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We want to make use of pte_next_pfn() outside of set_ptes(). Let's simply
define PFN_PTE_SHIFT, required by pte_next_pfn().
Link: https://lkml.kernel.org/r/20240129124649.189745-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Tested-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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All architectures using the core ptdump functionality also implement
CONFIG_DEBUG_WX, and they all do it more or less the same way, with a
function called debug_checkwx() that is called by mark_rodata_ro(), which
is a substitute to ptdump_check_wx() when CONFIG_DEBUG_WX is set and a
no-op otherwise.
Refactor by centrally defining debug_checkwx() in linux/ptdump.h and call
debug_checkwx() immediately after calling mark_rodata_ro() instead of
calling it at the end of every mark_rodata_ro().
On x86_32, mark_rodata_ro() first checks __supported_pte_mask has _PAGE_NX
before calling debug_checkwx(). Now the check is inside the callee
ptdump_walk_pgd_level_checkwx().
On powerpc_64, mark_rodata_ro() bails out early before calling
ptdump_check_wx() when the MMU doesn't have KERNEL_RO feature. The check
is now also done in ptdump_check_wx() as it is called outside
mark_rodata_ro().
Link: https://lkml.kernel.org/r/a59b102d7964261d31ead0316a9f18628e4e7a8e.1706610398.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg KH <greg@kroah.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Phong Tran <tranmanphong@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Steven Price <steven.price@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The routine ar_translation() can be reached by both the instruction
intercept path (where the access registers had been loaded with the
guest register contents), and the MEM_OP ioctls (which hadn't).
Since this routine saves the current registers to vcpu->run,
this routine erroneously saves host registers into the guest space.
Introduce a boolean in the kvm_vcpu_arch struct to indicate whether
the registers contain guest contents. If they do (the instruction
intercept path), the save can be performed and the AR translation
is done just as it is today. If they don't (the MEM_OP path), the
AR can be read from vcpu->run without stashing the current contents.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Link: https://lore.kernel.org/r/20240220211211.3102609-2-farman@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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vdso/datapage.h includes the architecture specific vdso/data.h header
file. So there is no need to do it also the other way round and including
the generic vdso/datapage.h header file inside the architecture specific
data.h header file.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20240219153939.75719-3-anna-maria@linutronix.de
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On s390, currently kernel uses the '-fPIE' compiler flag for compiling
vmlinux. This has a few problems:
- It uses dynamic symbols (.dynsym), for which the linker refuses to
allow more than 64k sections. This can break features which use
'-ffunction-sections' and '-fdata-sections', including kpatch-build
[1] and Function Granular KASLR.
- It unnecessarily uses GOT relocations, adding an extra layer of
indirection for many memory accesses.
Instead of using '-fPIE', resolve all the relocations at link time and
then manually adjust any absolute relocations (R_390_64) during boot.
This is done by first telling the linker to preserve all relocations
during the vmlinux link. (Note this is harmless: they are later
stripped in the vmlinux.bin link.)
Then use the 'relocs' tool to find all absolute relocations (R_390_64)
which apply to allocatable sections. The offsets of those relocations
are saved in a special section which is then used to adjust the
relocations during boot.
(Note: For some reason, Clang occasionally creates a GOT reference, even
without '-fPIE'. So Clang-compiled kernels have a GOT, which needs to
be adjusted.)
On my mostly-defconfig kernel, this reduces kernel text size by ~1.3%.
[1] https://github.com/dynup/kpatch/issues/1284
[2] https://gcc.gnu.org/pipermail/gcc-patches/2023-June/622872.html
[3] https://gcc.gnu.org/pipermail/gcc-patches/2023-August/625986.html
Compiler consideration:
Gcc recently implemented an optimization [2] for loading symbols without
explicit alignment, aligning with the IBM Z ELF ABI. This ABI mandates
symbols to reside on a 2-byte boundary, enabling the use of the larl
instruction. However, kernel linker scripts may still generate unaligned
symbols. To address this, a new -munaligned-symbols option has been
introduced [3] in recent gcc versions. This option has to be used with
future gcc versions.
Older Clang lacks support for handling unaligned symbols generated
by kernel linker scripts when the kernel is built without -fPIE. However,
future versions of Clang will include support for the -munaligned-symbols
option. When the support is unavailable, compile the kernel with -fPIE
to maintain the existing behavior.
