diff options
| author | Marshall Dawson <marshalldawson3rd@gmail.com> | 2017-07-11 17:39:01 -0600 |
|---|---|---|
| committer | Martin Roth <martinroth@google.com> | 2017-07-20 15:34:21 +0000 |
| commit | fb66e81e6c58b0825e85b2c0afabbe032f103d6e (patch) | |
| tree | c2fabc3c95ea48bb21244d89767f152e20ca26d9 /src/cpu | |
| parent | fb95a52b6e927891509006f3c14124af4dc1d890 (diff) | |
x86/lapic/secondary.S: Align stack for _secondary_start
At a process _start, the stack is expected to be aligned to a
16-byte boundary. Upon entry to any function the stack frame
must have the end of any arguments also aligned. In other words
the value of %esp+4 or %rsp+8 is always a multiple of 16 (1).
Align the stack down inside _secondary_start and preserve proper
alignment for the call to secondary_cpu_init.
Although 4-byte alignment is the minimum requirement for i386,
some AMD platforms use SSE instructions which expect 16-byte.
1) http://wiki.osdev.org/System_V_ABI
See "Initial Stack and Register State" and "The Stack Frame"
in the supplements.
BUG=chrome-os-partner:62841664
Change-Id: I72b7a474013e5caf67aedfabeb8d8d2553499b73
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/20537
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Diffstat (limited to 'src/cpu')
| -rw-r--r-- | src/cpu/x86/lapic/secondary.S | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/cpu/x86/lapic/secondary.S b/src/cpu/x86/lapic/secondary.S index a36502b1ac..27ee697db1 100644 --- a/src/cpu/x86/lapic/secondary.S +++ b/src/cpu/x86/lapic/secondary.S @@ -69,6 +69,8 @@ __ap_protected_start: /* Set the stack pointer, and flag that we are done */ xorl %eax, %eax movl secondary_stack, %esp + andl $0xfffffff0, %esp + sub $12, %esp /* maintain 16-byte alignment for the call below */ movl secondary_cpu_index, %edi pushl %edi movl %eax, secondary_stack |