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    SubjectRe: [PATCH 0/2] [GIT PULL] tracing: various bug fixes
    * Chris Wright (chrisw@sous-sol.org) wrote:
    > * Jeremy Fitzhardinge (jeremy@goop.org) wrote:
    > > OK, the good news is that its not a callee-save calling convention
    > > problem, which is what I feared. But it does sound pretty awkward to
    > > fix. Does __native_flush_tlb_global() have to use
    > > raw_local_irq_save/restore?
    >
    > Vaguely related...makes sense to do native_(read/write)_cr4 since it's
    > the native tlb flushing implementation, no?
    >
    > looks ok from inspection, not tested yet...

    BTW, Steve, does that fix it for you? Sure makes the code cleaner:

    410: 0f 20 e2 mov %cr4,%rdx
    413: 48 89 d0 mov %rdx,%rax
    416: 24 7f and $0x7f,%al
    418: 0f 22 e0 mov %rax,%cr4
    41b: 0f 22 e2 mov %rdx,%cr4

    thanks,
    -chris

    > Subject: [PATCH] x86: use native register access for native tlb flushing
    >
    > currently these are paravirtulaized, doesn't appear any callers rely on
    > this (no pv_ops backends are using native_tlb and overriding cr3/4
    > access).
    >
    > Signed-off-by: Chris Wright <chrisw@sous-sol.org>
    > ---
    > arch/x86/include/asm/tlbflush.h | 8 ++++----
    > 1 files changed, 4 insertions(+), 4 deletions(-)
    >
    > diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
    > index 16a5c84..a5ecc9c 100644
    > --- a/arch/x86/include/asm/tlbflush.h
    > +++ b/arch/x86/include/asm/tlbflush.h
    > @@ -17,7 +17,7 @@
    >
    > static inline void __native_flush_tlb(void)
    > {
    > - write_cr3(read_cr3());
    > + native_write_cr3(native_read_cr3());
    > }
    >
    > static inline void __native_flush_tlb_global(void)
    > @@ -32,11 +32,11 @@ static inline void __native_flush_tlb_global(void)
    > */
    > raw_local_irq_save(flags);
    >
    > - cr4 = read_cr4();
    > + cr4 = native_read_cr4();
    > /* clear PGE */
    > - write_cr4(cr4 & ~X86_CR4_PGE);
    > + native_write_cr4(cr4 & ~X86_CR4_PGE);
    > /* write old PGE again and flush TLBs */
    > - write_cr4(cr4);
    > + native_write_cr4(cr4);
    >
    > raw_local_irq_restore(flags);
    > }


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