1. 10 Nov, 2020 4 commits
  2. 05 Nov, 2020 1 commit
  3. 03 Nov, 2020 2 commits
  4. 30 Oct, 2020 2 commits
  5. 29 Oct, 2020 2 commits
  6. 28 Oct, 2020 12 commits
    • Catalin Marinas's avatar
      arm64: mte: Document that user PSTATE.TCO is ignored by kernel uaccess · ef5dd6a0
      Catalin Marinas authored
      On exception entry, the kernel explicitly resets the PSTATE.TCO (tag
      check override) so that any kernel memory accesses will be checked (the
      bit is restored on exception return). This has the side-effect that the
      uaccess routines will not honour the PSTATE.TCO that may have been set
      by the user prior to a syscall.
      
      There is no issue in practice since PSTATE.TCO is expected to be used
      only for brief periods in specific routines (e.g. garbage collection).
      To control the tag checking mode of the uaccess routines, the user will
      have to invoke a corresponding prctl() call.
      
      Document the kernel behaviour w.r.t. PSTATE.TCO accordingly.
      Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
      Fixes: df9d7a22 ("arm64: mte: Add Memory Tagging Extension documentation")
      Reviewed-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
      Cc: Will Deacon <will@kernel.org>
      Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
      Signed-off-by: default avatarWill Deacon <will@kernel.org>
      ef5dd6a0
    • Ard Biesheuvel's avatar
      module: use hidden visibility for weak symbol references · 13150bc5
      Ard Biesheuvel authored
      Geert reports that commit be288182 ("arm64/build: Assert for
      unwanted sections") results in build errors on arm64 for configurations
      that have CONFIG_MODULES disabled.
      
      The commit in question added ASSERT()s to the arm64 linker script to
      ensure that linker generated sections such as .got.plt etc are empty,
      but as it turns out, there are corner cases where the linker does emit
      content into those sections. More specifically, weak references to
      function symbols (which can remain unsatisfied, and can therefore not
      be emitted as relative references) will be emitted as GOT and PLT
      entries when linking the kernel in PIE mode (which is the case when
      CONFIG_RELOCATABLE is enabled, which is on by default).
      
      What happens is that code such as
      
      	struct device *(*fn)(struct device *dev);
      	struct device *iommu_device;
      
      	fn = symbol_get(mdev_get_iommu_device);
      	if (fn) {
      		iommu_device = fn(dev);
      
      essentially gets converted into the following when CONFIG_MODULES is off:
      
      	struct device *iommu_device;
      
      	if (&mdev_get_iommu_device) {
      		iommu_device = mdev_get_iommu_device(dev);
      
      where mdev_get_iommu_device is emitted as a weak symbol reference into
      the object file. The first reference is decorated with an ordinary
      ABS64 data relocation (which yields 0x0 if the reference remains
      unsatisfied). However, the indirect call is turned into a direct call
      covered by a R_AARCH64_CALL26 relocation, which is converted into a
      call via a PLT entry taking the target address from the associated
      GOT entry.
      
      Given that such GOT and PLT entries are unnecessary for fully linked
      binaries such as the kernel, let's give these weak symbol references
      hidden visibility, so that the linker knows that the weak reference
      via R_AARCH64_CALL26 can simply remain unsatisfied.
      Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      Tested-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
      Reviewed-by: default avatarFangrui Song <maskray@google.com>
      Acked-by: default avatarJessica Yu <jeyu@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/20201027151132.14066-1-ardb@kernel.orgSigned-off-by: default avatarWill Deacon <will@kernel.org>
      13150bc5
    • Ard Biesheuvel's avatar
      arm64: efi: increase EFI PE/COFF header padding to 64 KB · a2d50c1c
      Ard Biesheuvel authored
      Commit 76085aff ("efi/libstub/arm64: align PE/COFF sections to segment
      alignment") increased the PE/COFF section alignment to match the minimum
      segment alignment of the kernel image, which ensures that the kernel does
      not need to be moved around in memory by the EFI stub if it was built as
      relocatable.
      
      However, the first PE/COFF section starts at _stext, which is only 4 KB
      aligned, and so the section layout is inconsistent. Existing EFI loaders
      seem to care little about this, but it is better to clean this up.
      
      So let's pad the header to 64 KB to match the PE/COFF section alignment.
      