In addition to it:
move vmlinux.relocs to safe relocation
When the kernel is built with CONFIG_KERNEL_UNCOMPRESSED, the entire
uncompressed vmlinux.bin is positioned in the bzImage decompressor
image at the default kernel LMA of 0x100000, enabling it to be executed
in-place. However, the size of .vmlinux.relocs could be large enough to
cause an overlap with the uncompressed kernel at the address 0x100000.
To address this issue, .vmlinux.relocs is positioned after the
.rodata.compressed in the bzImage. Nevertheless, in this configuration,
vmlinux.relocs will overlap with the .bss section of vmlinux.bin. To
overcome that, move vmlinux.relocs to a safe location before clearing
.bss and handling relocs.
Compile warning fix from Sumanth Korikkar:
When kernel is built with CONFIG_LD_ORPHAN_WARN and -fno-PIE, there are
several warnings:
ld: warning: orphan section `.rela.iplt' from
`arch/s390/kernel/head64.o' being placed in section `.rela.dyn'
ld: warning: orphan section `.rela.head.text' from
`arch/s390/kernel/head64.o' being placed in section `.rela.dyn'
ld: warning: orphan section `.rela.init.text' from
`arch/s390/kernel/head64.o' being placed in section `.rela.dyn'
ld: warning: orphan section `.rela.rodata.cst8' from
`arch/s390/kernel/head64.o' being placed in section `.rela.dyn'
Orphan sections are sections that exist in an object file but don't have
a corresponding output section in the final executable. ld raises a
warning when it identifies such sections.
Eliminate the warning by placing all .rela orphan sections in .rela.dyn
and raise an error when size of .rela.dyn is greater than zero. i.e.
Dont just neglect orphan sections.
This is similar to adjustment performed in x86, where kernel is built
with -fno-PIE.
commit 5354e84598f2 ("x86/build: Add asserts for unwanted sections")
[sumanthk@linux.ibm.com: rebased Josh Poimboeuf patches and move
vmlinux.relocs to safe location]
[hca@linux.ibm.com: merged compile warning fix from Sumanth]
Tested-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Link: https://lore.kernel.org/r/20240219132734.22881-4-sumanthk@linux.ibm.com
Link: https://lore.kernel.org/r/20240219132734.22881-5-sumanthk@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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There's a number of tasks that need the state of a zpci device
to be stable. Other tasks need to be synchronized as they change the state.
State changes could be generated by the system as availability or error
events, or be requested by the user through manipulations in sysfs.
Some other actions accessible through sysfs - like device resets - need the
state to be stable.
Unsynchronized state handling could lead to unusable devices. This has
been observed in cases of concurrent state changes through systemd udev
rules and DPM boot control. Some breakage can be provoked by artificial
tests, e.g. through repetitively injecting "recover" on a PCI function
through sysfs while running a "hotplug remove/add" in a loop through a
PCI slot's "power" attribute in sysfs. After a few iterations this could
result in a kernel oops.
So introduce a new mutex "state_lock" to guard the state property of the
struct zpci_dev. Acquire this lock in all task that modify the state:
- hotplug add and remove, through the PCI hotplug slot entry,
- avaiability events, as reported by the platform,
- error events, as reported by the platform,
- during device resets, explicit through sysfs requests or
implict through the common PCI layer.
Break out an inner _do_recover() routine out of recover_store() to
separte the necessary synchronizations from the actual manipulations of
the zpci_dev required for the reset.
With the following changes I was able to run the inject loops for hours
without hitting an error.
Signed-off-by: Gerd Bayer <gbayer@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Since this guards only the Function Measurement Block, rename from
generic lock to fmb_lock in preparation to introduce another lock
that guards the state member
Signed-off-by: Gerd Bayer <gbayer@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Adjust whitespace indentation. No functional change.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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When the PAI events ALL_CRYPTO or ALL_NNPA are created
for system wide sampling, all PAI counters are monitored.
On each process schedule out, the values of all PAI counters
are investigated. Non-zero values are saved in the event's ring
buffer as raw data. This scheme expects the start value of each counter
to be reset to zero after each read operation performed by the PAI
PMU device driver. This allows for only one active event at any one
time as it relies on the start value of counters to be reset to zero.
Create a save area for each installed PAI XXXX_ALL event and save all
PAI counter values in this save area. Instead of clearing the
PAI counter lowcore area to zero after each read operation,
copy them from the lowcore area to the event's save area at process
schedule out time.
