FRED and IDT differ by a Supervisor Token on the base of the shstk. This
means that switch_stack_and_jump() needs to discard one extra word when FRED
is active.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Roger Pau Monné <roger....@citrix.com>
v2:
* Use X86_FEATURE_XEN_FRED
---
xen/arch/x86/include/asm/current.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/xen/arch/x86/include/asm/current.h
b/xen/arch/x86/include/asm/current.h
index c1eb27b1c4c2..35cc61fa88e7 100644
--- a/xen/arch/x86/include/asm/current.h
+++ b/xen/arch/x86/include/asm/current.h
@@ -154,7 +154,9 @@ unsigned long get_stack_dump_bottom (unsigned long sp);
"rdsspd %[ssp];" \
"cmp $1, %[ssp];" \
"je .L_shstk_done.%=;" /* CET not active? Skip. */ \
- "mov $%c[skstk_base], %[val];" \
+ ALTERNATIVE("mov $%c[skstk_base], %[val];", \
+ "mov $%c[skstk_base] + 8, %[val];", \
+ X86_FEATURE_XEN_FRED) \
"and $%c[stack_mask], %[ssp];" \
"sub %[ssp], %[val];" \
"shr $3, %[val];" \
--
2.39.5
