--- ./gdb/rs6000-tdep.h_orig 2018-08-26 12:58:08 +0000 +++ ./gdb/rs6000-tdep.h 2018-08-26 12:57:45 +0000 @@ -18,3 +18,21 @@ /* Minimum possible text address in AIX. */ #define AIX_TEXT_SEGMENT_BASE 0x10000000 +/* For sighandler */ + +/* STKMIN(minimum stack size) is 56 for 32-bit process + and iar offset under sc_jmpbuf.jmp_context is 40 under the sigconext structure. + ie offsetof(struct sigcontext, sc_jmpbuf.jmp_context.iar). + so PC offset in this case is STKIM+iar offset, which is 96 */ +#define SIG_FRAME_PC_OFFSET 96 +#define SIG_FRAME_LR_OFFSET 108 +/* STKMIN+grp1 offset, which is 56+228=284 */ +#define SIG_FRAME_FP_OFFSET 284 + +/* 64 bit process */ +/* STKMIN64 is 112 and iar offset is 312. So 112+312=424 */ +#define SIG_FRAME_PC_OFFSET64 424 +/* STKMIN64+grp1 offset. 112+56=168 */ +#define SIG_FRAME_FP_OFFSET64 168 + +#define EXT_CONTEXT64 452 --- ./gdb/rs6000-tdep.c_orig 2018-08-26 12:58:45 +0000 +++ ./gdb/rs6000-tdep.c 2018-08-26 13:04:19 +0000 @@ -61,6 +61,8 @@ #include "trad-frame.h" #include "frame-unwind.h" #include "frame-base.h" +#include "rs6000-tdep.h" +#include "xcoffread.h" #include "ax.h" #include "ax-gdb.h" @@ -3273,7 +3275,7 @@ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); struct rs6000_framedata fdata; int wordsize = tdep->wordsize; - CORE_ADDR func = 0, pc = 0; + CORE_ADDR func = 0, pc = 0, save_cache_base; if ((*this_cache) != NULL) return (struct rs6000_frame_cache *) (*this_cache); @@ -3298,6 +3300,7 @@ base address of this frame. */ cache->base = get_frame_register_unsigned (this_frame, gdbarch_sp_regnum (gdbarch)); + save_cache_base = cache->base; } CATCH (ex, RETURN_MASK_ERROR) { @@ -3347,6 +3350,39 @@ byte_order, &backchain)) cache->base = (CORE_ADDR) backchain; } + /* If frame is a AIX signal handler frame, we need to read the base + address from sigconext offset. Backchain at an offset 0 will be 0, so backchain + will be at an offset SIG_FRAME_FP_OFFSET(284)+8 for 32-bit applications. */ + if (!cache->base && !fdata.frameless) + { + CORE_ADDR backchain, sig_pc = 0, msr = 0, msr_chain; + + if (is64) { + if (safe_read_memory_integer (save_cache_base+16, wordsize, byte_order, &sig_pc) && + (sig_pc && (sig_pc < AIX_TEXT_SEGMENT_BASE))) { + /* Check if we have VMS/VXS extended context saved */ + if (safe_read_memory_integer (save_cache_base+EXT_CONTEXT64, 4, byte_order, &msr) && + (msr == 0x20000000)) { + if (safe_read_memory_integer (save_cache_base+SIG_FRAME_FP_OFFSET64, + wordsize, byte_order, &msr_chain)) + if (safe_read_memory_integer (msr_chain, wordsize, byte_order, &backchain)) + cache->base = (CORE_ADDR) backchain; + } else { + /* printf("In read stack sig previous\n"); */ + if (safe_read_memory_integer (save_cache_base+SIG_FRAME_FP_OFFSET64, + wordsize, byte_order, &backchain)) + cache->base = (CORE_ADDR) backchain; + /* printf("In read stack sig previous %lu\n", backchain); */ + } + } + } else { + if (safe_read_memory_integer (save_cache_base+8, wordsize, byte_order, &sig_pc) && + (sig_pc && (sig_pc < AIX_TEXT_SEGMENT_BASE))) + if (safe_read_memory_integer (save_cache_base+SIG_FRAME_FP_OFFSET+8, + wordsize, byte_order, &backchain)) + cache->base = (CORE_ADDR) backchain; + } + } trad_frame_set_value (cache->saved_regs, gdbarch_sp_regnum (gdbarch), cache->base); --- ./gdb/xcoffread.h_orig 