mirror of
https://github.com/speed47/spectre-meltdown-checker.git
synced 2025-10-31 20:50:55 +01:00
refacto: create a dedicated func to read cpuid bits
This commit is contained in:
Stéphane Lesimple
@@ -610,6 +610,36 @@ unload_cpuid()
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fi
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}
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read_cpuid()
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{
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_leaf="$1"
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_bytenum="$2"
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_and_operand="$3"
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if [ ! -e /dev/cpu/0/cpuid ]; then
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# try to load the module ourselves (and remember it so we can rmmod it afterwards)
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load_cpuid
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fi
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if [ ! -e /dev/cpu/0/cpuid ]; then
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return 2
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fi
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if [ "$opt_verbose" -ge 3 ]; then
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dd if=/dev/cpu/0/cpuid bs=16 skip="$_leaf" iflag=skip_bytes count=1 >/dev/null 2>/dev/null
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_debug "cpuid: reading leaf$_leaf of cpuid on cpu0, ret=$?"
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_debug "cpuid: leaf$_leaf eax-ebx-ecx-edx: $( dd if=/dev/cpu/0/cpuid bs=16 skip="$_leaf" iflag=skip_bytes count=1 2>/dev/null | od -x -A n)"
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_debug "cpuid: leaf$_leaf edx higher byte is: $(dd if=/dev/cpu/0/cpuid bs=16 skip="$_leaf" iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=$_bytenum count=1 2>/dev/null | od -x -A n)"
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fi
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# getting proper byte of edx on leaf$_leaf of cpuinfo in decimal
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_reg_byte=$(dd if=/dev/cpu/0/cpuid bs=16 skip="$_leaf" iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip="$_bytenum" count=1 2>/dev/null | od -t u1 -A n | awk '{print $1}')
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_debug "cpuid: leaf$_leaf byte $_bytenum: $_reg_byte (decimal)"
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_reg_bit=$(( _reg_byte & _and_operand ))
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_debug "cpuid: leaf$_leaf byte $_bytenum & $_and_operand = $_reg_bit"
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[ "$_reg_bit" -eq 0 ] && return 1
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# $_reg_bit is > 0, so the bit was found: return true (aka 0)
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return 0
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}
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dmesg_grep()
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{
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# grep for something in dmesg, ensuring that the dmesg buffer
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@@ -982,31 +1012,15 @@ check_cpu()
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fi
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_info_nol " * CPU indicates IBRS capability: "
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if [ ! -e /dev/cpu/0/cpuid ]; then
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# try to load the module ourselves (and remember it so we can rmmod it afterwards)
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load_cpuid
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fi
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if [ ! -e /dev/cpu/0/cpuid ]; then
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# from kernel src: { X86_FEATURE_SPEC_CTRL, CPUID_EDX,26, 0x00000007, 0 },
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read_cpuid 7 15 4; ret=$?
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if [ $ret -eq 0 ]; then
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pstatus green YES "SPEC_CTRL feature bit"
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cpuid_spec_ctrl=1
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elif [ $ret -eq 2 ]; then
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pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/cpuid, is cpuid support enabled in your kernel?"
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else
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# from kernel src: { X86_FEATURE_SPEC_CTRL, CPUID_EDX,26, 0x00000007, 0 },
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if [ "$opt_verbose" -ge 3 ]; then
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dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 >/dev/null 2>/dev/null
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_debug "cpuid: reading leaf7 of cpuid on cpu0, ret=$?"
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_debug "cpuid: leaf7 eax-ebx-ecx-edx: $(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | od -x -A n)"
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_debug "cpuid: leaf7 edx higher byte is: $(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=15 count=1 2>/dev/null | od -x -A n)"
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fi
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# getting high byte of edx on leaf7 of cpuinfo in decimal
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edx_hb=$(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=15 count=1 2>/dev/null | od -t u -A n | awk '{print $1}')
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_debug "cpuid: leaf7 edx higher byte: $edx_hb (decimal)"
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edx_bit26=$(( edx_hb & 4 ))
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_debug "cpuid: edx_bit26=$edx_bit26"
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if [ "$edx_bit26" -eq 4 ]; then
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pstatus green YES "SPEC_CTRL feature bit"
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cpuid_spec_ctrl=1
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else
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pstatus red NO
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fi
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pstatus red NO
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fi
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# hardware support according to kernel
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@@ -1043,29 +1057,18 @@ check_cpu()
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fi
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fi
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_info_nol " * CPU indicates IBPB capability: "
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if [ ! -e /dev/cpu/0/cpuid ]; then
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# CPUID EAX=0x80000008, ECX=0x00 return EBX[12] indicates support for just IBPB.
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read_cpuid 2147483656 5 16; ret=$?
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if [ $ret -eq 0 ]; then
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pstatus green YES "IBPB_SUPPORT feature bit"
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elif [ "$cpuid_spec_ctrl" = 1 ]; then
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pstatus green YES "SPEC_CTRL feature bit"
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elif [ $ret -eq 2 ]; then
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pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/cpuid, is cpuid support enabled in your kernel?"
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else
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# CPUID EAX=0x80000008, ECX=0x00 return EBX[12] indicates support for just IBPB.
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if [ "$opt_verbose" -ge 3 ]; then
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dd if=/dev/cpu/0/cpuid bs=16 skip=2147483656 iflag=skip_bytes count=1 >/dev/null 2>/dev/null
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_debug "cpuid: reading leaf80000008 of cpuid on cpu0, ret=$?"
