[Xen-changelog] [xen stable-4.8] x86emul/test: don't use *_len symbols

[patchbot@xxxxxxx]

commit 8099c04eb33a936bd5237212b9b1fa0e1731d142
Author:     Jan Beulich <JBeulich@xxxxxxxx>
AuthorDate: Tue Jan 24 16:22:03 2017 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed May 15 13:35:22 2019 +0100

    x86emul/test: don't use *_len symbols
    
    ... as they don't work as intended with -fPIC.
    
    I did prefer them over *_end ones at the time because older gcc would
    cause .L* symbols to be public, due to issuing .globl for all
    referenced externals. And labels at the end of instructions collide
    with the ones at the start of the next instruction, making disassembly
    harder to grok. Luckily recent gcc no longer issues those .globl
    directives, and hence .L* labels, staying local by default, no longer
    get in the way.
    
    Reported-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Tested-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    (cherry picked from commit 9315fa0ef736d1153c98ce42bff5853da5ec697f)
---
 tools/tests/x86_emulator/test_x86_emulator.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/tests/x86_emulator/test_x86_emulator.c 
b/tools/tests/x86_emulator/test_x86_emulator.c
index 7b467fe021..29c6cf1ec2 100644
--- a/tools/tests/x86_emulator/test_x86_emulator.c
+++ b/tools/tests/x86_emulator/test_x86_emulator.c
@@ -766,15 +766,16 @@ int main(int argc, char **argv)
         goto fail;
     printf("okay\n");
 
-#define decl_insn(which) extern const unsigned char which[], which##_len[]
+#define decl_insn(which) extern const unsigned char which[], \
+                         which##_end[] asm ( ".L" #which "_end" )
 #define put_insn(which, insn) ".pushsection .test, \"ax\", @progbits\n" \
                               #which ": " insn "\n"                     \
-                              ".equ " #which "_len, .-" #which "\n"     \
+                              ".L" #which "_end:\n"                     \
                               ".popsection"
 #define set_insn(which) (regs.eip = (unsigned long)memcpy(instr, which, \
-                                             (unsigned long)which##_len))
+                          (unsigned long)which##_end - (unsigned long)(which)))
 #define check_eip(which) (regs.eip == (unsigned long)instr + \
-                                      (unsigned long)which##_len)
+                          (unsigned long)which##_end - (unsigned long)(which))
 
     printf("%-40s", "Testing movq %mm3,(%ecx)...");
     if ( stack_exec && cpu_has_mmx )
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.8

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