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Subject[PATCH V2 13/17] riscv: compat: vdso: Add setup additional pages implementation
Date
From: Guo Ren <guoren@linux.alibaba.com>

Reconstruct __setup_additional_pages() by appending vdso info
pointer argument to meet compat_vdso_info requirement. And change
vm_special_mapping *dm, *cm initialization into static.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
---
arch/riscv/include/asm/elf.h | 5 ++
arch/riscv/include/asm/mmu.h | 1 +
arch/riscv/kernel/vdso.c | 104 +++++++++++++++++++++++++----------
3 files changed, 81 insertions(+), 29 deletions(-)

diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h
index 91b372d4e13b..9d108cf84b99 100644
--- a/arch/riscv/include/asm/elf.h
+++ b/arch/riscv/include/asm/elf.h
@@ -136,5 +136,10 @@ do { if ((ex).e_ident[EI_CLASS] == ELFCLASS32) \
typedef compat_ulong_t compat_elf_greg_t;
typedef compat_elf_greg_t compat_elf_gregset_t[ELF_NGREG];

+extern int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
+ int uses_interp);
+#define compat_arch_setup_additional_pages \
+ compat_arch_setup_additional_pages
+
#endif /* CONFIG_COMPAT */
#endif /* _ASM_RISCV_ELF_H */
diff --git a/arch/riscv/include/asm/mmu.h b/arch/riscv/include/asm/mmu.h
index 0099dc116168..cedcf8ea3c76 100644
--- a/arch/riscv/include/asm/mmu.h
+++ b/arch/riscv/include/asm/mmu.h
@@ -16,6 +16,7 @@ typedef struct {
atomic_long_t id;
#endif
void *vdso;
+ void *vdso_info;
#ifdef CONFIG_SMP
/* A local icache flush is needed before user execution can resume. */
cpumask_t icache_stale_mask;
diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
index a9436a65161a..deca69524799 100644
--- a/arch/riscv/kernel/vdso.c
+++ b/arch/riscv/kernel/vdso.c
@@ -23,6 +23,9 @@ struct vdso_data {
#endif

extern char vdso_start[], vdso_end[];
+#ifdef CONFIG_COMPAT
+extern char compat_vdso_start[], compat_vdso_end[];
+#endif

enum vvar_pages {
VVAR_DATA_PAGE_OFFSET,
@@ -30,6 +33,11 @@ enum vvar_pages {
VVAR_NR_PAGES,
};

+enum rv_vdso_map {
+ RV_VDSO_MAP_VVAR,
+ RV_VDSO_MAP_VDSO,
+};
+
#define VVAR_SIZE (VVAR_NR_PAGES << PAGE_SHIFT)

/*
@@ -52,12 +60,6 @@ struct __vdso_info {
struct vm_special_mapping *cm;
};

-static struct __vdso_info vdso_info __ro_after_init = {
- .name = "vdso",
- .vdso_code_start = vdso_start,
- .vdso_code_end = vdso_end,
-};
-
static int vdso_mremap(const struct vm_special_mapping *sm,
struct vm_area_struct *new_vma)
{
@@ -66,35 +68,35 @@ static int vdso_mremap(const struct vm_special_mapping *sm,
return 0;
}

-static int __init __vdso_init(void)
+static int __init __vdso_init(struct __vdso_info *vdso_info)
{
unsigned int i;
struct page **vdso_pagelist;
unsigned long pfn;

- if (memcmp(vdso_info.vdso_code_start, "\177ELF", 4)) {
+ if (memcmp(vdso_info->vdso_code_start, "\177ELF", 4)) {
pr_err("vDSO is not a valid ELF object!\n");
return -EINVAL;
}

- vdso_info.vdso_pages = (
- vdso_info.vdso_code_end -
- vdso_info.vdso_code_start) >>
+ vdso_info->vdso_pages = (
+ vdso_info->vdso_code_end -
+ vdso_info->vdso_code_start) >>
PAGE_SHIFT;

- vdso_pagelist = kcalloc(vdso_info.vdso_pages,
+ vdso_pagelist = kcalloc(vdso_info->vdso_pages,
sizeof(struct page *),
GFP_KERNEL);
if (vdso_pagelist == NULL)
return -ENOMEM;

/* Grab the vDSO code pages. */
- pfn = sym_to_pfn(vdso_info.vdso_code_start);
+ pfn = sym_to_pfn(vdso_info->vdso_code_start);

- for (i = 0; i < vdso_info.vdso_pages; i++)
+ for (i = 0; i < vdso_info->vdso_pages; i++)
vdso_pagelist[i] = pfn_to_page(pfn + i);

