[coreboot-gerrit] Change in coreboot[master]: cpu/x86/smm: Fix explicit 'addr32' usage in clang builds

[Damien Zammit (Code Review)]

Damien Zammit has uploaded this change for review. ( https://review.coreboot.org/21219


Change subject: cpu/x86/smm: Fix explicit 'addr32' usage in clang builds
......................................................................

cpu/x86/smm: Fix explicit 'addr32' usage in clang builds

The addr32 prefix is required by binutils, because even when
given an explicit address which is greater than 64KiB, it will
throw a warning about truncation, and stupidly emit the opcode
with a 16-bit addressing mode and the wrong address.

However, in the case of LLVM, this doesn't happen, and is happy
to just use 32-bit addressing whenever it may require it. This
means that LLVM never really needs an explicit addr32 prefix to
use 32-bit addressing in 16-bit mode.

Change-Id: Ia160d3f7da6653ea24c8229dc26f265e5f15aabb
Signed-off-by: Edward O'Callaghan <funfunctor at folklore1984.net>
Signed-off-by: Damien Zammit <damien at zamaudio.com>
---
M src/cpu/x86/smm/smmrelocate.S
1 file changed, 12 insertions(+), 0 deletions(-)



  git pull ssh://review.coreboot.org:29418/coreboot refs/changes/19/21219/1

diff --git a/src/cpu/x86/smm/smmrelocate.S b/src/cpu/x86/smm/smmrelocate.S
index 4d388a9..22fbaea 100644
--- a/src/cpu/x86/smm/smmrelocate.S
+++ b/src/cpu/x86/smm/smmrelocate.S
@@ -112,7 +112,11 @@
 	 */
 
 	mov $0x38000 + 0x7efc, %ebx
+#if IS_ENABLED(CONFIG_COMPILER_LLVM_CLANG)
+	mov (%ebx), %al
+#else
 	addr32 mov (%ebx), %al
+#endif
 	cmp $0x64, %al
 	je 1f
 
@@ -124,7 +128,11 @@
 smm_relocate:
 	/* Get this CPU's LAPIC ID */
 	movl $LAPIC_ID, %esi
+#if IS_ENABLED(CONFIG_COMPILER_LLVM_CLANG)
+	movl (%esi), %ecx
+#else
 	addr32 movl (%esi), %ecx
+#endif
 	shr  $24, %ecx
 
 	/* calculate offset by multiplying the
@@ -136,7 +144,11 @@
 	movl $0xa0000, %eax
 	subl %edx, %eax	/* subtract offset, see above */
 
+#if IS_ENABLED(CONFIG_COMPILER_LLVM_CLANG)
+	movl %eax, (%ebx)
+#else
 	addr32 movl %eax, (%ebx)
+#endif
 
 	/* The next section of code is potentially southbridge specific */
 

-- 
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Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: Ia160d3f7da6653ea24c8229dc26f265e5f15aabb
Gerrit-Change-Number: 21219
Gerrit-PatchSet: 1
Gerrit-Owner: Damien Zammit <damien at zamaudio.com>
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