[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[xen master] x86/entry: Introduce EFRAME_* constants



commit 37541208f119a9c552c6c6c3246ea61be0d44035
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Sat Jan 27 17:52:09 2024 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Mon Feb 26 18:20:27 2024 +0000

    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@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/x86_64/asm-offsets.c  | 17 ++++++++++
 xen/arch/x86/x86_64/compat/entry.S |  2 +-
 xen/arch/x86/x86_64/entry.S        | 68 +++++++++++++++++++-------------------
 3 files changed, 52 insertions(+), 35 deletions(-)

diff --git a/xen/arch/x86/x86_64/asm-offsets.c 
b/xen/arch/x86/x86_64/asm-offsets.c
index fee0edc61a..02242a9b73 100644
--- a/xen/arch/x86/x86_64/asm-offsets.c
+++ b/xen/arch/x86/x86_64/asm-offsets.c
@@ -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_area.map);
diff --git a/xen/arch/x86/x86_64/compat/entry.S 
b/xen/arch/x86/x86_64/compat/entry.S
index 727ab65290..2f8fe5ebfb 100644
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -15,7 +15,7 @@ FUNC(entry_int82)
         ENDBR64
         ALTERNATIVE "", clac, X86_FEATURE_XEN_SMAP
         pushq $0
-        movb  $HYPERCALL_VECTOR, 4(%rsp)
+        movb  $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 */
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index f8938b0b42..1b846f3aaf 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -188,15 +188,15 @@ FUNC_LOCAL(restore_all_guest)
 
         RESTORE_ALL
         BUILD_BUG_ON(TRAP_syscall & 0xff)
-        testb $TRAP_syscall >> 8, 4+1(%rsp)
+        testb $TRAP_syscall >> 8, EFRAME_entry_vector + 1(%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
@@ -211,19 +211,19 @@ FUNC_LOCAL(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
 
 LABEL_LOCAL(.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)
@@ -256,7 +256,7 @@ FUNC(lstar_enter)
         pushq %rcx
         pushq $0
         BUILD_BUG_ON(TRAP_syscall & 0xff)
-        movb  $TRAP_syscall >> 8, 4+1(%rsp)
+        movb  $TRAP_syscall >> 8, EFRAME_entry_vector + 1(%rsp)
         SAVE_ALL
 
         SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
@@ -295,7 +295,7 @@ FUNC(cstar_enter)
         pushq %rcx
         pushq $0
         BUILD_BUG_ON(TRAP_syscall & 0xff)
-        movb  $TRAP_syscall >> 8, 4+1(%rsp)
+        movb  $TRAP_syscall >> 8, EFRAME_entry_vector + 1(%rsp)
         SAVE_ALL
 
         SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
@@ -338,7 +338,7 @@ LABEL(sysenter_eflags_saved, 0)
         pushq $0 /* null rip */
         pushq $0
         BUILD_BUG_ON(TRAP_syscall & 0xff)
-        movb  $TRAP_syscall >> 8, 4+1(%rsp)
+        movb  $TRAP_syscall >> 8, EFRAME_entry_vector + 1(%rsp)
         SAVE_ALL
 
         SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
@@ -393,7 +393,7 @@ FUNC(entry_int80)
         ENDBR64
         ALTERNATIVE "", clac, X86_FEATURE_XEN_SMAP
         pushq $0
-        movb  $0x80, 4(%rsp)
+        movb  $0x80, EFRAME_entry_vector(%rsp)
         SAVE_ALL
 
         SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
@@ -658,7 +658,7 @@ END(ret_from_intr)
         .section .init.text, "ax", @progbits
 FUNC(early_page_fault)
         ENDBR64
-        movb  $X86_EXC_PF, 4(%rsp)
+        movb  $X86_EXC_PF, EFRAME_entry_vector(%rsp)
         SAVE_ALL
         movq  %rsp, %rdi
         call  do_early_page_fault
@@ -727,7 +727,7 @@ END(common_interrupt)
 
