projects/linux·commit a2ff8206

Merge branch 'parisc-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

a2ff8206 · Linus Torvalds <[email protected]> · 2013-10-27 10:45:00 -07:00

Pull parisc fix from Helge Deller:
 "This is a 2-line patch to save the CPU register which holds our task
  thread info pointer before calling a firmware function and then to
  restore it again afterwards.

  This is necessary because on some 64bit machines the high-order 32bits
  are being clobbered by the firmware call, and thus we failed to bring
  up secondary CPUs (and instead crashed the kernel) in some situations
  eg if we had more than 4GB RAM.  This patch fixes a bug which has been
  since ever in the parisc linux kernel and which prevented some people
  to use a 64bit kernel"

* 'parisc-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Do not crash 64bit SMP kernels on machines with >= 4GB RAM
Commit
a2ff82065b5b2807e699995671dc282be20ce8fd
Parents
aff22d3f · 54e181e0

Merge commit. Changes below are compared with the first parent: aff22d3f.

Changes

1 files changed · +4 −0

FileStatusAddDelContent
arch/parisc/kernel/head.Smodified+4−0View file

arch/parisc/kernel/head.S

View file
diff --git a/arch/parisc/kernel/head.S b/arch/parisc/kernel/head.S
index 37aabd7..d2d5825 100644
--- a/arch/parisc/kernel/head.S
+++ b/arch/parisc/kernel/head.S
@@ -195,6 +195,8 @@ common_stext:
ldw MEM_PDC_HI(%r0),%r6
depd %r6, 31, 32, %r3 /* move to upper word */
+ mfctl %cr30,%r6 /* PCX-W2 firmware bug */
+
ldo PDC_PSW(%r0),%arg0 /* 21 */
ldo PDC_PSW_SET_DEFAULTS(%r0),%arg1 /* 2 */
ldo PDC_PSW_WIDE_BIT(%r0),%arg2 /* 2 */
@@ -203,6 +205,8 @@ common_stext:
copy %r0,%arg3
stext_pdc_ret:
+ mtctl %r6,%cr30 /* restore task thread info */
+
/* restore rfi target address*/
ldd TI_TASK-THREAD_SZ_ALGN(%sp), %r10
tophys_r1 %r10