2018-08-26 13:09:30 +0000 +++ ./gdb/xcoffread.h 2018-08-26 12:57:45 +0000 @@ -23,4 +23,6 @@ extern int xcoff_get_n_import_files (bfd *abfd); +extern int is64; + #endif /* xcoffread.h */ --- ./gdb/xcoffread.c_orig 2018-08-26 13:05:15 +0000 +++ ./gdb/xcoffread.c 2018-08-26 12:57:45 +0000 @@ -49,6 +49,8 @@ #include "gdb-stabs.h" +int is64; + /* For interface with stabsread.c. */ #include "aout/stab_gnu.h" @@ -1747,6 +1749,7 @@ { struct objfile *objfile = this_symtab_objfile; int xcoff64 = bfd_xcoff_is_xcoff64 (objfile->obfd); + is64 = xcoff64; struct coff_symfile_info *info = XCOFF_DATA (objfile); int nsyms = info->symtbl_num_syms; --- ./gdb/frame.c_orig 2018-08-26 13:06:21 +0000 +++ ./gdb/frame.c 2018-08-26 12:57:45 +0000 @@ -42,6 +42,10 @@ #include "tracepoint.h" #include "hashtab.h" #include "valprint.h" +#include "rs6000-tdep.h" +#include "xcoffread.h" + +CORE_ADDR aix_sig_millicode; /* The sentinel frame terminates the innermost end of the frame chain. If unwound, it returns the information needed to construct an @@ -787,7 +791,16 @@ comment in "frame.h", there is some fuzz here. Frameless functions are not strictly inner than (same .stack but different .code and/or .special address). */ - inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr); + + /* For xlc generated address and signal handler case, their can be cases where + stack address of l frame is less than r frame. + We may need to skip those cases for checking inner than. */ + if (aix_sig_millicode && (aix_sig_millicode < AIX_TEXT_SEGMENT_BASE)) { + inner = 0; + aix_sig_millicode = 0; + } + else + inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr); if (frame_debug) { fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l="); @@ -1282,6 +1295,7 @@ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); int size = register_size (gdbarch, regnum); struct value *value = frame_unwind_register_value (frame, regnum); + ULONGEST base_addr; gdb_assert (value != NULL); @@ -1298,7 +1312,38 @@ ULONGEST r = extract_unsigned_integer (value_contents_all (value), size, byte_order); - + /* Like to save the orignal pc value when handler is being called in AIX + When signal handler is being called pc value is actually the millicode address. */ + /* if pc is something like 0x46dc, 0x4a5c etc.. + Then it is most likekly the aix signal handler frame. + Read the pc from the signal handler frame at an offset 96+lr_offset. */ + if (r && (r < AIX_TEXT_SEGMENT_BASE)) { + aix_sig_millicode = r; + if (is64) { + if (frame_id_p(get_frame_id (frame)) == 0) { + base_addr = get_frame_register_unsigned (frame, gdbarch_sp_regnum (gdbarch)); + r = read_memory_unsigned_integer + (base_addr + SIG_FRAME_PC_OFFSET64, + size, byte_order); + } else { + r = read_memory_unsigned_integer + (get_frame_base (frame) + SIG_FRAME_PC_OFFSET64, + size, byte_order); + } + } + else { + if (frame_id_p(get_frame_id (frame)) == 0) { + base_addr = get_frame_register_unsigned (frame, gdbarch_sp_regnum (gdbarch)); + r = read_memory_unsigned_integer + (base_addr + SIG_FRAME_PC_OFFSET+8, + size, byte_order); + } else { + r = read_memory_unsigned_integer + (get_frame_base (frame) + SIG_FRAME_PC_OFFSET+8, + size, byte_order); + } + } + } release_value (value); value_free (value); return r;