The delta of each PAI counter is calculated by subtracting the
old counter's value stored in the event's save area from the current
value stored in the lowcore area.
With this scheme, mulitple events of the PAI counters XXXX_ALL
can be handled at the same time. This will be addressed in a
follow-on patch.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Provide various vector instruction inline assemblies for crc32
calculations.
This is just preparation to keep the conversion of the existing crc32
implementations from assembly to C small.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Provide several one instruction fpu inline assemebles and use them to
implement the bogomips calculation in C like style. This is more for
illustration purposes on how kernel fpu code can be written in C.
This has the advantage that the author only has to take care of the
floating point instructions, but doesn't need to take care of general
purpose register allocation (if needed), and the semantics of all other
instructions not related to fpu.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Move the s390 specific raid6 inline assemblies, make them generic, and
reuse them to implement the raid6 gen/xor implementation.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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With csum_partial(), which reads all bytes into registers it is easy to
also implement csum_partial_copy_nocheck() which copies the buffer while
calculating its checksum.
For a 512 byte buffer this reduces the runtime by 19%. Compared to the old
generic variant (memcpy() + cksm instruction) runtime is reduced by 42%).
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Provide a faster variant of csum_partial() which uses vector registers
instead of the cksm instruction.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Convert those callers of csum_partial() to use the cksm instruction,
which are either very early or in critical paths, like panic/dump, so
they don't have to rely on a working kernel infrastructure, which will
be introduced with a subsequent patch.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Call instrument_read() from csum_partial() instead of kasan_check_read().
instrument_read() covers all memory access instrumentation methods.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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TIF_FPU is unused - remove it.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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The first invocation of kernel_fpu_begin() after switching from user to
kernel context will save all vector registers, even if only parts of the
vector registers are used within the kernel fpu context. Given that save
and restore of all vector registers is quite expensive change the current
approach in several ways:
- Instead of saving and restoring all user registers limit this to those
registers which are actually used within an kernel fpu context.
- On context switch save all remaining user fpu registers, so they can be
restored when the task is rescheduled.
- Saving user registers within kernel_fpu_begin() is done without disabling
and enabling interrupts - which also slightly reduces runtime. In worst
case (e.g. interrupt context uses the same registers) this may lead to
the situation that registers are saved several times, however the
assumption is that this will not happen frequently, so that the new
method is faster in nearly all cases.
- save_user_fpu_regs() can still be called from all contexts and saves all
(or all remaining) user registers to a tasks ufpu user fpu save area.
Overall this reduces the time required to save and restore the user fpu
context for nearly all cases.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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The kernel_fpu structure has a quite large size of 520 bytes. In order to
reduce stack footprint introduce several kernel fpu structures with
different and also smaller sizes. This way every kernel fpu user must use
the correct variant. A compile time check verifies that the correct variant
is used.
There are several users which use only 16 instead of all 32 vector
registers. For those users the new kernel_fpu_16 structure with a size of
only 266 bytes can be used.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Let fpu_vlm() and fpu_vstm() macros return the number of registers saved /
loaded. This is helpful to read easy to read code in case there are several
subsequent fpu_vlm() or fpu_vstm() calls:
__vector128 *vxrs = ....
vxrs += fpu_vstm(0, 15, vxrs);
vxrs += fpu_vstm(16, 31, vxrs);
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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The anonymous union within struct fpu contains a floating point register
array and a vector register array. Given that the vector register is always
present remove the floating point register array. For configurations
without vector registers save the floating point register contents within
their corresponding vector register location.
This allows to remove the union, and also to simplify ptrace and perf code.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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KVM was the only user which modified the regs pointer in struct fpu. Remove
the pointer and convert the rest of the core fpu code to directly access
the save area embedded within struct fpu.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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KVM modifies the kernel fpu's regs pointer to its own area to implement its
custom version of preemtible kernel fpu context. With general support for
preemptible kernel fpu context there is no need for the extra complexity in
KVM code anymore.
Therefore convert KVM to a regular kernel fpu user. In particular this
means that all TIF_FPU checks can be removed, since the fpu register
context will never be changed by other kernel fpu users, and also the fpu
register context will be restored if a thread is preempted.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Make the kernel fpu context preemptible. Add another fpu structure to the
thread_struct, and use it to save and restore the kernel fpu context if its
task uses fpu registers when it is preempted.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Change type of fpu mask consistently from u32 to int. This is a
prerequisite to make the kernel fpu usage preemptible. Upcoming code
uses __atomic* ops which work with int pointers.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Rename save_fpu_regs(), load_fpu_regs(), and struct thread_struct's fpu
member to save_user_fpu_regs(), load_user_fpu_regs(), and ufpu. This way
the function and variable names reflect for which context they are supposed
to be used.
