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# Copyright 2018-2024 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# This file is part of the gdb testsuite.
# Test initial values of x87 control registers, before any x87
# instructions have been executed in the inferior.
require is_amd64_regs_target
standard_testfile .S
set options [list debug \
additional_flags=-static \
additional_flags=-nostartfiles]
if { [build_executable "failed to prepare" ${testfile} ${srcfile} $options] } {
return -1
}
# Start the test file, and check the x87 control registers (and
# mxcsr), we expect the default values in all registers.
#
# Step forward until the x87 unit is enabled, recheck the register
# values; they should still have the default values.
#
# Finally, step forward until the x87 state has changed, and then
# recheck the register state to view the changes.
proc_with_prefix check_x87_regs_around_init {} {
global binfile
clean_restart ${binfile}
# Get things started.
if {![runto_main]} {
return 0
}
# Check initial values of x87 control registers. The MXCSR isn't part
# of the x87 set, it belongs with SSE/AVX, however we test it here
# too, it should have its default value in both cases.
foreach {regname regvalue} { "fctrl" "0x37f" \
"fstat" "0x0" \
"ftag" "0xffff" \
"fiseg" "0x0" \
"fioff" "0x0" \
"foseg" "0x0" \
"fooff" "0x0" \
"fop" "0x0" \
"mxcsr" "0x1f80"} {
gdb_test "p/x \$${regname}" " = ${regvalue}" "check initial value of \$${regname}"
}
# No x87 instructions have been executed yet. Step up to FWAIT
# instruction. Executing this instruction will enable the x87 unit,
# causing the kernel to place the default values into all registers.
# After this GDB will no longer supply the default values itself but
# will instread read the values out of the xsave buffer.
gdb_test "stepi" "fwait" "step to FWAIT instruction"
gdb_test "stepi" "nop" "step past FWAIT instruction"
# The x87 unit is now enabled, but the register values should be
# unchanged.
foreach {regname regvalue} { "fctrl" "0x37f" \
"fstat" "0x0" \
"ftag" "0xffff" \
"fiseg" "0x0" \
"fioff" "0x0" \
"foseg" "0x0" \
"fooff" "0x0" \
"fop" "0x0" \
"mxcsr" "0x1f80"} {
gdb_test "p/x \$${regname}" " = ${regvalue}" "check post FWAIT value of \$${regname}"
}
# Now step to an x87 instruction that modifies some state.
gdb_test "stepi" "fld1" "step to FLD1 instruction"
# Grab the address of this instruction, it will appear in later
# results.
set addr [get_hexadecimal_valueof "\$pc" "0"]
# Step past the FLD1 instruction.
gdb_test "stepi" "nop" "step past FLD1 instruction"
# Check new values of x87 control registers (and MXCSR).
foreach {regname regvalue} [list "fctrl" "0x37f" \
"fstat" "0x3800" \
"ftag" "0x3fff" \
"fiseg" "0x0" \
"fioff" "($addr|0x0)" \
"foseg" "0x0" \
"fooff" "0x0" \
"fop" "0x0" \
"mxcsr" "0x1f80" ] {
gdb_test "p/x \$${regname}" " = ${regvalue}" "check post FLD1 value of \$${regname}"
}
}
# Start the test file, all FP features will be disabled. Set a new
# value into the MXCSR register, then step forward one instruction (a
# nop that does not enable any FP features). Finally check that the
# mxcsr register still has the value we set.
proc_with_prefix check_setting_mxcsr_before_enable {} {
global binfile gdb_prompt
clean_restart ${binfile}
if {![runto_main]} {
return 0
}
gdb_test_no_output "set \$mxcsr=0x9f80" "set a new value for MXCSR"
gdb_test "stepi" "fwait" "step forward one instruction for mxcsr test"
set test "check new value of MXCSR is still in place"
set pass_pattern " = 0x9f80"
# Pre-4.14 kernels have a bug (fixed by commit 0852b374173b "x86/fpu:
# Add FPU state copying quirk to handle XRSTOR failure on Intel Skylake
# CPUs") that causes mxcsr not to be copied, in which case we get 0 instead of
# the just saved value.
set xfail_pattern " = 0x0"
gdb_test_multiple "p/x \$mxcsr" $test {
-re "\[\r\n\]*(?:$pass_pattern)\[\r\n\]+$gdb_prompt $" {
pass $test
}
-re "\[\r\n\]*(?:$xfail_pattern)\[\r\n\]+$gdb_prompt $" {
xfail $test
}
}
}
# Start the test file, all FP features will be disabled. Set new
# values into the x87 control-registers, then step forward one
# instruction (a nop that does not enable any FP features). Finally
# check that all the x87 control-registers still have the values we
# set.
proc_with_prefix check_setting_x87_regs_before_enable {} {
global binfile
clean_restart ${binfile}
if {![runto_main]} {
return 0
}
foreach {regname regvalue} [list "fctrl" "0x37f" \
"fstat" "0x3800" \
"ftag" "0x7777" \
"fiseg" "0x12" \
"fioff" "0x2418" \
"foseg" "0x24" \
"fooff" "0x36" \
"fop" "0x100" ] {
gdb_test_no_output "set \$$regname=$regvalue" "set a new value for $regname"
}
gdb_test "stepi" "fwait" "step forward one instruction for x87 test"
foreach {regname regvalue} [list "fctrl" "0x37f" \
"fstat" "0x3800" \
"ftag" "0x7777" \
"fiseg" "0x12" \
"fioff" "0x2418" \
"foseg" "0x24" \
"fooff" "0x36" \
"fop" "0x100" ] {
gdb_test "p/x \$$regname" "= $regvalue" "check new value of $regname"
}
}
check_x87_regs_around_init
check_setting_mxcsr_before_enable
check_setting_x87_regs_before_enable
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