 FUNC(entry_PF)
         ENDBR64
-        movb  $X86_EXC_PF, 4(%rsp)
+        movb  $X86_EXC_PF, EFRAME_entry_vector(%rsp)
 END(entry_PF)
 /* No special register assumptions. */
 FUNC(handle_exception, 0)
@@ -911,98 +911,98 @@ END(entry_DE)
 FUNC(entry_MF)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_MF, 4(%rsp)
+        movb  $X86_EXC_MF, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_MF)
 
 FUNC(entry_XM)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_XM, 4(%rsp)
+        movb  $X86_EXC_XM, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_XM)
 
 FUNC(entry_NM)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_NM, 4(%rsp)
+        movb  $X86_EXC_NM, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_NM)
 
 FUNC(entry_DB)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_DB, 4(%rsp)
+        movb  $X86_EXC_DB, EFRAME_entry_vector(%rsp)
         jmp   handle_ist_exception
 END(entry_DB)
 
 FUNC(entry_BP)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_BP, 4(%rsp)
+        movb  $X86_EXC_BP, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_BP)
 
 FUNC(entry_OF)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_OF, 4(%rsp)
+        movb  $X86_EXC_OF, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_OF)
 
 FUNC(entry_BR)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_BR, 4(%rsp)
+        movb  $X86_EXC_BR, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_BR)
 
 FUNC(entry_UD)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_UD, 4(%rsp)
+        movb  $X86_EXC_UD, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_UD)
 
 FUNC(entry_TS)
         ENDBR64
-        movb  $X86_EXC_TS, 4(%rsp)
+        movb  $X86_EXC_TS, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_TS)
 
 FUNC(entry_NP)
         ENDBR64
-        movb  $X86_EXC_NP, 4(%rsp)
+        movb  $X86_EXC_NP, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_NP)
 
 FUNC(entry_SS)
         ENDBR64
-        movb  $X86_EXC_SS, 4(%rsp)
+        movb  $X86_EXC_SS, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_SS)
 
 FUNC(entry_GP)
         ENDBR64
-        movb  $X86_EXC_GP, 4(%rsp)
+        movb  $X86_EXC_GP, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_GP)
 
 FUNC(entry_AC)
         ENDBR64
-        movb  $X86_EXC_AC, 4(%rsp)
+        movb  $X86_EXC_AC, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_AC)
 
 FUNC(entry_CP)
         ENDBR64
-        movb  $X86_EXC_CP, 4(%rsp)
+        movb  $X86_EXC_CP, EFRAME_entry_vector(%rsp)
         jmp   handle_exception
 END(entry_CP)
 
 FUNC(entry_DF)
         ENDBR64
-        movb  $X86_EXC_DF, 4(%rsp)
+        movb  $X86_EXC_DF, EFRAME_entry_vector(%rsp)
         /* Set AC to reduce chance of further SMAP faults */
         ALTERNATIVE "", stac, X86_FEATURE_XEN_SMAP
         SAVE_ALL
@@ -1028,7 +1028,7 @@ END(entry_DF)
 FUNC(entry_NMI)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_NMI, 4(%rsp)
+        movb  $X86_EXC_NMI, EFRAME_entry_vector(%rsp)
 END(entry_NMI)
 
 FUNC(handle_ist_exception)
@@ -1164,7 +1164,7 @@ END(handle_ist_exception)
 FUNC(entry_MC)
         ENDBR64
         pushq $0
-        movb  $X86_EXC_MC, 4(%rsp)
+        movb  $X86_EXC_MC, EFRAME_entry_vector(%rsp)
         jmp   handle_ist_exception
 END(entry_MC)
 
@@ -1203,7 +1203,7 @@ FUNC_LOCAL(autogen_stubs, 0) /* Automatically generated 
stubs. */
 1:
         ENDBR64
         pushq $0
-        movb  $vec,4(%rsp)
+        movb  $vec, EFRAME_entry_vector(%rsp)
         jmp   common_interrupt
 
         entrypoint 1b
@@ -1217,7 +1217,7 @@ FUNC_LOCAL(autogen_stubs, 0) /* 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
--
generated by git-patchbot for /home/xen/git/xen.git#master



 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.