Merge tag 'amd_ucode_fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/urgent

Pull AMD microcode fixes from Borislav Petkov:

 " Those are basically two fixes which correct the AMD early ucode loader
   from accessing cpu_data too early, i.e. before smp_store_cpu_info()
   has copied the boot_cpu_data ontop and overwritten an already empty
   structure (which we shouldn't access that early in the first place
   anyway).

   The second patch is kinda largish for that late in the game but it
   shouldn't be problematic because we're simply switching from using
   cpu_data to use the CPU family number directly and thus again, not use
   uninitialized cpu_data structure. "

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index c517dbe705fd..8083be20fe5e 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -600,6 +600,16 @@ struct task_struct *__switch_to(struct task_struct *prev,
 	struct ppc64_tlb_batch *batch;
 #endif
 
+	/* Back up the TAR across context switches.
+	 * Note that the TAR is not available for use in the kernel.  (To
+	 * provide this, the TAR should be backed up/restored on exception
+	 * entry/exit instead, and be in pt_regs.  FIXME, this should be in
+	 * pt_regs anyway (for debug).)
+	 * Save the TAR here before we do treclaim/trecheckpoint as these
+	 * will change the TAR.
+	 */
+	save_tar(&prev->thread);
+
 	__switch_to_tm(prev);
 
 #ifdef CONFIG_SMP