| Message ID | 1361268973-14584-1-git-send-email-josephl@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/19/2013 03:16 AM, Joseph Lo wrote: > There is no need to unlock MMIO access to the DBGLAR all the time. Doing > so may even cause problems if a SW bug causes writes to that MMIO region. > > Cortex-A15 processors do not support the CP14 register write the code > currently uses to unlock the DBGLAR; the instruction throws an undefined > instruction exceptions. This prevents tegra_secondary_startup() from > executing on Tegra114, and hence prevents SMP. > > Remove the code that unlocks this access. I have applied this to Tegra's for-3.10/fixes branch.
diff --git a/arch/arm/mach-tegra/headsmp.S b/arch/arm/mach-tegra/headsmp.S index fd473f2..045c16f 100644 --- a/arch/arm/mach-tegra/headsmp.S +++ b/arch/arm/mach-tegra/headsmp.S @@ -7,8 +7,5 @@ ENTRY(tegra_secondary_startup) bl v7_invalidate_l1 - /* Enable coresight */ - mov32 r0, 0xC5ACCE55 - mcr p14, 0, r0, c7, c12, 6 b secondary_startup ENDPROC(tegra_secondary_startup) diff --git a/arch/arm/mach-tegra/reset-handler.S b/arch/arm/mach-tegra/reset-handler.S index 54382ce..68b8bfc 100644 --- a/arch/arm/mach-tegra/reset-handler.S +++ b/arch/arm/mach-tegra/reset-handler.S @@ -41,9 +41,6 @@ */ ENTRY(tegra_resume) bl v7_invalidate_l1 - /* Enable coresight */ - mov32 r0, 0xC5ACCE55 - mcr p14, 0, r0, c7, c12, 6 cpu_id r0 cmp r0, #0 @ CPU0?
There is no need to unlock MMIO access to the DBGLAR all the time. Doing so may even cause problems if a SW bug causes writes to that MMIO region. Cortex-A15 processors do not support the CP14 register write the code currently uses to unlock the DBGLAR; the instruction throws an undefined instruction exceptions. This prevents tegra_secondary_startup() from executing on Tegra114, and hence prevents SMP. Remove the code that unlocks this access. Signed-off-by: Joseph Lo <josephl@nvidia.com> --- arch/arm/mach-tegra/headsmp.S | 3 --- arch/arm/mach-tegra/reset-handler.S | 3 --- 2 files changed, 6 deletions(-)