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from MMIO trace type
Both <linux/mmiotrace.h> and <asm/insn-eval.h> define various MMIO_ enum constants,
whose namespace overlaps.
Rename the <asm/insn-eval.h> ones to have a INSN_ prefix, so that the headers can be
used from the same source file.
Signed-off-by: Jason A. Donenfeld <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 core updates from Borislav Petkov:
- Get rid of all the .fixup sections because this generates
misleading/wrong stacktraces and confuse RELIABLE_STACKTRACE and
LIVEPATCH as the backtrace misses the function which is being fixed
up.
- Add Straight Line Speculation mitigation support which uses a new
compiler switch -mharden-sls= which sticks an INT3 after a RET or an
indirect branch in order to block speculation after them. Reportedly,
CPUs do speculate behind such insns.
- The usual set of cleanups and improvements
* tag 'x86_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
x86/entry_32: Fix segment exceptions
objtool: Remove .fixup handling
x86: Remove .fixup section
x86/word-at-a-time: Remove .fixup usage
x86/usercopy: Remove .fixup usage
x86/usercopy_32: Simplify __copy_user_intel_nocache()
x86/sgx: Remove .fixup usage
x86/checksum_32: Remove .fixup usage
x86/vmx: Remove .fixup usage
x86/kvm: Remove .fixup usage
x86/segment: Remove .fixup usage
x86/fpu: Remove .fixup usage
x86/xen: Remove .fixup usage
x86/uaccess: Remove .fixup usage
x86/futex: Remove .fixup usage
x86/msr: Remove .fixup usage
x86/extable: Extend extable functionality
x86/entry_32: Remove .fixup usage
x86/entry_64: Remove .fixup usage
x86/copy_mc_64: Remove .fixup usage
...
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In order to remove further .fixup usage, extend the extable
infrastructure to take additional information from the extable entry
sites.
Specifically add _ASM_EXTABLE_TYPE_REG() and EX_TYPE_IMM_REG that
extend the existing _ASM_EXTABLE_TYPE() by taking an additional
register argument and encoding that and an s16 immediate into the
existing s32 type field. This limits the actual types to the first
byte, 255 seem plenty.
Also add a few flags into the type word, specifically CLEAR_AX and
CLEAR_DX which clear the return and extended return register.
Notes:
- due to the % in our register names it's hard to make it more
generally usable as arm64 did.
- the s16 is far larger than used in these patches, future extentions
can easily shrink this to get more bits.
- without the bitfield fix this will not compile, because: 0xFF > -1
and we can't even extract the TYPE field.
[nathanchance: Build fix for clang-lto builds:
https://lkml.kernel.org/r/[email protected]
]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Josh Poimboeuf <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Tested-by: Nick Desaulniers <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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In preparation for sharing MMIO instruction decode between SEV-ES and
TDX, factor out the common decode into a new insn_decode_mmio() helper.
For regular virtual machine, MMIO is handled by the VMM and KVM
emulates instructions that caused MMIO. But, this model doesn't work
for a secure VMs (like SEV or TDX) as VMM doesn't have access to the
guest memory and register state. So, for TDX or SEV VMM needs
assistance in handling MMIO. It induces exception in the guest. Guest
has to decode the instruction and handle it on its own.
The code is based on the current SEV MMIO implementation.
Signed-off-by: Kirill A. Shutemov <[email protected]>
Signed-off-by: Dave Hansen <[email protected]>
Reviewed-by: Andi Kleen <[email protected]>
Reviewed-by: Tony Luck <[email protected]>
Tested-by: Joerg Roedel <[email protected]>
Acked-by: Tom Lendacky <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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The helper returns a pointer to the register indicated by
ModRM byte.
It's going to replace vc_insn_get_reg() in the SEV MMIO
implementation. TDX MMIO implementation will also use it.
