej W. Rozycki <macro(a)linux-mips.org> * elf32-vax.c (elf_vax_relocate_section): For symbol references from an executable to a shared library treat R_VAX_PC32 relocations as R_VAX_PLT32 ones. OK to apply? Maciej binutils-2.19.51-20090531-vax-pcplt.patch diff -up --recursive --new-file binutils-2.19.51-20090531.macro/bfd/elf32-vax.c binutils-2.19.51-20090531/bfd/elf32-vax.c --- binutils-2.19.51-20090531.macro/bfd/elf32-vax.c 2009-06-01 23:23:15.000000000 +0000 +++ binutils-2.19.51-20090531/bfd/elf32-vax.c 2009-06-01 23:29:01.000000000 +0000 @@ -1534,6 +1534,14 @@ elf_vax_relocate_section (bfd *output_bf } break; + case R_VAX_PC32: + /* If we are creating an executable and the function this + reloc refers to is in a shared lib, then we made a PLT + entry for this symbol and need to handle the reloc like + a PLT reloc. */ + if (info->shared) + goto r_vax_pc32_shared; + /* Fall through. */ case R_VAX_PLT32: /* Relocation is to the entry for this symbol in the procedure linkage table. */ @@ -1595,7 +1603,7 @@ elf_vax_relocate_section (bfd *output_bf case R_VAX_PC8: case R_VAX_PC16: - case R_VAX_PC32: + r_vax_pc32_shared: if (h == NULL || ELF_ST_VISIBILITY (h->other) != STV_DEFAULT || h->forced_local) _______________________________________________ Linux-Vax mailing list Linux-Vax(a)mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax

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[LV] [PATCH] VAX/ELF: Do not allocate GOT space for local symbols
by Maciej W. Rozycki 15 Jun '09

15 Jun '09

Hello, Here is a fix to exclude local symbols from GOT space calculation. These GOT entries would never be used anyway, because the VAX supports unlimited PC-relative addressing for all kinds of memory references. Regression-tested successfully with the vax-linux target; running dynamically-linked `bash' on the target system (about the best native testing possible atm) revealed no problems either. bfd/ 2009-06-04 Maciej W. Rozycki <macro(a)linux-mips.org> * elf32-vax.c (elf_vax_instantiate_got_entries): Skip local symbols in GOT space calculation. (elf_vax_relocate_section): Adjust accordingly. OK to apply? Maciej binutils-2.19.51-20090531-vax-got-rel.patch diff -up --recursive --new-file binutils-2.19.51-20090531.macro/bfd/elf32-vax.c binutils-2.19.51-20090531/bfd/elf32-vax.c --- binutils-2.19.51-20090531.macro/bfd/elf32-vax.c 2009-04-02 04:25:18.000000000 +0000 +++ binutils-2.19.51-20090531/bfd/elf32-vax.c 2009-06-03 02:19:19.000000000 +0000 @@ -1322,6 +1322,8 @@ elf_vax_instantiate_got_entries (struct } else if (h->got.refcount > 0) { + bfd_boolean dyn; + /* Make sure this symbol is output as a dynamic symbol. */ if (h->dynindx == -1) { @@ -1329,9 +1331,15 @@ elf_vax_instantiate_got_entries (struct return FALSE; } + dyn = elf_hash_table (info)->dynamic_sections_created; /* Allocate space in the .got and .rela.got sections. */ - sgot->size += 4; - srelgot->size += sizeof (Elf32_External_Rela); + if (ELF_ST_VISIBILITY (h->other) == STV_DEFAULT + && (info->shared + || WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, 0, h))) + { + sgot->size += 4; + srelgot->size += sizeof (Elf32_External_Rela); + } } return TRUE; @@ -1472,6 +1480,7 @@ elf_vax_relocate_section (bfd *output_bf the global offset table. */ { + bfd_boolean dyn; bfd_vma off; if (sgot == NULL) @@ -1485,9 +1494,10 @@ elf_vax_relocate_section (bfd *output_bf BFD_ASSERT (off != (bfd_vma) -1); BFD_ASSERT (off < sgot->size); - if (info->shared - && h->dynindx == -1 - && h->def_regular) + dyn = elf_hash_table (info)->dynamic_sections_created; + if (! WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, info->shared, h) + || (info->shared + && SYMBOL_REFERENCES_LOCAL (info, h))) { /* The symbol was forced to be local because of a version file.. We must initialize _______________________________________________ Linux-Vax mailing list Linux-Vax(a)mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax

