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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-06 17:54:22 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-06 17:54:22 -0700 |
commit | c620f7bd0ba5c882b3e7fc199a8d5c2f6c2f5263 (patch) | |
tree | d44e53b3ec7a9cba43540c7e6cea7df3adae5ba2 /arch/arm64/kernel/vdso.c | |
parent | Merge tag 'arm64-mmiowb' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux (diff) | |
parent | Merge branch 'for-next/perf' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into for-next/core (diff) | |
download | linux-dev-c620f7bd0ba5c882b3e7fc199a8d5c2f6c2f5263.tar.xz linux-dev-c620f7bd0ba5c882b3e7fc199a8d5c2f6c2f5263.zip |
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
"Mostly just incremental improvements here:
- Introduce AT_HWCAP2 for advertising CPU features to userspace
- Expose SVE2 availability to userspace
- Support for "data cache clean to point of deep persistence" (DC PODP)
- Honour "mitigations=off" on the cmdline and advertise status via
sysfs
- CPU timer erratum workaround (Neoverse-N1 #1188873)
- Introduce perf PMU driver for the SMMUv3 performance counters
- Add config option to disable the kuser helpers page for AArch32 tasks
- Futex modifications to ensure liveness under contention
- Rework debug exception handling to seperate kernel and user
handlers
- Non-critical fixes and cleanup"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (92 commits)
Documentation: Add ARM64 to kernel-parameters.rst
arm64/speculation: Support 'mitigations=' cmdline option
arm64: ssbs: Don't treat CPUs with SSBS as unaffected by SSB
arm64: enable generic CPU vulnerabilites support
arm64: add sysfs vulnerability show for speculative store bypass
arm64: Fix size of __early_cpu_boot_status
clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters
clocksource/arm_arch_timer: Remove use of workaround static key
clocksource/arm_arch_timer: Drop use of static key in arch_timer_reg_read_stable
clocksource/arm_arch_timer: Direcly assign set_next_event workaround
arm64: Use arch_timer_read_counter instead of arch_counter_get_cntvct
watchdog/sbsa: Use arch_timer_read_counter instead of arch_counter_get_cntvct
ARM: vdso: Remove dependency with the arch_timer driver internals
arm64: Apply ARM64_ERRATUM_1188873 to Neoverse-N1
arm64: Add part number for Neoverse N1
arm64: Make ARM64_ERRATUM_1188873 depend on COMPAT
arm64: Restrict ARM64_ERRATUM_1188873 mitigation to AArch32
arm64: mm: Remove pte_unmap_nested()
arm64: Fix compiler warning from pte_unmap() with -Wunused-but-set-variable
arm64: compat: Reduce address limit for 64K pages
...
Diffstat (limited to 'arch/arm64/kernel/vdso.c')
-rw-r--r-- | arch/arm64/kernel/vdso.c | 139 |
1 files changed, 104 insertions, 35 deletions
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index 2d419006ad43..8074cbd3a3a8 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -1,5 +1,5 @@ /* - * VDSO implementation for AArch64 and vector page setup for AArch32. + * VDSO implementations. * * Copyright (C) 2012 ARM Limited * @@ -53,61 +53,129 @@ struct vdso_data *vdso_data = &vdso_data_store.data; /* * Create and map the vectors page for AArch32 tasks. */ -static struct page *vectors_page[1] __ro_after_init; +#define C_VECTORS 0 +#define C_SIGPAGE 1 +#define C_PAGES (C_SIGPAGE + 1) +static struct page *aarch32_vdso_pages[C_PAGES] __ro_after_init; +static const struct vm_special_mapping aarch32_vdso_spec[C_PAGES] = { + { + .name = "[vectors]", /* ABI */ + .pages = &aarch32_vdso_pages[C_VECTORS], + }, + { + .name = "[sigpage]", /* ABI */ + .pages = &aarch32_vdso_pages[C_SIGPAGE], + }, +}; -static int __init alloc_vectors_page(void) +static int aarch32_alloc_kuser_vdso_page(void) { extern char __kuser_helper_start[], __kuser_helper_end[]; - extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[]; - int kuser_sz = __kuser_helper_end - __kuser_helper_start; - int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start; - unsigned long vpage; + unsigned long vdso_page; - vpage = get_zeroed_page(GFP_ATOMIC); + if (!IS_ENABLED(CONFIG_KUSER_HELPERS)) + return 0; - if (!vpage) + vdso_page = get_zeroed_page(GFP_ATOMIC); + if (!vdso_page) return -ENOMEM; - /* kuser helpers */ - memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start, - kuser_sz); + memcpy((void *)(vdso_page + 0x1000 - kuser_sz), __kuser_helper_start, + kuser_sz); + aarch32_vdso_pages[C_VECTORS] = virt_to_page(vdso_page); + flush_dcache_page(aarch32_vdso_pages[C_VECTORS]); + return 0; +} - /* sigreturn code */ - memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET, - __aarch32_sigret_code_start, sigret_sz); +static int __init aarch32_alloc_vdso_pages(void) +{ + extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[]; + int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start; + unsigned long sigpage; + int ret; - flush_icache_range(vpage, vpage + PAGE_SIZE); - vectors_page[0] = virt_to_page(vpage); + sigpage = get_zeroed_page(GFP_ATOMIC); + if (!sigpage) + return -ENOMEM; - return 0; + memcpy((void *)sigpage, __aarch32_sigret_code_start, sigret_sz); + aarch32_vdso_pages[C_SIGPAGE] = virt_to_page(sigpage); + flush_dcache_page(aarch32_vdso_pages[C_SIGPAGE]); + + ret = aarch32_alloc_kuser_vdso_page(); + if (ret) + free_page(sigpage); + + return ret; } -arch_initcall(alloc_vectors_page); +arch_initcall(aarch32_alloc_vdso_pages); -int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) +static int aarch32_kuser_helpers_setup(struct mm_struct *mm) { - struct mm_struct *mm = current->mm; - unsigned long addr = AARCH32_VECTORS_BASE; - static const struct vm_special_mapping spec = { - .name = "[vectors]", - .pages = vectors_page, + void *ret; + + if (!IS_ENABLED(CONFIG_KUSER_HELPERS)) + return 0; + + /* + * Avoid VM_MAYWRITE for compatibility with arch/arm/, where it's + * not safe to CoW the page containing the CPU exception vectors. + */ + ret = _install_special_mapping(mm, AARCH32_VECTORS_BASE, PAGE_SIZE, + VM_READ | VM_EXEC | + VM_MAYREAD | VM_MAYEXEC, + &aarch32_vdso_spec[C_VECTORS]); - }; + return PTR_ERR_OR_ZERO(ret); +} + +static int aarch32_sigreturn_setup(struct mm_struct *mm) +{ + unsigned long addr; void *ret; - if (down_write_killable(&mm->mmap_sem)) - return -EINTR; - current->mm->context.vdso = (void *)addr; + addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0); + if (IS_ERR_VALUE(addr)) { + ret = ERR_PTR(addr); + goto out; + } - /* Map vectors page at the high address. */ + /* + * VM_MAYWRITE is required to allow gdb to Copy-on-Write and + * set breakpoints. + */ ret = _install_special_mapping(mm, addr, PAGE_SIZE, - VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, - &spec); + VM_READ | VM_EXEC | VM_MAYREAD | + VM_MAYWRITE | VM_MAYEXEC, + &aarch32_vdso_spec[C_SIGPAGE]); + if (IS_ERR(ret)) + goto out; - up_write(&mm->mmap_sem); + mm->context.vdso = (void *)addr; +out: return PTR_ERR_OR_ZERO(ret); } + +int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + struct mm_struct *mm = current->mm; + int ret; + + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + + ret = aarch32_kuser_helpers_setup(mm); + if (ret) + goto out; + + ret = aarch32_sigreturn_setup(mm); + +out: + up_write(&mm->mmap_sem); + return ret; +} #endif /* CONFIG_COMPAT */ static int vdso_mremap(const struct vm_special_mapping *sm, @@ -146,8 +214,6 @@ static int __init vdso_init(void) } vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT; - pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n", - vdso_pages + 1, vdso_pages, vdso_start, 1L, vdso_data); /* Allocate the vDSO pagelist, plus a page for the data. */ vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *), @@ -232,6 +298,9 @@ void update_vsyscall(struct timekeeper *tk) vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec; vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec; + /* Read without the seqlock held by clock_getres() */ + WRITE_ONCE(vdso_data->hrtimer_res, hrtimer_resolution); + if (!use_syscall) { /* tkr_mono.cycle_last == tkr_raw.cycle_last */ vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last; |