kernel-packages team mailing list archive

[Andy Whitcroft <apw@xxxxxxxxxxxxx>]

Public bug reported:

Hi Ubuntu kernel folks,                                                                                
                                                                                                       
This patch isn't quite upstream stable material, but might still be nice to                            
have. It prevents smt-enabled=off on the kernel command line causing a hung                            
system at boot.                                                                                        
                                                                                                       
cheers                                                               

===

From: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>                                                             
                                                                                                       
Commit d70a54e2d08510a99b1f10eceeae6f2f7086e226 upstream.                                              
                                                                                                       
Starting with POWER8, the subcore logic relies on all threads of a core                                
being booted so that they can participate in split mode switches. So on                                
those machines we ignore the smt_enabled_at_boot setting (smt-enabled on                               
the kernel command line).                                                                              
                                                                                                       
Signed-off-by: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>                                                    
[mpe: Update comment and change log to be more precise]                                                
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>                                                   
---                                                                                                    
 arch/powerpc/platforms/powernv/smp.c | 16 +++++++++++++++-                                            
 1 file changed, 15 insertions(+), 1 deletion(-)

** Affects: linux (Ubuntu)
     Importance: Medium
         Status: Confirmed

** Affects: linux (Ubuntu Utopic)
     Importance: Medium
         Status: Confirmed

** Affects: linux (Ubuntu Vivid)
     Importance: Medium
         Status: Confirmed

** Changed in: linux (Ubuntu)
       Status: New => Confirmed

** Changed in: linux (Ubuntu)
   Importance: Undecided => Medium

** Also affects: linux (Ubuntu Vivid)
   Importance: Medium
       Status: Confirmed

** Also affects: linux (Ubuntu Utopic)
   Importance: Undecided
       Status: New

** Changed in: linux (Ubuntu Utopic)
       Status: New => Confirmed

** Changed in: linux (Ubuntu Utopic)
   Importance: Undecided => Medium

-- 
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https://bugs.launchpad.net/bugs/1425004

Title:
  powerpc/powernv: Ignore smt-enabled on Power8 and later

Status in linux package in Ubuntu:
  Confirmed
Status in linux source package in Utopic:
  Confirmed
Status in linux source package in Vivid:
  Confirmed

Bug description:
  Hi Ubuntu kernel folks,                                                                                
                                                                                                         
  This patch isn't quite upstream stable material, but might still be nice to                            
  have. It prevents smt-enabled=off on the kernel command line causing a hung                            
  system at boot.                                                                                        
                                                                                                         
  cheers                                                               

  ===

  From: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>                                                             
                                                                                                         
  Commit d70a54e2d08510a99b1f10eceeae6f2f7086e226 upstream.                                              
                                                                                                         
  Starting with POWER8, the subcore logic relies on all threads of a core                                
  being booted so that they can participate in split mode switches. So on                                
  those machines we ignore the smt_enabled_at_boot setting (smt-enabled on                               
  the kernel command line).                                                                              
                                                                                                         
  Signed-off-by: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>                                                    
  [mpe: Update comment and change log to be more precise]                                                
  Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>                                                   
  ---                                                                                                    
   arch/powerpc/platforms/powernv/smp.c | 16 +++++++++++++++-                                            
   1 file changed, 15 insertions(+), 1 deletion(-)

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