Signed-off-by: Kirill A. Shutemov <[email protected]>
Signed-off-by: Dave Hansen <[email protected]>
Reviewed-by: Andi Kleen <[email protected]>
Reviewed-by: Tony Luck <[email protected]>
Tested-by: Joerg Roedel <[email protected]>
Acked-by: Tom Lendacky <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Since commit c8137ace5638 ("x86/iopl: Restrict iopl() permission
scope") it's possible to emulate iopl(3) using ioperm(), except for
the CLI/STI usage.
Userspace CLI/STI usage is very dubious (read broken), since any
exception taken during that window can lead to rescheduling anyway (or
worse). The IOPL(2) manpage even states that usage of CLI/STI is highly
discouraged and might even crash the system.
Of course, that won't stop people and HP has the dubious honour of
being the first vendor to be found using this in their hp-health
package.
In order to enable this 'software' to still 'work', have the #GP treat
the CLI/STI instructions as NOPs when iopl(3). Warn the user that
their program is doing dubious things.
Fixes: a24ca9976843 ("x86/iopl: Remove legacy IOPL option")
Reported-by: Ondrej Zary <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Cc: [email protected] # v5.5+
Link: https://lkml.kernel.org/r/[email protected]
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Rename insn_decode() to insn_decode_from_regs() to denote that it
receives regs as param and uses registers from there during decoding.
Free the former name for a more generic version of the function.
No functional changes.
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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The #VC handler must run in atomic context and cannot sleep. This is a
problem when it tries to fetch instruction bytes from user-space via
copy_from_user().
Introduce a insn_fetch_from_user_inatomic() helper which uses
__copy_from_user_inatomic() to safely copy the instruction bytes to
kernel memory in the #VC handler.
Fixes: 5e3427a7bc432 ("x86/sev-es: Handle instruction fetches from user-space")
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: [email protected] # v5.10+
Link: https://lkml.kernel.org/r/[email protected]
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Add a function to check whether an instruction has a REP prefix.
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Masami Hiramatsu <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Add a function to the instruction decoder which returns the pt_regs
offset of the register specified in the reg field of the modrm byte.
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Acked-by: Masami Hiramatsu <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Factor out the code used to decode an instruction with the correct
address and operand sizes to a helper function.
No functional changes.
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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Factor out the code to fetch the instruction from user-space to a helper
function.
No functional changes.
Signed-off-by: Joerg Roedel <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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In order to save on redundant structs definitions
insn_get_code_seg_params() was made to return two 4-bit values in a char
but clang complains:
arch/x86/lib/insn-eval.c:780:10: warning: implicit conversion from 'int' to 'char'
changes value from 132 to -124 [-Wconstant-conversion]
return INSN_CODE_SEG_PARAMS(4, 8);
~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~
./arch/x86/include/asm/insn-eval.h:16:57: note: expanded from macro 'INSN_CODE_SEG_PARAMS'
#define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4))
Those two values do get picked apart afterwards the opposite way of how
they were ORed so wrt to the LSByte, the return value is the same.
But this function returns -EINVAL in the error case, which is an int. So
make it return an int which is the native word size anyway and thus fix
the clang warning.
Reported-by: Kees Cook <[email protected]>
Reported-by: Nick Desaulniers <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
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Obtain the default values of the address and operand sizes as specified in
the D and L bits of the the segment descriptor selected by the register
CS. The function can be used for both protected and long modes.
For virtual-8086 mode, the default address and operand sizes are always 2
bytes.
The returned parameters are encoded in a signed 8-bit data type. Auxiliar
macros are provided to encode and decode such values.
Improvements-by: Borislav Petkov <[email protected]>
Signed-off-by: Ricardo Neri <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: [email protected]
Cc: Adrian Hunter <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: Huang Rui <[email protected]>
Cc: Qiaowei Ren <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Ravi V. Shankar" <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Colin Ian King <[email protected]>
Cc: Chen Yucong <[email protected]>
Cc: Adam Buchbinder <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Thomas Garnier <[email protected]>
Link: https://lkml.kernel.org/r/1509135945-13762-17-git-send-email-ricardo.neri-calderon@linux.intel.com
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and limit
With segmentation, the base address of the segment is needed to compute a
linear address. This base address is obtained from the applicable segment
descriptor. Such segment descriptor is referenced from a segment selector.
