linux-stable.git/arch/arm64/kernel/entry.S, branch v5.8 Linux kernel stable tree arm64: entry: Tidy up block comments and label numbers 2020-07-08T21:13:33+00:00 Will Deacon will@kernel.org 2020-07-08T21:10:01+00:00 8c3001b9252d8dbf72289d3590a723eea8cfe824 Continually butchering our entry code with CPU errata workarounds has led to it looking a little scruffy. Consistently used /* */ comment style for multi-line block comments and ensure that small numeric labels use consecutive integers. No functional change, but the state of things was irritating. Signed-off-by: Will Deacon <will@kernel.org> 
Continually butchering our entry code with CPU errata workarounds has
led to it looking a little scruffy. Consistently used /* */ comment
style for multi-line block comments and ensure that small numeric labels
use consecutive integers.

No functional change, but the state of things was irritating.

Signed-off-by: Will Deacon <will@kernel.org>
arm64: Rework ARM_ERRATUM_1414080 handling 2020-07-08T21:07:19+00:00 Marc Zyngier maz@kernel.org 2020-07-06T16:38:02+00:00 dc802f2bc0208f4abca420705a860c5175db4bee The current handling of erratum 1414080 has the side effect that cntkctl_el1 can get changed for both 32 and 64bit tasks. This isn't a problem so far, but if we ever need to mitigate another of these errata on the 64bit side, we'd better keep the messing with cntkctl_el1 local to 32bit tasks. For that, make sure that on entering the kernel from a 32bit tasks, userspace access to cntvct gets enabled, and disabled returning to userspace, while it never gets changed for 64bit tasks. Signed-off-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20200706163802.1836732-5-maz@kernel.org [will: removed branch instructions per Mark's review comments] Signed-off-by: Will Deacon <will@kernel.org> 
The current handling of erratum 1414080 has the side effect that
cntkctl_el1 can get changed for both 32 and 64bit tasks.

This isn't a problem so far, but if we ever need to mitigate another
of these errata on the 64bit side, we'd better keep the messing with
cntkctl_el1 local to 32bit tasks.

