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bianbu-linux-6.6/arch/microblaze/include/asm/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

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2008-2009 PetaLogix
* Copyright (C) 2006 Atmark Techno, Inc.
*/
#ifndef _ASM_MICROBLAZE_PGTABLE_H
#define _ASM_MICROBLAZE_PGTABLE_H
#include <asm/setup.h>
#ifndef __ASSEMBLY__
extern int mem_init_done;
#endif
#include <asm-generic/pgtable-nopmd.h>
#ifdef __KERNEL__
#ifndef __ASSEMBLY__
#include <linux/sched.h>
#include <linux/threads.h>
#include <asm/processor.h> /* For TASK_SIZE */
#include <asm/mmu.h>
#include <asm/page.h>
extern unsigned long va_to_phys(unsigned long address);
extern pte_t *va_to_pte(unsigned long address);
/*
* The following only work if pte_present() is true.
* Undefined behaviour if not..
*/
/* Start and end of the vmalloc area. */
/* Make sure to map the vmalloc area above the pinned kernel memory area
of 32Mb. */
#define VMALLOC_START (CONFIG_KERNEL_START + CONFIG_LOWMEM_SIZE)
#define VMALLOC_END ioremap_bot
#endif /* __ASSEMBLY__ */
/*
* Macro to mark a page protection value as "uncacheable".
*/
#define _PAGE_CACHE_CTL (_PAGE_GUARDED | _PAGE_NO_CACHE | \
_PAGE_WRITETHRU)
#define pgprot_noncached(prot) \
(__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
_PAGE_NO_CACHE | _PAGE_GUARDED))
#define pgprot_noncached_wc(prot) \
(__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
_PAGE_NO_CACHE))
/*
* The MicroBlaze MMU is identical to the PPC-40x MMU, and uses a hash
* table containing PTEs, together with a set of 16 segment registers, to
* define the virtual to physical address mapping.
*
* We use the hash table as an extended TLB, i.e. a cache of currently
* active mappings. We maintain a two-level page table tree, much
* like that used by the i386, for the sake of the Linux memory
* management code. Low-level assembler code in hashtable.S
* (procedure hash_page) is responsible for extracting ptes from the
* tree and putting them into the hash table when necessary, and
* updating the accessed and modified bits in the page table tree.
*/
/*
* The MicroBlaze processor has a TLB architecture identical to PPC-40x. The
* instruction and data sides share a unified, 64-entry, semi-associative
* TLB which is maintained totally under software control. In addition, the
* instruction side has a hardware-managed, 2,4, or 8-entry, fully-associative
* TLB which serves as a first level to the shared TLB. These two TLBs are
* known as the UTLB and ITLB, respectively (see "mmu.h" for definitions).
*/
/*
* The normal case is that PTEs are 32-bits and we have a 1-page
* 1024-entry pgdir pointing to 1-page 1024-entry PTE pages. -- paulus
*
*/
/* PGDIR_SHIFT determines what a top-level page table entry can map */
#define PGDIR_SHIFT (PAGE_SHIFT + PTE_SHIFT)
#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
#define PGDIR_MASK (~(PGDIR_SIZE-1))
/*
* entries per page directory level: our page-table tree is two-level, so
* we don't really have any PMD directory.
*/
#define PTRS_PER_PTE (1 << PTE_SHIFT)
#define PTRS_PER_PMD 1
#define PTRS_PER_PGD (1 << (32 - PGDIR_SHIFT))
#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
#define FIRST_USER_PGD_NR 0
#define USER_PGD_PTRS (PAGE_OFFSET >> PGDIR_SHIFT)
#define KERNEL_PGD_PTRS (PTRS_PER_PGD-USER_PGD_PTRS)
#define pte_ERROR(e) \
printk(KERN_ERR "%s:%d: bad pte "PTE_FMT".\n", \
__FILE__, __LINE__, pte_val(e))
#define pgd_ERROR(e) \
printk(KERN_ERR "%s:%d: bad pgd %08lx.\n", \
__FILE__, __LINE__, pgd_val(e))
/*
* Bits in a linux-style PTE. These match the bits in the
* (hardware-defined) PTE as closely as possible.
