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gdb-tdep-fix-avx512-m32-support-in-gdbserver.patch
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File gdb-tdep-fix-avx512-m32-support-in-gdbserver.patch of Package gdb
[gdb/tdep] Fix avx512 -m32 support in gdbserver PR27257 reports a problem that can be reproduced as follows: - use x86_64 machine with avx512 support - compile a hello world with -m32 to a.out - start a gdbserver session with a.out - use gdb to connect to the gdbserver session This makes us run into: ... Listening on port 2346 Remote debugging from host ::1, port 34940 src/gdbserver/regcache.cc:257: \ A problem internal to GDBserver has been detected. Unknown register zmm16h requested ... The problem is that i387_xsave_to_cache in gdbserver/i387-fp.cc can't find a register zmm16h in the register cache. To understand how this happens, first some background. SSE has 16 128-bit wide xmm registers. AVX extends the SSE registers set as follows: - it extends the 16 existing 128-bit wide xmm registers to 256-bit wide ymm registers. AVX512 extends the AVX register set as follows: - it extends the 16 existing 256-bit wide ymm registers to 512-bit wide zmm registers. - it adds 16 additional 512-bit wide zmm registers (with corresponding ymm and xmm subregisters added as well) However, in 32-bit mode, there are only 8 xmm/ymm/zmm registers. The problem we're running into is that gdbserver/i387-fp.cc uses these constants to describe the size of the register file: ... static const int num_avx512_zmmh_low_registers = 16; static const int num_avx512_zmmh_high_registers = 16; static const int num_avx512_ymmh_registers = 16; static const int num_avx512_xmm_registers = 16; ... which are all incorrect for the 32-bit case. Fix this by replacing the constants with variables that have the appropriate values in 64-bit and 32-bit mode. Tested on x86_64-linux with native and unix/-m32. --- gdbserver/i387-fp.cc | 50 +++++++++++++++++++++++++++++++++++++------------- 1 file changed, 37 insertions(+), 13 deletions(-) diff --git a/gdbserver/i387-fp.cc b/gdbserver/i387-fp.cc index 6d9b62ed8ce..9b07ded592d 100644 --- a/gdbserver/i387-fp.cc +++ b/gdbserver/i387-fp.cc @@ -23,10 +23,6 @@ static const int num_mpx_bnd_registers = 4; static const int num_mpx_cfg_registers = 2; static const int num_avx512_k_registers = 8; -static const int num_avx512_zmmh_low_registers = 16; -static const int num_avx512_zmmh_high_registers = 16; -static const int num_avx512_ymmh_registers = 16; -static const int num_avx512_xmm_registers = 16; static const int num_pkeys_registers = 1; /* Note: These functions preserve the reserved bits in control registers. @@ -256,14 +252,22 @@ void i387_cache_to_xsave (struct regcache *regcache, void *buf) { struct i387_xsave *fp = (struct i387_xsave *) buf; + bool amd64 = register_size (regcache->tdesc, 0) == 8; int i; unsigned long val, val2; unsigned long long xstate_bv = 0; unsigned long long clear_bv = 0; char raw[64]; char *p; + /* Amd64 has 16 xmm regs; I386 has 8 xmm regs. */ - int num_xmm_registers = register_size (regcache->tdesc, 0) == 8 ? 16 : 8; + int num_xmm_registers = amd64 ? 16 : 8; + /* AVX512 extends the existing xmm/ymm registers to a wider mode: zmm. */ + int num_avx512_zmmh_low_registers = num_xmm_registers; + /* AVX512 adds 16 extra regs in Amd64 mode, but none in I386 mode.*/ + int num_avx512_zmmh_high_registers = amd64 ? 16 : 0; + int num_avx512_ymmh_registers = amd64 ? 16 : 0; + int num_avx512_xmm_registers = amd64 ? 16 : 0; /* The supported bits in `xstat_bv' are 8 bytes. Clear part in vector registers if its bit in xstat_bv is zero. */ @@ -452,7 +456,9 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf) /* Check if any of ZMM16H-ZMM31H registers are changed. */ if ((x86_xcr0 & X86_XSTATE_ZMM)) { - int zmm16h_regnum = find_regno (regcache->tdesc, "zmm16h"); + int zmm16h_regnum = (num_avx512_zmmh_high_registers == 0 + ? -1 + : find_regno (regcache->tdesc, "zmm16h")); for (i = 0; i < num_avx512_zmmh_high_registers; i++) { @@ -469,7 +475,9 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf) /* Check if any XMM_AVX512 registers are changed. */ if ((x86_xcr0 & X86_XSTATE_ZMM)) { - int xmm_avx512_regnum = find_regno (regcache->tdesc, "xmm16"); + int xmm_avx512_regnum = (num_avx512_xmm_registers == 0 + ? -1 + : find_regno (regcache->tdesc, "xmm16")); for (i = 0; i < num_avx512_xmm_registers; i++) { @@ -486,7 +494,9 @@ i387_cache_to_xsave (struct regcache *regcache, void *buf) /* Check if any YMMH_AVX512 registers are changed. */ if ((x86_xcr0 & X86_XSTATE_ZMM)) { - int ymmh_avx512_regnum = find_regno (regcache->tdesc, "ymm16h"); + int ymmh_avx512_regnum = (num_avx512_ymmh_registers == 0 + ? -1 + : find_regno (regcache->tdesc, "ymm16h")); for (i = 0; i < num_avx512_ymmh_registers; i++) { @@ -710,12 +720,20 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf) { struct i387_xsave *fp = (struct i387_xsave *) buf; struct i387_fxsave *fxp = (struct i387_fxsave *) buf; + bool amd64 = register_size (regcache->tdesc, 0) == 8; int i, top; unsigned long val; unsigned long long clear_bv; gdb_byte *p; - /* Amd64 has 16 xmm regs; I386 has 8 xmm regs. */ - int num_xmm_registers = register_size (regcache->tdesc, 0) == 8 ? 16 : 8; + + /* Amd64 has 16 xmm regs; I386 has 8 xmm regs. */ + int num_xmm_registers = amd64 ? 16 : 8; + /* AVX512 extends the existing xmm/ymm registers to a wider mode: zmm. */ + int num_avx512_zmmh_low_registers = num_xmm_registers; + /* AVX512 adds 16 extra regs in Amd64 mode, but none in I386 mode.*/ + int num_avx512_zmmh_high_registers = amd64 ? 16 : 0; + int num_avx512_ymmh_registers = amd64 ? 16 : 0; + int num_avx512_xmm_registers = amd64 ? 16 : 0; /* The supported bits in `xstat_bv' are 8 bytes. Clear part in vector registers if its bit in xstat_bv is zero. */ @@ -845,9 +863,15 @@ i387_xsave_to_cache (struct regcache *regcache, const void *buf) if ((x86_xcr0 & X86_XSTATE_ZMM) != 0) { - int zmm16h_regnum = find_regno (regcache->tdesc, "zmm16h"); - int ymm16h_regnum = find_regno (regcache->tdesc, "ymm16h"); - int xmm16_regnum = find_regno (regcache->tdesc, "xmm16"); + int zmm16h_regnum = (num_avx512_zmmh_high_registers == 0 + ? -1 + : find_regno (regcache->tdesc, "zmm16h")); + int ymm16h_regnum = (num_avx512_ymmh_registers == 0 + ? -1 + : find_regno (regcache->tdesc, "ymm16h")); + int xmm16_regnum = (num_avx512_xmm_registers == 0 + ? -1 + : find_regno (regcache->tdesc, "xmm16")); if ((clear_bv & X86_XSTATE_ZMM) != 0) {
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