The asm version of the kernel mapping code works fine for creating a
coarse grained identity map, but for mapping the kernel down to its
exact boundaries with the right attributes, it is not suitable. This is
why we create a preliminary RWX kernel mapping first, and then rebuild
it from scratch later on.
So let's reimplement this in C, in a way that will make it unnecessary
to create the kernel page tables yet another time in paging_init().
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-63-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
To permit the feature overrides to be taken into account before the
KASLR init code runs and the kernel mapping is created, move the
detection code to an earlier stage in the boot.
In a subsequent patch, this will be taken advantage of by merging the
preliminary and permanent mappings of the kernel text and data into a
single one that gets created and relocated before start_kernel() is
called.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-53-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We will move the CPU feature overrides into BSS in a subsequent patch,
and this requires that BSS is zeroed before the feature override
detection code runs. So let's map BSS read-write in the ID map, and zero
it via this mapping.
Since the kernel page tables are right next to it, and also zeroed via
the ID map, let's drop the separate clear_page_tables() function, and
just zero everything in one go.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-51-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Now that we have a mini C runtime before the kernel mapping is up, we
can move the non-trivial relocation processing code out of head.S and
reimplement it in C.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-48-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Currently, the .got section is placed within the output section .text.
However, when .got is non-empty, the SHF_WRITE flag is set for .text
when linked by lld. GNU ld recognizes .text as a special section and
ignores the SHF_WRITE flag. By renaming .text, we can also get the
SHF_WRITE flag.
The kernel has performed R_AARCH64_RELATIVE resolving very early, and can
then assume that .got is read-only. Let's move .got to the vmlinux_rodata
pseudo-segment.
As Ard Biesheuvel notes:
"This matters to consumers of the vmlinux ELF representation of the
kernel image, such as syzkaller, which disregards writable PT_LOAD
segments when resolving code symbols. The kernel itself does not care
about this distinction, but given that the GOT contains data and not
code, it does not require executable permissions, and therefore does
not belong in .text to begin with."
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20230502074105.1541926-1-maskray@google.com
Signed-off-by: Will Deacon <will@kernel.org>
- Support for arm64 SME 2 and 2.1. SME2 introduces a new 512-bit
architectural register (ZT0, for the look-up table feature) that Linux
needs to save/restore.
- Include TPIDR2 in the signal context and add the corresponding
kselftests.
- Perf updates: Arm SPEv1.2 support, HiSilicon uncore PMU updates, ACPI
support to the Marvell DDR and TAD PMU drivers, reset DTM_PMU_CONFIG
(ARM CMN) at probe time.
- Support for DYNAMIC_FTRACE_WITH_CALL_OPS on arm64.
- Permit EFI boot with MMU and caches on. Instead of cleaning the entire
loaded kernel image to the PoC and disabling the MMU and caches before
branching to the kernel bare metal entry point, leave the MMU and
caches enabled and rely on EFI's cacheable 1:1 mapping of all of
system RAM to populate the initial page tables.
- Expose the AArch32 (compat) ELF_HWCAP features to user in an arm64
kernel (the arm32 kernel only defines the values).
- Harden the arm64 shadow call stack pointer handling: stash the shadow
stack pointer in the task struct on interrupt, load it directly from
this structure.
- Signal handling cleanups to remove redundant validation of size
information and avoid reading the same data from userspace twice.
- Refactor the hwcap macros to make use of the automatically generated
ID registers. It should make new hwcaps writing less error prone.
- Further arm64 sysreg conversion and some fixes.
- arm64 kselftest fixes and improvements.
- Pointer authentication cleanups: don't sign leaf functions, unify
asm-arch manipulation.
- Pseudo-NMI code generation optimisations.
- Minor fixes for SME and TPIDR2 handling.
- Miscellaneous updates: ARCH_FORCE_MAX_ORDER is now selectable, replace
strtobool() to kstrtobool() in the cpufeature.c code, apply dynamic
shadow call stack in two passes, intercept pfn changes in set_pte_at()
without the required break-before-make sequence, attempt to dump all
instructions on unhandled kernel faults.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- Support for arm64 SME 2 and 2.1. SME2 introduces a new 512-bit
architectural register (ZT0, for the look-up table feature) that
Linux needs to save/restore
- Include TPIDR2 in the signal context and add the corresponding
kselftests
- Perf updates: Arm SPEv1.2 support, HiSilicon uncore PMU updates, ACPI
support to the Marvell DDR and TAD PMU drivers, reset DTM_PMU_CONFIG
(ARM CMN) at probe time
- Support for DYNAMIC_FTRACE_WITH_CALL_OPS on arm64
- Permit EFI boot with MMU and caches on. Instead of cleaning the
entire loaded kernel image to the PoC and disabling the MMU and
caches before branching to the kernel bare metal entry point, leave
the MMU and caches enabled and rely on EFI's cacheable 1:1 mapping of
all of system RAM to populate the initial page tables
- Expose the AArch32 (compat) ELF_HWCAP features to user in an arm64
kernel (the arm32 kernel only defines the values)
- Harden the arm64 shadow call stack pointer handling: stash the shadow
stack pointer in the task struct on interrupt, load it directly from
this structure
- Signal handling cleanups to remove redundant validation of size
information and avoid reading the same data from userspace twice
- Refactor the hwcap macros to make use of the automatically generated
ID registers. It should make new hwcaps writing less error prone
- Further arm64 sysreg conversion and some fixes
- arm64 kselftest fixes and improvements
- Pointer authentication cleanups: don't sign leaf functions, unify
asm-arch manipulation
- Pseudo-NMI code generation optimisations
- Minor fixes for SME and TPIDR2 handling
- Miscellaneous updates: ARCH_FORCE_MAX_ORDER is now selectable,
replace strtobool() to kstrtobool() in the cpufeature.c code, apply
dynamic shadow call stack in two passes, intercept pfn changes in
set_pte_at() without the required break-before-make sequence, attempt
to dump all instructions on unhandled kernel faults
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (130 commits)
arm64: fix .idmap.text assertion for large kernels
kselftest/arm64: Don't require FA64 for streaming SVE+ZA tests
kselftest/arm64: Copy whole EXTRA context
arm64: kprobes: Drop ID map text from kprobes blacklist
perf: arm_spe: Print the version of SPE detected
perf: arm_spe: Add support for SPEv1.2 inverted event filtering
perf: Add perf_event_attr::config3
arm64/sme: Fix __finalise_el2 SMEver check
drivers/perf: fsl_imx8_ddr_perf: Remove set-but-not-used variable
arm64/signal: Only read new data when parsing the ZT context
arm64/signal: Only read new data when parsing the ZA context
arm64/signal: Only read new data when parsing the SVE context
arm64/signal: Avoid rereading context frame sizes
arm64/signal: Make interface for restore_fpsimd_context() consistent
arm64/signal: Remove redundant size validation from parse_user_sigframe()
arm64/signal: Don't redundantly verify FPSIMD magic
arm64/cpufeature: Use helper macros to specify hwcaps
arm64/cpufeature: Always use symbolic name for feature value in hwcaps
arm64/sysreg: Initial unsigned annotations for ID registers
arm64/sysreg: Initial annotation of signed ID registers
...
