From d40dc7a8d850464cac07725c257f662e81f894a4 Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Fri, 4 May 2012 18:36:30 +0000 Subject: [PATCH] Segment register reading on Windows targets. This patch makes sure that the value of segment registers are read properly as 16bit values on Windows. gdb/ChangeLog: * windows-nat.h (segment_register_p_ftype): New typedef. (windows_set_segment_register_p): Add declaration. * windows-nat.c (segment_register_p): New static global. (windows_set_segment_register_p): New function. (do_windows_fetch_inferior_registers): Add special handling for segment registers. * amd64-windows-nat.c: #include "amd64-tdep.h". (amd64_windows_segment_register_p): New function. (_initialize_amd64_windows_nat): Call windows_set_segment_register_p. * i386-windows-nat.c: #include "i386-tdep.h". (i386_windows_segment_register_p): New function. (_initialize_i386_windows_nat): Call windows_set_segment_register_p. --- gdb/ChangeLog | 15 +++++++++++++++ gdb/amd64-windows-nat.c | 11 +++++++++++ gdb/i386-windows-nat.c | 10 ++++++++++ gdb/windows-nat.c | 20 ++++++++++++++++++++ gdb/windows-nat.h | 8 ++++++++ 5 files changed, 64 insertions(+) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index a073454d0e..5e63549049 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,18 @@ +2012-05-04 Joel Brobecker + + * windows-nat.h (segment_register_p_ftype): New typedef. + (windows_set_segment_register_p): Add declaration. + * windows-nat.c (segment_register_p): New static global. + (windows_set_segment_register_p): New function. + (do_windows_fetch_inferior_registers): Add special handling + for segment registers. + * amd64-windows-nat.c: #include "amd64-tdep.h". + (amd64_windows_segment_register_p): New function. + (_initialize_amd64_windows_nat): Call windows_set_segment_register_p. + * i386-windows-nat.c: #include "i386-tdep.h". + (i386_windows_segment_register_p): New function. + (_initialize_i386_windows_nat): Call windows_set_segment_register_p. + 2012-05-04 Tristan Gingold * printcmd.c (set_command): Emit a warning if the expression is not diff --git a/gdb/amd64-windows-nat.c b/gdb/amd64-windows-nat.c index bc2c0475eb..e5fb0e0031 100644 --- a/gdb/amd64-windows-nat.c +++ b/gdb/amd64-windows-nat.c @@ -18,6 +18,8 @@ #include "defs.h" #include "windows-nat.h" #include "i386-nat.h" +#include "amd64-tdep.h" + #include #define context_offset(x) (offsetof (CONTEXT, x)) @@ -85,6 +87,14 @@ static const int mappings[] = }; #undef context_offset +/* segment_register_p_ftype implementation for amd64. */ + +static int +amd64_windows_segment_register_p (int regnum) +{ + return regnum >= AMD64_CS_REGNUM && regnum <= AMD64_GS_REGNUM; +} + /* -Wmissing-prototypes */ extern initialize_file_ftype _initialize_amd64_windows_nat; @@ -92,5 +102,6 @@ void _initialize_amd64_windows_nat (void) { windows_set_context_register_offsets (mappings); + windows_set_segment_register_p (amd64_windows_segment_register_p); i386_set_debug_register_length (8); } diff --git a/gdb/i386-windows-nat.c b/gdb/i386-windows-nat.c index 5d93915a72..0928c9fcc6 100644 --- a/gdb/i386-windows-nat.c +++ b/gdb/i386-windows-nat.c @@ -18,6 +18,7 @@ #include "defs.h" #include "windows-nat.h" #include "i386-nat.h" +#include "i386-tdep.h" #include @@ -70,6 +71,14 @@ static const int mappings[] = }; #undef context_offset +/* segment_register_p_ftype implementation for x86. */ + +static int +i386_windows_segment_register_p (int regnum) +{ + return regnum >= I386_CS_REGNUM && regnum <= I386_GS_REGNUM; +} + /* -Wmissing-prototypes */ extern initialize_file_ftype _initialize_i386_windows_nat; @@ -77,5 +86,6 @@ void _initialize_i386_windows_nat (void) { windows_set_context_register_offsets (mappings); + windows_set_segment_register_p (i386_windows_segment_register_p); i386_set_debug_register_length (4); } diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c index f536ed1ce9..000c86f5cc 100644 --- a/gdb/windows-nat.c +++ b/gdb/windows-nat.c @@ -243,6 +243,10 @@ static int useshell = 0; /* use shell for subprocesses */ static const int *mappings; +/* The function to use in order to determine whether a register is + a segment register or not. */ +static segment_register_p_ftype *segment_register_p; + /* This vector maps the target's idea of an exception (extracted from the DEBUG_EVENT structure) to GDB's idea. */ @@ -272,6 +276,14 @@ windows_set_context_register_offsets (const int *offsets) mappings = offsets; } +/* See windows-nat.h. */ + +void +windows_set_segment_register_p (segment_register_p_ftype *fun) +{ + segment_register_p = fun; +} + static void check (BOOL ok, const char *file, int line) { @@ -456,6 +468,14 @@ do_windows_fetch_inferior_registers (struct regcache *regcache, int r) l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1); regcache_raw_supply (regcache, r, (char *) &l); } + else if (segment_register_p (r)) + { + /* GDB treats segment registers as 32bit registers, but they are + in fact only 16 bits long. Make sure we do not read extra + bits from our source buffer. */ + l = *((long *) context_offset) & 0xffff; + regcache_raw_supply (regcache, r, (char *) &l); + } else if (r >= 0) regcache_raw_supply (regcache, r, context_offset); else diff --git a/gdb/windows-nat.h b/gdb/windows-nat.h index 08200b98ae..a6cc5ec676 100644 --- a/gdb/windows-nat.h +++ b/gdb/windows-nat.h @@ -20,5 +20,13 @@ extern void windows_set_context_register_offsets (const int *offsets); +/* A pointer to a function that should return non-zero iff REGNUM + corresponds to one of the segment registers. */ +typedef int (segment_register_p_ftype) (int regnum); + +/* Set the function that should be used by this module to determine + whether a given register is a segment register or not. */ +extern void windows_set_segment_register_p (segment_register_p_ftype *fun); + #endif -- 2.34.1