FROMLIST: arm64: make mrs_s and msr_s macros work with LTO

Clang's integrated assembler does not allow assembly macros defined
in one inline asm block using the .macro directive to be used across
separate asm blocks. LLVM developers consider this a feature and not a
bug, recommending code refactoring:

  https://bugs.llvm.org/show_bug.cgi?id=19749

As binutils doesn't allow macros to be redefined, this change uses
UNDEFINE_MRS_S and UNDEFINE_MSR_S to define corresponding macros
in-place and workaround gcc and clang limitations on redefining macros
across different assembler blocks.

Bug: 62093296
Bug: 67506682
Change-Id: I803fff57f639b0921ef81f90ec4befe802e7eecf
(am from https://patchwork.kernel.org/patch/10060343/)
Signed-off-by: Alex Matveev <alxmtvv@gmail.com>
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 4572a9b560fa3d73a7db4a850215bcbc9049c8f1..20bfb8e676e043236f63a0165eb78e63437284ac 100644 (file)
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -29,7 +29,9 @@
        ({                                                              \
                u64 reg;                                                \
                asm volatile(ALTERNATIVE("mrs %0, " __stringify(r##nvh),\
-                                        "mrs_s %0, " __stringify(r##vh),\
+                                        DEFINE_MRS_S                   \
+                                        "mrs_s %0, " __stringify(r##vh) "\n"\
+                                        UNDEFINE_MRS_S,                \
                                         ARM64_HAS_VIRT_HOST_EXTN)      \
                             : "=r" (reg));                             \
                reg;                                                    \
@@ -39,7 +41,9 @@
        do {                                                            \
                u64 __val = (u64)(v);                                   \
                asm volatile(ALTERNATIVE("msr " __stringify(r##nvh) ", %x0",\
-                                        "msr_s " __stringify(r##vh) ", %x0",\
+                                        DEFINE_MSR_S                   \
+                                        "msr_s " __stringify(r##vh) ", %x0\n"\
+                                        UNDEFINE_MSR_S,                \
                                         ARM64_HAS_VIRT_HOST_EXTN)      \
                                         : : "rZ" (__val));             \
        } while (0)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index ede80d47d0effdb749a51df45d39dd576611fc9c..3bdec2f5cbb423bbdce450375e492ac45c2be1f7 100644 (file)
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -465,20 +465,39 @@
 
 #include <linux/types.h>
 
-asm(
-"      .irp    num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30\n"
-"      .equ    .L__reg_num_x\\num, \\num\n"
-"      .endr\n"
+#define __DEFINE_MRS_MSR_S_REGNUM                              \
+"      .irp    num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30\n" \
+"      .equ    .L__reg_num_x\\num, \\num\n"                    \
+"      .endr\n"                                                \
 "      .equ    .L__reg_num_xzr, 31\n"
-"\n"
-"      .macro  mrs_s, rt, sreg\n"
-       __emit_inst(0xd5200000|(\\sreg)|(.L__reg_num_\\rt))
+
+#define DEFINE_MRS_S                                           \
+       __DEFINE_MRS_MSR_S_REGNUM                               \
+"      .macro  mrs_s, rt, sreg\n"                              \
+"      .inst 0xd5200000|(\\sreg)|(.L__reg_num_\\rt)\n" \
 "      .endm\n"
-"\n"
-"      .macro  msr_s, sreg, rt\n"
-       __emit_inst(0xd5000000|(\\sreg)|(.L__reg_num_\\rt))
+
+#define DEFINE_MSR_S                                           \
+       __DEFINE_MRS_MSR_S_REGNUM                               \
+"      .macro  msr_s, sreg, rt\n"                              \
+"      .inst 0xd5000000|(\\sreg)|(.L__reg_num_\\rt)\n"         \
 "      .endm\n"
-);
+
+#define UNDEFINE_MRS_S                                         \
+"      .purgem mrs_s\n"
+
+#define UNDEFINE_MSR_S                                         \
+"      .purgem msr_s\n"
+
+#define __mrs_s(r, v)                                          \
+       DEFINE_MRS_S                                            \
+"      mrs_s %0, " __stringify(r) "\n"                         \
+       UNDEFINE_MRS_S : "=r" (v)
+
+#define __msr_s(r, v)                                          \
+       DEFINE_MSR_S                                            \
+"      msr_s " __stringify(r) ", %x0\n"                        \
+       UNDEFINE_MSR_S : : "rZ" (v)
 
 /*
  * Unlike read_cpuid, calls to read_sysreg are never expected to be
@@ -504,15 +523,15 @@ asm(
  * For registers without architectural names, or simply unsupported by
  * GAS.
  */
-#define read_sysreg_s(r) ({                                            \
-       u64 __val;                                                      \
-       asm volatile("mrs_s %0, " __stringify(r) : "=r" (__val));       \
-       __val;                                                          \
+#define read_sysreg_s(r) ({                                    \
+       u64 __val;                                              \
+       asm volatile(__mrs_s(r, __val));                        \
+       __val;                                                  \
 })
 
-#define write_sysreg_s(v, r) do {                                      \
-       u64 __val = (u64)(v);                                           \
-       asm volatile("msr_s " __stringify(r) ", %x0" : : "rZ" (__val)); \
+#define write_sysreg_s(v, r) do {                              \
+       u64 __val = (u64)(v);                                   \
+       asm volatile(__msr_s(r, __val));                        \
 } while (0)
 
 static inline void config_sctlr_el1(u32 clear, u32 set)