kernel.git/arch/arm64/kernel/vdso.c, branch linux-5.8.y

arm64: compat: Allow 32-bit vdso and sigpage to co-exist

2020-06-23T13:47:03Z

In preparation for removing the signal trampoline from the compat vDSO, allow the sigpage and the compat vDSO to co-exist. For the moment the vDSO signal trampoline will still be used when built. Subsequent patches will move to the sigpage consistently. Acked-by: Dave Martin Reviewed-by: Vincenzo Frascino Reviewed-by: Ard Biesheuvel Reviewed-by: Mark Rutland Signed-off-by: Will Deacon

mmap locking API: use coccinelle to convert mmap_sem rwsem call sites

2020-06-09T16:39:14Z

This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Daniel Jordan Reviewed-by: Laurent Dufour Reviewed-by: Vlastimil Babka Cc: Davidlohr Bueso Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds

Merge branch 'for-next/bti' into for-next/core

2020-05-28T17:00:51Z

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: vdso: Map the vDSO text with guarded pages when built for BTI

2020-05-07T16:53:20Z

The kernel is responsible for mapping the vDSO into userspace processes, including mapping the text section as executable. Handle the mapping of the vDSO for BTI similarly, mapping the text section as guarded pages so the BTI annotations in the vDSO become effective when they are present. This will mean that we can have BTI active for the vDSO in processes that do not otherwise support BTI. This should not be an issue for any expected use of the vDSO. Signed-off-by: Mark Brown Reviewed-by: Catalin Marinas Link: https://lore.kernel.org/r/20200506195138.22086-12-broonie@kernel.org Signed-off-by: Will Deacon

arm64: vdso: use consistent 'map' nomenclature

2020-04-29T09:52:53Z

The current code doesn't use a consistent naming scheme for structures, enums, or variables, making it harder than necessary to determine the relationship between these. Let's make this easier by consistently using 'map' nomenclature for mappings created in userspace, minimizing redundant comments, and using designated array initializers to tie indices to their respective elements. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Vincenzo Frascino Cc: Will Deacon Link: https://lore.kernel.org/r/20200428164921.41641-5-mark.rutland@arm.com Signed-off-by: Will Deacon

arm64: vdso: use consistent 'abi' nomenclature

2020-04-29T09:52:53Z

The current code doesn't use a consistent naming scheme for structures, enums, or variables, making it harder than necessary to determine the relationship between these. Let's make this easier by consistently using 'vdso_abi' nomenclature. The 'vdso_lookup' array is renamed to 'vdso_info' to describe what it contains rather than how it is consumed. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Vincenzo Frascino Cc: Will Deacon Link: https://lore.kernel.org/r/20200428164921.41641-4-mark.rutland@arm.com Signed-off-by: Will Deacon

arm64: vdso: simplify arch_vdso_type ifdeffery

2020-04-29T09:52:53Z

Currently we have some ifdeffery to determine the number of elements in enum arch_vdso_type as VDSO_TYPES, rather that the usual pattern of having the enum define this: | enum foo_type { | FOO_TYPE_A, | FOO_TYPE_B, | #ifdef CONFIG_C | FOO_TYPE_C, | #endif | NR_FOO_TYPES | } ... however, given we only use this number to size the vdso_lookup[] array, this is redundant anyway as the compiler can automatically size the array to fit all defined elements. So let's remove the VDSO_TYPES to simplify the code. At the same time, let's use designated initializers for the array elements so that these are guarnateed to be at the expected indices, regardless of how we modify the structure. For clariy the redundant explicit initialization of the enum elements is dropped. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Vincenzo Frascino Cc: Will Deacon Link: https://lore.kernel.org/r/20200428164921.41641-3-mark.rutland@arm.com Signed-off-by: Will Deacon

arm64: vdso: remove aarch32_vdso_pages[]

2020-04-29T09:52:53Z

The aarch32_vdso_pages[] array is unnecessarily confusing. We only ever use the C_VECTORS and C_SIGPAGE slots, and the other slots are unused despite having corresponding mappings (sharing pages with the AArch64 vDSO). Let's make this clearer by using separate variables for the vectors page and the sigreturn page. A subsequent patch will clean up the C_* naming and conflation of pages with mappings. Note that since both the vectors page and sig page are single pages, and the mapping is a single page long, their pages array do not need to be NULL-terminated (and this was not the case with the existing code for the sig page as it was the last entry in the aarch32_vdso_pages array). There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Vincenzo Frascino Cc: Will Deacon Link: https://lore.kernel.org/r/20200428164921.41641-2-mark.rutland@arm.com Signed-off-by: Will Deacon

arm64: vdso: don't free unallocated pages

2020-04-15T10:13:16Z

The aarch32_vdso_pages[] array never has entries allocated in the C_VVAR or C_VDSO slots, and as the array is zero initialized these contain NULL. However in __aarch32_alloc_vdso_pages() when aarch32_alloc_kuser_vdso_page() fails we attempt to free the page whose struct page is at NULL, which is obviously nonsensical. This patch removes the erroneous page freeing. Fixes: 7c1deeeb0130 ("arm64: compat: VDSO setup for compat layer") Cc: # 5.3.x- Cc: Vincenzo Frascino Acked-by: Will Deacon Signed-off-by: Mark Rutland Signed-off-by: Catalin Marinas

arm64: compat: VDSO setup for compat layer

2019-06-22T19:21:08Z

If CONFIG_GENERIC_COMPAT_VDSO is enabled, compat vDSO is installed in a compat (32 bit) process instead of sigpage. Add the necessary code to setup the vDSO required pages. Signed-off-by: Vincenzo Frascino Signed-off-by: Thomas Gleixner Tested-by: Shijith Thotton Tested-by: Andre Przywara Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: Catalin Marinas Cc: Will Deacon Cc: Arnd Bergmann Cc: Russell King Cc: Ralf Baechle Cc: Paul Burton Cc: Daniel Lezcano Cc: Mark Salyzyn Cc: Peter Collingbourne Cc: Shuah Khan Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Rasmus Villemoes Cc: Huw Davies Link: https://lkml.kernel.org/r/20190621095252.32307-13-vincenzo.frascino@arm.com