This large and trivial conversion is a prerequisite for making the kernel
fpu usage preemptible.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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The FPU state, as represented by the CIF_FPU flag reflects the FPU state of
a task, not the CPU it is running on. Therefore convert the flag to a
regular TIF flag.
This removes the magic in switch_to() where a save_fpu_regs() call for the
currently (previous) running task sets the per-cpu CIF_FPU flag, which is
required to restore FPU register contents of the next task, when it returns
to user space.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Convert the rather large __kernel_fpu_begin()/__kernel_fpu_end() inline
assemblies to C. The C variant is much more readable, and this also allows
to get rid of the non-obvious usage of KERNEL_VXR_* constants within the
inline assemblies. E.g. "tmll %[m],6" correlates with the two bits set in
KERNEL_VXR_LOW. If the corresponding defines would be changed, the inline
assembles would break in a subtle way.
Therefore convert to C, use the proper defines, and allow the compiler to
generate code using the (hopefully) most efficient instructions.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Instead of open-coding vlm and vstm inline assemblies at several locations,
provide an fpu_* function for each instruction, and use them in the new
save_vx_regs() and load_vx_regs() helper functions.
Note that "O" and "R" inline assembly operand modifiers are used in order
to pass the displacement and base register of the memory operands to the
existing VLM and VSTM macros. The two operand modifiers are not available
for clang. Therefore provide two variants of each inline assembly.
The clang variant always uses and clobbers general purpose register 1, like
in the previous inline assemblies, so it can be used as base register with
a zero displacement. This generates slightly less efficient code, but can
be removed as soon as clang has support for the used operand modifiers.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Instead of open-coding lfpc, sfpc, and stfpc inline assemblies at
several locations, provide an fpu_* function for each instruction and
use the function instead.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Deduplicate the 64 ld and std inline assemblies. Provide an fpu inline
assembly for both instructions, and use them in the new save_fp_regs()
and load_fp_regs() helper functions.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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The only user of sfpc_safe() needs to read the new fpc register value
from memory before it is set with sfpc.
Avoid this indirection and use lfpc, which reads the new value from
memory. Also add the "fpu_" prefix to have a common name space for fpu
related inline assemblies, and provide memory access instrumentation.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Add documentation which describes what the fpu helper functions are
good for, and why they should be used.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Move, rename, and merge the fpu and vx header files. This way fpu header
files have a consistent naming scheme (fpu*.h).
Also get rid of the fpu subdirectory and move header files to asm
directory, so that all fpu and vx header files can be found at the same
location.
Merge internal.h header file into other header files, since the internal
helpers are used at many locations. so those helper functions are really
not internal.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Address various checkpatch warnings, adjust whitespace, and try to increase
readability. This is just preparation, in order to avoid that subsequent
patches contain any distracting drive-by coding style changes.
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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The v1, v2, v3, and v4 parameters of the RXB macro are a bit misleading,
since the reader can assume that the parameters always correlate with the
instructions format fields V1, V2, V3, and V4 as defined in the Principles
of Operation.
This is not the case for a couple of instructions, therefore improve the
description of the macro.
Suggested by Jens Remus, who also provided the improved description.
Suggested-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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The VLGV macro generates the VLGV instruction and has a vr parameter which
correlates to the V3 vector register field of the instruction (bits 12-15).
Due to its position in the VRS-c instruction format of the VLGV
instruction, this field correlates to the second bit of the RXB byte of the
instruction (see Principles of Operation, Chapter "Vector Overview and
Support Instructions").
Within the VLGV macro the MRXBOPC macro is used to generate the RXB field
of the instruction. The usage of the MRXBOPC macro is incorrect, since the
vector register number is passed as third parameter (which correlates to
the first bit of the RXB byte), while it should be passed as fourth
parameter (second bit of the RXB byte). In result an incorrect instruction
would be generated if the VLGV macro would be used for vector register
numbers larger than 15.
Fix this and pass the vector register number as fourth parameter.
Currently there are no users within the kernel which use the macro in a way
that broken code would be generated.