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[LV] [PATCH] VAX/ELF: Symbol visibility support
by Maciej W. Rozycki 15 Jun '09

15 Jun '09

Hello, This is a patch to add symbol visibility support to the VAX/ELF backend. Changes include attribute recognition in BFD so that GOT or PLT entries are not created as expected (unlimited PC-relative addressing is supported by VAX for all kinds of memory references, so there is no need for run-time relocation of local symbols) as well as a fix to GAS so as to permit indirect symbol references which inevitably will be generated for some hidden symbols by GCC. Any errors resulting from the inability to route indirect references via the GOT -- which may happen for handcoded assembly only -- are already reported by the linker as they should be. Regression-tested successfully with the vax-linux target; running dynamically-linked `bash' on the target system (about the best native testing possible atm) revealed no problems either. bfd/ 2009-06-04 Maciej W. Rozycki <macro(a)linux-mips.org> * elf32-vax.c (elf_vax_check_relocs): Handle the visibility attribute. (elf_vax_relocate_section): Likewise. gas/ 2009-06-04 Maciej W. Rozycki <macro(a)linux-mips.org> * config/tc-vax.c (md_estimate_size_before_relax): Accept indirect symbol references in the PIC mode and emit a PC-relative relocation instead of a GOT/PLT one. Likewise for symbols known to be hidden at this point. OK to apply? Maciej binutils-2.19.51-20090531-vax-elf-visibility.patch diff -up --recursive --new-file binutils-2.19.51-20090531.macro/bfd/elf32-vax.c binutils-2.19.51-20090531/bfd/elf32-vax.c --- binutils-2.19.51-20090531.macro/bfd/elf32-vax.c 2009-04-02 04:25:18.000000000 +0000 +++ binutils-2.19.51-20090531/bfd/elf32-vax.c 2009-06-01 23:23:15.000000000 +0000 @@ -605,6 +605,11 @@ elf_vax_check_relocs (bfd *abfd, struct || h == elf_hash_table (info)->hplt) break; + /* If this is a local symbol, we resolve it directly without + creating a global offset table entry. */ + if (h == NULL || ELF_ST_VISIBILITY (h->other) != STV_DEFAULT) + break; + /* This symbol requires a global offset table entry. */ if (dynobj == NULL) @@ -677,7 +682,7 @@ elf_vax_check_relocs (bfd *abfd, struct /* If this is a local symbol, we resolve it directly without creating a procedure linkage table entry. */ BFD_ASSERT (h != NULL); - if (h->forced_local) + if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT || h->forced_local) break; h->needs_plt = 1; @@ -706,7 +711,9 @@ elf_vax_check_relocs (bfd *abfd, struct && (!info->symbolic || !h->def_regular))) { - if (h != NULL && !h->forced_local) + if (h != NULL + && ELF_ST_VISIBILITY (h->other) == STV_DEFAULT + && !h->forced_local) { /* Make sure a plt entry is created for this symbol if it turns out to be a function defined by a dynamic @@ -718,14 +725,17 @@ elf_vax_check_relocs (bfd *abfd, struct } break; } - if (h != NULL && h->forced_local) + /* If this is a local symbol, we can resolve it directly. */ + if (h != NULL + && (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT + || h->forced_local)) break; /* Fall through. */ case R_VAX_8: case