These new functions obtain the segment base and limit of the segment
selector indicated by segment register index given as argument. This index
is any of the INAT_SEG_REG_* family of #define's.
The logic to obtain the segment selector is wrapped in the function
get_segment_selector() with the inputs described above. Once the selector
is known, the base address is determined. In protected mode, the selector
is used to obtain the segment descriptor and then its base address. In
long mode, the segment base address is zero except when FS or GS are used.
In virtual-8086 mode, the base address is computed as the value of the
segment selector shifted 4 positions to the left.
In protected mode, segment limits are enforced. Thus, a function to
determine the limit of the segment is added. Segment limits are not
enforced in long or virtual-8086. For the latter, addresses are limited
to 20 bits; address size will be handled when computing the linear
address.
Improvements-by: Borislav Petkov <[email protected]>
Signed-off-by: Ricardo Neri <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: [email protected]
Cc: Adrian Hunter <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: Huang Rui <[email protected]>
Cc: Qiaowei Ren <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Ravi V. Shankar" <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Colin Ian King <[email protected]>
Cc: Chen Yucong <[email protected]>
Cc: Adam Buchbinder <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Thomas Garnier <[email protected]>
Link: https://lkml.kernel.org/r/1509135945-13762-16-git-send-email-ricardo.neri-calderon@linux.intel.com
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The function get_reg_offset() returns the offset to the register the
argument specifies as indicated in an enumeration of type offset. Callers
of this function would need the definition of such enumeration. This is
not needed. Instead, add helper functions for this purpose. These functions
are useful in cases when, for instance, the caller needs to decide whether
the operand is a register or a memory location by looking at the rm part
of the ModRM byte. As of now, this is the only helper function that is
needed.
Signed-off-by: Ricardo Neri <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: [email protected]
Cc: Adrian Hunter <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: Huang Rui <[email protected]>
Cc: Qiaowei Ren <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Ravi V. Shankar" <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Colin Ian King <[email protected]>
Cc: Chen Yucong <[email protected]>
Cc: Adam Buchbinder <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Thomas Garnier <[email protected]>
Link: https://lkml.kernel.org/r/1509135945-13762-12-git-send-email-ricardo.neri-calderon@linux.intel.com
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Other kernel submodules can benefit from using the utility functions
defined in mpx.c to obtain the addresses and values of operands contained
in the general purpose registers. An instance of this is the emulation code
used for instructions protected by the Intel User-Mode Instruction
Prevention feature.
Thus, these functions are relocated to a new insn-eval.c file. The reason
to not relocate these utilities into insn.c is that the latter solely
analyses instructions given by a struct insn without any knowledge of the
meaning of the values of instruction operands. This new utility insn-
eval.c aims to be used to resolve userspace linear addresses based on
the contents of the instruction operands as well as the contents of pt_regs
structure.
These utilities come with a separate header. This is to avoid taking insn.c
out of sync from the instructions decoders under tools/obj and tools/perf.
This also avoids adding cumbersome #ifdef's for the #include'd files
required to decode instructions in a kernel context.
Functions are simply relocated. There are not functional or indentation
changes.
Signed-off-by: Ricardo Neri <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Borislav Petkov <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: [email protected]
Cc: Adrian Hunter <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: Huang Rui <[email protected]>
Cc: Qiaowei Ren <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: "Ravi V. Shankar" <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Colin Ian King <[email protected]>
Cc: Chen Yucong <[email protected]>
Cc: Adam Buchbinder <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Thomas Garnier <[email protected]>
Link: https://lkml.kernel.org/r/1509135945-13762-10-git-send-email-ricardo.neri-calderon@linux.intel.com
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