diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2019-07-15 11:51:39 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-11 12:22:19 +0200 |
| commit | 6583ecced632cf7f92ff8313d9a6d168df291124 (patch) | |
| tree | 5875e24f50b66d92439d640d771a4aa31463c611 | |
| parent | 90d45f0856f3479a742ae29d5150c59116d3f34a (diff) | |
x86/entry/64: Use JMP instead of JMPQ
commit 64dbc122b20f75183d8822618c24f85144a5a94d upstream.
Somehow the swapgs mitigation entry code patch ended up with a JMPQ
instruction instead of JMP, where only the short jump is needed. Some
assembler versions apparently fail to optimize JMPQ into a two-byte JMP
when possible, instead always using a 7-byte JMP with relocation. For
some reason that makes the entry code explode with a #GP during boot.
Change it back to "JMP" as originally intended.
Fixes: 18ec54fdd6d1 ("x86/speculation: Prepare entry code for Spectre v1 swapgs mitigations")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/entry/entry_64.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 592f62fc49f0..10ecfba43dff 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -434,7 +434,7 @@ END(irq_entries_start) TRACE_IRQS_OFF CALL_enter_from_user_mode - jmpq 2f + jmp 2f 1: FENCE_SWAPGS_KERNEL_ENTRY 2: |