R_VAX_16: case R_VAX_32: - if (h != NULL) + if (h != NULL && ELF_ST_VISIBILITY (h->other) == STV_DEFAULT) { /* Make sure a plt entry is created for this symbol if it turns out to be a function defined by a dynamic object. */ @@ -1465,7 +1475,10 @@ elf_vax_relocate_section (bfd *output_bf case R_VAX_GOT32: /* Relocation is to the address of the entry for this symbol in the global offset table. */ - if (h == NULL || h->got.offset == (bfd_vma) -1 || h->forced_local) + if (h == NULL + || ELF_ST_VISIBILITY (h->other) != STV_DEFAULT + || h->got.offset == (bfd_vma) -1 + || h->forced_local) break; /* Relocation is the offset of the entry for this symbol in @@ -1527,7 +1540,9 @@ elf_vax_relocate_section (bfd *output_bf /* Resolve a PLTxx reloc against a local symbol directly, without using the procedure linkage table. */ - if (h == NULL || h->forced_local) + if (h == NULL + || ELF_ST_VISIBILITY (h->other) != STV_DEFAULT + || h->forced_local) break; if (h->plt.offset == (bfd_vma) -1 @@ -1581,7 +1596,9 @@ elf_vax_relocate_section (bfd *output_bf case R_VAX_PC8: case R_VAX_PC16: case R_VAX_PC32: - if (h == NULL || h->forced_local) + if (h == NULL + || ELF_ST_VISIBILITY (h->other) != STV_DEFAULT + || h->forced_local) break; /* Fall through. */ case R_VAX_8: diff -up --recursive --new-file binutils-2.19.51-20090531.macro/gas/config/tc-vax.c binutils-2.19.51-20090531/gas/config/tc-vax.c --- binutils-2.19.51-20090531.macro/gas/config/tc-vax.c 2009-04-02 04:25:28.000000000 +0000 +++ binutils-2.19.51-20090531/gas/config/tc-vax.c 2009-06-01 23:23:15.000000000 +0000 @@ -396,23 +396,20 @@ md_estimate_size_before_relax (fragS *fr || S_IS_WEAK (fragP->fr_symbol) || S_IS_EXTERNAL (fragP->fr_symbol))) { - if (p[0] & 0x10) - { - if (flag_want_pic) - as_fatal ("PIC reference to %s is indirect.\n", - S_GET_NAME (fragP->fr_symbol)); - } + /* Indirect references cannot go through the GOT or PLT, + let's hope they'll become local in the final link. */ + if ((ELF_ST_VISIBILITY (S_GET_OTHER (fragP->fr_symbol)) + != STV_DEFAULT) + || (p[0] & 0x10)) + reloc_type = BFD_RELOC_32_PCREL; + else if (((unsigned char *) fragP->fr_opcode)[0] == VAX_CALLS + || ((unsigned char *) fragP->fr_opcode)[0] == VAX_CALLG + || ((unsigned char *) fragP->fr_opcode)[0] == VAX_JSB + || ((unsigned char *) fragP->fr_opcode)[0] == VAX_JMP + || S_IS_FUNCTION (fragP->fr_symbol)) + reloc_type = BFD_RELOC_32_PLT_PCREL; else - { - if (((unsigned char *) fragP->fr_opcode)[0] == VAX_CALLS - || ((unsigned char *) fragP->fr_opcode)[0] == VAX_CALLG - || ((unsigned char *) fragP->fr_opcode)[0] == VAX_JSB - || ((unsigned char *) fragP->fr_opcode)[0] == VAX_JMP - || S_IS_FUNCTION (fragP->fr_symbol)) - reloc_type = BFD_RELOC_32_PLT_PCREL; - else - reloc_type = BFD_RELOC_32_GOT_PCREL; - } + reloc_type = BFD_RELOC_32_GOT_PCREL; } #endif switch (RELAX_STATE (fragP->fr_subtype)) _______________________________________________ Linux-Vax mailing list Linux-Vax(a)mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax

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[LV] [PATCH] Rework IPL arrangement with interrupts
by Maciej W. Rozycki 14 Jun '09

