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| author | Hugh Dickins <hughd@google.com> | 2017-09-25 02:59:49 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-05 17:44:25 +0300 |
| commit | e345dcc9481543edf4a0a5df4c4c2f9597b0a997 (patch) | |
| tree | ed084a4c22b576f9ed6b3980b0e383b1ac09f38f /arch/x86/mm/pgtable.c | |
| parent | 500943e57db8d3e298e98f595f835c5b613e843b (diff) | |
| download | linux-e345dcc9481543edf4a0a5df4c4c2f9597b0a997.tar.xz | |
kaiser: add "nokaiser" boot option, using ALTERNATIVE
Added "nokaiser" boot option: an early param like "noinvpcid".
Most places now check int kaiser_enabled (#defined 0 when not
CONFIG_KAISER) instead of #ifdef CONFIG_KAISER; but entry_64.S
and entry_64_compat.S are using the ALTERNATIVE technique, which
patches in the preferred instructions at runtime. That technique
is tied to x86 cpu features, so X86_FEATURE_KAISER is fabricated.
Prior to "nokaiser", Kaiser #defined _PAGE_GLOBAL 0: revert that,
but be careful with both _PAGE_GLOBAL and CR4.PGE: setting them when
nokaiser like when !CONFIG_KAISER, but not setting either when kaiser -
neither matters on its own, but it's hard to be sure that _PAGE_GLOBAL
won't get set in some obscure corner, or something add PGE into CR4.
By omitting _PAGE_GLOBAL from __supported_pte_mask when kaiser_enabled,
all page table setup which uses pte_pfn() masks it out of the ptes.
It's slightly shameful that the same declaration versus definition of
kaiser_enabled appears in not one, not two, but in three header files
(asm/kaiser.h, asm/pgtable.h, asm/tlbflush.h). I felt safer that way,
than with #including any of those in any of the others; and did not
feel it worth an asm/kaiser_enabled.h - kernel/cpu/common.c includes
them all, so we shall hear about it if they get out of synch.
Cleanups while in the area: removed the silly #ifdef CONFIG_KAISER
from kaiser.c; removed the unused native_get_normal_pgd(); removed
the spurious reg clutter from SWITCH_*_CR3 macro stubs; corrected some
comments. But more interestingly, set CR4.PSE in secondary_startup_64:
the manual is clear that it does not matter whether it's 0 or 1 when
4-level-pts are enabled, but I was distracted to find cr4 different on
BSP and auxiliaries - BSP alone was adding PSE, in probe_page_size_mask().
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/mm/pgtable.c')
| -rw-r--r-- | arch/x86/mm/pgtable.c | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index d0a424988f82..dbc27a2b4ad5 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -341,16 +341,12 @@ static inline void _pgd_free(pgd_t *pgd) } #else -#ifdef CONFIG_KAISER /* - * Instead of one pmd, we aquire two pmds. Being order-1, it is + * Instead of one pgd, Kaiser acquires two pgds. Being order-1, it is * both 8k in size and 8k-aligned. That lets us just flip bit 12 * in a pointer to swap between the two 4k halves. */ -#define PGD_ALLOCATION_ORDER 1 -#else -#define PGD_ALLOCATION_ORDER 0 -#endif +#define PGD_ALLOCATION_ORDER kaiser_enabled static inline pgd_t *_pgd_alloc(void) { |