* arm64/for-next/perf:
perf: arm_spe: Print the version of SPE detected
perf: arm_spe: Add support for SPEv1.2 inverted event filtering
perf: Add perf_event_attr::config3
drivers/perf: fsl_imx8_ddr_perf: Remove set-but-not-used variable
perf: arm_spe: Support new SPEv1.2/v8.7 'not taken' event
perf: arm_spe: Use new PMSIDR_EL1 register enums
perf: arm_spe: Drop BIT() and use FIELD_GET/PREP accessors
arm64/sysreg: Convert SPE registers to automatic generation
arm64: Drop SYS_ from SPE register defines
perf: arm_spe: Use feature numbering for PMSEVFR_EL1 defines
perf/marvell: Add ACPI support to TAD uncore driver
perf/marvell: Add ACPI support to DDR uncore driver
perf/arm-cmn: Reset DTM_PMU_CONFIG at probe
drivers/perf: hisi: Extract initialization of "cpa_pmu->pmu"
drivers/perf: hisi: Simplify the parameters of hisi_pmu_init()
drivers/perf: hisi: Advertise the PERF_PMU_CAP_NO_EXCLUDE capability
* for-next/sysreg:
: arm64 sysreg and cpufeature fixes/updates
KVM: arm64: Use symbolic definition for ISR_EL1.A
arm64/sysreg: Add definition of ISR_EL1
arm64/sysreg: Add definition for ICC_NMIAR1_EL1
arm64/cpufeature: Remove 4 bit assumption in ARM64_FEATURE_MASK()
arm64/sysreg: Fix errors in 32 bit enumeration values
arm64/cpufeature: Fix field sign for DIT hwcap detection
* for-next/sme:
: SME-related updates
arm64/sme: Optimise SME exit on syscall entry
arm64/sme: Don't use streaming mode to probe the maximum SME VL
arm64/ptrace: Use system_supports_tpidr2() to check for TPIDR2 support
* for-next/kselftest: (23 commits)
: arm64 kselftest fixes and improvements
kselftest/arm64: Don't require FA64 for streaming SVE+ZA tests
kselftest/arm64: Copy whole EXTRA context
kselftest/arm64: Fix enumeration of systems without 128 bit SME for SSVE+ZA
kselftest/arm64: Fix enumeration of systems without 128 bit SME
kselftest/arm64: Don't require FA64 for streaming SVE tests
kselftest/arm64: Limit the maximum VL we try to set via ptrace
kselftest/arm64: Correct buffer size for SME ZA storage
kselftest/arm64: Remove the local NUM_VL definition
kselftest/arm64: Verify simultaneous SSVE and ZA context generation
kselftest/arm64: Verify that SSVE signal context has SVE_SIG_FLAG_SM set
kselftest/arm64: Remove spurious comment from MTE test Makefile
kselftest/arm64: Support build of MTE tests with clang
kselftest/arm64: Initialise current at build time in signal tests
kselftest/arm64: Don't pass headers to the compiler as source
kselftest/arm64: Remove redundant _start labels from FP tests
kselftest/arm64: Fix .pushsection for strings in FP tests
kselftest/arm64: Run BTI selftests on systems without BTI
kselftest/arm64: Fix test numbering when skipping tests
kselftest/arm64: Skip non-power of 2 SVE vector lengths in fp-stress
kselftest/arm64: Only enumerate power of two VLs in syscall-abi
...
* for-next/misc:
: Miscellaneous arm64 updates
arm64/mm: Intercept pfn changes in set_pte_at()
Documentation: arm64: correct spelling
arm64: traps: attempt to dump all instructions
arm64: Apply dynamic shadow call stack patching in two passes
arm64: el2_setup.h: fix spelling typo in comments
arm64: Kconfig: fix spelling
arm64: cpufeature: Use kstrtobool() instead of strtobool()
arm64: Avoid repeated AA64MMFR1_EL1 register read on pagefault path
arm64: make ARCH_FORCE_MAX_ORDER selectable
* for-next/sme2: (23 commits)
: Support for arm64 SME 2 and 2.1
arm64/sme: Fix __finalise_el2 SMEver check
kselftest/arm64: Remove redundant _start labels from zt-test
kselftest/arm64: Add coverage of SME 2 and 2.1 hwcaps
kselftest/arm64: Add coverage of the ZT ptrace regset
kselftest/arm64: Add SME2 coverage to syscall-abi
kselftest/arm64: Add test coverage for ZT register signal frames
kselftest/arm64: Teach the generic signal context validation about ZT
kselftest/arm64: Enumerate SME2 in the signal test utility code
kselftest/arm64: Cover ZT in the FP stress test
kselftest/arm64: Add a stress test program for ZT0
arm64/sme: Add hwcaps for SME 2 and 2.1 features
arm64/sme: Implement ZT0 ptrace support
arm64/sme: Implement signal handling for ZT
arm64/sme: Implement context switching for ZT0
arm64/sme: Provide storage for ZT0
arm64/sme: Add basic enumeration for SME2
arm64/sme: Enable host kernel to access ZT0
arm64/sme: Manually encode ZT0 load and store instructions
arm64/esr: Document ISS for ZT0 being disabled
arm64/sme: Document SME 2 and SME 2.1 ABI
...