For that, make sure that on entering the kernel from a 32bit tasks,
userspace access to cntvct gets enabled, and disabled returning to
userspace, while it never gets changed for 64bit tasks.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200706163802.1836732-5-maz@kernel.org
[will: removed branch instructions per Mark's review comments]
Signed-off-by: Will Deacon <will@kernel.org>
Merge branch 'for-next/scs' into for-next/core 2020-05-28T17:03:40+00:00 Will Deacon will@kernel.org 2020-05-28T17:03:40+00:00 082af5ec5080b028f7d0846a6c27cbb87f288205 Support for Clang's Shadow Call Stack in the kernel (Sami Tolvanen and Will Deacon) * for-next/scs: arm64: entry-ftrace.S: Update comment to indicate that x18 is live scs: Move DEFINE_SCS macro into core code scs: Remove references to asm/scs.h from core code scs: Move scs_overflow_check() out of architecture code arm64: scs: Use 'scs_sp' register alias for x18 scs: Move accounting into alloc/free functions arm64: scs: Store absolute SCS stack pointer value in thread_info efi/libstub: Disable Shadow Call Stack arm64: scs: Add shadow stacks for SDEI arm64: Implement Shadow Call Stack arm64: Disable SCS for hypervisor code arm64: vdso: Disable Shadow Call Stack arm64: efi: Restore register x18 if it was corrupted arm64: Preserve register x18 when CPU is suspended arm64: Reserve register x18 from general allocation with SCS scs: Disable when function graph tracing is enabled scs: Add support for stack usage debugging scs: Add page accounting for shadow call stack allocations scs: Add support for Clang's Shadow Call Stack (SCS) 
Support for Clang's Shadow Call Stack in the kernel
(Sami Tolvanen and Will Deacon)
* for-next/scs:
  arm64: entry-ftrace.S: Update comment to indicate that x18 is live
  scs: Move DEFINE_SCS macro into core code
  scs: Remove references to asm/scs.h from core code
  scs: Move scs_overflow_check() out of architecture code
  arm64: scs: Use 'scs_sp' register alias for x18
  scs: Move accounting into alloc/free functions
  arm64: scs: Store absolute SCS stack pointer value in thread_info
  efi/libstub: Disable Shadow Call Stack
  arm64: scs: Add shadow stacks for SDEI
  arm64: Implement Shadow Call Stack
  arm64: Disable SCS for hypervisor code
  arm64: vdso: Disable Shadow Call Stack
  arm64: efi: Restore register x18 if it was corrupted
  arm64: Preserve register x18 when CPU is suspended
  arm64: Reserve register x18 from general allocation with SCS
  scs: Disable when function graph tracing is enabled
  scs: Add support for stack usage debugging
  scs: Add page accounting for shadow call stack allocations
  scs: Add support for Clang's Shadow Call Stack (SCS)
Merge branch 'for-next/bti' into for-next/core 2020-05-28T17:00:51+00:00 Will Deacon will@kernel.org 2020-05-28T17:00:51+00:00 d27865279f12035c730818aa1a0280fada866a37 Support for Branch Target Identification (BTI) in user and kernel (Mark Brown and others) * for-next/bti: (39 commits) arm64: vdso: Fix CFI directives in sigreturn trampoline arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction arm64: bti: Fix support for userspace only BTI arm64: kconfig: Update and comment GCC version check for kernel BTI arm64: vdso: Map the vDSO text with guarded pages when built for BTI arm64: vdso: Force the vDSO to be linked as BTI when built for BTI arm64: vdso: Annotate for BTI arm64: asm: Provide a mechanism for generating ELF note for BTI arm64: bti: Provide Kconfig for kernel mode BTI arm64: mm: Mark executable text as guarded pages arm64: bpf: Annotate JITed code for BTI arm64: Set GP bit in kernel page tables to enable BTI for the kernel arm64: asm: Override SYM_FUNC_START when building the kernel with BTI arm64: bti: Support building kernel C code using BTI arm64: Document why we enable PAC support for leaf functions arm64: insn: Report PAC and BTI instructions as skippable arm64: insn: Don't assume unrecognized HINTs are skippable arm64: insn: Provide a better name for aarch64_insn_is_nop() arm64: insn: Add constants for new HINT instruction decode arm64: Disable old style assembly annotations ... 
Support for Branch Target Identification (BTI) in user and kernel
(Mark Brown and others)
* for-next/bti: (39 commits)
  arm64: vdso: Fix CFI directives in sigreturn trampoline
  arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
  arm64: bti: Fix support for userspace only BTI
  arm64: kconfig: Update and comment GCC version check for kernel BTI
  arm64: vdso: Map the vDSO text with guarded pages when built for BTI
  arm64: vdso: Force the vDSO to be linked as BTI when built for BTI
  arm64: vdso: Annotate for BTI
  arm64: asm: Provide a mechanism for generating ELF note for BTI
  arm64: bti: Provide Kconfig for kernel mode BTI
  arm64: mm: Mark executable text as guarded pages
  arm64: bpf: Annotate JITed code for BTI
  arm64: Set GP bit in kernel page tables to enable BTI for the kernel
  arm64: asm: Override SYM_FUNC_START when building the kernel with BTI
  arm64: bti: Support building kernel C code using BTI
  arm64: Document why we enable PAC support for leaf functions
  arm64: insn: Report PAC and BTI instructions as skippable
  arm64: insn: Don't assume unrecognized HINTs are skippable
  arm64: insn: Provide a better name for aarch64_insn_is_nop()
  arm64: insn: Add constants for new HINT instruction decode
  arm64: Disable old style assembly annotations
  ...
arm64: scs: Use 'scs_sp' register alias for x18 2020-05-18T16:47:37+00:00 Will Deacon will@kernel.org 2020-05-15T13:46:46+00:00 711e8b0de0d63c70c825b473da01288b661a2386 x18 holds the SCS stack pointer value, so introduce a register alias to make this easier to read in assembly code. Tested-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will@kernel.org> 
x18 holds the SCS stack pointer value, so introduce a register alias to
make this easier to read in assembly code.

