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lib/ioremap: ensure phys_addr actually corresponds to a physical address 

The current ioremap() code uses a phys_addr variable at each level of page
table, which is confusingly offset by subtracting the base virtual address
being mapped so that adding the current virtual address back on when
iterating through the page table entries gives back the corresponding
physical address.

This is fairly confusing and results in all users of phys_addr having to
add the current virtual address back on.  Instead, this patch just updates
phys_addr when iterating over the page table entries, ensuring that it's
always up-to-date and doesn't require explicit offsetting.

Link: http://lkml.kernel.org/r/1544120495-17438-5-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Will Deacon 2018-12-28 00:37:49 -08:00 committed by Linus Torvalds
parent 48e178ab0d
commit 36ddc5a78c
1 changed files with 12 additions and 16 deletions
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28
lib/ioremap.c
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@ -101,19 +101,18 @@ static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
pmd_t *pmd;
unsigned long next;
phys_addr -= addr;
pmd = pmd_alloc(&init_mm, pud, addr);
if (!pmd)
return -ENOMEM;
do {
next = pmd_addr_end(addr, end);
if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr + addr, prot))
if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot))
continue;
if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))
if (ioremap_pte_range(pmd, addr, next, phys_addr, prot))
return -ENOMEM;
} while (pmd++, addr = next, addr != end);
} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
return 0;
}
@ -142,19 +141,18 @@ static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
pud_t *pud;
unsigned long next;
phys_addr -= addr;
pud = pud_alloc(&init_mm, p4d, addr);
if (!pud)
return -ENOMEM;
do {
next = pud_addr_end(addr, end);
if (ioremap_try_huge_pud(pud, addr, next, phys_addr + addr, prot))
if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot))
continue;
if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))
if (ioremap_pmd_range(pud, addr, next, phys_addr, prot))
return -ENOMEM;
} while (pud++, addr = next, addr != end);
} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
return 0;
}
@ -164,7 +162,6 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
p4d_t *p4d;
unsigned long next;
phys_addr -= addr;
p4d = p4d_alloc(&init_mm, pgd, addr);
if (!p4d)
return -ENOMEM;
@ -173,14 +170,14 @@ static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
if (ioremap_p4d_enabled() &&
((next - addr) == P4D_SIZE) &&
IS_ALIGNED(phys_addr + addr, P4D_SIZE)) {
if (p4d_set_huge(p4d, phys_addr + addr, prot))
IS_ALIGNED(phys_addr, P4D_SIZE)) {
if (p4d_set_huge(p4d, phys_addr, prot))
continue;
}
if (ioremap_pud_range(p4d, addr, next, phys_addr + addr, prot))
if (ioremap_pud_range(p4d, addr, next, phys_addr, prot))
return -ENOMEM;
} while (p4d++, addr = next, addr != end);
} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
return 0;
}
@ -196,14 +193,13 @@ int ioremap_page_range(unsigned long addr,
BUG_ON(addr >= end);
start = addr;
phys_addr -= addr;
pgd = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, end);
err = ioremap_p4d_range(pgd, addr, next, phys_addr+addr, prot);
err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot);
if (err)
break;
} while (pgd++, addr = next, addr != end);
} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
flush_cache_vmap(start, end);