diff options
| author | Borislav Petkov <bp@suse.de> | 2016-03-31 16:21:02 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-04-13 11:52:19 +0200 |
| commit | 91ed140d6c1e168b11bbbddac4f6066f40a0c6b5 (patch) | |
| tree | e583014dbc2759b04ba3e1ff09af0e1683f09ad7 /arch/x86/kernel/head_64.S | |
| parent | 60a0e2039e3df6c0a2b896bd78af36ff36fb629c (diff) | |
x86/asm: Make sure verify_cpu() has a good stack
04633df0c43d ("x86/cpu: Call verify_cpu() after having entered long mode too")
added the call to verify_cpu() for sanitizing CPU configuration.
The latter uses the stack minimally and it can happen that we land in
startup_64() directly from a 64-bit bootloader. Then we want to use our
own, known good stack.
Do that.
APs don't need this as the trampoline sets up a stack for them.
Reported-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1459434062-31055-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/head_64.S')
| -rw-r--r-- | arch/x86/kernel/head_64.S | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 3de91a7e6c99..5df831ef1442 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -65,6 +65,14 @@ startup_64: * tables and then reload them. */ + /* + * Setup stack for verify_cpu(). "-8" because stack_start is defined + * this way, see below. Our best guess is a NULL ptr for stack + * termination heuristics and we don't want to break anything which + * might depend on it (kgdb, ...). + */ + leaq (__end_init_task - 8)(%rip), %rsp + /* Sanitize CPU configuration */ call verify_cpu |