| Message ID | 1579527498-31081-1-git-send-email-vladimir.murzin@arm.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 6849b5eba1965ceb0cad3a75877ef4569dd3638e |
| Headers | show |
| Series | [v2] ARM: virt: Relax arch timer version check during early boot | expand |
On 2020-01-20 13:38, Vladimir Murzin wrote: > Updates to the Generic Timer architecture allow ID_PFR1.GenTimer to > have values other than 0 or 1 while still preserving backward > compatibility. At the moment, Linux is quite strict in the way it > handles this field at early boot and will not configure arch timer if > it doesn't find the value 1. > > Since here use ubfx for arch timer version extraction (hyb-stub build > with -march=armv7-a, so it is safe) > > To help backports (even though the code was correct at the time of > writing) > Fixes: 8ec58be9f3ff ("ARM: virt: arch_timers: enable access to physical > timers") > Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Acked-by: Marc Zyngier <maz@kernel.org> Feel free to put it into Russell's patch system. Thanks, M.
On 1/20/20 2:01 PM, Marc Zyngier wrote: > On 2020-01-20 13:38, Vladimir Murzin wrote: >> Updates to the Generic Timer architecture allow ID_PFR1.GenTimer to >> have values other than 0 or 1 while still preserving backward >> compatibility. At the moment, Linux is quite strict in the way it >> handles this field at early boot and will not configure arch timer if >> it doesn't find the value 1. >> >> Since here use ubfx for arch timer version extraction (hyb-stub build >> with -march=armv7-a, so it is safe) >> >> To help backports (even though the code was correct at the time of writing) >> Fixes: 8ec58be9f3ff ("ARM: virt: arch_timers: enable access to physical timers") >> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> > > Acked-by: Marc Zyngier <maz@kernel.org> > > Feel free to put it into Russell's patch system. Patch has been accepted as patch 8955/1 Thanks! Vladimir > > Thanks, > > M.
diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S index ae50203..6607fa8 100644 --- a/arch/arm/kernel/hyp-stub.S +++ b/arch/arm/kernel/hyp-stub.S @@ -146,10 +146,9 @@ ARM_BE8(orr r7, r7, #(1 << 25)) @ HSCTLR.EE #if !defined(ZIMAGE) && defined(CONFIG_ARM_ARCH_TIMER) @ make CNTP_* and CNTPCT accessible from PL1 mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1 - lsr r7, #16 - and r7, #0xf - cmp r7, #1 - bne 1f + ubfx r7, r7, #16, #4 + teq r7, #0 + beq 1f mrc p15, 4, r7, c14, c1, 0 @ CNTHCTL orr r7, r7, #3 @ PL1PCEN | PL1PCTEN mcr p15, 4, r7, c14, c1, 0 @ CNTHCTL
Updates to the Generic Timer architecture allow ID_PFR1.GenTimer to have values other than 0 or 1 while still preserving backward compatibility. At the moment, Linux is quite strict in the way it handles this field at early boot and will not configure arch timer if it doesn't find the value 1. Since here use ubfx for arch timer version extraction (hyb-stub build with -march=armv7-a, so it is safe) To help backports (even though the code was correct at the time of writing) Fixes: 8ec58be9f3ff ("ARM: virt: arch_timers: enable access to physical timers") Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> --- Changelog: v1 -> v2 - Clarify that backward compatibility is preserved (per Marc) arch/arm/kernel/hyp-stub.S | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)