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Commit e21f8baf8d9a ("s390/bug: add entry size to the __bug_table section")
changed the __EMIT_BUG() inline assembly to emit mergeable __bug_table
entries. This is at least currently not needed, but causes problems with
the upcoming s390 ld.lld support:
ld.lld: error: drivers/nvme/host/fc.o:(__bug_table): writable SHF_MERGE section is not supported
Therefore revert the change for now.
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/all/20240207-s390-lld-and-orphan-warn-v1-0-8a665b3346ab@kernel.org/
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Move the switch_to() implementation to process.c and use the generic
switch_to.h header file instead, like some other architectures.
This addresses also the oddity that the old switch_to() implementation
assigns the return value of __switch_to() to 'prev' instead of 'last',
like it should.
Remove also all includes of switch_to.h from C files, except process.c.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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save_access_regs() and restore_access_regs() are only available by
including switch_to.h. This is done by a couple of C files, which have
nothing to do with switch_to(), but only need these functions.
Move both functions to a new header file and improve the implementation:
- Get rid of typedef
- Add memory access instrumentation support
- Use long displacement instructions lamy/stamy instead of lam/stam - all
current users end up with better code because of this
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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We've had issues with gcc and 'asm goto' before, and we created a
'asm_volatile_goto()' macro for that in the past: see commits
3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation
bug") and a9f180345f53 ("compiler/gcc4: Make quirk for
asm_volatile_goto() unconditional").
Then, much later, we ended up removing the workaround in commit
43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR
58670") because we no longer supported building the kernel with the
affected gcc versions, but we left the macro uses around.
Now, Sean Christopherson reports a new version of a very similar
problem, which is fixed by re-applying that ancient workaround. But the
problem in question is limited to only the 'asm goto with outputs'
cases, so instead of re-introducing the old workaround as-is, let's
rename and limit the workaround to just that much less common case.
It looks like there are at least two separate issues that all hit in
this area:
(a) some versions of gcc don't mark the asm goto as 'volatile' when it
has outputs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420
which is easy to work around by just adding the 'volatile' by hand.
(b) Internal compiler errors:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422
which are worked around by adding the extra empty 'asm' as a
barrier, as in the original workaround.
but the problem Sean sees may be a third thing since it involves bad
code generation (not an ICE) even with the manually added 'volatile'.
but the same old workaround works for this case, even if this feels a
bit like voodoo programming and may only be hiding the issue.
Reported-and-tested-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Andrew Pinski <quic_apinski@quicinc.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Code sections in s390 specific kernel code which use floating point or
vector registers all come with a 520 byte stack variable to save already in
use registers, if required.
With INIT_STACK_ALL_PATTERN or INIT_STACK_ALL_ZERO enabled this variable
will always be initialized on function entry in addition to saving register
contents, which contradicts the intention (performance improvement) of such
code sections.
Therefore provide a DECLARE_KERNEL_FPU_ONSTACK() macro which provides
struct kernel_fpu variables with an __uninitialized attribute, and convert
all existing code to use this.
This way only this specific type of stack variable will not be initialized,
regardless of config options.
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240205154844.3757121-3-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Add missing virt_to_phys() translation to diag0c(). This doesn't fix a
bug since virtual and physical addresses are currently the same.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Fix virtual vs physical address confusion (which currently are the same).
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Fix virtual vs physical address confusion (which currently are the same).
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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This patch creates wordpart.h and includes it in asm/word-at-a-time.h
for all architectures. WORD_AT_A_TIME_CONSTANTS depends on kernel.h
because of REPEAT_BYTE. Moving this to another header and including it
where necessary allows us to not include the bloated kernel.h. Making
this implicit dependency on REPEAT_BYTE explicit allows for later
improvements in the lib/string.c inclusion list.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Tanzir Hasan <tanzirh@google.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20231226-libstringheader-v6-1-80aa08c7652c@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull more s390 updates from Alexander Gordeev:
- do not enable by default the support of 31-bit Enterprise Systems
Architecture (ESA) ELF binaries
- drop automatic CONFIG_KEXEC selection, while set CONFIG_KEXEC=y
explicitly for defconfig and debug_defconfig only
- fix zpci_get_max_io_size() to allow PCI block stores where normal PCI
stores were used otherwise
- remove unneeded tsk variable in do_exception() fault handler
- __load_fpu_regs() is only called from the core kernel code.
Therefore, remove not needed EXPORT_SYMBOL.