* for-next/tpidr2:
: Include TPIDR2 in the signal context
kselftest/arm64: Add test case for TPIDR2 signal frame records
kselftest/arm64: Add TPIDR2 to the set of known signal context records
arm64/signal: Include TPIDR2 in the signal context
arm64/sme: Document ABI for TPIDR2 signal information
* for-next/scs:
: arm64: harden shadow call stack pointer handling
arm64: Stash shadow stack pointer in the task struct on interrupt
arm64: Always load shadow stack pointer directly from the task struct
* for-next/compat-hwcap:
: arm64: Expose compat ARMv8 AArch32 features (HWCAPs)
arm64: Add compat hwcap SSBS
arm64: Add compat hwcap SB
arm64: Add compat hwcap I8MM
arm64: Add compat hwcap ASIMDBF16
arm64: Add compat hwcap ASIMDFHM
arm64: Add compat hwcap ASIMDDP
arm64: Add compat hwcap FPHP and ASIMDHP
* for-next/ftrace:
: Add arm64 support for DYNAMICE_FTRACE_WITH_CALL_OPS
arm64: avoid executing padding bytes during kexec / hibernation
arm64: Implement HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS
arm64: ftrace: Update stale comment
arm64: patching: Add aarch64_insn_write_literal_u64()
arm64: insn: Add helpers for BTI
arm64: Extend support for CONFIG_FUNCTION_ALIGNMENT
ACPI: Don't build ACPICA with '-Os'
Compiler attributes: GCC cold function alignment workarounds
ftrace: Add DYNAMIC_FTRACE_WITH_CALL_OPS
* for-next/efi-boot-mmu-on:
: Permit arm64 EFI boot with MMU and caches on
arm64: kprobes: Drop ID map text from kprobes blacklist
arm64: head: Switch endianness before populating the ID map
efi: arm64: enter with MMU and caches enabled
arm64: head: Clean the ID map and the HYP text to the PoC if needed
arm64: head: avoid cache invalidation when entering with the MMU on
arm64: head: record the MMU state at primary entry
arm64: kernel: move identity map out of .text mapping
arm64: head: Move all finalise_el2 calls to after __enable_mmu
* for-next/ptrauth:
: arm64 pointer authentication cleanup
arm64: pauth: don't sign leaf functions
arm64: unify asm-arch manipulation
* for-next/pseudo-nmi:
: Pseudo-NMI code generation optimisations
arm64: irqflags: use alternative branches for pseudo-NMI logic
arm64: add ARM64_HAS_GIC_PRIO_RELAXED_SYNC cpucap
arm64: make ARM64_HAS_GIC_PRIO_MASKING depend on ARM64_HAS_GIC_CPUIF_SYSREGS
arm64: rename ARM64_HAS_IRQ_PRIO_MASKING to ARM64_HAS_GIC_PRIO_MASKING
arm64: rename ARM64_HAS_SYSREG_GIC_CPUIF to ARM64_HAS_GIC_CPUIF_SYSREGS
Currently we rely on the HIBERNATE_TEXT section starting with the entry
point to swsusp_arch_suspend_exit, and the KEXEC_TEXT section starting
with the entry point to arm64_relocate_new_kernel. In both cases we copy
the entire section into a dynamically-allocated page, and then later
branch to the start of this page.
SYM_FUNC_START() will align the function entry points to
CONFIG_FUNCTION_ALIGNMENT, and when the linker later processes the
assembled code it will place padding bytes before the function entry
point if the location counter was not already sufficiently aligned. The
linker happens to use the value zero for these padding bytes.
This padding may end up being applied whenever CONFIG_FUNCTION_ALIGNMENT
is greater than 4, which can be the case with
CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B=y or
CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS=y.
When such padding is applied, attempting to kexec or resume from
hibernate will result ina crash: the kernel will branch to the padding
bytes as the start of the dynamically-allocated page, and as those bytes
are zero they will decode as UDF #0, which reliably triggers an
UNDEFINED exception. For example:
| # ./kexec --reuse-cmdline -f Image
| [ 46.965800] kexec_core: Starting new kernel
| [ 47.143641] psci: CPU1 killed (polled 0 ms)
| [ 47.233653] psci: CPU2 killed (polled 0 ms)
| [ 47.323465] psci: CPU3 killed (polled 0 ms)
| [ 47.324776] Bye!
| [ 47.327072] Internal error: Oops - Undefined instruction: 0000000002000000 [#1] SMP
| [ 47.328510] Modules linked in:
| [ 47.329086] CPU: 0 PID: 259 Comm: kexec Not tainted 6.2.0-rc5+ #3
| [ 47.330223] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
| [ 47.331497] pstate: 604003c5 (nZCv DAIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| [ 47.332782] pc : 0x43a95000
| [ 47.333338] lr : machine_kexec+0x190/0x1e0
| [ 47.334169] sp : ffff80000d293b70
| [ 47.334845] x29: ffff80000d293b70 x28: ffff000002cc0000 x27: 0000000000000000
| [ 47.336292] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
| [ 47.337744] x23: ffff80000a837858 x22: 0000000048ec9000 x21: 0000000000000010
| [ 47.339192] x20: 00000000adc83000 x19: ffff000000827000 x18: 0000000000000006
| [ 47.340638] x17: ffff800075a61000 x16: ffff800008000000 x15: ffff80000d293658
| [ 47.342085] x14: 0000000000000000 x13: ffff80000d2937f7 x12: ffff80000a7ff6e0
| [ 47.343530] x11: 00000000ffffdfff x10: ffff80000a8ef8e0 x9 : ffff80000813ef00
| [ 47.344976] x8 : 000000000002ffe8 x7 : c0000000ffffdfff x6 : 00000000000affa8
| [ 47.346431] x5 : 0000000000001fff x4 : 0000000000000001 x3 : ffff80000a0a3008
| [ 47.347877] x2 : ffff80000a8220f8 x1 : 0000000043a95000 x0 : ffff000000827000
| [ 47.349334] Call trace:
| [ 47.349834] 0x43a95000
| [ 47.350338] kernel_kexec+0x88/0x100
| [ 47.351070] __do_sys_reboot+0x108/0x268
| [ 47.351873] __arm64_sys_reboot+0x2c/0x40
| [ 47.352689] invoke_syscall+0x78/0x108
| [ 47.353458] el0_svc_common.constprop.0+0x4c/0x100
| [ 47.354426] do_el0_svc+0x34/0x50
| [ 47.355102] el0_svc+0x34/0x108
| [ 47.355747] el0t_64_sync_handler+0xf4/0x120
| [ 47.356617] el0t_64_sync+0x194/0x198
| [ 47.357374] Code: bad PC value
| [ 47.357999] ---[ end trace 0000000000000000 ]---
| [ 47.358937] Kernel panic - not syncing: Oops - Undefined instruction: Fatal exception
| [ 47.360515] Kernel Offset: disabled
| [ 47.361230] CPU features: 0x002000,00050108,c8004203
| [ 47.362232] Memory Limit: none
Note: Unfortunately the code dump reports "bad PC value" as it attempts
to dump some instructions prior to the UDF (i.e. before the start of the
page), and terminates early upon a fault, obscuring the problem.