      Fixes: 76085aff ("efi/libstub/arm64: align PE/COFF sections to segment alignment")
      Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      Link: https://lore.kernel.org/r/20201027073209.2897-2-ardb@kernel.orgSigned-off-by: default avatarWill Deacon <will@kernel.org>
      a2d50c1c
    • Ard Biesheuvel's avatar
      arm64: vmlinux.lds: account for spurious empty .igot.plt sections · 5f692a81
      Ard Biesheuvel authored
      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: default avatarArd 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.orgSigned-off-by: default avatarWill Deacon <will@kernel.org>
      5f692a81
    • Vincenzo Frascino's avatar
      kselftest/arm64: Fix check_user_mem test · 493b35db
      Vincenzo Frascino authored
      The check_user_mem test reports the error below because the test
      plan is not declared correctly:
      
        # Planned tests != run tests (0 != 4)
      
      Fix the test adding the correct test plan declaration.
      
      Fixes: 4dafc08d ("kselftest/arm64: Check mte tagged user address in kernel")
      Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will@kernel.org>
      Cc: Gabor Kertesz <gabor.kertesz@arm.com>
      Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
      Link: https://lore.kernel.org/r/20201026121248.2340-7-vincenzo.frascino@arm.comSigned-off-by: default avatarWill Deacon <will@kernel.org>
      493b35db
    • Vincenzo Frascino's avatar
      kselftest/arm64: Fix check_ksm_options test · cbb268af
      Vincenzo Frascino authored
      The check_ksm_options test reports the error below because the test
      plan is not declared correctly:
      
        # Planned tests != run tests (0 != 4)
      
      Fix the test adding the correct test plan declaration.
      
      Fixes: f981d8fa ("kselftest/arm64: Verify KSM page merge for MTE pages")
      Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will@kernel.org>
      Cc: Gabor Kertesz <gabor.kertesz@arm.com>
      Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
      Link: https://lore.kernel.org/r/20201026121248.2340-6-vincenzo.frascino@arm.comSigned-off-by: default avatarWill Deacon <will@kernel.org>
      cbb268af
    • Vincenzo Frascino's avatar
      kselftest/arm64: Fix check_mmap_options test · 7419390a
      Vincenzo Frascino authored
      The check_mmap_options test reports the error below because the test
      plan is not declared correctly:
      
        # Planned tests != run tests (0 != 22)
      
      Fix the test adding the correct test plan declaration.
      
      Fixes: 53ec81d2 ("kselftest/arm64: Verify all different mmap MTE options")
      Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will@kernel.org>
      Cc: Gabor Kertesz <gabor.kertesz@arm.com>
      Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
      Link: https://lore.kernel.org/r/20201026121248.2340-5-vincenzo.frascino@arm.comSigned-off-by: default avatarWill Deacon <will@kernel.org>
      7419390a
    • Vincenzo Frascino's avatar
      kselftest/arm64: Fix check_child_memory test · 386cf789
      Vincenzo Frascino authored
      The check_child_memory test reports the error below because the test
      plan is not declared correctly:
      
        # Planned tests != run tests (0 != 12)
      
      Fix the test adding the correct test plan declaration.
      
      Fixes: dfe537cf ("kselftest/arm64: Check forked child mte memory accessibility")
      Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will@kernel.org>
      Cc: Gabor Kertesz <gabor.kertesz@arm.com>
      Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
      Link: https://lore.kernel.org/r/20201026121248.2340-4-vincenzo.frascino@arm.comSigned-off-by: default avatarWill Deacon <will@kernel.org>
      386cf789
    • Vincenzo Frascino's avatar
      kselftest/arm64: Fix check_tags_inclusion test · 041fa41f
      Vincenzo Frascino authored
      The check_tags_inclusion test reports the error below because the test
      plan is not declared correctly:
      
        # Planned tests != run tests (0 != 4)
      
      Fix the test adding the correct test plan declaration.
      
      Fixes: f3b2a26c ("kselftest/arm64: Verify mte tag inclusion via prctl")
      Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will@kernel.org>
      Cc: Gabor Kertesz <gabor.kertesz@arm.com>
      Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
      Link: https://lore.kernel.org/r/20201026121248.2340-3-vincenzo.frascino@arm.comSigned-off-by: default avatarWill Deacon <will@kernel.org>
      041fa41f
    • Vincenzo Frascino's avatar
      kselftest/arm64: Fix check_buffer_fill test · 5bc7c115
      Vincenzo Frascino authored
      The check_buffer_fill test reports the error below because the test
      plan is not declared correctly:
      
        # Planned tests != run tests (0 != 20)
      
      Fix the test adding the correct test plan declaration.
      
