[Xen-changelog] [xen stable-4.8] setup vwfi correctly on cpu0

[patchbot@xxxxxxx]

commit c2a541500d5e0684f18ed9739dc8d18b39496244
Author:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
AuthorDate: Fri Mar 31 15:37:07 2017 -0700
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Fri Apr 7 16:11:19 2017 -0700

    setup vwfi correctly on cpu0
    
    parse_vwfi runs after init_traps on cpu0, potentially resulting in the
    wrong HCR_EL2 for it. Secondary cpus boot after parse_vwfi, so in their
    case init_traps will write the correct set of flags to HCR_EL2.
    
    For cpu0, fix the issue by changing HCR_EL2 setting from a new
    presmp_initcall.
    
    Signed-off-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Reviewed-by: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/arm/traps.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 90aba2a..91c926e 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -115,6 +115,25 @@ static void __init parse_vwfi(const char *s)
 }
 custom_param("vwfi", parse_vwfi);
 
+static int __init vwfi_init(void)
+{
+    /*
+     * HCR_EL2 has already been set on cpu0, change the setting here, if
+     * needed. Other cpus haven't booted yet, init_traps will setup
+     * HCR_EL2 correctly.
+     */
+    if ( vwfi == NATIVE )
+    {
+        register_t hcr;
+
+        hcr = READ_SYSREG(HCR_EL2);
+        WRITE_SYSREG(hcr & ~(HCR_TWI|HCR_TWE), HCR_EL2);
+    }
+
+    return 0;
+}
+presmp_initcall(vwfi_init);
+
 void init_traps(void)
 {
     /* Setup Hyp vector base */
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.8

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