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https://github.com/edk2-porting/linux-next.git
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e47690d756
struct mm_struct is quite large (~1664 bytes) and so allocating on the stack may cause problems as the kernel stack size is small. Since ptdump_walk_pgd_level_core() was only allocating the structure so that it could modify the pgd argument we can instead introduce a pgd override in struct mm_walk and pass this down the call stack to where it is needed. Since the correct mm_struct is now being passed down, it is now also unnecessary to take the mmap_sem semaphore because ptdump_walk_pgd() will now take the semaphore on the real mm. [steven.price@arm.com: restore missed arm64 changes] Link: http://lkml.kernel.org/r/20200108145710.34314-1-steven.price@arm.com Link: http://lkml.kernel.org/r/20200108145710.34314-1-steven.price@arm.com Signed-off-by: Steven Price <steven.price@arm.com> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Hogan <jhogan@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Liang, Kan" <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Burton <paul.burton@mips.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Zong Li <zong.li@sifive.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
140 lines
3.4 KiB
C
140 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/pagewalk.h>
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#include <linux/ptdump.h>
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#include <linux/kasan.h>
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#ifdef CONFIG_KASAN
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/*
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* This is an optimization for KASAN=y case. Since all kasan page tables
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* eventually point to the kasan_early_shadow_page we could call note_page()
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* right away without walking through lower level page tables. This saves
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* us dozens of seconds (minutes for 5-level config) while checking for
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* W+X mapping or reading kernel_page_tables debugfs file.
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*/
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static inline int note_kasan_page_table(struct mm_walk *walk,
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unsigned long addr)
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{
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struct ptdump_state *st = walk->private;
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st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]));
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walk->action = ACTION_CONTINUE;
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return 0;
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}
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#endif
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static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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pgd_t val = READ_ONCE(*pgd);
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#if CONFIG_PGTABLE_LEVELS > 4 && defined(CONFIG_KASAN)
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if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d)))
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return note_kasan_page_table(walk, addr);
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#endif
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if (pgd_leaf(val))
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st->note_page(st, addr, 0, pgd_val(val));
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return 0;
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}
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static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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p4d_t val = READ_ONCE(*p4d);
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#if CONFIG_PGTABLE_LEVELS > 3 && defined(CONFIG_KASAN)
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if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud)))
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return note_kasan_page_table(walk, addr);
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#endif
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if (p4d_leaf(val))
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st->note_page(st, addr, 1, p4d_val(val));
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return 0;
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}
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static int ptdump_pud_entry(pud_t *pud, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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pud_t val = READ_ONCE(*pud);
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#if CONFIG_PGTABLE_LEVELS > 2 && defined(CONFIG_KASAN)
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if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd)))
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return note_kasan_page_table(walk, addr);
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#endif
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if (pud_leaf(val))
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st->note_page(st, addr, 2, pud_val(val));
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return 0;
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}
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static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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pmd_t val = READ_ONCE(*pmd);
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#if defined(CONFIG_KASAN)
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if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte)))
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return note_kasan_page_table(walk, addr);
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#endif
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if (pmd_leaf(val))
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st->note_page(st, addr, 3, pmd_val(val));
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return 0;
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}
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static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
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unsigned long next, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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st->note_page(st, addr, 4, pte_val(READ_ONCE(*pte)));
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return 0;
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}
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static int ptdump_hole(unsigned long addr, unsigned long next,
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int depth, struct mm_walk *walk)
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{
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struct ptdump_state *st = walk->private;
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st->note_page(st, addr, depth, 0);
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return 0;
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}
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static const struct mm_walk_ops ptdump_ops = {
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.pgd_entry = ptdump_pgd_entry,
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.p4d_entry = ptdump_p4d_entry,
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.pud_entry = ptdump_pud_entry,
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.pmd_entry = ptdump_pmd_entry,
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.pte_entry = ptdump_pte_entry,
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.pte_hole = ptdump_hole,
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};
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void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd)
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{
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const struct ptdump_range *range = st->range;
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down_read(&mm->mmap_sem);
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while (range->start != range->end) {
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walk_page_range_novma(mm, range->start, range->end,
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&ptdump_ops, pgd, st);
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range++;
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}
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up_read(&mm->mmap_sem);
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/* Flush out the last page */
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st->note_page(st, 0, -1, 0);
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}
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