[Xen-devel] [PATCH v2] x86/link: Don't merge .init.text and .init.data

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

c/s 1308f0170c merged .init.text and .init.data, because EFI might properly
write-protect r/o sections.

However, that change makes xen-syms unusable for disassembly analysis.  In
particular, searching for indirect branches as part of the SP2/Spectre
mitigation series.

As the merging isn't necessary for ELF targets at all, make it conditional on
the EFI side of the build.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>

v2:
 * Reimplement using linker ifdefary
---
 xen/arch/x86/xen.lds.S | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 25c6cbc..e9f2ecd 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -172,7 +172,11 @@ SECTIONS
   __2M_init_start = .;         /* Start of 2M superpages, mapped RWX (boot 
only). */
   . = ALIGN(PAGE_SIZE);             /* Init code and data */
   __init_begin = .;
+#ifdef EFI /* EFI wants to merge all of .init.*  ELF doesn't. */
   DECL_SECTION(.init) {
+#else
+  DECL_SECTION(.init.text) {
+#endif
        _sinittext = .;
        *(.init.text)
        /*
@@ -183,7 +187,12 @@ SECTIONS
        *(.altinstr_replacement)
        _einittext = .;
 
+#ifdef EFI /* EFI wants to merge all of .init.*  ELF doesn't. */
        . = ALIGN(SMP_CACHE_BYTES);
+#else
+  } :text
+  DECL_SECTION(.init.data) {
+#endif
 
        *(.init.rodata)
        *(.init.rodata.rel)
-- 
2.1.4


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