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| author | Ingo Molnar <mingo@kernel.org> | 2015-05-08 13:33:33 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-05-08 13:33:33 +0200 |
| commit | 7ae383be81781c5e1347f71c3eb0d53ce5188200 (patch) | |
| tree | d2dfedb78cf4ee2bc9cc460af3be106b08e01050 /arch/x86/ia32 | |
| parent | 2a4e90b18c256d52a7f3f77d58114f6d4e4a7f9f (diff) | |
| parent | 3e0283a53f7d2f2dae7bc4aa7f3104cb5988018f (diff) | |
Merge branch 'linus' into x86/asm, before applying dependent patch
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/ia32')
| -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 56fd6dd2e342..2ab0f7182df3 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -418,6 +418,13 @@ 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 |