From cc2c4da8813b980a4e68272bb43583f4af6fe89c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marcin=20Ko=C5=9Bcielnicki?= Date: Sun, 6 Mar 2016 16:38:52 +0100 Subject: [PATCH] gdb/rs6000: Read backchain as unsigned. Previously, backchain was read as a signed quantity, resulting in addresses like 0xfffffffffffeded0 instead of 0xfffeded0 returned by unwinder on 32-bit powerpc. While normally such addresses are masked off, this causes problems for tracepoints, since 0xfffffffffffeded0 is considered unavailable. Fixes a test failure in gdb.trace/entry-values.exp. gdb/ChangeLog: * corefile.c (safe_read_memory_unsigned_integer): New function. * gdbcore.h (safe_read_memory_unsigned_integer): New prototype. * rs6000-tdep.c (rs6000_frame_cache): Read backchain as unsigned. --- gdb/ChangeLog | 6 ++++++ gdb/corefile.c | 18 ++++++++++++++++++ gdb/gdbcore.h | 3 +++ gdb/rs6000-tdep.c | 6 +++--- 4 files changed, 30 insertions(+), 3 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 74dec87054..83eef37474 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2016-03-09 Marcin Kościelnicki + + * corefile.c (safe_read_memory_unsigned_integer): New function. + * gdbcore.h (safe_read_memory_unsigned_integer): New prototype. + * rs6000-tdep.c (rs6000_frame_cache): Read backchain as unsigned. + 2016-03-09 Marcin Kościelnicki * rs6000-tdep.c: Add "ax.h" and "ax-gdb.h" includes. diff --git a/gdb/corefile.c b/gdb/corefile.c index dbdbafc41f..5ad4d40ec6 100644 --- a/gdb/corefile.c +++ b/gdb/corefile.c @@ -306,6 +306,24 @@ safe_read_memory_integer (CORE_ADDR memaddr, int len, return 1; } +/* Read memory at MEMADDR of length LEN and put the contents in + RETURN_VALUE. Return 0 if MEMADDR couldn't be read and non-zero + if successful. */ + +int +safe_read_memory_unsigned_integer (CORE_ADDR memaddr, int len, + enum bfd_endian byte_order, + ULONGEST *return_value) +{ + gdb_byte buf[sizeof (ULONGEST)]; + + if (target_read_memory (memaddr, buf, len)) + return 0; + + *return_value = extract_unsigned_integer (buf, len, byte_order); + return 1; +} + LONGEST read_memory_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order) diff --git a/gdb/gdbcore.h b/gdb/gdbcore.h index 5db80e56a1..8b101bcabe 100644 --- a/gdb/gdbcore.h +++ b/gdb/gdbcore.h @@ -76,6 +76,9 @@ extern int safe_read_memory_integer (CORE_ADDR memaddr, int len, extern ULONGEST read_memory_unsigned_integer (CORE_ADDR memaddr, int len, enum bfd_endian byte_order); +extern int safe_read_memory_unsigned_integer (CORE_ADDR memaddr, int len, + enum bfd_endian byte_order, + ULONGEST *return_value); /* Read an integer from debugged code memory, given address, number of bytes, and byte order for code. */ diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c index 565c6201bc..2460eb5b8d 100644 --- a/gdb/rs6000-tdep.c +++ b/gdb/rs6000-tdep.c @@ -3336,10 +3336,10 @@ rs6000_frame_cache (struct frame_info *this_frame, void **this_cache) if (!fdata.frameless) { /* Frameless really means stackless. */ - LONGEST backchain; + ULONGEST backchain; - if (safe_read_memory_integer (cache->base, wordsize, - byte_order, &backchain)) + if (safe_read_memory_unsigned_integer (cache->base, wordsize, + byte_order, &backchain)) cache->base = (CORE_ADDR) backchain; }