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| author | Thomas Gleixner <tglx@linutronix.de> | 2015-05-19 17:12:32 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-05-19 17:12:32 +0300 |
| commit | c3b5d3cea508d2c8ff493ef18c45a9cc58fb7015 (patch) | |
| tree | a80672ee82fcc3d9c8d486e53731eb19cd968eb0 /arch/x86/ia32/ia32entry.S | |
| parent | daa67b4b70568a07fef3cffacb2055891bf42ddb (diff) | |
| parent | e26081808edadfd257c6c9d81014e3b25e9a6118 (diff) | |
| download | linux-c3b5d3cea508d2c8ff493ef18c45a9cc58fb7015.tar.xz | |
Merge branch 'linus' into timers/core
Make sure the upstream fixes are applied before adding further
modifications.
Diffstat (limited to 'arch/x86/ia32/ia32entry.S')
| -rw-r--r-- | arch/x86/ia32/ia32entry.S | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index a821b1cd4fa7..72bf2680f819 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -427,6 +427,13 @@ sysretl_from_sys_call: * cs and ss are loaded from MSRs. * (Note: 32bit->32bit SYSRET is different: since r11 * does not exist, it merely sets eflags.IF=1). + * + * NB: On AMD CPUs with the X86_BUG_SYSRET_SS_ATTRS bug, the ss + * descriptor is not reinitialized. This means that we must + * avoid SYSRET with SS == NULL, which could happen if we schedule, + * exit the kernel, and re-enter using an interrupt vector. (All + * interrupt entries on x86_64 set SS to NULL.) We prevent that + * from happening by reloading SS in __switch_to. */ USERGS_SYSRET32 |