diff options
| author | Scott Wood <scottwood@freescale.com> | 2014-03-10 17:29:38 -0500 |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2014-03-19 19:57:14 -0500 |
| commit | 9d378dfac885f72b8b369d08fc61bef36e2f2dd1 (patch) | |
| tree | 8790aa68cd0944e031b35eb63f5be14ec678be2d /arch/powerpc/kvm/bookehv_interrupts.S | |
| parent | 82d86de25b9c99db546e17c6f7ebf9a691da557e (diff) | |
| download | linux-9d378dfac885f72b8b369d08fc61bef36e2f2dd1.tar.bz2 | |
powerpc/booke64: Use SPRG7 for VDSO
Previously SPRG3 was marked for use by both VDSO and critical
interrupts (though critical interrupts were not fully implemented).
In commit 8b64a9dfb091f1eca8b7e58da82f1e7d1d5fe0ad ("powerpc/booke64:
Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman
made an attempt to resolve this conflict by restoring the VDSO value
early in the critical interrupt, but this has some issues:
- It's incompatible with EXCEPTION_COMMON which restores r13 from the
by-then-overwritten scratch (this cost me some debugging time).
- It forces critical exceptions to be a special case handled
differently from even machine check and debug level exceptions.
- It didn't occur to me that it was possible to make this work at all
(by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after
I made (most of) this patch. :-)
It might be worth investigating using a load rather than SPRG on return
from all exceptions (except TLB misses where the scratch never leaves
the SPRG) -- it could save a few cycles. Until then, let's stick with
SPRG for all exceptions.
Since we cannot use SPRG4-7 for scratch without corrupting the state of
a KVM guest, move VDSO to SPRG7 on book3e. Since neither SPRG4-7 nor
critical interrupts exist on book3s, SPRG3 is still used for VDSO
there.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: kvm-ppc@vger.kernel.org
Diffstat (limited to 'arch/powerpc/kvm/bookehv_interrupts.S')
| -rw-r--r-- | arch/powerpc/kvm/bookehv_interrupts.S | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/powerpc/kvm/bookehv_interrupts.S b/arch/powerpc/kvm/bookehv_interrupts.S index e4185f6b3309..99635a37c78c 100644 --- a/arch/powerpc/kvm/bookehv_interrupts.S +++ b/arch/powerpc/kvm/bookehv_interrupts.S @@ -229,11 +229,7 @@ stw r10, VCPU_CR(r4) PPC_STL r11, VCPU_GPR(R4)(r4) PPC_STL r5, VCPU_GPR(R5)(r4) - .if \type == EX_CRIT - PPC_LL r5, (\paca_ex + EX_R13)(r13) - .else mfspr r5, \scratch - .endif PPC_STL r6, VCPU_GPR(R6)(r4) PPC_STL r8, VCPU_GPR(R8)(r4) PPC_STL r9, VCPU_GPR(R9)(r4) @@ -435,10 +431,16 @@ _GLOBAL(kvmppc_resume_host) PPC_STL r5, VCPU_LR(r4) mfspr r7, SPRN_SPRG5 stw r3, VCPU_VRSAVE(r4) +#ifdef CONFIG_64BIT + PPC_LL r3, PACA_SPRG_VDSO(r13) +#endif PPC_STD(r6, VCPU_SHARED_SPRG4, r11) mfspr r8, SPRN_SPRG6 PPC_STD(r7, VCPU_SHARED_SPRG5, r11) mfspr r9, SPRN_SPRG7 +#ifdef CONFIG_64BIT + mtspr SPRN_SPRG_VDSO_WRITE, r3 +#endif PPC_STD(r8, VCPU_SHARED_SPRG6, r11) mfxer r3 PPC_STD(r9, VCPU_SHARED_SPRG7, r11) |