- remove leftover comment from s390_fpregs_set() callback
- few cleanups to Processor Activity Instrumentation (PAI) code (which
perf framework is based on)
- replace Wenjia Zhang with Thorsten Winkler as s390 Inter-User
Communication Vehicle (IUCV) networking maintainer
- Fix all scenarios where queues previously removed from a guest's
Adjunct-Processor (AP) configuration do not re-appear in a reset
state when they are subsequently made available to a guest again
* tag 's390-6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/vfio-ap: do not reset queue removed from host config
s390/vfio-ap: reset queues associated with adapter for queue unbound from driver
s390/vfio-ap: reset queues filtered from the guest's AP config
s390/vfio-ap: let on_scan_complete() callback filter matrix and update guest's APCB
s390/vfio-ap: loop over the shadow APCB when filtering guest's AP configuration
s390/vfio-ap: always filter entire AP matrix
s390/net: add Thorsten Winkler as maintainer
s390/pai_ext: split function paiext_push_sample
s390/pai_ext: rework function paiext_copy argments
s390/pai: rework paiXXX_start and paiXXX_stop functions
s390/pai_crypto: split function paicrypt_push_sample
s390/pai: rework paixxxx_getctr interface
s390/ptrace: remove leftover comment
s390/fpu: remove __load_fpu_regs() export
s390/mm,fault: remove not needed tsk variable
s390/pci: fix max size calculation in zpci_memcpy_toio()
s390/kexec: do not automatically select KEXEC option
s390/compat: change default for CONFIG_COMPAT to "n"
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Pull kvm updates from Paolo Bonzini:
"Generic:
- Use memdup_array_user() to harden against overflow.
- Unconditionally advertise KVM_CAP_DEVICE_CTRL for all
architectures.
- Clean up Kconfigs that all KVM architectures were selecting
- New functionality around "guest_memfd", a new userspace API that
creates an anonymous file and returns a file descriptor that refers
to it. guest_memfd files are bound to their owning virtual machine,
cannot be mapped, read, or written by userspace, and cannot be
resized. guest_memfd files do however support PUNCH_HOLE, which can
be used to switch a memory area between guest_memfd and regular
anonymous memory.
- New ioctl KVM_SET_MEMORY_ATTRIBUTES allowing userspace to specify
per-page attributes for a given page of guest memory; right now the
only attribute is whether the guest expects to access memory via
guest_memfd or not, which in Confidential SVMs backed by SEV-SNP,
TDX or ARM64 pKVM is checked by firmware or hypervisor that
guarantees confidentiality (AMD PSP, Intel TDX module, or EL2 in
the case of pKVM).
x86:
- Support for "software-protected VMs" that can use the new
guest_memfd and page attributes infrastructure. This is mostly
useful for testing, since there is no pKVM-like infrastructure to
provide a meaningfully reduced TCB.
- Fix a relatively benign off-by-one error when splitting huge pages
during CLEAR_DIRTY_LOG.
- Fix a bug where KVM could incorrectly test-and-clear dirty bits in
non-leaf TDP MMU SPTEs if a racing thread replaces a huge SPTE with
a non-huge SPTE.
- Use more generic lockdep assertions in paths that don't actually
care about whether the caller is a reader or a writer.
- let Xen guests opt out of having PV clock reported as "based on a
stable TSC", because some of them don't expect the "TSC stable" bit
(added to the pvclock ABI by KVM, but never set by Xen) to be set.
- Revert a bogus, made-up nested SVM consistency check for
TLB_CONTROL.
- Advertise flush-by-ASID support for nSVM unconditionally, as KVM
always flushes on nested transitions, i.e. always satisfies flush
requests. This allows running bleeding edge versions of VMware
Workstation on top of KVM.
- Sanity check that the CPU supports flush-by-ASID when enabling SEV
support.
- On AMD machines with vNMI, always rely on hardware instead of
intercepting IRET in some cases to detect unmasking of NMIs
- Support for virtualizing Linear Address Masking (LAM)
- Fix a variety of vPMU bugs where KVM fail to stop/reset counters
and other state prior to refreshing the vPMU model.
- Fix a double-overflow PMU bug by tracking emulated counter events
using a dedicated field instead of snapshotting the "previous"
counter. If the hardware PMC count triggers overflow that is
recognized in the same VM-Exit that KVM manually bumps an event
count, KVM would pend PMIs for both the hardware-triggered overflow
and for KVM-triggered overflow.
- Turn off KVM_WERROR by default for all configs so that it's not
inadvertantly enabled by non-KVM developers, which can be
problematic for subsystems that require no regressions for W=1
builds.