This patch fixes this issue by aligning the section starter markes to
CONFIG_FUNCTION_ALIGNMENT using the ALIGN_FUNCTION() helper, which
ensures that the linker never needs to place padding bytes within the
section. Assertions are added to verify each section begins with the
function we expect, making our implicit requirement explicit.
In future it might be nice to rework the kexec and hibernation code to
decouple the section start from the entry point, but that involves much
more significant changes that come with a higher risk of error, so I've
tried to keep this fix as simple as possible for now.
Fixes: 47a15aa544 ("arm64: Extend support for CONFIG_FUNCTION_ALIGNMENT")
Reported-by: CKI Project <cki-project@redhat.com>
Link: https://lore.kernel.org/linux-arm-kernel/29992.123012504212600261@us-mta-139.us.mimecast.lan/
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reorganize the ID map slightly so that only code that is executed with
the MMU off or via the 1:1 mapping remains. This allows us to move the
identity map out of the .text segment, as it will no longer need
executable permissions via the kernel mapping.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230111102236.1430401-3-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Idle code is very like entry code in that RCU isn't available. As
such, add a little validation.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.373461409@infradead.org
Enable asynchronous unwind table generation for both the core kernel as
well as modules, and emit the resulting .eh_frame sections as init code
so we can use the unwind directives for code patching at boot or module
load time.
This will be used by dynamic shadow call stack support, which will rely
on code patching rather than compiler codegen to emit the shadow call
stack push and pop instructions.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20221027155908.1940624-2-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
* for-next/boot: (34 commits)
arm64: fix KASAN_INLINE
arm64: Add an override for ID_AA64SMFR0_EL1.FA64
arm64: Add the arm64.nosve command line option
arm64: Add the arm64.nosme command line option
arm64: Expose a __check_override primitive for oddball features
arm64: Allow the idreg override to deal with variable field width
arm64: Factor out checking of a feature against the override into a macro
arm64: Allow sticky E2H when entering EL1
arm64: Save state of HCR_EL2.E2H before switch to EL1
arm64: Rename the VHE switch to "finalise_el2"
arm64: mm: fix booting with 52-bit address space
arm64: head: remove __PHYS_OFFSET
arm64: lds: use PROVIDE instead of conditional definitions
arm64: setup: drop early FDT pointer helpers
arm64: head: avoid relocating the kernel twice for KASLR
arm64: kaslr: defer initialization to initcall where permitted
arm64: head: record CPU boot mode after enabling the MMU
arm64: head: populate kernel page tables with MMU and caches on
arm64: head: factor out TTBR1 assignment into a macro
arm64: idreg-override: use early FDT mapping in ID map
...
Formerly, we had to access the RELA and RELR tables via the kernel
mapping that was being relocated, and so deriving the start and end
addresses using ADRP/ADD references was not possible, as the relocation
code runs from the ID map.
Now that we map the entire kernel image via the ID map, we can simplify
this, and just load the entries via the ID map as well.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220624150651.1358849-14-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
As a first step towards avoiding the need to create, tear down and
recreate the kernel virtual mapping with MMU and caches disabled, start
by expanding the ID map so it covers the page tables as well as all
executable code. This will allow us to populate the page tables with the
MMU and caches on, and call KASLR init code before setting up the
virtual mapping.
Since this ID map is only needed at boot, create it as a temporary set
of page tables, and populate the permanent ID map after enabling the MMU
and caches. While at it, switch to read-only attributes for the where
possible, as writable permissions are only needed for the initial kernel
page tables. Note that on 4k granule configurations, the permanent ID
map will now be reduced to a single page rather than a 2M block mapping.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220624150651.1358849-13-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Get rid of some clunky open coded arithmetic on section addresses, by
emitting the trampoline data variables into a separate, dedicated r/o
data section, and putting it at the next page boundary. This way, we can
access the literals via single LDR instruction.
While at it, get rid of other, implicit literals, and use ADRP/ADD or
MOVZ/MOVK sequences, as appropriate. Note that the latter are only
supported for CONFIG_RELOCATABLE=n (which is usually the case if
CONFIG_RANDOMIZE_BASE=n), so update the CPP conditionals to reflect
this.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220622161010.3845775-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
There are a few code sections that are emitted into the kernel's
executable .text segment simply because they contain code, but are
actually never executed via this mapping, so they can happily live in a
region that gets mapped without executable permissions, reducing the
risk of being gadgetized.
Note that the kexec and hibernate region contents are always copied into
a fresh page, and so there is no need to align them as long as the
overall size of each is below 4 KiB.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220429131347.3621090-2-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Adding a second set of vectors to .entry.tramp.text will make it
larger than a single 4K page.
Allow the trampoline text to occupy up to three pages by adding two
more fixmap slots. Previous changes to tramp_valias allowed it to reach
beyond a single page.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
* for-next/kexec:
arm64: trans_pgd: remove trans_pgd_map_page()
arm64: kexec: remove cpu-reset.h
arm64: kexec: remove the pre-kexec PoC maintenance
arm64: kexec: keep MMU enabled during kexec relocation
arm64: kexec: install a copy of the linear-map
arm64: kexec: use ld script for relocation function
arm64: kexec: relocate in EL1 mode
arm64: kexec: configure EL2 vectors for kexec
arm64: kexec: pass kimage as the only argument to relocation function
arm64: kexec: Use dcache ops macros instead of open-coding
arm64: kexec: skip relocation code for inplace kexec
arm64: kexec: flush image and lists during kexec load time
arm64: hibernate: abstract ttrb0 setup function
arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors
arm64: kernel: add helper for booted at EL2 and not VHE
We no longer place anything into a `.fixup` section, so we no longer
need to place those sections into the `.text` section in the main kernel
Image.
Remove the use of `.fixup`.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-14-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Subsequent patches will add specialized handlers for fixups, in addition
to the simple PC fixup and BPF handlers we have today. In preparation,
this patch adds a new `type` field to struct exception_table_entry, and
uses this to distinguish the fixup and BPF cases. A `data` field is also
added so that subsequent patches can associate data specific to each
exception site (e.g. register numbers).
Handlers are named ex_handler_*() for consistency, following the exmaple
of x86. At the same time, get_ex_fixup() is split out into a helper so
that it can be used by other ex_handler_*() functions ins subsequent
patches.
This patch will increase the size of the exception tables, which will be
remedied by subsequent patches removing redundant fixup code. There
should be no functional change as a result of this patch.