14 Jun '09

We've got a problem with how the IPL is set in hardirqs. All handlers are run with IPL set to 31, i.e. with all the interrupts masked, which makes interrupt latencies unacceptable. This rework addresses the problem by carefully managing the IPL in the handlers. This is loosely based on an approach taken for one of the Alpha platforms where a silicon erratum prevents the usual mask-and-ack approach from working. We are in a similar position as for most of our platforms we do not have an interrupt mask register and all the interrupt scheduling is based on the IPL. The basic idea is to make interrupt masking to set the IPL to the max and interrupt unmasking to the original IPL of the handler. The latter is saved ASAP upon entry and further interrupts are masked like for other platforms. Later on interrupts may be unmasked based on the absence of the IRQF_DISABLED flag at the time the corresponding handler had been installed. To prevent looping because of the original interrupt request still being asserted the IPL must not be lowered below the original value. Once the handler has run interrupts are masked again. At this point the interrupt source has been acked by the driver so it is safe to lower the IPL so as to permit all the hardware interrupts. Therefore the saved IPL is set appropriately -- I have chosen the highest software interrupt setting so that actual software interrupts, if we want to use them at one point in the future, work as expected. If any softirqs are run at this stage, they will unmask hardware interrupts the usual way and per IPL setting let all of them come. Finally, at the conclusion of the interrupt handler the saved IPL is replaced with one to become in effect after the REI instruction has restored the previous state. The exception handler has been adjusted accordingly. Signed-off-by: Maciej W. Rozycki <macro(a)linux-mips.org> --- Comments are welcome. I'll think yet about unhandled_exception() and machine_check_handler() -- these probably just need to run at max IPL throughout. Jan-Benedict, what's your status on the tree update? If the patch needs an update, I'll be happy to make it fit into your current tree; otherwise please apply. We might think about switching to generic hardirq handlers at some point too; I will need to get a better understanding of how our IRQ probes work before I feel ready to work on it though. Maciej patch-mips-2.6.18-20060920-vax-irq-3 Index: linux-mips-2.6.18-20060920-cougar/arch/vax/kernel/entry.S =================================================================== --- linux-mips-2.6.18-20060920-cougar.orig/arch/vax/kernel/entry.S +++ linux-mips-2.6.18-20060920-cougar/arch/vax/kernel/entry.S @@ -4,6 +4,7 @@ * Copyright 2000, Kenn Humborg <kenn(a)linux.ie> * 2001 atp. Additions for Machine check handling. * Copyright 2004, 2005 Jan-Benedict Glaw <jbglaw(a)lug-owl.de> + * Copyright (c) 2009 Maciej W. Rozycki */ #include <linux/sys.h> @@ -50,6 +51,10 @@ ENTRY(irqvec_handler) * irqvector structure (at our "return address") */ + /* Save current IPL for interrupt unmasking and mask interrupts. */ + mfpr $PR_IPL, __min_ipl + mtpr $31, $PR_IPL + pushl %r0 /* Push R0 to have a free working register */ /* @@ -196,10 +201,13 @@ ret_from_syscall: * +8 saved PSL */ - /* Restore R0 and dismiss exception */ - movl (%sp)+, %r0 + movl (%sp)+, %r0 /* Restore R0. */ + + /* Retrieve previous IPL from saved PSL for interrupt unmasking. */ mtpr $31, $PR_IPL - rei + extzv $16, $5, 4(%sp), __min_ipl + + rei /* That's it! */ ENTRY(ret_from_fork) Index: linux-mips-2.6.18-20060920-cougar/arch/vax/kernel/interrupt.c =================================================================== --- linux-mips-2.6.18-20060920-cougar.orig/arch/vax/kernel/interrupt.c +++ linux-mips-2.6.18-20060920-cougar/arch/vax/kernel/interrupt.c @@ -5,9 +5,11 @@ * need to be a separate interrupt stack per-cpu, within the * per-cpu data structures. * + * Copyright (c) 2009 Maciej W. Rozycki + * * FIXME: We should use the new interrupt architecture. It looks like * a closer match to the VAX SCB. -*/ + */ #include <linux/types.h> #include <linux/errno.h> @@ -53,6 +55,13 @@ static struct stray_handler stray_handle /* Non-zero when autoprobing interrupt vectors */ static int autoprobing; +/* + * Minimum IPL during interrupt processing. Values other than the + * current IPL may be written only while interrupts are disabled + * (IPL set to MAX). For SMP this will have to be defined per CPU. + */ +int __min_ipl; + void guard_int_stack(void) { @@ -414,41 +423,40 @@ static inline void dispatch_irq(struct p vec_num = vec->vec_num; kstat_cpu(smp_processor_id()).irqs[vec_num]++; + + if (!(action->flags & IRQF_DISABLED)) + local_irq_enable(); + action->handler(vec_num, action->dev_id, regs); - if (action->flags & SA_SAMPLE_RANDOM) + if (action->flags & IRQF_SAMPLE_RANDOM) add_interrupt_randomness(vec_num); + + local_irq_disable(); } /* - * This is called once we know that an interrupt or exception is actually - * an interrupt. + * Call the appropriate hardirq handler. Once all the hardirq processing + * has been done adjust the IPL saved for interrupt unmasking suitably for + * softirq handling. We could actually send ourselves a software interrupt + * instead, which would be taken straight away once we have got back to the + * process level, but that would only incur unnecessary overhead with no + * gain in return. */ static inline void do_irq(struct pt_regs *regs, struct irqvector *vec) { - int flags; - - /* Fake a single-priority-level interrupt system by raising IPL - to 31 for _any_ interrupt. This is such a waste of the VAX's - hardware capabilities... */ - irq_enter(); - - local_irq_save(flags); - dispatch_irq(regs, vec); + __min_ipl = IPL_SWF; irq_exit(); - - local_irq_restore(flags); - - if (local_softirq_pending()) - do_softirq(); } static inline void do_exception(struct pt_regs *regs, struct irqvector *vec, void *excep_info) { kstat_cpu(smp_processor_id()).irqs[vec->vec_num]++; + local_irq_enable(); vec->excep_handler(regs, excep_info); + local_irq_disable(); } /* Index: linux-mips-2.6.18-20060920-cougar/arch/vax/kernel/time.c =================================================================== --- linux-mips-2.6.18-20060920-cougar.orig/arch/vax/kernel/time.c +++ linux-mips-2.6.18-20060920-cougar/arch/vax/kernel/time.c @@ -2,6 +2,7 @@ * Copyright (C) 1995 Linus Torvalds * VAX port copyright atp 1998. * (C) 2000 Erik Mouw <J.A.K.Mouw(a)its.tudelft.nl> + * Copyright (c) 2009 Maciej W. Rozycki * * 22-oct-2000: Erik Mouw * Added some simple do_gettimeofday() and do_settimeofday() @@ -59,7 +60,8 @@ void __init time_init(void) wall_to_monotonic.tv_sec = -xtime.tv_sec; wall_to_monotonic.tv_nsec = -xtime.tv_nsec; - if (request_irq(0x30, do_timer_interrupt, 0, "timer", NULL)) { + if (request_irq(0x30, do_timer_interrupt, IRQF_DISABLED, + "timer", NULL)) { printk("Panic: unable to register timer interrupt handler\n"); HALT; } Index: linux-mips-2.6.18-20060920-cougar/include/asm-vax/system.h =================================================================== --- linux-mips-2.6.18-20060920-cougar.orig/include/asm-vax/system.h +++ linux-mips-2.6.18-20060920-cougar/include/asm-vax/system.h @@ -1,3 +1,6 @@ +/* + * Copyright (c) 2009 Maciej W. Rozycki + */ #ifndef _VAX_SYSTEM_H #define _VAX_SYSTEM_H @@ -77,6 +80,42 @@ struct task_struct *__switch_to(struct t #define smp_rmb() rmb() #define smp_wmb() wmb() + +#define IPL_USR 0 +#define IPL_SW1 1 +#define IPL_SW2 2 +#define IPL_SW3 3 +#define IPL_SW4 4 +#define IPL_SW5 5 +#define IPL_SW6 6 +#define IPL_SW7 7 +#define IPL_SW8 8 +#define IPL_SW9 9 +#define IPL_SWA 10 +#define IPL_SWB 11 +#define IPL_SWC 12 +#define IPL_SWD 13 +#define IPL_SWE 14 +#define IPL_SWF 15 +#define IPL_DEV0 16 +#define IPL_DEV1 17 +#define IPL_DEV2 18 +#define IPL_DEV3 19 +#define IPL_DEV4 20 +#define IPL_DEV5 21 +#define IPL_DEV6 22 +#define IPL_DEV7 23 +#define IPL_ERR0 24 +#define IPL_ERR1 25 +#define IPL_ERR2 26 +#define IPL_ERR3 27 +#define IPL_ERR4 28 +#define IPL_ERR5 29 +#define IPL_POWERFAIL 30 +#define IPL_MAX 31 + +extern int __min_ipl; + #define getipl() __mfpr(PR_IPL) #define setipl(ipl) __mtpr(ipl, PR_IPL) @@ -97,32 +136,14 @@ struct task_struct *__switch_to(struct t __r0; \ }) -#define local_save_flags(flags) ((flags) = getipl()) -#define local_irq_save(flags) ((flags) = swpipl(31)) -#define local_irq_restore(flags) setipl(flags) -#define local_irq_disable() setipl(31) - -#define irqs_disabled() (__psl.ipl == 31) - -/* If we're handling an interrupt (i.e. the IS bit is set in the - PSL and we're on the interrupt stack), then we must not enable - interrupts by dropping IPL all the way to 0. If we do, and - another interrupt comes in, then this second interrupt will - be handled normally, but will REI to a PSL with IS set and - an IPL of 0, which REI doesn't like at all. +#define local_irq_disable() setipl(IPL_MAX) +#define local_irq_enable() setipl(__min_ipl) - So, instead, we drop IPL to 1 if we're running on the interrupt - stack, thus making sure that REI will be kept happy. */ +#define local_save_flags(flags) do { (flags) = getipl(); } while (0) +#define local_irq_save(flags) do { (flags) = swpipl(IPL_MAX); } while (0) +#define local_irq_restore(flags) setipl(flags) -extern __inline__ void -local_irq_enable(void) -{ - if (__psl.is) { - setipl(1); - } else { - setipl(0); - } -} +#define irqs_disabled() (getipl() == IPL_MAX) #ifdef __SMP__ # error "SMP not supported" _______________________________________________ Linux-Vax mailing list Linux-Vax(a)mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax

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[LV] [PATCH] swpipl: Remove bogus R10 clobber
by Maciej W. Rozycki 14 Jun '09

14 Jun '09

There is no need to mark R10 as clobbered in swpipl(); the inline asm used does not touch the register. Signed-off-by: Maciej W. Rozycki <macro(a)linux-mips.org> --- Jan-Benedict, please apply. Maciej patch-mips-2.6.18-20060920-vax-swpipl-0 Index: linux-mips-2.6.18-20060920-cougar/include/asm-vax/system.h =================================================================== --- linux-mips-2.6.18-20060920-cougar.orig/include/asm-vax/system.h +++ linux-mips-2.6.18-20060920-cougar/include/asm-vax/system.h @@ -92,7 +92,7 @@ struct task_struct *__switch_to(struct t " mtpr %1, $0x12 #swpipl \n" \ : "=&r" (__r0) \ : "r" (ipl) \ - : "r10", "memory"); \ + : "memory"); \ \ __r0; \ }) _______________________________________________ Linux-Vax mailing list Linux-Vax(a)mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax

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