lkml.org 
[lkml]   [2010]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: [PATCH v2 01/20] ARM: LPAE: Use PMD_(SHIFT|SIZE|MASK) instead of PGDIR_*
    On Mon, Nov 22, 2010 at 01:00:10PM +0000, Catalin Marinas wrote:
    > On Mon, 2010-11-22 at 12:43 +0000, Russell King - ARM Linux wrote:
    > > On Fri, Nov 12, 2010 at 06:00:21PM +0000, Catalin Marinas wrote:
    > > > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
    > > > index 8c19595..40b386c 100644
    > > > --- a/arch/arm/kernel/smp.c
    > > > +++ b/arch/arm/kernel/smp.c
    > > > @@ -78,7 +78,7 @@ static inline void identity_mapping_add(pgd_t *pgd, unsigned long start,
    > > > if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
    > > > prot |= PMD_BIT4;
    > > >
    > > > - for (addr = start & PGDIR_MASK; addr < end;) {
    > > > + for (addr = start & PMD_MASK; addr < end;) {
    > > > pmd = pmd_offset(pgd + pgd_index(addr), addr);
    > > > pmd[0] = __pmd(addr | prot);
    > > > addr += SECTION_SIZE;
    > > > @@ -95,7 +95,7 @@ static inline void identity_mapping_del(pgd_t *pgd, unsigned long start,
    > > > unsigned long addr;
    > > > pmd_t *pmd;
    > > >
    > > > - for (addr = start & PGDIR_MASK; addr < end; addr += PGDIR_SIZE) {
    > > > + for (addr = start & PMD_MASK; addr < end; addr += PMD_SIZE) {
    > > > pmd = pmd_offset(pgd + pgd_index(addr), addr);
    > > > pmd[0] = __pmd(0);
    > > > pmd[1] = __pmd(0);
    > > ...
    > > > @@ -1068,12 +1068,12 @@ void setup_mm_for_reboot(char mode)
    > > > base_pmdval |= PMD_BIT4;
    > > >
    > > > for (i = 0; i < FIRST_USER_PGD_NR + USER_PTRS_PER_PGD; i++, pgd++) {
    > > > - unsigned long pmdval = (i << PGDIR_SHIFT) | base_pmdval;
    > > > + unsigned long pmdval = (i << PMD_SHIFT) | base_pmdval;
    > > > pmd_t *pmd;
    > > >
    > > > - pmd = pmd_off(pgd, i << PGDIR_SHIFT);
    > > > + pmd = pmd_off(pgd, i << PMD_SHIFT);
    > > > pmd[0] = __pmd(pmdval);
    > > > - pmd[1] = __pmd(pmdval + (1 << (PGDIR_SHIFT - 1)));
    > > > + pmd[1] = __pmd(pmdval + (1 << (PMD_SHIFT - 1)));
    > > > flush_pmd_entry(pmd);
    > > > }
    > > >
    > >
    > > This lot really does need unifying - and in any case this last addition
    > > should be using 'SECTION SIZE' not something related to PMD shifts.
    >
    > On the classic page tables, the PMD_SHIFT is 21 while the SECTION_SHIFT
    > is 20. They have slightly different meaning.

    Correct, and if you look at the code again and analyze what it's doing,
    you'll see that it's using the wrong thing. The code pre-exists the
    SECTION_* macros, and was never fixed up when they were introduced.

    SECTION_SIZE is the right thing here - it's setting up sections.

    Just look at identity_mapping_add() to see how the code _should_ be.


    \
     
     \ /
      Last update: 2010-11-22 14:31    [W:0.022 / U:64.640 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site