Since each entry is now 12 bytes in size, we must reduce the alignment
of each entry from `.align 3` (i.e. 8 bytes) to `.align 2` (i.e. 4
bytes), which is the natrual alignment of the `insn` and `fixup` fields.
The current 8-byte alignment is a holdover from when the `insn` and
`fixup` fields was 8 bytes, and while not harmful has not been necessary
since commit:
6c94f27ac8 ("arm64: switch to relative exception tables")
Similarly, RO_EXCEPTION_TABLE_ALIGN is dropped to 4 bytes.
Concurrently with this patch, x86's exception table entry format is
being updated (similarly to a 12-byte format, with 32-bytes of absolute
data). Once both have been merged it should be possible to unify the
sorttable logic for the two.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: James Morse <james.morse@arm.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-11-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Currently, relocation code declares start and end variables
which are used to compute its size.
The better way to do this is to use ld script, and put relocation
function in its own section.
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210930143113.1502553-11-pasha.tatashin@soleen.com
Signed-off-by: Will Deacon <will@kernel.org>
The HYP rodata section is currently lumped together with the BSS,
which isn't exactly what is expected (it gets registered with
kmemleak, for example).
Move it away so that it is actually marked RO. As an added
benefit, it isn't registered with kmemleak anymore.
Fixes: 380e18ade4 ("KVM: arm64: Introduce a BSS section for use at Hyp")
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org #5.13
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210802123830.2195174-2-maz@kernel.org
We will soon unmap the .hyp sections from the host stage 2 in Protected
nVHE mode, which obviously works with at least page granularity, so make
sure to align them correctly.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-37-qperret@google.com
Currently, the hyp code cannot make full use of a bss, as the kernel
section is mapped read-only.
While this mapping could simply be changed to read-write, it would
intermingle even more the hyp and kernel state than they currently are.
Instead, introduce a __hyp_bss section, that uses reserved pages, and
create the appropriate RW hyp mappings during KVM init.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-8-qperret@google.com
- Support for userspace to emulate Xen hypercalls
- Raise the maximum number of user memslots
- Scalability improvements for the new MMU. Instead of the complex
"fast page fault" logic that is used in mmu.c, tdp_mmu.c uses an
rwlock so that page faults are concurrent, but the code that can run
against page faults is limited. Right now only page faults take the
lock for reading; in the future this will be extended to some
cases of page table destruction. I hope to switch the default MMU
around 5.12-rc3 (some testing was delayed due to Chinese New Year).
- Cleanups for MAXPHYADDR checks
- Use static calls for vendor-specific callbacks
- On AMD, use VMLOAD/VMSAVE to save and restore host state
- Stop using deprecated jump label APIs
- Workaround for AMD erratum that made nested virtualization unreliable
- Support for LBR emulation in the guest
- Support for communicating bus lock vmexits to userspace
- Add support for SEV attestation command
- Miscellaneous cleanups
PPC:
- Support for second data watchpoint on POWER10
- Remove some complex workarounds for buggy early versions of POWER9
- Guest entry/exit fixes
ARM64
- Make the nVHE EL2 object relocatable
- Cleanups for concurrent translation faults hitting the same page
- Support for the standard TRNG hypervisor call
- A bunch of small PMU/Debug fixes
- Simplification of the early init hypercall handling
Non-KVM changes (with acks):
- Detection of contended rwlocks (implemented only for qrwlocks,
because KVM only needs it for x86)
- Allow __DISABLE_EXPORTS from assembly code
- Provide a saner follow_pfn replacements for modules
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"x86:
- Support for userspace to emulate Xen hypercalls
- Raise the maximum number of user memslots
- Scalability improvements for the new MMU.
Instead of the complex "fast page fault" logic that is used in
mmu.c, tdp_mmu.c uses an rwlock so that page faults are concurrent,
but the code that can run against page faults is limited. Right now
only page faults take the lock for reading; in the future this will
be extended to some cases of page table destruction. I hope to
switch the default MMU around 5.12-rc3 (some testing was delayed
due to Chinese New Year).
- Cleanups for MAXPHYADDR checks
- Use static calls for vendor-specific callbacks
- On AMD, use VMLOAD/VMSAVE to save and restore host state
- Stop using deprecated jump label APIs
- Workaround for AMD erratum that made nested virtualization
unreliable
- Support for LBR emulation in the guest
- Support for communicating bus lock vmexits to userspace
- Add support for SEV attestation command
- Miscellaneous cleanups
PPC:
- Support for second data watchpoint on POWER10
- Remove some complex workarounds for buggy early versions of POWER9
- Guest entry/exit fixes
ARM64:
- Make the nVHE EL2 object relocatable
- Cleanups for concurrent translation faults hitting the same page
- Support for the standard TRNG hypervisor call
- A bunch of small PMU/Debug fixes
- Simplification of the early init hypercall handling
Non-KVM changes (with acks):
- Detection of contended rwlocks (implemented only for qrwlocks,
because KVM only needs it for x86)
- Allow __DISABLE_EXPORTS from assembly code
- Provide a saner follow_pfn replacements for modules"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (192 commits)
KVM: x86/xen: Explicitly pad struct compat_vcpu_info to 64 bytes
KVM: selftests: Don't bother mapping GVA for Xen shinfo test
KVM: selftests: Fix hex vs. decimal snafu in Xen test
KVM: selftests: Fix size of memslots created by Xen tests
KVM: selftests: Ignore recently added Xen tests' build output
KVM: selftests: Add missing header file needed by xAPIC IPI tests
KVM: selftests: Add operand to vmsave/vmload/vmrun in svm.c
KVM: SVM: Make symbol 'svm_gp_erratum_intercept' static
locking/arch: Move qrwlock.h include after qspinlock.h
KVM: PPC: Book3S HV: Fix host radix SLB optimisation with hash guests
KVM: PPC: Book3S HV: Ensure radix guest has no SLB entries
KVM: PPC: Don't always report hash MMU capability for P9 < DD2.2
KVM: PPC: Book3S HV: Save and restore FSCR in the P9 path
KVM: PPC: remove unneeded semicolon
KVM: PPC: Book3S HV: Use POWER9 SLBIA IH=6 variant to clear SLB
KVM: PPC: Book3S HV: No need to clear radix host SLB before loading HPT guest
KVM: PPC: Book3S HV: Fix radix guest SLB side channel
KVM: PPC: Book3S HV: Remove support for running HPT guest on RPT host without mixed mode support
KVM: PPC: Book3S HV: Introduce new capability for 2nd DAWR
KVM: PPC: Book3S HV: Add infrastructure to support 2nd DAWR
...