*/
/* There are several potential gotchas here. The hardware TLBLO
* field looks like this:
*
* 0 1 2 3 4 ... 18 19 20 21 22 23 24 25 26 27 28 29 30 31
* RPN..................... 0 0 EX WR ZSEL....... W I M G
*
* Where possible we make the Linux PTE bits match up with this
*
* - bits 20 and 21 must be cleared, because we use 4k pages (4xx can
* support down to 1k pages), this is done in the TLBMiss exception
* handler.
* - We use only zones 0 (for kernel pages) and 1 (for user pages)
* of the 16 available. Bit 24-26 of the TLB are cleared in the TLB
* miss handler. Bit 27 is PAGE_USER, thus selecting the correct
* zone.
* - PRESENT *must* be in the bottom two bits because swap PTEs use the top
* 30 bits. Because 4xx doesn't support SMP anyway, M is irrelevant so we
* borrow it for PAGE_PRESENT. Bit 30 is cleared in the TLB miss handler
* before the TLB entry is loaded.
* - All other bits of the PTE are loaded into TLBLO without
* * modification, leaving us only the bits 20, 21, 24, 25, 26, 30 for
* software PTE bits. We actually use bits 21, 24, 25, and
* 30 respectively for the software bits: ACCESSED, DIRTY, RW, and
* PRESENT.
*/
/* Definitions for MicroBlaze. */
#define _PAGE_GUARDED 0x001 /* G: page is guarded from prefetch */
#define _PAGE_PRESENT 0x002 /* software: PTE contains a translation */
#define _PAGE_NO_CACHE 0x004 /* I: caching is inhibited */
#define _PAGE_WRITETHRU 0x008 /* W: caching is write-through */
#define _PAGE_USER 0x010 /* matches one of the zone permission bits */
#define _PAGE_RW 0x040 /* software: Writes permitted */
#define _PAGE_DIRTY 0x080 /* software: dirty page */
#define _PAGE_HWWRITE 0x100 /* hardware: Dirty & RW, set in exception */
#define _PAGE_HWEXEC 0x200 /* hardware: EX permission */
#define _PAGE_ACCESSED 0x400 /* software: R: page referenced */
#define _PMD_PRESENT PAGE_MASK
/* We borrow bit 24 to store the exclusive marker in swap PTEs. */
#define _PAGE_SWP_EXCLUSIVE _PAGE_DIRTY
/*
* Some bits are unused...
*/
#ifndef _PAGE_HASHPTE
#define _PAGE_HASHPTE 0
#endif
#ifndef _PTE_NONE_MASK
#define _PTE_NONE_MASK 0
#endif
#ifndef _PAGE_SHARED
#define _PAGE_SHARED 0
#endif
#ifndef _PAGE_EXEC
#define _PAGE_EXEC 0
#endif
#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
/*
* Note: the _PAGE_COHERENT bit automatically gets set in the hardware
* PTE if CONFIG_SMP is defined (hash_page does this); there is no need
* to have it in the Linux PTE, and in fact the bit could be reused for
* another purpose. -- paulus.
*/
#define _PAGE_BASE (_PAGE_PRESENT | _PAGE_ACCESSED)
#define _PAGE_WRENABLE (_PAGE_RW | _PAGE_DIRTY | _PAGE_HWWRITE)
#define _PAGE_KERNEL \
(_PAGE_BASE | _PAGE_WRENABLE | _PAGE_SHARED | _PAGE_HWEXEC)
#define _PAGE_IO (_PAGE_KERNEL | _PAGE_NO_CACHE | _PAGE_GUARDED)
#define PAGE_NONE __pgprot(_PAGE_BASE)
#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER)
#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
#define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)
#define PAGE_SHARED_X \
__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC)
#define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER)
#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
#define PAGE_KERNEL __pgprot(_PAGE_KERNEL)
#define PAGE_KERNEL_RO __pgprot(_PAGE_BASE | _PAGE_SHARED)
#define PAGE_KERNEL_CI __pgprot(_PAGE_IO)
/*
* We consider execute permission the same as read.
