[PATCH v4 5/8] RISC-V: annotate entry points with type and size

[Jan Beulich <jbeulich@xxxxxxxx>]

Use the generic framework in xen/linkage.h. No change in generated code
except of course the converted symbols change to be hidden ones and gain
a valid size.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
Probably count_args_exp() should move to macros.h, but I first wanted to
see whether anyone can suggest any better approach for checking whether
a defined macro expands to nothing.
---
v4: Also drop #undef-s from linker script.
v3: New.

--- a/xen/arch/riscv/entry.S
+++ b/xen/arch/riscv/entry.S
@@ -5,7 +5,7 @@
 #include <asm/traps.h>
 
 /* WIP: only works while interrupting Xen context */
-ENTRY(handle_trap)
+FUNC(handle_trap)
 
     /* Exceptions from xen */
 save_to_stack:
@@ -92,3 +92,4 @@ restore_registers:
         REG_L   sp, CPU_USER_REGS_SP(sp)
 
         sret
+END(handle_trap)
--- a/xen/arch/riscv/include/asm/asm.h
+++ b/xen/arch/riscv/include/asm/asm.h
@@ -7,6 +7,7 @@
 #define _ASM_RISCV_ASM_H
 
 #ifdef __ASSEMBLY__
+#include <xen/linkage.h>
 #define __ASM_STR(x)   x
 #else
 #define __ASM_STR(x)   #x
--- a/xen/arch/riscv/include/asm/config.h
+++ b/xen/arch/riscv/include/asm/config.h
@@ -69,12 +69,8 @@
 
 /* Linkage for RISCV */
 #ifdef __ASSEMBLY__
-#define ALIGN .align 4
-
-#define ENTRY(name)                                \
-  .globl name;                                     \
-  ALIGN;                                           \
-  name:
+#define CODE_ALIGN 16
+#define CODE_FILL /* empty */
 #endif
 
 #ifdef CONFIG_RISCV_64
--- a/xen/arch/riscv/riscv64/head.S
+++ b/xen/arch/riscv/riscv64/head.S
@@ -8,7 +8,7 @@
          *   a0 -> hart_id ( bootcpu_id )
          *   a1 -> dtb_base 
          */
-ENTRY(start)
+FUNC(start)
         /* Mask all interrupts */
         csrw    CSR_SIE, zero
 
@@ -30,13 +30,14 @@ ENTRY(start)
         jal     reset_stack
 
         tail    start_xen
+END(start)
 
         .section .text, "ax", %progbits
 
-ENTRY(reset_stack)
+FUNC(reset_stack)
         la      sp, cpu0_boot_stack
         li      t0, STACK_SIZE
         add     sp, sp, t0
 
         ret
-
+END(reset_stack)
--- a/xen/arch/riscv/xen.lds.S
+++ b/xen/arch/riscv/xen.lds.S
@@ -1,9 +1,6 @@
 #include <xen/lib.h>
 #include <xen/xen.lds.h>
 
-#undef ENTRY
-#undef ALIGN
-
 OUTPUT_ARCH(riscv)
 ENTRY(start)
 
--- a/xen/include/xen/linkage.h
+++ b/xen/include/xen/linkage.h
@@ -37,17 +37,28 @@
 
 #define END(name) .size name, . - name
 
+/*
+ * CODE_FILL in particular may need to expand to nothing (e.g. for RISC-V), in
+ * which case we also need to get rid of the comma in the .balign directive.
+ */
+#define count_args_exp(args...) count_args(args)
+#if count_args_exp(CODE_FILL)
+# define DO_CODE_ALIGN(algn...) LASTARG(CODE_ALIGN, ## algn), CODE_FILL
+#else
+# define DO_CODE_ALIGN(algn...) LASTARG(CODE_ALIGN, ## algn)
+#endif
+
 #define FUNC(name, algn...) \
-        SYM(name, FUNC, GLOBAL, LASTARG(CODE_ALIGN, ## algn), CODE_FILL)
+        SYM(name, FUNC, GLOBAL, DO_CODE_ALIGN(algn))
 #define LABEL(name, algn...) \
-        SYM(name, NONE, GLOBAL, LASTARG(CODE_ALIGN, ## algn), CODE_FILL)
+        SYM(name, NONE, GLOBAL, DO_CODE_ALIGN(algn))
 #define DATA(name, algn...) \
         SYM(name, DATA, GLOBAL, LASTARG(DATA_ALIGN, ## algn), DATA_FILL)
 
 #define FUNC_LOCAL(name, algn...) \
-        SYM(name, FUNC, LOCAL, LASTARG(CODE_ALIGN, ## algn), CODE_FILL)
+        SYM(name, FUNC, LOCAL, DO_CODE_ALIGN(algn))
 #define LABEL_LOCAL(name, algn...) \
-        SYM(name, NONE, LOCAL, LASTARG(CODE_ALIGN, ## algn), CODE_FILL)
+        SYM(name, NONE, LOCAL, DO_CODE_ALIGN(algn))
 #define DATA_LOCAL(name, algn...) \
         SYM(name, DATA, LOCAL, LASTARG(DATA_ALIGN, ## algn), DATA_FILL)