Tested-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
arm64: scs: Add shadow stacks for SDEI 2020-05-15T15:35:50+00:00 Sami Tolvanen samitolvanen@google.com 2020-04-27T16:00:17+00:00 439dc2a11727314cdc3ad0ad13c122d910dae411 This change adds per-CPU shadow call stacks for the SDEI handler. Similarly to how the kernel stacks are handled, we add separate shadow stacks for normal and critical events. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: James Morse <james.morse@arm.com> Tested-by: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will@kernel.org> 
This change adds per-CPU shadow call stacks for the SDEI handler.
Similarly to how the kernel stacks are handled, we add separate shadow
stacks for normal and critical events.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: James Morse <james.morse@arm.com>
Tested-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
arm64: Implement Shadow Call Stack 2020-05-15T15:35:50+00:00 Sami Tolvanen samitolvanen@google.com 2020-04-27T16:00:16+00:00 5287569a790d2546a06db07e391bf84b8bd6cf51 This change implements shadow stack switching, initial SCS set-up, and interrupt shadow stacks for arm64. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Will Deacon <will@kernel.org> 
This change implements shadow stack switching, initial SCS set-up,
and interrupt shadow stacks for arm64.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will@kernel.org>
arm64: entry: Refactor and modernise annotation for ret_to_user 2020-05-04T11:46:03+00:00 Mark Brown broonie@kernel.org 2020-05-01T11:54:28+00:00 06607c7e93f2a4799346baa262d4304681e4b528 As part of an effort to clarify and clean up the assembler annotations new macros have been introduced which annotate the start and end of blocks of code in assembler files. Currently ret_to_user has an out of line slow path work_pending placed above the main function which makes annotating the start and end of these blocks of code awkward. Since work_pending is only referenced from within ret_to_user try to make things a bit clearer by moving it after the current ret_to_user and then marking both ret_to_user and work_pending as part of a single ret_to_user code block. Signed-off-by: Mark Brown <broonie@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20200501115430.37315-2-broonie@kernel.org Signed-off-by: Will Deacon <will@kernel.org> 
As part of an effort to clarify and clean up the assembler annotations
new macros have been introduced which annotate the start and end of blocks
of code in assembler files. Currently ret_to_user has an out of line slow
path work_pending placed above the main function which makes annotating the
start and end of these blocks of code awkward.

Since work_pending is only referenced from within ret_to_user try to make
things a bit clearer by moving it after the current ret_to_user and then
marking both ret_to_user and work_pending as part of a single ret_to_user
code block.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200501115430.37315-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
arm64: remove ptrauth_keys_install_kernel sync arg 2020-04-28T10:23:21+00:00 Mark Rutland mark.rutland@arm.com 2020-04-23T10:16:05+00:00 d0055da5266acd316b8cb22b6086b8f9ac2d72cb The 'sync' argument to ptrauth_keys_install_kernel macro is somewhat opaque at callsites, so instead lets have regular and _nosync variants of the macro to make this a little more obvious. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20200423101606.37601-2-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> 
The 'sync' argument to ptrauth_keys_install_kernel macro is somewhat
opaque at callsites, so instead lets have regular and _nosync variants
of the macro to make this a little more obvious.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200423101606.37601-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Merge branch 'for-next/kernel-ptrauth' into for-next/core 2020-03-25T11:11:08+00:00 Catalin Marinas catalin.marinas@arm.com 2020-03-25T11:11:08+00:00 44ca0e00b6a05ea9cf89d8a5290a225de19f4a2a * for-next/kernel-ptrauth: : Return address signing - in-kernel support arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH lkdtm: arm64: test kernel pointer authentication arm64: compile the kernel with ptrauth return address signing kconfig: Add support for 'as-option' arm64: suspend: restore the kernel ptrauth keys arm64: __show_regs: strip PAC from lr in printk arm64: unwind: strip PAC from kernel addresses arm64: mask PAC bits of __builtin_return_address arm64: initialize ptrauth keys for kernel booting task arm64: initialize and switch ptrauth kernel keys arm64: enable ptrauth earlier arm64: cpufeature: handle conflicts based on capability arm64: cpufeature: Move cpu capability helpers inside C file arm64: ptrauth: Add bootup/runtime flags for __cpu_setup arm64: install user ptrauth keys at kernel exit time arm64: rename ptrauth key structures to be user-specific arm64: cpufeature: add pointer auth meta-capabilities arm64: cpufeature: Fix meta-capability cpufeature check 
* for-next/kernel-ptrauth:
  : Return address signing - in-kernel support
  arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH
  lkdtm: arm64: test kernel pointer authentication
  arm64: compile the kernel with ptrauth return address signing
  kconfig: Add support for 'as-option'
  arm64: suspend: restore the kernel ptrauth keys
  arm64: __show_regs: strip PAC from lr in printk
  arm64: unwind: strip PAC from kernel addresses
  arm64: mask PAC bits of __builtin_return_address
  arm64: initialize ptrauth keys for kernel booting task
  arm64: initialize and switch ptrauth kernel keys
  arm64: enable ptrauth earlier
  arm64: cpufeature: handle conflicts based on capability
  arm64: cpufeature: Move cpu capability helpers inside C file
  arm64: ptrauth: Add bootup/runtime flags for __cpu_setup
  arm64: install user ptrauth keys at kernel exit time
  arm64: rename ptrauth key structures to be user-specific
  arm64: cpufeature: add pointer auth meta-capabilities
  arm64: cpufeature: Fix meta-capability cpufeature check