diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.9.21/0093-x86-amd-don-t-set-X86_BUG_SYSRET_SS_ATTRS-when-runni.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.9.21/0093-x86-amd-don-t-set-X86_BUG_SYSRET_SS_ATTRS-when-runni.patch | 65 |
1 files changed, 0 insertions, 65 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.9.21/0093-x86-amd-don-t-set-X86_BUG_SYSRET_SS_ATTRS-when-runni.patch b/common/recipes-kernel/linux/linux-yocto-4.9.21/0093-x86-amd-don-t-set-X86_BUG_SYSRET_SS_ATTRS-when-runni.patch deleted file mode 100644 index e2416627..00000000 --- a/common/recipes-kernel/linux/linux-yocto-4.9.21/0093-x86-amd-don-t-set-X86_BUG_SYSRET_SS_ATTRS-when-runni.patch +++ /dev/null @@ -1,65 +0,0 @@ -From 7a5ded1f7c88ae162c525486f4be8030fa54fa26 Mon Sep 17 00:00:00 2001 -From: Juergen Gross <jgross@suse.com> -Date: Wed, 30 May 2018 13:09:58 +0200 -Subject: [PATCH 93/93] x86/amd: don't set X86_BUG_SYSRET_SS_ATTRS when running - under Xen - -Upstream commit: def9331a12977770cc6132d79f8e6565871e8e38 ("x86/amd: -don't set X86_BUG_SYSRET_SS_ATTRS when running under Xen") - -When running as Xen pv guest X86_BUG_SYSRET_SS_ATTRS must not be set -on AMD cpus. - -This bug/feature bit is kind of special as it will be used very early -when switching threads. Setting the bit and clearing it a little bit -later leaves a critical window where things can go wrong. This time -window has enlarged a little bit by using setup_clear_cpu_cap() instead -of the hypervisor's set_cpu_features callback. It seems this larger -window now makes it rather easy to hit the problem. - -The proper solution is to never set the bit in case of Xen. - -Signed-off-by: Juergen Gross <jgross@suse.com> -Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> -Acked-by: Thomas Gleixner <tglx@linutronix.de> -Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> ---- - arch/x86/kernel/cpu/amd.c | 5 +++-- - arch/x86/xen/enlighten.c | 4 +--- - 2 files changed, 4 insertions(+), 5 deletions(-) - -diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c -index cd0abf8..4c2be99 100644 ---- a/arch/x86/kernel/cpu/amd.c -+++ b/arch/x86/kernel/cpu/amd.c -@@ -857,8 +857,9 @@ static void init_amd(struct cpuinfo_x86 *c) - if (cpu_has(c, X86_FEATURE_3DNOW) || cpu_has(c, X86_FEATURE_LM)) - set_cpu_cap(c, X86_FEATURE_3DNOWPREFETCH); - -- /* AMD CPUs don't reset SS attributes on SYSRET */ -- set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); -+ /* AMD CPUs don't reset SS attributes on SYSRET, Xen does. */ -+ if (!cpu_has(c, X86_FEATURE_XENPV)) -+ set_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); - } - - #ifdef CONFIG_X86_32 -diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c -index 01120da..fc63c84 100644 ---- a/arch/x86/xen/enlighten.c -+++ b/arch/x86/xen/enlighten.c -@@ -472,10 +472,8 @@ static void __init xen_init_cpuid_mask(void) - - static void __init xen_init_capabilities(void) - { -- if (xen_pv_domain()) { -- setup_clear_cpu_cap(X86_BUG_SYSRET_SS_ATTRS); -+ if (xen_pv_domain()) - setup_force_cpu_cap(X86_FEATURE_XENPV); -- } - } - - static void xen_set_debugreg(int reg, unsigned long val) --- -2.7.4 - |