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-rw-r--r--arch/arm64/include/asm/elf.h6
-rw-r--r--arch/arm64/include/asm/signal32.h2
-rw-r--r--arch/arm64/kernel/signal32.c3
-rw-r--r--arch/arm64/kernel/vdso.c116
4 files changed, 93 insertions, 34 deletions
diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 6adc1a90e7e6..355d120b78cb 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -214,10 +214,10 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG];
set_thread_flag(TIF_32BIT); \
})
#define COMPAT_ARCH_DLINFO
-extern int aarch32_setup_vectors_page(struct linux_binprm *bprm,
- int uses_interp);
+extern int aarch32_setup_additional_pages(struct linux_binprm *bprm,
+ int uses_interp);
#define compat_arch_setup_additional_pages \
- aarch32_setup_vectors_page
+ aarch32_setup_additional_pages
#endif /* CONFIG_COMPAT */
diff --git a/arch/arm64/include/asm/signal32.h b/arch/arm64/include/asm/signal32.h
index 81abea0b7650..58e288aaf0ba 100644
--- a/arch/arm64/include/asm/signal32.h
+++ b/arch/arm64/include/asm/signal32.h
@@ -20,8 +20,6 @@
#ifdef CONFIG_COMPAT
#include <linux/compat.h>
-#define AARCH32_KERN_SIGRET_CODE_OFFSET 0x500
-
int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs);
int compat_setup_rt_frame(int usig, struct ksignal *ksig, sigset_t *set,
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index cb7800acd19f..caea6e25db2a 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -403,8 +403,7 @@ static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka,
if (ka->sa.sa_flags & SA_SIGINFO)
idx += 3;
- retcode = AARCH32_VECTORS_BASE +
- AARCH32_KERN_SIGRET_CODE_OFFSET +
+ retcode = (unsigned long)current->mm->context.vdso +
(idx << 2) + thumb;
}
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 42b7082029e1..6bb7038dc96c 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 +53,123 @@ 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 __init aarch32_alloc_vdso_pages(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_pages[C_PAGES];
- vpage = get_zeroed_page(GFP_ATOMIC);
+ vdso_pages[C_VECTORS] = get_zeroed_page(GFP_ATOMIC);
+ if (!vdso_pages[C_VECTORS])
+ return -ENOMEM;
- if (!vpage)
+ vdso_pages[C_SIGPAGE] = get_zeroed_page(GFP_ATOMIC);
+ if (!vdso_pages[C_SIGPAGE]) {
+ free_page(vdso_pages[C_VECTORS]);
return -ENOMEM;
+ }
/* kuser helpers */
- memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start,
- kuser_sz);
+ memcpy((void *)(vdso_pages[C_VECTORS] + 0x1000 - kuser_sz),
+ __kuser_helper_start,
+ kuser_sz);
/* sigreturn code */
- memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET,
- __aarch32_sigret_code_start, sigret_sz);
+ memcpy((void *)vdso_pages[C_SIGPAGE], __aarch32_sigret_code_start,
+ sigret_sz);
+
+ flush_icache_range(vdso_pages[C_VECTORS],
+ vdso_pages[C_VECTORS] + PAGE_SIZE);
+ flush_icache_range(vdso_pages[C_SIGPAGE],
+ vdso_pages[C_SIGPAGE] + PAGE_SIZE);
- flush_icache_range(vpage, vpage + PAGE_SIZE);
- vectors_page[0] = virt_to_page(vpage);
+ aarch32_vdso_pages[C_VECTORS] = virt_to_page(vdso_pages[C_VECTORS]);
+ aarch32_vdso_pages[C_SIGPAGE] = virt_to_page(vdso_pages[C_SIGPAGE]);
return 0;
}
-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;
+
+ /*
+ * 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,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.