[Xen-devel] [PATCH] x86/boot: Improve code generation from bootsym()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

The code generation for bootsym() is atrocious, and unnecesserily
complicated.  Given the appropriate physical address, all we need is to
construct a virtual address of the appropriate type.

  add/remove: 0/0 grow/shrink: 0/9 up/down: 0/-4256 (-4256)
  Function                                     old     new   delta
  kexec_reserve_area.constprop                 165     159      -6
  reset_videomode_after_s3                     231      70    -161
  identify_cpu                                1341    1176    -165
  parse_acpi_sleep                             408     240    -168
  early_init_intel                             632     440    -192
  __cpu_up                                    1983    1682    -301
  do_platform_op                              6469    5526    -943
  compat_platform_op                          6433    5482    -951
  __start_xen                                12939   11570   -1369
  Total: Before=3341298, After=3337042, chg -0.13%

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/include/asm-x86/config.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
index f950247029..dab7d7bade 100644
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -91,8 +91,8 @@ extern unsigned long trampoline_phys;
 #define bootsym_phys(sym)                                 \
     (((unsigned long)&(sym)-(unsigned long)&trampoline_start)+trampoline_phys)
 #define bootsym(sym)                                      \
-    (*RELOC_HIDE((typeof(&(sym)))__va(__pa(&(sym))),      \
-                 trampoline_phys-__pa(trampoline_start)))
+    (*((typeof(sym) *)__va(bootsym_phys(sym))))
+
 extern char trampoline_start[], trampoline_end[];
 extern char trampoline_realmode_entry[];
 extern unsigned int trampoline_xen_phys_start;
-- 
2.11.0


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