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_debug "cpuid: leaf80000008 eax-ebx-ecx-edx: $(dd if=/dev/cpu/0/cpuid bs=16 skip=2147483656 iflag=skip_bytes count=1 2>/dev/null | od -x -A n)"
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_debug "cpuid: leaf80000008 ebx 3rd byte is: $(dd if=/dev/cpu/0/cpuid bs=16 skip=2147483656 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=5 count=1 2>/dev/null | od -x -A n)"
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fi
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# getting high byte of edx on leaf7 of cpuinfo in decimal
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ebx_b3=$(dd if=/dev/cpu/0/cpuid bs=16 skip=2147483656 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=5 count=1 2>/dev/null | od -t u -A n | awk '{print $1}')
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_debug "cpuid: leaf80000008 ebx 3rd byte: $ebx_b3 (decimal)"
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ebx_bit12=$(( ebx_b3 & 16 ))
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_debug "cpuid: ebx_bit12=$ebx_bit12"
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if [ "$ebx_bit12" -eq 16 ]; then
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pstatus green YES "IBPB_SUPPORT feature bit"
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elif [ "$cpuid_spec_ctrl" = 1 ]; then
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pstatus green YES "SPEC_CTRL feature bit"
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else
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pstatus red NO
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fi
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pstatus red NO
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fi
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# STIBP
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@@ -1080,53 +1083,29 @@ check_cpu()
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fi
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_info_nol " * CPU indicates STIBP capability: "
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if [ ! -e /dev/cpu/0/cpuid ]; then
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# A processor supports STIBP if it enumerates CPUID (EAX=7H,ECX=0):EDX[27] as 1
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read_cpuid 7 15 8; ret=$?
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if [ $ret -eq 0 ]; then
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pstatus green YES
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elif [ $ret -eq 2 ]; then
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pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/cpuid, is cpuid support enabled in your kernel?"
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else
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# A processor supports STIBP if it enumerates CPUID (EAX=7H,ECX=0):EDX[27] as 1
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if [ "$opt_verbose" -ge 3 ]; then
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dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 >/dev/null 2>/dev/null
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_debug "cpuid: reading leaf7 of cpuid on cpu0, ret=$?"
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_debug "cpuid: leaf7 eax-ebx-ecx-edx: $(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | od -x -A n)"
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_debug "cpuid: leaf7 edx higher byte is: $(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=15 count=1 2>/dev/null | od -x -A n)"
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fi
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# getting high byte of edx on leaf7 of cpuinfo in decimal
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edx_hb=$(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=15 count=1 2>/dev/null | od -t u -A n | awk '{print $1}')
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_debug "cpuid: leaf7 edx higher byte: $edx_hb (decimal)"
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edx_bit27=$(( edx_hb & 8 ))
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_debug "cpuid: edx_bit27=$edx_bit27"
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if [ "$edx_bit27" -eq 8 ]; then
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pstatus green YES
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else
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pstatus red NO
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fi
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pstatus red NO
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fi
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_info " * Enhanced IBRS (IBRS_ALL)"
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_info_nol " * CPU indicates ARCH_CAPABILITIES MSR availability: "
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cpuid_arch_capabilities=-1
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if [ ! -e /dev/cpu/0/cpuid ]; then
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# A processor supports STIBP if it enumerates CPUID (EAX=7H,ECX=0):EDX[27] as 1
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read_cpuid 7 15 32; ret=$?
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if [ $ret -eq 0 ]; then
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pstatus green YES
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cpuid_arch_capabilities=1
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elif [ $ret -eq 2 ]; then
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pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/cpuid, is cpuid support enabled in your kernel?"
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else
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# A processor supports STIBP if it enumerates CPUID (EAX=7H,ECX=0):EDX[27] as 1
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if [ "$opt_verbose" -ge 3 ]; then
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dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 >/dev/null 2>/dev/null
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_debug "cpuid: reading leaf7 of cpuid on cpu0, ret=$?"
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_debug "cpuid: leaf7 eax-ebx-ecx-edx: $(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | od -x -A n)"
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_debug "cpuid: leaf7 edx higher byte is: $(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=15 count=1 2>/dev/null | od -x -A n)"
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fi
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# getting high byte of edx on leaf7 of cpuinfo in decimal
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edx_hb=$(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=15 count=1 2>/dev/null | od -t u -A n | awk '{print $1}')
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_debug "cpuid: leaf7 edx higher byte: $edx_hb (decimal)"
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edx_bit29=$(( edx_hb & 32 ))
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_debug "cpuid: edx_bit29=$edx_bit29"
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if [ "$edx_bit27" -eq 32 ]; then
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pstatus green YES
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cpuid_arch_capabilities=1
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else
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pstatus red NO
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cpuid_arch_capabilities=0
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fi
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pstatus red NO
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cpuid_arch_capabilities=0
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fi
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_info_nol " * ARCH_CAPABILITIES MSR advertises IBRS_ALL capability: "
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@@ -1470,9 +1449,6 @@ check_variant2()
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pstatus blue N/A "not testable in offline mode"
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fi
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unload_msr
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unload_cpuid
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_info "* Mitigation 2"
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_info_nol " * Kernel compiled with retpoline option: "
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# We check the RETPOLINE kernel options
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@@ -1827,6 +1803,9 @@ _info "A false sense of security is worse than no security at all, see --disclai
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# this'll umount only if we mounted debugfs ourselves
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umount_debugfs
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# same for modules
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unload_msr
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unload_cpuid
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# cleanup the temp decompressed config
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[ -n "$dumped_config" ] && [ -f "$dumped_config" ] && rm -f "$dumped_config"
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