linx/x86-64: cleanup the Xen-specific macros in entry-xen.S
PATCH 1/1 linx/x86-64: cleanup the Xen-specific macros in entry-xen.S
- SWITCH_TO_KERNEL is dead (and was broken)
- comments to HYPERVISOR_IRET were somewhat outdated
- updates of selecor RPLs shouldn't be done with byte size to avoid store-to-load forwarding issues
Signed-off-by Jan Beulich <[email protected]>
arch/x86_64/kernel/entry-xen.S +5 -11
@@ -148,11 +148,11 @@ NMI_MASK = 0x80000000 .endm /* - * Must be consistent with the definition in arch-x86_64.h: + * Must be consistent with the definition in arch-x86/xen-x86_64.h: * struct iret_context { * u64 rax, r11, rcx, flags, rip, cs, rflags, rsp, ss; * }; - * #define VGCF_IN_SYSCALL (1<<8) + * with rax, r11, and rcx being taken care of in the hypercall stub. */ .macro HYPERVISOR_IRET flag testb $3,1*8(%rsp)
@@ -164,22 +164,16 @@ NMI_MASK = 0x80000000 jnz 1f /* Direct iret to kernel space. Correct CS and SS. */ - orb $3,1*8(%rsp) - orb $3,4*8(%rsp) + orl $3,1*8(%rsp) + orl $3,4*8(%rsp) 1: iretq 2: /* Slow iret via hypervisor. */ - andl $~NMI_MASK, 16(%rsp) + andl $~NMI_MASK, 2*8(%rsp) pushq $\flag jmp hypercall_page + (__HYPERVISOR_iret * 32) .endm - .macro SWITCH_TO_KERNEL ssoff,adjust=0 - jc 1f - orb $1,\ssoff-\adjust+4(%rsp) -1: - .endm - /* * A newly forked process directly context switches into this. */