Linux no-xsave.patch: commit patch into Nixpkgs since fetchurl no longer works

Patch submitted by Jan Malakhovski <oxij@oxij.org>.
This commit is contained in:
Peter Simons 2012-07-02 16:16:27 +02:00
parent a2f4366497
commit 82b2588e35
2 changed files with 86 additions and 5 deletions

View file

@ -0,0 +1,85 @@
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -168,21 +168,23 @@ static void __init xen_banner(void)
xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
}
+static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0;
+static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0;
+
static void xen_cpuid(unsigned int *ax, unsigned int *bx,
unsigned int *cx, unsigned int *dx)
{
+ unsigned maskecx = ~0;
unsigned maskedx = ~0;
/*
* Mask out inconvenient features, to try and disable as many
* unsupported kernel subsystems as possible.
*/
- if (*ax == 1)
- maskedx = ~((1 << X86_FEATURE_APIC) | /* disable APIC */
- (1 << X86_FEATURE_ACPI) | /* disable ACPI */
- (1 << X86_FEATURE_MCE) | /* disable MCE */
- (1 << X86_FEATURE_MCA) | /* disable MCA */
- (1 << X86_FEATURE_ACC)); /* thermal monitoring */
+ if (*ax == 1) {
+ maskecx = cpuid_leaf1_ecx_mask;
+ maskedx = cpuid_leaf1_edx_mask;
+ }
asm(XEN_EMULATE_PREFIX "cpuid"
: "=a" (*ax),
@@ -190,9 +192,43 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
"=c" (*cx),
"=d" (*dx)
: "0" (*ax), "2" (*cx));
+
+ *cx &= maskecx;
*dx &= maskedx;
}
+static __init void xen_init_cpuid_mask(void)
+{
+ unsigned int ax, bx, cx, dx;
+
+ cpuid_leaf1_edx_mask =
+ ~((1 << X86_FEATURE_MCE) | /* disable MCE */
+ (1 << X86_FEATURE_MCA) | /* disable MCA */
+ (1 << X86_FEATURE_ACC)); /* thermal monitoring */
+
+ if (!xen_initial_domain())
+ cpuid_leaf1_edx_mask &=
+ ~((1 << X86_FEATURE_APIC) | /* disable local APIC */
+ (1 << X86_FEATURE_ACPI)); /* disable ACPI */
+
+ ax = 1;
+ xen_cpuid(&ax, &bx, &cx, &dx);
+
+ /* cpuid claims we support xsave; try enabling it to see what happens */
+ if (cx & (1 << (X86_FEATURE_XSAVE % 32))) {
+ unsigned long cr4;
+
+ set_in_cr4(X86_CR4_OSXSAVE);
+
+ cr4 = read_cr4();
+
+ if ((cr4 & X86_CR4_OSXSAVE) == 0)
+ cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_XSAVE % 32));
+
+ clear_in_cr4(X86_CR4_OSXSAVE);
+ }
+}
+
static void xen_set_debugreg(int reg, unsigned long val)
{
HYPERVISOR_set_debugreg(reg, val);
@@ -903,6 +939,8 @@ asmlinkage void __init xen_start_kernel(void)
xen_init_irq_ops();
+ xen_init_cpuid_mask();
+
#ifdef CONFIG_X86_LOCAL_APIC
/*
* set up the basic apic ops.

View file

@ -203,11 +203,7 @@ rec {
no_xsave =
{ name = "no-xsave";
patch = fetchurl {
url = "http://kernel.ubuntu.com/git?p=rtg/ubuntu-maverick.git;a=blobdiff_plain;f=arch/x86/xen/enlighten.c;h=f7ff4c7d22954ab5eda464320241300bd5a32ee5;hp=1ea06f842a921557e958110e22941d53a2822f3c;hb=1a30f99;hpb=8f2ff69dce18ed856a8d1b93176f768b47eeed86";
name = "no-xsave.patch";
sha256 = "18732s3vmav5rpg6zqpiw2i0ll83pcc4gw266h6545pmbh9p7hky";
};
patch = ./no-xsave.patch;
features.noXsave = true;
};