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riscv: compat: vdso: Add setup additional pages implementation
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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>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220405071314.3225832-18-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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@guoren83 @palmer-dabbelt
guoren83 authored and palmer-dabbelt committed Apr 26, 2022
1 parent 0715372 commit 3092eb4
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Showing 3 changed files with 76 additions and 35 deletions.
5 changes: 5 additions & 0 deletions arch/riscv/include/asm/elf.h
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Original file line number Diff line number Diff line change
Expand Up @@ -130,5 +130,10 @@ 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 */
1 change: 1 addition & 0 deletions arch/riscv/include/asm/mmu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
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105 changes: 70 additions & 35 deletions arch/riscv/kernel/vdso.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,13 +23,21 @@ 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,
VVAR_TIMENS_PAGE_OFFSET,
VVAR_NR_PAGES,
};

enum rv_vdso_map {
RV_VDSO_MAP_VVAR,
RV_VDSO_MAP_VDSO,
};

#define VVAR_SIZE (VVAR_NR_PAGES << PAGE_SHIFT)

/*
Expand All @@ -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)
{
Expand All @@ -66,37 +68,33 @@ static int vdso_mremap(const struct vm_special_mapping *sm,
return 0;
}

static int __init __vdso_init(void)
static void __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)) {
pr_err("vDSO is not a valid ELF object!\n");
return -EINVAL;
}
if (memcmp(vdso_info->vdso_code_start, "\177ELF", 4))
panic("vDSO is not a valid ELF object!\n");

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;
panic("vDSO kcalloc failed!\n");

/* 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;

return 0;
vdso_info->cm->pages = vdso_pagelist;
}

#ifdef CONFIG_TIME_NS
Expand All @@ -116,13 +114,14 @@ 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);
}

Expand Down Expand Up @@ -187,11 +186,6 @@ 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]",
Expand All @@ -203,25 +197,46 @@ 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];
__vdso_init(&vdso_info);
#ifdef CONFIG_COMPAT
__vdso_init(&compat_vdso_info);
#endif

return __vdso_init();
return 0;
}
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;

Expand All @@ -232,16 +247,18 @@ 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;
Expand All @@ -253,6 +270,24 @@ 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;
Expand All @@ -261,7 +296,7 @@ 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;
Expand Down

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