- Advertise all of the host-supported CPUID bits that enumerate
IA32_SPEC_CTRL "features".
- Don't force a masterclock update when a vCPU synchronizes to the
current TSC generation, as updating the masterclock can cause
kvmclock's time to "jump" unexpectedly, e.g. when userspace
hotplugs a pre-created vCPU.
- Use RIP-relative address to read kvm_rebooting in the VM-Enter
fault paths, partly as a super minor optimization, but mostly to
make KVM play nice with position independent executable builds.
- Guard KVM-on-HyperV's range-based TLB flush hooks with an #ifdef on
CONFIG_HYPERV as a minor optimization, and to self-document the
code.
- Add CONFIG_KVM_HYPERV to allow disabling KVM support for HyperV
"emulation" at build time.
ARM64:
- LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB base
granule sizes. Branch shared with the arm64 tree.
- Large Fine-Grained Trap rework, bringing some sanity to the
feature, although there is more to come. This comes with a prefix
branch shared with the arm64 tree.
- Some additional Nested Virtualization groundwork, mostly
introducing the NV2 VNCR support and retargetting the NV support to
that version of the architecture.
- A small set of vgic fixes and associated cleanups.
Loongarch:
- Optimization for memslot hugepage checking
- Cleanup and fix some HW/SW timer issues
- Add LSX/LASX (128bit/256bit SIMD) support
RISC-V:
- KVM_GET_REG_LIST improvement for vector registers
- Generate ISA extension reg_list using macros in get-reg-list
selftest
- Support for reporting steal time along with selftest
s390:
- Bugfixes
Selftests:
- Fix an annoying goof where the NX hugepage test prints out garbage
instead of the magic token needed to run the test.
- Fix build errors when a header is delete/moved due to a missing
flag in the Makefile.
- Detect if KVM bugged/killed a selftest's VM and print out a helpful
message instead of complaining that a random ioctl() failed.
- Annotate the guest printf/assert helpers with __printf(), and fix
the various bugs that were lurking due to lack of said annotation"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (185 commits)
x86/kvm: Do not try to disable kvmclock if it was not enabled
KVM: x86: add missing "depends on KVM"
KVM: fix direction of dependency on MMU notifiers
KVM: introduce CONFIG_KVM_COMMON
KVM: arm64: Add missing memory barriers when switching to pKVM's hyp pgd
KVM: arm64: vgic-its: Avoid potential UAF in LPI translation cache
RISC-V: KVM: selftests: Add get-reg-list test for STA registers
RISC-V: KVM: selftests: Add steal_time test support
RISC-V: KVM: selftests: Add guest_sbi_probe_extension
RISC-V: KVM: selftests: Move sbi_ecall to processor.c
RISC-V: KVM: Implement SBI STA extension
RISC-V: KVM: Add support for SBI STA registers
RISC-V: KVM: Add support for SBI extension registers
RISC-V: KVM: Add SBI STA info to vcpu_arch
RISC-V: KVM: Add steal-update vcpu request
RISC-V: KVM: Add SBI STA extension skeleton
RISC-V: paravirt: Implement steal-time support
RISC-V: Add SBI STA extension definitions
RISC-V: paravirt: Add skeleton for pv-time support
RISC-V: KVM: Fix indentation in kvm_riscv_vcpu_set_reg_csr()
...
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The zpci_get_max_write_size() helper is used to determine the maximum
size a PCI store or load can use at a given __iomem address.
For the PCI block store the following restrictions apply:
1. The dst + len must not cross a 4K boundary in the (pseudo-)MMIO space
2. len must not exceed ZPCI_MAX_WRITE_SIZE
3. len must be a multiple of 8 bytes
4. The src address must be double word (8 byte) aligned
5. The dst address must be double word (8 byte) aligned
Otherwise only a normal PCI store which takes its src value from
a register can be used. For these PCI store restriction 1 still applies.
Similarly 1 also applies to PCI loads.
It turns out zpci_max_write_size() instead implements stricter
conditions which prevents PCI block stores from being used where they
can and should be used. In particular instead of conditions 4 and 5 it
wrongly enforces both dst and src to be size aligned. This indirectly
covers condition 1 but also prevents many legal PCI block stores.
On top of the functional shortcomings the zpci_get_max_write_size() is
misnamed as it is used for both read and write size calculations. Rename
it to zpci_get_max_io_size() and implement the listed conditions
explicitly.