Add TRAMP_SWAPPER_OFFSET and use that instead of hardcoding
the offset between swapper_pg_dir and tramp_pg_dir.
Then use TRAMP_SWAPPER_OFFSET to assert that the offset is
correct at link time.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210202123658.22308-3-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Add RESERVED_SWAPPER_OFFSET and use that instead of hardcoding
the offset between swapper_pg_dir and reserved_pg_dir.
Then use RESERVED_SWAPPER_OFFSET to assert that the offset is
correct at link time.
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210202123658.22308-2-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Add a post-processing step to compilation of KVM nVHE hyp code which
calls a custom host tool (gen-hyprel) on the partially linked object
file (hyp sections' names prefixed).
The tool lists all R_AARCH64_ABS64 data relocations targeting hyp
sections and generates an assembly file that will form a new section
.hyp.reloc in the kernel binary. The new section contains an array of
32-bit offsets to the positions targeted by these relocations.
Since these addresses of those positions will not be determined until
linking of `vmlinux`, each 32-bit entry carries a R_AARCH64_PREL32
relocation with addend <section_base_sym> + <r_offset>. The linker of
`vmlinux` will therefore fill the slot accordingly.
This relocation data will be used at runtime to convert the kernel VAs
at those positions to hyp VAs.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210105180541.65031-5-dbrazdil@google.com
We will need to recognize pointers in .rodata specific to hyp, so
establish a .hyp.rodata ELF section. Merge it with the existing
.hyp.data..ro_after_init as they are treated the same at runtime.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210105180541.65031-3-dbrazdil@google.com
* PSCI relay at EL2 when "protected KVM" is enabled
* New exception injection code
* Simplification of AArch32 system register handling
* Fix PMU accesses when no PMU is enabled
* Expose CSV3 on non-Meltdown hosts
* Cache hierarchy discovery fixes
* PV steal-time cleanups
* Allow function pointers at EL2
* Various host EL2 entry cleanups
* Simplification of the EL2 vector allocation
s390:
* memcg accouting for s390 specific parts of kvm and gmap
* selftest for diag318
* new kvm_stat for when async_pf falls back to sync
x86:
* Tracepoints for the new pagetable code from 5.10
* Catch VFIO and KVM irqfd events before userspace
* Reporting dirty pages to userspace with a ring buffer
* SEV-ES host support
* Nested VMX support for wait-for-SIPI activity state
* New feature flag (AVX512 FP16)
* New system ioctl to report Hyper-V-compatible paravirtualization features
Generic:
* Selftest improvements
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"Much x86 work was pushed out to 5.12, but ARM more than made up for it.
ARM:
- PSCI relay at EL2 when "protected KVM" is enabled
- New exception injection code
- Simplification of AArch32 system register handling
- Fix PMU accesses when no PMU is enabled
- Expose CSV3 on non-Meltdown hosts
- Cache hierarchy discovery fixes
- PV steal-time cleanups
- Allow function pointers at EL2
- Various host EL2 entry cleanups
- Simplification of the EL2 vector allocation
s390:
- memcg accouting for s390 specific parts of kvm and gmap
- selftest for diag318
- new kvm_stat for when async_pf falls back to sync
x86:
- Tracepoints for the new pagetable code from 5.10
- Catch VFIO and KVM irqfd events before userspace
- Reporting dirty pages to userspace with a ring buffer
- SEV-ES host support
- Nested VMX support for wait-for-SIPI activity state
- New feature flag (AVX512 FP16)
- New system ioctl to report Hyper-V-compatible paravirtualization features
Generic:
- Selftest improvements"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (171 commits)
KVM: SVM: fix 32-bit compilation
KVM: SVM: Add AP_JUMP_TABLE support in prep for AP booting
KVM: SVM: Provide support to launch and run an SEV-ES guest
KVM: SVM: Provide an updated VMRUN invocation for SEV-ES guests
KVM: SVM: Provide support for SEV-ES vCPU loading
KVM: SVM: Provide support for SEV-ES vCPU creation/loading
KVM: SVM: Update ASID allocation to support SEV-ES guests
KVM: SVM: Set the encryption mask for the SVM host save area
KVM: SVM: Add NMI support for an SEV-ES guest
KVM: SVM: Guest FPU state save/restore not needed for SEV-ES guest
KVM: SVM: Do not report support for SMM for an SEV-ES guest
KVM: x86: Update __get_sregs() / __set_sregs() to support SEV-ES
KVM: SVM: Add support for CR8 write traps for an SEV-ES guest
KVM: SVM: Add support for CR4 write traps for an SEV-ES guest
KVM: SVM: Add support for CR0 write traps for an SEV-ES guest
KVM: SVM: Add support for EFER write traps for an SEV-ES guest
KVM: SVM: Support string IO operations for an SEV-ES guest
KVM: SVM: Support MMIO for an SEV-ES guest
KVM: SVM: Create trace events for VMGEXIT MSR protocol processing
KVM: SVM: Create trace events for VMGEXIT processing
...
