diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c index 28f142c1c6a..6fdd1f3a151 100644 --- a/gdb/windows-nat.c +++ b/gdb/windows-nat.c @@ -662,23 +662,19 @@ windows_fetch_one_register (struct regcache *regcache, gdb_assert (gdbarch_pc_regnum (gdbarch) >= 0); gdb_assert (!gdbarch_write_pc_p (gdbarch)); - if (r == I387_FISEG_REGNUM (tdep)) + /* GDB treats some registers as 32-bit, where they are in fact only + 16 bits long. These cases must be handled specially to avoid + reading extraneous bits from the context. */ + if (r == I387_FISEG_REGNUM (tdep) || windows_process.segment_register_p (r)) { - long l = *((long *) context_offset) & 0xffff; - regcache->raw_supply (r, (char *) &l); + gdb_byte bytes[4] = {}; + memcpy (bytes, context_offset, 2); + regcache->raw_supply (r, bytes); } else if (r == I387_FOP_REGNUM (tdep)) { long l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1); - regcache->raw_supply (r, (char *) &l); - } - else if (windows_process.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. */ - long l = *((long *) context_offset) & 0xffff; - regcache->raw_supply (r, (char *) &l); + regcache->raw_supply (r, &l); } else { @@ -799,7 +795,29 @@ windows_store_one_register (const struct regcache *regcache, context_ptr = (char *) &th->wow64_context; #endif - regcache->raw_collect (r, context_ptr + windows_process.mappings[r]); + struct gdbarch *gdbarch = regcache->arch (); + i386_gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); + + /* GDB treats some registers as 32-bit, where they are in fact only + 16 bits long. These cases must be handled specially to avoid + overwriting other registers in the context. */ + if (r == I387_FISEG_REGNUM (tdep) || windows_process.segment_register_p (r)) + { + gdb_byte bytes[4]; + regcache->raw_collect (r, bytes); + memcpy (context_ptr + windows_process.mappings[r], bytes, 2); + } + else if (r == I387_FOP_REGNUM (tdep)) + { + gdb_byte bytes[4]; + regcache->raw_collect (r, bytes); + /* The value of FOP occupies the top two bytes in the context, + so write the two low-order bytes from the cache into the + appropriate spot. */ + memcpy (context_ptr + windows_process.mappings[r] + 2, bytes, 2); + } + else + regcache->raw_collect (r, context_ptr + windows_process.mappings[r]); } /* Store a new register value into the context of the thread tied to diff --git a/gdbserver/win32-i386-low.cc b/gdbserver/win32-i386-low.cc index 783e61f6f33..44490300b69 100644 --- a/gdbserver/win32-i386-low.cc +++ b/gdbserver/win32-i386-low.cc @@ -32,8 +32,17 @@ using namespace windows_nat; #define CONTEXT_EXTENDED_REGISTERS 0 #endif -#define FCS_REGNUM 27 -#define FOP_REGNUM 31 +#define I386_FISEG_REGNUM 27 +#define I386_FOP_REGNUM 31 + +#define I386_CS_REGNUM 10 +#define I386_GS_REGNUM 15 + +#define AMD64_FISEG_REGNUM 35 +#define AMD64_FOP_REGNUM 39 + +#define AMD64_CS_REGNUM 18 +#define AMD64_GS_REGNUM 23 #define FLAG_TRACE_BIT 0x100 @@ -459,6 +468,42 @@ static const int amd64_mappings[] = #endif /* __x86_64__ */ +/* Return true if R is the FISEG register. */ +static bool +is_fiseg_register (int r) +{ +#ifdef __x86_64__ + if (!windows_process.wow64_process) + return r == AMD64_FISEG_REGNUM; + else +#endif + return r == I386_FISEG_REGNUM; +} + +/* Return true if R is the FOP register. */ +static bool +is_fop_register (int r) +{ +#ifdef __x86_64__ + if (!windows_process.wow64_process) + return r == AMD64_FOP_REGNUM; + else +#endif + return r == I386_FOP_REGNUM; +} + +/* Return true if R is a segment register. */ +static bool +is_segment_register (int r) +{ +#ifdef __x86_64__ + if (!windows_process.wow64_process) + return r >= AMD64_CS_REGNUM && r <= AMD64_GS_REGNUM; + else +#endif + return r >= I386_CS_REGNUM && r <= I386_GS_REGNUM; +} + /* Fetch register from gdbserver regcache data. */ static void i386_fetch_inferior_register (struct regcache *regcache, @@ -480,15 +525,18 @@ i386_fetch_inferior_register (struct regcache *regcache, #endif context_offset = (char *) &th->context + mappings[r]; - long l; - if (r == FCS_REGNUM) + /* GDB treats some registers as 32-bit, where they are in fact only + 16 bits long. These cases must be handled specially to avoid + reading extraneous bits from the context. */ + if (is_fiseg_register (r) || is_segment_register (r)) { - l = *((long *) context_offset) & 0xffff; - supply_register (regcache, r, (char *) &l); + gdb_byte bytes[4] = {}; + memcpy (bytes, context_offset, 2); + supply_register (regcache, r, bytes); } - else if (r == FOP_REGNUM) + else if (is_fop_register (r)) { - l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1); + long l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1); supply_register (regcache, r, (char *) &l); } else @@ -516,7 +564,26 @@ i386_store_inferior_register (struct regcache *regcache, #endif context_offset = (char *) &th->context + mappings[r]; - collect_register (regcache, r, context_offset); + /* GDB treats some registers as 32-bit, where they are in fact only + 16 bits long. These cases must be handled specially to avoid + overwriting other registers in the context. */ + if (is_fiseg_register (r) || is_segment_register (r)) + { + gdb_byte bytes[4]; + collect_register (regcache, r, bytes); + memcpy (context_offset, bytes, 2); + } + else if (is_fop_register (r)) + { + gdb_byte bytes[4]; + collect_register (regcache, r, bytes); + /* The value of FOP occupies the top two bytes in the context, + so write the two low-order bytes from the cache into the + appropriate spot. */ + memcpy (context_offset + 2, bytes, 2); + } + else + collect_register (regcache, r, context_offset); } static const unsigned char i386_win32_breakpoint = 0xcc;