This is the unexpected second patch to go with my previous post: http://post-office.corp.redhat.com/archives/rhkernel-list/2013-December/msg01419.html RHBZ#: ------ RHEL7.0: https://bugzilla.redhat.com/show_bug.cgi?id=1019549 RHEL6.6: https://bugzilla.redhat.com/show_bug.cgi?id=1044117 RHEL6.5.z: https://bugzilla.redhat.com/show_bug.cgi?id=1044566 Upstream commit: ec67ad82814bee92251fd963bf01c7a173856555 Description ---------- This patch reverts and improves the fix done by upstream commit c13f20ac48328b05cd3b8c19e31ed6c132b44b42 aka RHEL7 commit 2228939116d89e7c182987c5d86a93323eec1bd4. These two patches should be applied in series, even though the second reverts the first to maintain consistency with upstream commits. Brew ------ https://brewweb.devel.redhat.com/taskinfo?taskID=6755949 (includes both patches) Upstream description ------------ In a recent patch: commit c13f20ac48328b05cd3b8c19e31ed6c132b44b42 Author: Michael Neuling <mikey@xxxxxxxxxxx> powerpc/signals: Mark VSX not saved with small contexts We fixed an issue but an improved solution was later discussed after the patch was merged. Firstly, this patch doesn't handle the 64bit signals case, which could also hit this issue (but has never been reported). Secondly, the original patch isn't clear what MSR VSX should be set to. The new approach below always clears the MSR VSX bit (to indicate no VSX is in the context) and sets it only in the specific case where VSX is available (ie. when VSX has been used and the signal context passed has space to provide the state). This reverts the original patch and replaces it with the improved solution. It also adds a 64 bit version. Signed-off-by: Michael Neuling <mikey@xxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> --- arch/powerpc/kernel/signal_32.c | 16 +++++++--------- arch/powerpc/kernel/signal_64.c | 6 ++++++ 2 files changed, 13 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index 8deb21c..92bba96 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -444,6 +444,12 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame, #endif /* CONFIG_ALTIVEC */ if (copy_fpr_to_user(&frame->mc_fregs, current)) return 1; + + /* + * Clear the MSR VSX bit to indicate there is no valid state attached + * to this context, except in the specific case below where we set it. + */ + msr &= ~MSR_VSX; #ifdef CONFIG_VSX /* * Copy VSR 0-31 upper half from thread_struct to local @@ -456,15 +462,7 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame, if (copy_vsx_to_user(&frame->mc_vsregs, current)) return 1; msr |= MSR_VSX; - } else if (!ctx_has_vsx_region) - /* - * With a small context structure we can't hold the VSX - * registers, hence clear the MSR value to indicate the state - * was not saved. - */ - msr &= ~MSR_VSX; - - + } #endif /* CONFIG_VSX */ #ifdef CONFIG_SPE /* save spe registers */ diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index 2fe6fc6..e056618 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c @@ -116,6 +116,12 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, flush_fp_to_thread(current); /* copy fpr regs and fpscr */ err |= copy_fpr_to_user(&sc->fp_regs, current); + + /* + * Clear the MSR VSX bit to indicate there is no valid state attached + * to this context, except in the specific case below where we set it. + */ + msr &= ~MSR_VSX; #ifdef CONFIG_VSX /* * Copy VSX low doubleword to local buffer for formatting, -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html