* for-next/kvm-build-fix:
: Fix KVM build issues with 64K pages
KVM: arm64: Fix build error in user_mem_abort()
* for-next/va-refactor:
: VA layout changes
arm64: mm: don't assume struct page is always 64 bytes
Documentation/arm64: fix RST layout of memory.rst
arm64: mm: tidy up top of kernel VA space
arm64: mm: make vmemmap region a projection of the linear region
arm64: mm: extend linear region for 52-bit VA configurations
* for-next/lto:
: Upgrade READ_ONCE() to RCpc acquire on arm64 with LTO
arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y
arm64: alternatives: Remove READ_ONCE() usage during patch operation
arm64: cpufeatures: Add capability for LDAPR instruction
arm64: alternatives: Split up alternative.h
arm64: uaccess: move uao_* alternatives to asm-uaccess.h
* for-next/mem-hotplug:
: Memory hotplug improvements
arm64/mm/hotplug: Ensure early memory sections are all online
arm64/mm/hotplug: Enable MEM_OFFLINE event handling
arm64/mm/hotplug: Register boot memory hot remove notifier earlier
arm64: mm: account for hotplug memory when randomizing the linear region
* for-next/cppc-ffh:
: Add CPPC FFH support using arm64 AMU counters
arm64: abort counter_read_on_cpu() when irqs_disabled()
arm64: implement CPPC FFH support using AMUs
arm64: split counter validation function
arm64: wrap and generalise counter read functions
* for-next/pad-image-header:
: Pad Image header to 64KB and unmap it
arm64: head: tidy up the Image header definition
arm64/head: avoid symbol names pointing into first 64 KB of kernel image
arm64: omit [_text, _stext) from permanent kernel mapping
* for-next/zone-dma-default-32-bit:
: Default to 32-bit wide ZONE_DMA (previously reduced to 1GB for RPi4)
of: unittest: Fix build on architectures without CONFIG_OF_ADDRESS
mm: Remove examples from enum zone_type comment
arm64: mm: Set ZONE_DMA size based on early IORT scan
arm64: mm: Set ZONE_DMA size based on devicetree's dma-ranges
of: unittest: Add test for of_dma_get_max_cpu_address()
of/address: Introduce of_dma_get_max_cpu_address()
arm64: mm: Move zone_dma_bits initialization into zone_sizes_init()
arm64: mm: Move reserve_crashkernel() into mem_init()
arm64: Force NO_BLOCK_MAPPINGS if crashkernel reservation is required
arm64: Ignore any DMA offsets in the max_zone_phys() calculation
* for-next/signal-tag-bits:
: Expose the FAR_EL1 tag bits in siginfo
arm64: expose FAR_EL1 tag bits in siginfo
signal: define the SA_EXPOSE_TAGBITS bit in sa_flags
signal: define the SA_UNSUPPORTED bit in sa_flags
arch: provide better documentation for the arch-specific SA_* flags
signal: clear non-uapi flag bits when passing/returning sa_flags
arch: move SA_* definitions to generic headers
parisc: start using signal-defs.h
parisc: Drop parisc special case for __sighandler_t
* for-next/cmdline-extended:
: Add support for CONFIG_CMDLINE_EXTENDED
arm64: Extend the kernel command line from the bootloader
arm64: kaslr: Refactor early init command line parsing
Add rules for renaming the .data..ro_after_init ELF section in KVM nVHE
object files to .hyp.data..ro_after_init, linking it into the kernel
and mapping it in hyp at runtime.
The section is RW to the host, then mapped RO in hyp. The expectation is
that the host populates the variables in the section and they are never
changed by hyp afterwards.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201202184122.26046-13-dbrazdil@google.com
We currently try to emit *.init.rodata.* twice, once in INIT_DATA, and once
in the line immediately following it. As the two section definitions are
identical, the latter is redundant and can be dropped.
This patch drops the redundant *.init.rodata.* section definition.
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/1605750340-910-1-git-send-email-tangyouling@loongson.cn
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
In a previous patch, we increased the size of the EFI PE/COFF header
to 64 KB, which resulted in the _stext symbol to appear at a fixed
offset of 64 KB into the image.
Since 64 KB is also the largest page size we support, this completely
removes the need to map the first 64 KB of the kernel image, given that
it only contains the arm64 Image header and the EFI header, neither of
which we ever access again after booting the kernel. More importantly,
we should avoid an executable mapping of non-executable and not entirely
predictable data, to deal with the unlikely event that we inadvertently
emitted something that looks like an opcode that could be used as a
gadget for speculative execution.
So let's limit the kernel mapping of .text to the [_stext, _etext)
region, which matches the view of generic code (such as kallsyms) when
it reasons about the boundaries of the kernel's .text section.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201117124729.12642-2-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Depending on configuration options and specific code paths, we either
use the empty_zero_page or the configuration-dependent reserved_ttbr0
as a reserved value for TTBR{0,1}_EL1.
To simplify this code, let's always allocate and use the same
reserved_pg_dir, replacing reserved_ttbr0. Note that this is allocated
(and hence pre-zeroed), and is also marked as read-only in the kernel
Image mapping.
Keeping this separate from the empty_zero_page potentially helps with
robustness as the empty_zero_page is used in a number of cases where a
failure to map it read-only could allow it to become corrupted.
The (presently unused) swapper_pg_end symbol is also removed, and
comments are added wherever we rely on the offsets between the
pre-allocated pg_dirs to keep these cases easily identifiable.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201103102229.8542-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
When building with LTO, there is an increased risk of the compiler
converting an address dependency headed by a READ_ONCE() invocation
into a control dependency and consequently allowing for harmful
reordering by the CPU.
Ensure that such transformations are harmless by overriding the generic
READ_ONCE() definition with one that provides acquire semantics when
building with LTO.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Now that we started making the linker warn about orphan sections
(input sections that are not explicitly consumed by an output section),
some configurations produce the following warning:
aarch64-linux-gnu-ld: warning: orphan section `.igot.plt' from
`arch/arm64/kernel/head.o' being placed in section `.igot.plt'
It could be any file that triggers this - head.o is simply the first
input file in the link - and the resulting .igot.plt section never
actually appears in vmlinux as it turns out to be empty.
So let's add .igot.plt to our collection of input sections to disregard
unless they are empty.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20201028133332.5571-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
- New page table code for both hypervisor and guest stage-2
- Introduction of a new EL2-private host context
- Allow EL2 to have its own private per-CPU variables
- Support of PMU event filtering
- Complete rework of the Spectre mitigation
PPC:
- Fix for running nested guests with in-kernel IRQ chip
- Fix race condition causing occasional host hard lockup
- Minor cleanups and bugfixes
x86:
- allow trapping unknown MSRs to userspace
- allow userspace to force #GP on specific MSRs
- INVPCID support on AMD
- nested AMD cleanup, on demand allocation of nested SVM state
- hide PV MSRs and hypercalls for features not enabled in CPUID
- new test for MSR_IA32_TSC writes from host and guest
- cleanups: MMU, CPUID, shared MSRs
- LAPIC latency optimizations ad bugfixes
For x86, also included in this pull request is a new alternative and
(in the future) more scalable implementation of extended page tables
that does not need a reverse map from guest physical addresses to
host physical addresses. For now it is disabled by default because
it is still lacking a few of the existing MMU's bells and whistles.
However it is a very solid piece of work and it is already available
for people to hammer on it.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"For x86, there is a new alternative and (in the future) more scalable
implementation of extended page tables that does not need a reverse
map from guest physical addresses to host physical addresses.
For now it is disabled by default because it is still lacking a few of
the existing MMU's bells and whistles. However it is a very solid
piece of work and it is already available for people to hammer on it.