* Also, write permissions imply read permissions.
*/
#ifndef __ASSEMBLY__
/*
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..
*/
extern unsigned long empty_zero_page[1024];
#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
#endif /* __ASSEMBLY__ */
#define pte_none(pte) ((pte_val(pte) & ~_PTE_NONE_MASK) == 0)
#define pte_present(pte) (pte_val(pte) & _PAGE_PRESENT)
#define pte_clear(mm, addr, ptep) \
do { set_pte_at((mm), (addr), (ptep), __pte(0)); } while (0)
#define pmd_none(pmd) (!pmd_val(pmd))
#define pmd_bad(pmd) ((pmd_val(pmd) & _PMD_PRESENT) == 0)
#define pmd_present(pmd) ((pmd_val(pmd) & _PMD_PRESENT) != 0)
#define pmd_clear(pmdp) do { pmd_val(*(pmdp)) = 0; } while (0)
#define pte_page(x) (mem_map + (unsigned long) \
((pte_val(x) - memory_start) >> PAGE_SHIFT))
#define PFN_SHIFT_OFFSET (PAGE_SHIFT)
#define pte_pfn(x) (pte_val(x) >> PFN_SHIFT_OFFSET)
#define pfn_pte(pfn, prot) \
__pte(((pte_basic_t)(pfn) << PFN_SHIFT_OFFSET) | pgprot_val(prot))
#ifndef __ASSEMBLY__
/*
* The following only work if pte_present() is true.
* Undefined behaviour if not..
*/
static inline int pte_read(pte_t pte) { return pte_val(pte) & _PAGE_USER; }
static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_RW; }
static inline int pte_exec(pte_t pte) { return pte_val(pte) & _PAGE_EXEC; }
static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
static inline void pte_uncache(pte_t pte) { pte_val(pte) |= _PAGE_NO_CACHE; }
static inline void pte_cache(pte_t pte) { pte_val(pte) &= ~_PAGE_NO_CACHE; }
static inline pte_t pte_rdprotect(pte_t pte) \
{ pte_val(pte) &= ~_PAGE_USER; return pte; }
static inline pte_t pte_wrprotect(pte_t pte) \
{ pte_val(pte) &= ~(_PAGE_RW | _PAGE_HWWRITE); return pte; }
static inline pte_t pte_exprotect(pte_t pte) \
{ pte_val(pte) &= ~_PAGE_EXEC; return pte; }
static inline pte_t pte_mkclean(pte_t pte) \
{ pte_val(pte) &= ~(_PAGE_DIRTY | _PAGE_HWWRITE); return pte; }
static inline pte_t pte_mkold(pte_t pte) \
{ pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
static inline pte_t pte_mkread(pte_t pte) \
{ pte_val(pte) |= _PAGE_USER; return pte; }
static inline pte_t pte_mkexec(pte_t pte) \
{ pte_val(pte) |= _PAGE_USER | _PAGE_EXEC; return pte; }
static inline pte_t pte_mkwrite_novma(pte_t pte) \
{ pte_val(pte) |= _PAGE_RW; return pte; }
static inline pte_t pte_mkdirty(pte_t pte) \
{ pte_val(pte) |= _PAGE_DIRTY; return pte; }
static inline pte_t pte_mkyoung(pte_t pte) \
{ pte_val(pte) |= _PAGE_ACCESSED; return pte; }
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
*/
static inline pte_t mk_pte_phys(phys_addr_t physpage, pgprot_t pgprot)
{
pte_t pte;
pte_val(pte) = physpage | pgprot_val(pgprot);
return pte;
}
#define mk_pte(page, pgprot) \
({ \
pte_t pte; \
pte_val(pte) = (((page - mem_map) << PAGE_SHIFT) + memory_start) | \
pgprot_val(pgprot); \
pte; \
})
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot);
return pte;
}
/*
* Atomic PTE updates.