- vdso_info.cm->pages = vdso_pagelist;
+ vdso_info->cm->pages = vdso_pagelist;

return 0;
}
@@ -116,13 +118,14 @@ int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
{
struct mm_struct *mm = task->mm;
struct vm_area_struct *vma;
+ struct __vdso_info *vdso_info = mm->context.vdso_info;

mmap_read_lock(mm);

for (vma = mm->mmap; vma; vma = vma->vm_next) {
unsigned long size = vma->vm_end - vma->vm_start;

- if (vma_is_special_mapping(vma, vdso_info.dm))
+ if (vma_is_special_mapping(vma, vdso_info->dm))
zap_page_range(vma, vma->vm_start, size);
}

@@ -187,11 +190,6 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
return vmf_insert_pfn(vma, vmf->address, pfn);
}

-enum rv_vdso_map {
- RV_VDSO_MAP_VVAR,
- RV_VDSO_MAP_VDSO,
-};
-
static struct vm_special_mapping rv_vdso_maps[] __ro_after_init = {
[RV_VDSO_MAP_VVAR] = {
.name = "[vvar]",
@@ -203,25 +201,53 @@ static struct vm_special_mapping rv_vdso_maps[] __ro_after_init = {
},
};

+static struct __vdso_info vdso_info __ro_after_init = {
+ .name = "vdso",
+ .vdso_code_start = vdso_start,
+ .vdso_code_end = vdso_end,
+ .dm = &rv_vdso_maps[RV_VDSO_MAP_VVAR],
+ .cm = &rv_vdso_maps[RV_VDSO_MAP_VDSO],
+};
+
+#ifdef CONFIG_COMPAT
+static struct __vdso_info compat_vdso_info __ro_after_init = {
+ .name = "compat_vdso",
+ .vdso_code_start = compat_vdso_start,
+ .vdso_code_end = compat_vdso_end,
+ .dm = &rv_vdso_maps[RV_VDSO_MAP_VVAR],
+ .cm = &rv_vdso_maps[RV_VDSO_MAP_VDSO],
+};
+#endif
+
static int __init vdso_init(void)
{
- vdso_info.dm = &rv_vdso_maps[RV_VDSO_MAP_VVAR];
- vdso_info.cm = &rv_vdso_maps[RV_VDSO_MAP_VDSO];
+ int ret;
+
+ ret = __vdso_init(&vdso_info);
+ if (ret)
+ goto out;

- return __vdso_init();
+#ifdef CONFIG_COMPAT
+ ret = __vdso_init(&compat_vdso_info);
+ if (ret)
+ goto out;
+#endif
+out:
+ return ret;
}
arch_initcall(vdso_init);

static int __setup_additional_pages(struct mm_struct *mm,
struct linux_binprm *bprm,
- int uses_interp)
+ int uses_interp,
+ struct __vdso_info *vdso_info)
{
unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
void *ret;

BUILD_BUG_ON(VVAR_NR_PAGES != __VVAR_PAGES);

- vdso_text_len = vdso_info.vdso_pages << PAGE_SHIFT;
+ vdso_text_len = vdso_info->vdso_pages << PAGE_SHIFT;
/* Be sure to map the data page */
vdso_mapping_len = vdso_text_len + VVAR_SIZE;

@@ -232,16 +258,18 @@ static int __setup_additional_pages(struct mm_struct *mm,
}

ret = _install_special_mapping(mm, vdso_base, VVAR_SIZE,
- (VM_READ | VM_MAYREAD | VM_PFNMAP), vdso_info.dm);
+ (VM_READ | VM_MAYREAD | VM_PFNMAP), vdso_info->dm);
if (IS_ERR(ret))
goto up_fail;

vdso_base += VVAR_SIZE;
mm->context.vdso = (void *)vdso_base;
+ mm->context.vdso_info = (void *)vdso_info;
+
ret =
_install_special_mapping(mm, vdso_base, vdso_text_len,
(VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC),
- vdso_info.cm);
+ vdso_info->cm);

if (IS_ERR(ret))
goto up_fail;
@@ -253,6 +281,24 @@ static int __setup_additional_pages(struct mm_struct *mm,
return PTR_ERR(ret);
}

+#ifdef CONFIG_COMPAT
+int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
+ int uses_interp)
+{
+ struct mm_struct *mm = current->mm;
+ int ret;
+
+ if (mmap_write_lock_killable(mm))
+ return -EINTR;
+
+ ret = __setup_additional_pages(mm, bprm, uses_interp,
+ &compat_vdso_info);
+ mmap_write_unlock(mm);
+
+ return ret;
+}
+#endif
+
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct mm_struct *mm = current->mm;
@@ -261,7 +307,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
if (mmap_write_lock_killable(mm))
return -EINTR;

- ret = __setup_additional_pages(mm, bprm, uses_interp);
+ ret = __setup_additional_pages(mm, bprm, uses_interp, &vdso_info);
mmap_write_unlock(mm);

return ret;
--
2.25.1
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