File xsa452-1.patch of Package xen.34726
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: x86/entry: Introduce EFRAME_* constants
restore_all_guest() does a lot of manipulation of the stack after popping the
GPRs, and uses raw %rsp displacements to do so. Also, almost all entrypaths
use raw %rsp displacements prior to pushing GPRs.
Provide better mnemonics, to aid readability and reduce the chance of errors
when editing.
No functional change. The resulting binary is identical.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
(cherry picked from commit 37541208f119a9c552c6c6c3246ea61be0d44035)
--- a/xen/arch/x86/x86_64/asm-offsets.c
+++ b/xen/arch/x86/x86_64/asm-offsets.c
@@ -49,6 +49,23 @@ void __dummy__(void)
OFFSET(UREGS_kernel_sizeof, struct cpu_user_regs, es);
BLANK();
+ /*
+ * EFRAME_* is for the entry/exit logic where %rsp is pointing at
+ * UREGS_error_code and GPRs are still/already guest values.
+ */
+#define OFFSET_EF(sym, mem) \
+ DEFINE(sym, offsetof(struct cpu_user_regs, mem) - \
+ offsetof(struct cpu_user_regs, error_code))
+
+ OFFSET_EF(EFRAME_entry_vector, entry_vector);
+ OFFSET_EF(EFRAME_rip, rip);
+ OFFSET_EF(EFRAME_cs, cs);
+ OFFSET_EF(EFRAME_eflags, eflags);
+ OFFSET_EF(EFRAME_rsp, rsp);
+ BLANK();
+
+#undef OFFSET_EF
+
OFFSET(VCPU_processor, struct vcpu, processor);
OFFSET(VCPU_domain, struct vcpu, domain);
OFFSET(VCPU_vcpu_info, struct vcpu, vcpu_info);
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -15,7 +15,7 @@ ENTRY(entry_int82)
ENDBR64
ASM_CLAC
pushq $0
- movl $HYPERCALL_VECTOR, 4(%rsp)
+ movl $HYPERCALL_VECTOR, EFRAME_entry_vector(%rsp)
SAVE_ALL compat=1 /* DPL1 gate, restricted to 32bit PV guests only. */
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
@@ -210,7 +210,7 @@ ENTRY(cstar_enter)
pushq $FLAT_USER_CS32
pushq %rcx
pushq $0
- movl $TRAP_syscall, 4(%rsp)
+ movl $TRAP_syscall, EFRAME_entry_vector(%rsp)
SAVE_ALL
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -178,15 +178,15 @@ restore_all_guest:
SPEC_CTRL_EXIT_TO_PV /* Req: a=spec_ctrl %rsp=regs/cpuinfo, Clob: cd */
RESTORE_ALL
- testw $TRAP_syscall,4(%rsp)
+ testw $TRAP_syscall, EFRAME_entry_vector(%rsp)
jz iret_exit_to_guest
- movq 24(%rsp),%r11 # RFLAGS
+ mov EFRAME_eflags(%rsp), %r11
andq $~(X86_EFLAGS_IOPL | X86_EFLAGS_VM), %r11
orq $X86_EFLAGS_IF,%r11
/* Don't use SYSRET path if the return address is not canonical. */
- movq 8(%rsp),%rcx
+ mov EFRAME_rip(%rsp), %rcx
sarq $47,%rcx
incl %ecx
cmpl $1,%ecx
@@ -201,20 +201,20 @@ restore_all_guest:
ALTERNATIVE "", rag_clrssbsy, X86_FEATURE_XEN_SHSTK
#endif
- movq 8(%rsp), %rcx # RIP
- cmpw $FLAT_USER_CS32,16(%rsp)# CS
- movq 32(%rsp),%rsp # RSP
+ mov EFRAME_rip(%rsp), %rcx
+ cmpw $FLAT_USER_CS32, EFRAME_cs(%rsp)
+ mov EFRAME_rsp(%rsp), %rsp
je 1f
sysretq
1: sysretl
ALIGN
.Lrestore_rcx_iret_exit_to_guest:
- movq 8(%rsp), %rcx # RIP
+ mov EFRAME_rip(%rsp), %rcx
/* No special register assumptions. */
iret_exit_to_guest:
- andl $~(X86_EFLAGS_IOPL | X86_EFLAGS_VM), 24(%rsp)
- orl $X86_EFLAGS_IF,24(%rsp)
+ andl $~(X86_EFLAGS_IOPL | X86_EFLAGS_VM), EFRAME_eflags(%rsp)
+ orl $X86_EFLAGS_IF, EFRAME_eflags(%rsp)
addq $8,%rsp
.Lft0: iretq
_ASM_PRE_EXTABLE(.Lft0, handle_exception)
@@ -245,7 +245,7 @@ ENTRY(lstar_enter)
pushq $FLAT_KERNEL_CS64
pushq %rcx
pushq $0
- movl $TRAP_syscall, 4(%rsp)
+ movl $TRAP_syscall, EFRAME_entry_vector(%rsp)
SAVE_ALL
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
@@ -283,7 +283,7 @@ GLOBAL(sysenter_eflags_saved)
pushq $3 /* ring 3 null cs */
pushq $0 /* null rip */
pushq $0
- movl $TRAP_syscall, 4(%rsp)
+ movl $TRAP_syscall, EFRAME_entry_vector(%rsp)
SAVE_ALL
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
@@ -335,7 +335,7 @@ ENTRY(int80_direct_trap)
ENDBR64
ASM_CLAC
pushq $0
- movl $0x80, 4(%rsp)
+ movl $0x80, EFRAME_entry_vector(%rsp)