Other updates:
ARM:
- New page table code for both hypervisor and guest stage-2
- Introduction of a new EL2-private host context
- Allow EL2 to have its own private per-CPU variables
- Support of PMU event filtering
- Complete rework of the Spectre mitigation
PPC:
- Fix for running nested guests with in-kernel IRQ chip
- Fix race condition causing occasional host hard lockup
- Minor cleanups and bugfixes
x86:
- allow trapping unknown MSRs to userspace
- allow userspace to force #GP on specific MSRs
- INVPCID support on AMD
- nested AMD cleanup, on demand allocation of nested SVM state
- hide PV MSRs and hypercalls for features not enabled in CPUID
- new test for MSR_IA32_TSC writes from host and guest
- cleanups: MMU, CPUID, shared MSRs
- LAPIC latency optimizations ad bugfixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (232 commits)
kvm: x86/mmu: NX largepage recovery for TDP MMU
kvm: x86/mmu: Don't clear write flooding count for direct roots
kvm: x86/mmu: Support MMIO in the TDP MMU
kvm: x86/mmu: Support write protection for nesting in tdp MMU
kvm: x86/mmu: Support disabling dirty logging for the tdp MMU
kvm: x86/mmu: Support dirty logging for the TDP MMU
kvm: x86/mmu: Support changed pte notifier in tdp MMU
kvm: x86/mmu: Add access tracking for tdp_mmu
kvm: x86/mmu: Support invalidate range MMU notifier for TDP MMU
kvm: x86/mmu: Allocate struct kvm_mmu_pages for all pages in TDP MMU
kvm: x86/mmu: Add TDP MMU PF handler
kvm: x86/mmu: Remove disallowed_hugepage_adjust shadow_walk_iterator arg
kvm: x86/mmu: Support zapping SPTEs in the TDP MMU
KVM: Cache as_id in kvm_memory_slot
kvm: x86/mmu: Add functions to handle changed TDP SPTEs
kvm: x86/mmu: Allocate and free TDP MMU roots
kvm: x86/mmu: Init / Uninit the TDP MMU
kvm: x86/mmu: Introduce tdp_iter
KVM: mmu: extract spte.h and spte.c
KVM: mmu: Separate updating a PTE from kvm_set_pte_rmapp
...
because the heuristics that various linkers & compilers use to handle them
(include these bits into the output image vs discarding them silently)
are both highly idiosyncratic and also version dependent.
Instead of this historically problematic mess, this tree by Kees Cook (et al)
adds build time asserts and build time warnings if there's any orphan section
in the kernel or if a section is not sized as expected.
And because we relied on so many silent assumptions in this area, fix a metric
ton of dependencies and some outright bugs related to this, before we can
finally enable the checks on the x86, ARM and ARM64 platforms.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'core-build-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull orphan section checking from Ingo Molnar:
"Orphan link sections were a long-standing source of obscure bugs,
because the heuristics that various linkers & compilers use to handle
them (include these bits into the output image vs discarding them
silently) are both highly idiosyncratic and also version dependent.
Instead of this historically problematic mess, this tree by Kees Cook
(et al) adds build time asserts and build time warnings if there's any
orphan section in the kernel or if a section is not sized as expected.
And because we relied on so many silent assumptions in this area, fix
a metric ton of dependencies and some outright bugs related to this,
before we can finally enable the checks on the x86, ARM and ARM64
platforms"
* tag 'core-build-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
x86/boot/compressed: Warn on orphan section placement
x86/build: Warn on orphan section placement
arm/boot: Warn on orphan section placement
arm/build: Warn on orphan section placement
arm64/build: Warn on orphan section placement
x86/boot/compressed: Add missing debugging sections to output
x86/boot/compressed: Remove, discard, or assert for unwanted sections
x86/boot/compressed: Reorganize zero-size section asserts
x86/build: Add asserts for unwanted sections
x86/build: Enforce an empty .got.plt section
x86/asm: Avoid generating unused kprobe sections
arm/boot: Handle all sections explicitly
arm/build: Assert for unwanted sections
arm/build: Add missing sections
arm/build: Explicitly keep .ARM.attributes sections
arm/build: Refactor linker script headers
arm64/build: Assert for unwanted sections
arm64/build: Add missing DWARF sections
arm64/build: Use common DISCARDS in linker script
arm64/build: Remove .eh_frame* sections due to unwind tables
...
Add hyp percpu section to linker script and rename the corresponding ELF
sections of hyp/nvhe object files. This moves all nVHE-specific percpu
variables to the new hyp percpu section.
Allocate sufficient amount of memory for all percpu hyp regions at global KVM
init time and create corresponding hyp mappings.
The base addresses of hyp percpu regions are kept in a dynamically allocated
array in the kernel.
Add NULL checks in PMU event-reset code as it may run before KVM memory is
initialized.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200922204910.7265-10-dbrazdil@google.com
Minor cleanup that only creates __kvm_ex_table ELF section and
related symbols if CONFIG_KVM is enabled. Also useful as more
hyp-specific sections will be added.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200922204910.7265-4-dbrazdil@google.com
Minor cleanup to move all macros related to prefixing nVHE hyp section
and symbol names into one place: hyp_image.h.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200922204910.7265-3-dbrazdil@google.com
TEXT_OFFSET serves no purpose, and for this reason, it was redefined
as 0x0 in the v5.8 timeframe. Since this does not appear to have caused
any issues that require us to revisit that decision, let's get rid of the
macro entirely, along with any references to it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200825135440.11288-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Use the common DISCARDS rule for the linker script in an effort to
regularize the linker script to prepare for warning on orphaned
sections. Additionally clean up left-over no-op macros.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200821194310.3089815-12-keescook@chromium.org
Avoid .eh_frame* section generation by making sure both CFLAGS and AFLAGS
contain -fno-asychronous-unwind-tables and -fno-unwind-tables.
With all sources of .eh_frame now removed from the build, drop this
DISCARD so we can be alerted in the future if it returns unexpectedly
once orphan section warnings have been enabled.
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200821194310.3089815-11-keescook@chromium.org
The .comment section doesn't belong in STABS_DEBUG. Split it out into a
new macro named ELF_DETAILS. This will gain other non-debug sections
that need to be accounted for when linking with --orphan-handling=warn.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/r/20200821194310.3089815-5-keescook@chromium.org
KVM has a one instruction window where it will allow an SError exception
to be consumed by the hypervisor without treating it as a hypervisor bug.
This is used to consume asynchronous external abort that were caused by
the guest.
As we are about to add another location that survives unexpected exceptions,
generalise this code to make it behave like the host's extable.
KVM's version has to be mapped to EL2 to be accessible on nVHE systems.
The SError vaxorcism code is a one instruction window, so has two entries
in the extable. Because the KVM code is copied for VHE and nVHE, we end up
with four entries, half of which correspond with code that isn't mapped.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
