bianbu-repo-mirror/bianbu-linux-6.6
1
0
Fork 0
mirror of https://gitee.com/bianbu-linux/linux-6.6 synced 2025-04-24 14:07:52 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions
bianbu-linux-6.6/arch/m68k/include/asm/sun3_pgtable.h
Rick Edgecombe 2f0584f3f4 mm: Rename arch pte_mkwrite()'s to pte_mkwrite_novma() 
The x86 Shadow stack feature includes a new type of memory called shadow
stack. This shadow stack memory has some unusual properties, which requires
some core mm changes to function properly.

One of these unusual properties is that shadow stack memory is writable,
but only in limited ways. These limits are applied via a specific PTE
bit combination. Nevertheless, the memory is writable, and core mm code
will need to apply the writable permissions in the typical paths that
call pte_mkwrite(). The goal is to make pte_mkwrite() take a VMA, so
that the x86 implementation of it can know whether to create regular
writable or shadow stack mappings.

But there are a couple of challenges to this. Modifying the signatures of
each arch pte_mkwrite() implementation would be error prone because some
are generated with macros and would need to be re-implemented. Also, some
pte_mkwrite() callers operate on kernel memory without a VMA.

So this can be done in a three step process. First pte_mkwrite() can be
renamed to pte_mkwrite_novma() in each arch, with a generic pte_mkwrite()
added that just calls pte_mkwrite_novma(). Next callers without a VMA can
be moved to pte_mkwrite_novma(). And lastly, pte_mkwrite() and all callers
can be changed to take/pass a VMA.

Start the process by renaming pte_mkwrite() to pte_mkwrite_novma() and
adding the pte_mkwrite() wrapper in linux/pgtable.h. Apply the same
pattern for pmd_mkwrite(). Since not all archs have a pmd_mkwrite_novma(),
create a new arch config HAS_HUGE_PAGE that can be used to tell if
pmd_mkwrite() should be defined. Otherwise in the !HAS_HUGE_PAGE cases the
compiler would not be able to find pmd_mkwrite_novma().

No functional change.

Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/lkml/CAHk-=wiZjSu7c9sFYZb3q04108stgHff2wfbokGCCgW7riz+8Q@mail.gmail.com/
Link: https://lore.kernel.org/all/20230613001108.3040476-2-rick.p.edgecombe%40intel.com
2023-07-11 14:10:56 -07:00