*
* pte_update clears and sets bit atomically, and returns
* the old pte value.
* The ((unsigned long)(p+1) - 4) hack is to get to the least-significant
* 32 bits of the PTE regardless of whether PTEs are 32 or 64 bits.
*/
static inline unsigned long pte_update(pte_t *p, unsigned long clr,
unsigned long set)
{
unsigned long flags, old, tmp;
raw_local_irq_save(flags);
__asm__ __volatile__( "lw %0, %2, r0 \n"
"andn %1, %0, %3 \n"
"or %1, %1, %4 \n"
"sw %1, %2, r0 \n"
: "=&r" (old), "=&r" (tmp)
: "r" ((unsigned long)(p + 1) - 4), "r" (clr), "r" (set)
: "cc");
raw_local_irq_restore(flags);
return old;
}
/*
* set_pte stores a linux PTE into the linux page table.
*/
static inline void set_pte(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
*ptep = pte;
}
static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
*ptep = pte;
}
#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
unsigned long address, pte_t *ptep)
{
return (pte_update(ptep, _PAGE_ACCESSED, 0) & _PAGE_ACCESSED) != 0;
}
static inline int ptep_test_and_clear_dirty(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
return (pte_update(ptep, \
(_PAGE_DIRTY | _PAGE_HWWRITE), 0) & _PAGE_DIRTY) != 0;
}
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
return __pte(pte_update(ptep, ~_PAGE_HASHPTE, 0));
}
/*static inline void ptep_set_wrprotect(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
pte_update(ptep, (_PAGE_RW | _PAGE_HWWRITE), 0);
}*/
static inline void ptep_mkdirty(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
pte_update(ptep, 0, _PAGE_DIRTY);
}
/*#define pte_same(A,B) (((pte_val(A) ^ pte_val(B)) & ~_PAGE_HASHPTE) == 0)*/
/* Convert pmd entry to page */
/* our pmd entry is an effective address of pte table*/
/* returns effective address of the pmd entry*/
static inline unsigned long pmd_page_vaddr(pmd_t pmd)
{
return ((unsigned long) (pmd_val(pmd) & PAGE_MASK));
}
/* returns pfn of the pmd entry*/
#define pmd_pfn(pmd) (__pa(pmd_val(pmd)) >> PAGE_SHIFT)
/* returns struct *page of the pmd entry*/
#define pmd_page(pmd) (pfn_to_page(__pa(pmd_val(pmd)) >> PAGE_SHIFT))
/* Find an entry in the third-level page table.. */
extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
/*
* Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
* are !pte_none() && !pte_present().
*
* 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* <------------------ offset -------------------> E < type -> 0 0
*
* E is the exclusive marker that is not stored in swap entries.
*/
#define __swp_type(entry) ((entry).val & 0x1f)
#define __swp_offset(entry) ((entry).val >> 6)
#define __swp_entry(type, offset) \
((swp_entry_t) { ((type) & 0x1f) | ((offset) << 6) })
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) >> 2 })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val << 2 })
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;
}
extern unsigned long iopa(unsigned long addr);
/* Values for nocacheflag and cmode */
/* These are not used by the APUS kernel_map, but prevents
* compilation errors.
*/
#define IOMAP_FULL_CACHING 0
#define IOMAP_NOCACHE_SER 1
#define IOMAP_NOCACHE_NONSER 2
#define IOMAP_NO_COPYBACK 3
void do_page_fault(struct pt_regs *regs, unsigned long address,
unsigned long error_code);
void mapin_ram(void);
int map_page(unsigned long va, phys_addr_t pa, int flags);
extern int mem_init_done;
asmlinkage void __init mmu_init(void);
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#ifndef __ASSEMBLY__
extern unsigned long ioremap_bot, ioremap_base;
void setup_memory(void);
#endif /* __ASSEMBLY__ */
#endif /* _ASM_MICROBLAZE_PGTABLE_H */
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