Messages in this thread Patch in this message | | | From | Dmitry Safonov <> | Subject | [PATCH v2 15/19] x86/vdso: Migrate to generic vdso_base | Date | Tue, 24 Nov 2020 00:29:28 +0000 |
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Generic way to track the landing vma area. As a bonus, after unmapping vdso, kernel won't try to land on its previous position (due to UNMAPPED_VDSO_BASE check instead of context.vdso ?= 0 check).
Signed-off-by: Dmitry Safonov <dima@arista.com> --- arch/x86/Kconfig | 1 + arch/x86/entry/common.c | 2 +- arch/x86/entry/vdso/extable.c | 4 ++-- arch/x86/entry/vdso/vma.c | 9 ++++----- arch/x86/ia32/ia32_signal.c | 4 ++-- arch/x86/include/asm/mmu.h | 1 - arch/x86/include/asm/vdso.h | 2 +- arch/x86/kernel/signal.c | 4 ++-- 8 files changed, 13 insertions(+), 14 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index d676e0bad1f1..4f06760f849e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -85,6 +85,7 @@ config X86 select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE select ARCH_HAS_SYSCALL_WRAPPER select ARCH_HAS_UBSAN_SANITIZE_ALL + select ARCH_HAS_VDSO_BASE select ARCH_HAS_DEBUG_WX select ARCH_HAVE_NMI_SAFE_CMPXCHG select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index d9ab58cc765b..655b7d8fe734 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -151,7 +151,7 @@ __visible noinstr long do_fast_syscall_32(struct pt_regs *regs) * Called using the internal vDSO SYSENTER/SYSCALL32 calling * convention. Adjust regs so it looks like we entered using int80. */ - landing_pad = (unsigned long)current->mm->context.vdso + + landing_pad = (unsigned long)current->mm->vdso_base + vdso_image_32.sym_int80_landing_pad; /* diff --git a/arch/x86/entry/vdso/extable.c b/arch/x86/entry/vdso/extable.c index afcf5b65beef..16688c2d032c 100644 --- a/arch/x86/entry/vdso/extable.c +++ b/arch/x86/entry/vdso/extable.c @@ -25,10 +25,10 @@ bool fixup_vdso_exception(struct pt_regs *regs, int trapnr, if (trapnr == X86_TRAP_DB || trapnr == X86_TRAP_BP) return false; - if (!current->mm->context.vdso) + if (current->mm->vdso_base == (void *)UNMAPPED_VDSO_BASE) return false; - base = (unsigned long)current->mm->context.vdso + image->extable_base; + base = (unsigned long)current->mm->vdso_base + image->extable_base; nr_entries = image->extable_len / (sizeof(*extable)); extable = image->extable; diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index 65780a0164e3..29a795face9d 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -77,7 +77,7 @@ static void vdso_fix_landing(const struct vdso_image *image, struct pt_regs *regs = current_pt_regs(); unsigned long vdso_land = image->sym_int80_landing_pad; unsigned long old_land_addr = vdso_land + - (unsigned long)current->mm->context.vdso; + (unsigned long)current->mm->vdso_base; /* Fixing userspace landing - look at do_fast_syscall_32 */ if (regs->ip == old_land_addr) @@ -92,7 +92,6 @@ static void vdso_mremap(const struct vm_special_mapping *sm, const struct vdso_image *image = current->mm->context.vdso_image; vdso_fix_landing(image, new_vma); - current->mm->context.vdso = (void __user *)new_vma->vm_start; } #ifdef CONFIG_TIME_NS @@ -287,7 +286,7 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr, ret = PTR_ERR(vma); do_munmap(mm, text_start, image->size, NULL); } else { - current->mm->context.vdso = (void __user *)text_start; + current->mm->vdso_base = (void __user *)text_start; current->mm->context.vdso_image = image; *sysinfo_ehdr = text_start; } @@ -362,8 +361,8 @@ int map_vdso_once(const struct vdso_image *image, unsigned long addr) * Check if we have already mapped vdso blob - fail to prevent * abusing from userspace install_speciall_mapping, which may * not do accounting and rlimit right. - * We could search vma near context.vdso, but it's a slowpath, - * so let's explicitly check all VMAs to be completely sure. + * It's a slowpath, let's explicitly check all VMAs to be + * completely sure. */ for (vma = mm->mmap; vma; vma = vma->vm_next) { if (vma_is_special_mapping(vma, &vdso_mapping) || diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c index f87ed1d53938..67204b1eeea0 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/ia32/ia32_signal.c @@ -256,7 +256,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, } else { /* Return stub is in 32bit vsyscall page */ if (current_has_vdso_image_32()) - restorer = current->mm->context.vdso + + restorer = current->mm->vdso_base + vdso_image_32.sym___kernel_sigreturn; else restorer = &frame->retcode; @@ -337,7 +337,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig, if (ksig->ka.sa.sa_flags & SA_RESTORER) restorer = ksig->ka.sa.sa_restorer; else if (current_has_vdso_image_32()) - restorer = current->mm->context.vdso + + restorer = current->mm->vdso_base + vdso_image_32.sym___kernel_rt_sigreturn; else restorer = &frame->retcode; diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 5d7494631ea9..7bd10e6b8386 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -43,7 +43,6 @@ typedef struct { #endif struct mutex lock; - void __user *vdso; /* vdso base address */ const struct vdso_image *vdso_image; /* vdso image in use */ atomic_t perf_rdpmc_allowed; /* nonzero if rdpmc is allowed */ diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index e3829c3a6149..31b5695eded4 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -44,7 +44,7 @@ extern const struct vdso_image vdso_image_32; #define current_has_vdso_image_32() \ likely(current->mm->context.vdso_image == &vdso_image_32 && \ - !!current->mm->context.vdso) + (unsigned long)current->mm->vdso_base != UNMAPPED_VDSO_BASE) #endif extern void __init init_vdso_image(const struct vdso_image *image); diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 6fed2e523e0a..85161df044f2 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -320,7 +320,7 @@ __setup_frame(int sig, struct ksignal *ksig, sigset_t *set, if (ksig->ka.sa.sa_flags & SA_RESTORER) restorer = ksig->ka.sa.sa_restorer; else if (current_has_vdso_image_32()) - restorer = current->mm->context.vdso + + restorer = current->mm->vdso_base + vdso_image_32.sym___kernel_sigreturn; else restorer = &frame->retcode; @@ -382,7 +382,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig, if (ksig->ka.sa.sa_flags & SA_RESTORER) restorer = ksig->ka.sa.sa_restorer; else if (current_has_vdso_image_32()) - restorer = current->mm->context.vdso + + restorer = current->mm->vdso_base + vdso_image_32.sym___kernel_rt_sigreturn; else restorer = &frame->retcode; -- 2.29.2
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