SAVE_ALL
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
@@ -632,7 +632,7 @@ ENTRY(common_interrupt)
ENTRY(page_fault)
ENDBR64
- movl $TRAP_page_fault,4(%rsp)
+ movl $TRAP_page_fault, EFRAME_entry_vector(%rsp)
/* No special register assumptions. */
GLOBAL(handle_exception)
SAVE_ALL CLAC
@@ -771,90 +771,90 @@ FATAL_exception_with_ints_disabled:
ENTRY(divide_error)
ENDBR64
pushq $0
- movl $TRAP_divide_error,4(%rsp)
+ movl $TRAP_divide_error, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(coprocessor_error)
ENDBR64
pushq $0
- movl $TRAP_copro_error,4(%rsp)
+ movl $TRAP_copro_error, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(simd_coprocessor_error)
ENDBR64
pushq $0
- movl $TRAP_simd_error,4(%rsp)
+ movl $TRAP_simd_error, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(device_not_available)
ENDBR64
pushq $0
- movl $TRAP_no_device,4(%rsp)
+ movl $TRAP_no_device, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(debug)
ENDBR64
pushq $0
- movl $TRAP_debug,4(%rsp)
+ movl $TRAP_debug, EFRAME_entry_vector(%rsp)
jmp handle_ist_exception
ENTRY(int3)
ENDBR64
pushq $0
- movl $TRAP_int3,4(%rsp)
+ movl $TRAP_int3, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(overflow)
ENDBR64
pushq $0
- movl $TRAP_overflow,4(%rsp)
+ movl $TRAP_overflow, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(bounds)
ENDBR64
pushq $0
- movl $TRAP_bounds,4(%rsp)
+ movl $TRAP_bounds, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(invalid_op)
ENDBR64
pushq $0
- movl $TRAP_invalid_op,4(%rsp)
+ movl $TRAP_invalid_op, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(invalid_TSS)
ENDBR64
- movl $TRAP_invalid_tss,4(%rsp)
+ movl $TRAP_invalid_tss, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(segment_not_present)
ENDBR64
- movl $TRAP_no_segment,4(%rsp)
+ movl $TRAP_no_segment, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(stack_segment)
ENDBR64
- movl $TRAP_stack_error,4(%rsp)
+ movl $TRAP_stack_error, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(general_protection)
ENDBR64
- movl $TRAP_gp_fault,4(%rsp)
+ movl $TRAP_gp_fault, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(alignment_check)
ENDBR64
- movl $TRAP_alignment_check,4(%rsp)
+ movl $TRAP_alignment_check, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(entry_CP)
ENDBR64
- movl $X86_EXC_CP, 4(%rsp)
+ movl $X86_EXC_CP, EFRAME_entry_vector(%rsp)
jmp handle_exception
ENTRY(double_fault)
ENDBR64
- movl $TRAP_double_fault,4(%rsp)
+ movl $TRAP_double_fault, EFRAME_entry_vector(%rsp)
/* Set AC to reduce chance of further SMAP faults */
SAVE_ALL STAC
@@ -879,7 +879,7 @@ ENTRY(double_fault)
.pushsection .init.text, "ax", @progbits
ENTRY(early_page_fault)
ENDBR64
- movl $TRAP_page_fault,4(%rsp)
+ movl $TRAP_page_fault, EFRAME_entry_vector(%rsp)
SAVE_ALL
movq %rsp,%rdi
call do_early_page_fault
@@ -889,7 +889,7 @@ ENTRY(early_page_fault)
ENTRY(nmi)
ENDBR64
pushq $0
- movl $TRAP_nmi,4(%rsp)
+ movl $TRAP_nmi, EFRAME_entry_vector(%rsp)
handle_ist_exception:
SAVE_ALL CLAC
@@ -990,7 +990,7 @@ handle_ist_exception:
ENTRY(machine_check)
ENDBR64
pushq $0
- movl $TRAP_machine_check,4(%rsp)
+ movl $TRAP_machine_check, EFRAME_entry_vector(%rsp)
jmp handle_ist_exception
/* No op trap handler. Required for kexec crash path. */
@@ -1025,7 +1025,7 @@ autogen_stubs: /* Automatically generate
1:
ENDBR64
pushq $0
- movb $vec,4(%rsp)
+ movb $vec, EFRAME_entry_vector(%rsp)
jmp common_interrupt
entrypoint 1b
@@ -1039,7 +1039,7 @@ autogen_stubs: /* Automatically generate
test $8,%spl /* 64bit exception frames are 16 byte aligned, but the word */
jz 2f /* size is 8 bytes. Check whether the processor gave us an */
pushq $0 /* error code, and insert an empty one if not. */
-2: movb $vec,4(%rsp)
+2: movb $vec, EFRAME_entry_vector(%rsp)
jmp handle_exception
entrypoint 1b