      Fixes: e9b60476 ("kselftest/arm64: Add utilities and a test to validate mte memory")
      Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
      Cc: Shuah Khan <shuah@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: Will Deacon <will@kernel.org>
      Cc: Gabor Kertesz <gabor.kertesz@arm.com>
      Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
      Link: https://lore.kernel.org/r/20201026121248.2340-2-vincenzo.frascino@arm.comSigned-off-by: default avatarWill Deacon <will@kernel.org>
      5bc7c115
    • Arnd Bergmann's avatar
      arm64: avoid -Woverride-init warning · 332576e6
      Arnd Bergmann authored
      The icache_policy_str[] definition causes a warning when extra
      warning flags are enabled:
      
      arch/arm64/kernel/cpuinfo.c:38:26: warning: initialized field overwritten [-Woverride-init]
         38 |  [ICACHE_POLICY_VIPT]  = "VIPT",
            |                          ^~~~~~
      arch/arm64/kernel/cpuinfo.c:38:26: note: (near initialization for 'icache_policy_str[2]')
      arch/arm64/kernel/cpuinfo.c:39:26: warning: initialized field overwritten [-Woverride-init]
         39 |  [ICACHE_POLICY_PIPT]  = "PIPT",
            |                          ^~~~~~
      arch/arm64/kernel/cpuinfo.c:39:26: note: (near initialization for 'icache_policy_str[3]')
      arch/arm64/kernel/cpuinfo.c:40:27: warning: initialized field overwritten [-Woverride-init]
         40 |  [ICACHE_POLICY_VPIPT]  = "VPIPT",
            |                           ^~~~~~~
      arch/arm64/kernel/cpuinfo.c:40:27: note: (near initialization for 'icache_policy_str[0]')
      
      There is no real need for the default initializer here, as printing a
      NULL string is harmless. Rewrite the logic to have an explicit
      reserved value for the only one that uses the default value.
      
      This partially reverts the commit that removed ICACHE_POLICY_AIVIVT.
      
      Fixes: 155433cb ("arm64: cache: Remove support for ASID-tagged VIVT I-caches")
      Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
      Link: https://lore.kernel.org/r/20201026193807.3816388-1-arnd@kernel.orgSigned-off-by: default avatarWill Deacon <will@kernel.org>
      332576e6
    • Stephen Boyd's avatar
      KVM: arm64: ARM_SMCCC_ARCH_WORKAROUND_1 doesn't return SMCCC_RET_NOT_REQUIRED · 1de111b5
      Stephen Boyd authored
      According to the SMCCC spec[1](7.5.2 Discovery) the
      ARM_SMCCC_ARCH_WORKAROUND_1 function id only returns 0, 1, and
      SMCCC_RET_NOT_SUPPORTED.
      
       0 is "workaround required and safe to call this function"
       1 is "workaround not required but safe to call this function"
       SMCCC_RET_NOT_SUPPORTED is "might be vulnerable or might not be, who knows, I give up!"
      
      SMCCC_RET_NOT_SUPPORTED might as well mean "workaround required, except
      calling this function may not work because it isn't implemented in some
      cases". Wonderful. We map this SMC call to
      
       0 is SPECTRE_MITIGATED
       1 is SPECTRE_UNAFFECTED
       SMCCC_RET_NOT_SUPPORTED is SPECTRE_VULNERABLE
      
      For KVM hypercalls (hvc), we've implemented this function id to return
      SMCCC_RET_NOT_SUPPORTED, 0, and SMCCC_RET_NOT_REQUIRED. One of those
      isn't supposed to be there. Per the code we call
      arm64_get_spectre_v2_state() to figure out what to return for this
      feature discovery call.
      
       0 is SPECTRE_MITIGATED
       SMCCC_RET_NOT_REQUIRED is SPECTRE_UNAFFECTED
       SMCCC_RET_NOT_SUPPORTED is SPECTRE_VULNERABLE
      
      Let's clean this up so that KVM tells the guest this mapping:
      
       0 is SPECTRE_MITIGATED
       1 is SPECTRE_UNAFFECTED
       SMCCC_RET_NOT_SUPPORTED is SPECTRE_VULNERABLE
      
      Note: SMCCC_RET_NOT_AFFECTED is 1 but isn't part of the SMCCC spec
      
      Fixes: c118bbb5 ("arm64: KVM: Propagate full Spectre v2 workaround state to KVM guests")
      Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
      Acked-by: default avatarMarc Zyngier <maz@kernel.org>
      Acked-by: default avatarWill Deacon <will@kernel.org>
      Cc: Andre Przywara <andre.przywara@arm.com>
      Cc: Steven Price <steven.price@arm.com>
      Cc: Marc Zyngier <maz@kernel.org>
      Cc: stable@vger.kernel.org
      Link: https://developer.arm.com/documentation/den0028/latest [1]
      Link: https://lore.kernel.org/r/20201023154751.1973872-1-swboyd@chromium.orgSigned-off-by: default avatarWill Deacon <will@kernel.org>
      1de111b5
  7. 26 Oct, 2020 1 commit
  8. 25 Oct, 2020 16 commits