195 lines
6.6 KiB
C
Raw Blame History

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _SUN3_PGTABLE_H
#define _SUN3_PGTABLE_H
#include <asm/sun3mmu.h>
#ifndef __ASSEMBLY__
#include <asm/virtconvert.h>
#include <linux/linkage.h>
/*
* This file contains all the things which change drastically for the sun3
* pagetable stuff, to avoid making too much of a mess of the generic m68k
* `pgtable.h'; this should only be included from the generic file. --m
*/
/* For virtual address to physical address conversion */
#define VTOP(addr) __pa(addr)
#define PTOV(addr) __va(addr)
#endif /* !__ASSEMBLY__ */
/* These need to be defined for compatibility although the sun3 doesn't use them */
#define _PAGE_NOCACHE030 0x040
#define _CACHEMASK040 (~0x060)
#define _PAGE_NOCACHE_S 0x040
/* Page protection values within PTE. */
#define SUN3_PAGE_VALID (0x80000000)
#define SUN3_PAGE_WRITEABLE (0x40000000)
#define SUN3_PAGE_SYSTEM (0x20000000)
#define SUN3_PAGE_NOCACHE (0x10000000)
#define SUN3_PAGE_ACCESSED (0x02000000)
#define SUN3_PAGE_MODIFIED (0x01000000)
/* Externally used page protection values. */
#define _PAGE_PRESENT (SUN3_PAGE_VALID)
#define _PAGE_ACCESSED (SUN3_PAGE_ACCESSED)
/* Compound page protection values. */
//todo: work out which ones *should* have SUN3_PAGE_NOCACHE and fix...
// is it just PAGE_KERNEL and PAGE_SHARED?
#define PAGE_NONE __pgprot(SUN3_PAGE_VALID \
| SUN3_PAGE_ACCESSED \
| SUN3_PAGE_NOCACHE)
#define PAGE_SHARED __pgprot(SUN3_PAGE_VALID \
| SUN3_PAGE_WRITEABLE \
| SUN3_PAGE_ACCESSED \
| SUN3_PAGE_NOCACHE)
#define PAGE_COPY __pgprot(SUN3_PAGE_VALID \
| SUN3_PAGE_ACCESSED \
| SUN3_PAGE_NOCACHE)
#define PAGE_READONLY __pgprot(SUN3_PAGE_VALID \
| SUN3_PAGE_ACCESSED \
| SUN3_PAGE_NOCACHE)
#define PAGE_KERNEL __pgprot(SUN3_PAGE_VALID \
| SUN3_PAGE_WRITEABLE \
| SUN3_PAGE_SYSTEM \
| SUN3_PAGE_NOCACHE \
| SUN3_PAGE_ACCESSED \
| SUN3_PAGE_MODIFIED)
#define PAGE_INIT __pgprot(SUN3_PAGE_VALID \
| SUN3_PAGE_WRITEABLE \
| SUN3_PAGE_SYSTEM \
| SUN3_PAGE_NOCACHE)
/* Use these fake page-protections on PMDs. */
#define SUN3_PMD_VALID (0x00000001)
#define SUN3_PMD_MASK (0x0000003F)
#define SUN3_PMD_MAGIC (0x0000002B)
/* We borrow bit 6 to store the exclusive marker in swap PTEs. */
#define _PAGE_SWP_EXCLUSIVE 0x040
#ifndef __ASSEMBLY__
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
*/
#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
pte_val(pte) = (pte_val(pte) & SUN3_PAGE_CHG_MASK) | pgprot_val(newprot);
return pte;
}
#define pmd_set(pmdp,ptep) do {} while (0)
#define __pte_page(pte) \
(__va ((pte_val (pte) & SUN3_PAGE_PGNUM_MASK) << PAGE_SHIFT))
static inline unsigned long pmd_page_vaddr(pmd_t pmd)
{
return (unsigned long)__va(pmd_val(pmd) & PAGE_MASK);
}
static inline int pte_none (pte_t pte) { return !pte_val (pte); }
static inline int pte_present (pte_t pte) { return pte_val (pte) & SUN3_PAGE_VALID; }
static inline void pte_clear (struct mm_struct *mm, unsigned long addr, pte_t *ptep)
{
pte_val (*ptep) = 0;
}
#define pte_pfn(pte) (pte_val(pte) & SUN3_PAGE_PGNUM_MASK)
#define pfn_pte(pfn, pgprot) \
({ pte_t __pte; pte_val(__pte) = pfn | pgprot_val(pgprot); __pte; })
#define pte_page(pte) virt_to_page(__pte_page(pte))
#define pmd_pfn(pmd) (pmd_val(pmd) >> PAGE_SHIFT)
#define pmd_page(pmd) virt_to_page((void *)pmd_page_vaddr(pmd))
static inline int pmd_none2 (pmd_t *pmd) { return !pmd_val (*pmd); }
#define pmd_none(pmd) pmd_none2(&(pmd))
//static inline int pmd_bad (pmd_t pmd) { return (pmd_val (pmd) & SUN3_PMD_MASK) != SUN3_PMD_MAGIC; }
static inline int pmd_bad2 (pmd_t *pmd) { return 0; }
#define pmd_bad(pmd) pmd_bad2(&(pmd))
static inline int pmd_present2 (pmd_t *pmd) { return pmd_val (*pmd) & SUN3_PMD_VALID; }
/* #define pmd_present(pmd) pmd_present2(&(pmd)) */
#define pmd_present(pmd) (!pmd_none2(&(pmd)))
static inline void pmd_clear (pmd_t *pmdp) { pmd_val (*pmdp) = 0; }
#define pte_ERROR(e) \
pr_err("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
#define pgd_ERROR(e) \
pr_err("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
/*
* The following only work if pte_present() is true.
* Undefined behaviour if not...
* [we have the full set here even if they don't change from m68k]
*/
static inline int pte_write(pte_t pte) { return pte_val(pte) & SUN3_PAGE_WRITEABLE; }
static inline int pte_dirty(pte_t pte) { return pte_val(pte) & SUN3_PAGE_MODIFIED; }
static inline int pte_young(pte_t pte) { return pte_val(pte) & SUN3_PAGE_ACCESSED; }
static inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) &= ~SUN3_PAGE_WRITEABLE; return pte; }
static inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~SUN3_PAGE_MODIFIED; return pte; }
static inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~SUN3_PAGE_ACCESSED; return pte; }
static inline pte_t pte_mkwrite_novma(pte_t pte){ pte_val(pte) |= SUN3_PAGE_WRITEABLE; return pte; }
static inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= SUN3_PAGE_MODIFIED; return pte; }
static inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= SUN3_PAGE_ACCESSED; return pte; }
static inline pte_t pte_mknocache(pte_t pte) { pte_val(pte) |= SUN3_PAGE_NOCACHE; return pte; }
// use this version when caches work...
//static inline pte_t pte_mkcache(pte_t pte) { pte_val(pte) &= SUN3_PAGE_NOCACHE; return pte; }
// until then, use:
static inline pte_t pte_mkcache(pte_t pte) { return pte; }
extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
extern pgd_t kernel_pg_dir[PTRS_PER_PGD];
/*
* Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
* are !pte_none() && !pte_present().
*
* Format of swap PTEs:
*
* 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
* 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
* 0 <--------------------- offset ----------------> E <- type -->
*
* E is the exclusive marker that is not stored in swap entries.
*/
#define __swp_type(x) ((x).val & 0x3f)
#define __swp_offset(x) (((x).val) >> 7)
#define __swp_entry(type, offset) ((swp_entry_t) { (((type) & 0x3f) | \
(((offset) << 7) & ~SUN3_PAGE_VALID)) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
static inline int pte_swp_exclusive(pte_t pte)
{
return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
}
static inline pte_t pte_swp_mkexclusive(pte_t pte)
{
pte_val(pte) |= _PAGE_SWP_EXCLUSIVE;
return pte;
}
static inline pte_t pte_swp_clear_exclusive(pte_t pte)
{
pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE;
return pte;
}
#endif /* !__ASSEMBLY__ */
#endif /* !_SUN3_PGTABLE_H */
Reference in a new issue View git blame Copy permalink