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Fixes: cd24834130ac ("s390/pci: base support")
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
[agordeev@linux.ibm.com replaced spaces with tabs]
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Alexander Gordeev:
- Add machine variable capacity information to /proc/sysinfo.
- Limit the waste of page tables and always align vmalloc area size and
base address on segment boundary.
- Fix a memory leak when an attempt to register interruption sub class
(ISC) for the adjunct-processor (AP) guest failed.
- Reset response code AP_RESPONSE_INVALID_GISA to understandable by
guest AP_RESPONSE_INVALID_ADDRESS in response to a failed
interruption sub class (ISC) registration attempt.
- Improve reaction to adjunct-processor (AP)
AP_RESPONSE_OTHERWISE_CHANGED response code when enabling interrupts
on behalf of a guest.
- Fix incorrect sysfs 'status' attribute of adjunct-processor (AP)
queue device bound to the vfio_ap device driver when the mediated
device is attached to a guest, but the queue device is not passed
through.
- Rework struct ap_card to hold the whole adjunct-processor (AP) card
hardware information. As result, all the ugly bit checks are replaced
by simple evaluations of the required bit fields.
- Improve handling of some weird scenarios between service element (SE)
host and SE guest with adjunct-processor (AP) pass-through support.
- Change local_ctl_set_bit() and local_ctl_clear_bit() so they return
the previous value of the to be changed control register. This is
useful if a bit is only changed temporarily and the previous content
needs to be restored.
- The kernel starts with machine checks disabled and is expected to
enable it once trap_init() is called. However the implementation
allows machine checks early. Consistently enable it in trap_init()
only.
- local_mcck_disable() and local_mcck_enable() assume that machine
checks are always enabled. Instead implement and use
local_mcck_save() and local_mcck_restore() to disable machine checks
and restore the previous state.
- Modification of floating point control (FPC) register of a traced
process using ptrace interface may lead to corruption of the FPC
register of the tracing process. Fix this.
- kvm_arch_vcpu_ioctl_set_fpu() allows to set the floating point
control (FPC) register in vCPU, but may lead to corruption of the FPC
register of the host process. Fix this.
- Use READ_ONCE() to read a vCPU floating point register value from the
memory mapped area. This avoids that, depending on code generation, a
different value is tested for validity than the one that is used.
- Get rid of test_fp_ctl(), since it is quite subtle to use it
correctly. Instead copy a new floating point control register value
into its save area and test the validity of the new value when
loading it.
- Remove superfluous save_fpu_regs() call.
- Remove s390 support for ARCH_WANTS_DYNAMIC_TASK_STRUCT. All machines
provide the vector facility since many years and the need to make the
task structure size dependent on the vector facility does not exist.
- Remove the "novx" kernel command line option, as the vector code runs
without any problems since many years.
- Add the vector facility to the z13 architecture level set (ALS). All
hypervisors support the vector facility since many years. This allows
compile time optimizations of the kernel.
- Get rid of MACHINE_HAS_VX and replace it with cpu_has_vx(). As
result, the compiled code will have less runtime checks and less
code.
- Convert pgste_get_lock() and pgste_set_unlock() ASM inlines to C.
- Convert the struct subchannel spinlock from pointer to member.
* tag 's390-6.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (24 commits)
Revert "s390: update defconfigs"
s390/cio: make sch->lock spinlock pointer a member
s390: update defconfigs
s390/mm: convert pgste locking functions to C
s390/fpu: get rid of MACHINE_HAS_VX
s390/als: add vector facility to z13 architecture level set
s390/fpu: remove "novx" option
s390/fpu: remove ARCH_WANTS_DYNAMIC_TASK_STRUCT support
KVM: s390: remove superfluous save_fpu_regs() call
s390/fpu: get rid of test_fp_ctl()
KVM: s390: use READ_ONCE() to read fpc register value
KVM: s390: fix setting of fpc register
s390/ptrace: handle setting of fpc register correctly
s390/nmi: implement and use local_mcck_save() / local_mcck_restore()
s390/nmi: consistently enable machine checks in trap_init()
s390/ctlreg: return old register contents when changing bits
s390/ap: handle outband SE bind state change
s390/ap: store TAPQ hwinfo in struct ap_card
s390/vfio-ap: fix sysfs status attribute for AP queue devices
s390/vfio-ap: improve reaction to response code 07 from PQAP(AQIC) command
...
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