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x86/entry: Introduce EFRAME_* constants

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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 37541208f1)
This commit is contained in:
Andrew Cooper committed 2024-03-08 18:59:44 +00:00
1 parent ffd75b161d
commit 91dbe4f238
3 files changed
+53 -36
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xen/arch/x86/x86_64/asm-offsets.c
+17
View File
@@ -51,6 +51,23 @@ 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);
xen/arch/x86/x86_64/compat/entry.S
+1 -1
View File
@@ -15,7 +15,7 @@ ENTRY(entry_int82)
ENDBR64
ALTERNATIVE "", clac, X86_FEATURE_XEN_SMAP
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 */
xen/arch/x86/x86_64/entry.S
+35 -35
View File
@@ -190,15 +190,15 @@ 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
@@ -213,20 +213,20 @@ 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)
@@ -257,7 +257,7 @@ 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 */
@@ -294,7 +294,7 @@ 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 */
@@ -335,7 +335,7 @@ 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 */
@@ -389,7 +389,7 @@ ENTRY(int80_direct_trap)
ENDBR64
ALTERNATIVE "", clac, X86_FEATURE_XEN_SMAP
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 */
@@ -707,7 +707,7 @@ 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)
ALTERNATIVE "", clac, X86_FEATURE_XEN_SMAP
@@ -849,90 +849,90 @@ 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 */
ALTERNATIVE "", stac, X86_FEATURE_XEN_SMAP
SAVE_ALL
@@ -958,7 +958,7 @@ 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
@@ -968,7 +968,7 @@ ENTRY(early_page_fault)
ENTRY(nmi)
ENDBR64
pushq $0
movl $TRAP_nmi,4(%rsp)
movl $TRAP_nmi, EFRAME_entry_vector(%rsp)
handle_ist_exception:
ALTERNATIVE "", clac, X86_FEATURE_XEN_SMAP
SAVE_ALL
@@ -1075,7 +1075,7 @@ 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. */
@@ -1112,7 +1112,7 @@ autogen_stubs: /* Automatically generated stubs. */
1:
ENDBR64
pushq $0
movb $vec,4(%rsp)
movb $vec, EFRAME_entry_vector(%rsp)
jmp common_interrupt
entrypoint 1b
@@ -1126,7 +1126,7 @@ autogen_stubs: /* Automatically generated stubs. */
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
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