powerpc: Define and use PPC64_ELF_ABI_v2/v1

We're approaching 20 locations where we need to check for ELF ABI v2.
That's fine, except the logic is a bit awkward, because we have to check
that _CALL_ELF is defined and then what its value is.

So check it once in asm/types.h and define PPC64_ELF_ABI_v2 when ELF ABI
v2 is detected.

We also have a few places where what we're really trying to check is
that we are using the 64-bit v1 ABI, ie. function descriptors. So also
add a #define for that, which simplifies several checks.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/code-patching.h

@@ -49,8 +49,7 @@ void __patch_exception(int exc, unsigned long addr);
 
 static inline unsigned long ppc_function_entry(void *func)
 {
-#if defined(CONFIG_PPC64)
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 	u32 *insn = func;
 
 	/*
@@ -75,14 +74,13 @@ static inline unsigned long ppc_function_entry(void *func)
 		return (unsigned long)(insn + 2);
 	else
 		return (unsigned long)func;
-#else
+#elif defined(PPC64_ELF_ABI_v1)
 	/*
 	 * On PPC64 ABIv1 the function pointer actually points to the
 	 * function's descriptor. The first entry in the descriptor is the
 	 * address of the function text.
 	 */
 	return ((func_descr_t *)func)->entry;
-#endif
 #else
 	return (unsigned long)func;
 #endif
@@ -90,7 +88,7 @@ static inline unsigned long ppc_function_entry(void *func)
 
 static inline unsigned long ppc_global_function_entry(void *func)
 {
-#if defined(CONFIG_PPC64) && defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 	/* PPC64 ABIv2 the global entry point is at the address */
 	return (unsigned long)func;
 #else
@@ -106,7 +104,7 @@ static inline unsigned long ppc_global_function_entry(void *func)
  */
 
 /* This must match the definition of STK_GOT in <asm/ppc_asm.h> */
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 #define R2_STACK_OFFSET         24
 #else
 #define R2_STACK_OFFSET         40

arch/powerpc/include/asm/ftrace.h

@@ -1,6 +1,8 @@
 #ifndef _ASM_POWERPC_FTRACE
 #define _ASM_POWERPC_FTRACE
 
+#include <asm/types.h>
+
 #ifdef CONFIG_FUNCTION_TRACER
 #define MCOUNT_ADDR		((unsigned long)(_mcount))
 #define MCOUNT_INSN_SIZE	4 /* sizeof mcount call */
@@ -65,8 +67,8 @@ struct dyn_arch_ftrace {
 #endif
 #endif
 
-#if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_PPC64) && !defined(__ASSEMBLY__)
-#if !defined(_CALL_ELF) || _CALL_ELF != 2
+#if defined(CONFIG_FTRACE_SYSCALLS) && !defined(__ASSEMBLY__)
+#ifdef PPC64_ELF_ABI_v1
 #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
 static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
 {
@@ -79,6 +81,6 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name
 	return !strcmp(sym + 4, name + 3);
 }
 #endif
-#endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_PPC64 && !__ASSEMBLY__ */
+#endif /* CONFIG_FTRACE_SYSCALLS && !__ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_FTRACE */

arch/powerpc/include/asm/kprobes.h

@@ -40,8 +40,7 @@ struct kprobe;
 typedef ppc_opcode_t kprobe_opcode_t;
 #define MAX_INSN_SIZE 1
 
-#ifdef CONFIG_PPC64
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 /* PPC64 ABIv2 needs local entry point */
 #define kprobe_lookup_name(name, addr)					\
 {									\
@@ -49,7 +48,7 @@ typedef ppc_opcode_t kprobe_opcode_t;
 	if (addr)							\
 		addr = (kprobe_opcode_t *)ppc_function_entry(addr);	\
 }
-#else
+#elif defined(PPC64_ELF_ABI_v1)
 /*
  * 64bit powerpc ABIv1 uses function descriptors:
  * - Check for the dot variant of the symbol first.
@@ -92,8 +91,7 @@ typedef ppc_opcode_t kprobe_opcode_t;
 		addr = (kprobe_opcode_t *)kallsyms_lookup_name(name);	\
 	}								\
 }
-#endif /* defined(_CALL_ELF) && _CALL_ELF == 2 */
-#endif /* CONFIG_PPC64 */
+#endif
 
 #define flush_insn_slot(p)	do { } while (0)
 #define kretprobe_blacklist_size 0

arch/powerpc/include/asm/linkage.h

@@ -1,8 +1,9 @@
 #ifndef _ASM_POWERPC_LINKAGE_H
 #define _ASM_POWERPC_LINKAGE_H
 
-#ifdef CONFIG_PPC64
-#if !defined(_CALL_ELF) || _CALL_ELF != 2
+#include <asm/types.h>
+
+#ifdef PPC64_ELF_ABI_v1
 #define cond_syscall(x) \
 	asm ("\t.weak " #x "\n\t.set " #x ", sys_ni_syscall\n"		\
 	     "\t.weak ." #x "\n\t.set ." #x ", .sys_ni_syscall\n")
@@ -10,6 +11,5 @@
 	asm ("\t.globl " #alias "\n\t.set " #alias ", " #name "\n"	\
 	     "\t.globl ." #alias "\n\t.set ." #alias ", ." #name)
 #endif
-#endif
 
 #endif	/* _ASM_POWERPC_LINKAGE_H */

arch/powerpc/include/asm/ppc_asm.h

@@ -189,7 +189,7 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
 #define __STK_REG(i)   (112 + ((i)-14)*8)
 #define STK_REG(i)     __STK_REG(__REG_##i)
 
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 #define STK_GOT		24
 #define __STK_PARAM(i)	(32 + ((i)-3)*8)
 #else
@@ -198,7 +198,7 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
 #endif
 #define STK_PARAM(i)	__STK_PARAM(__REG_##i)
 
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 
 #define _GLOBAL(name) \
 	.section ".text"; \

arch/powerpc/include/asm/ptrace.h

@@ -47,7 +47,7 @@
 				 STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
 #define STACK_FRAME_MARKER	12
 
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 #define STACK_FRAME_MIN_SIZE	32
 #else
 #define STACK_FRAME_MIN_SIZE	STACK_FRAME_OVERHEAD

arch/powerpc/include/asm/sections.h

@@ -62,7 +62,7 @@ static inline int overlaps_kvm_tmp(unsigned long start, unsigned long end)
 #endif
 }
 
-#if !defined(_CALL_ELF) || _CALL_ELF != 2
+#ifdef PPC64_ELF_ABI_v1
 #undef dereference_function_descriptor
 static inline void *dereference_function_descriptor(void *ptr)
 {
@@ -73,7 +73,7 @@ static inline void *dereference_function_descriptor(void *ptr)
 		ptr = p;
 	return ptr;
 }
-#endif
+#endif /* PPC64_ELF_ABI_v1 */
 
 #endif
 

arch/powerpc/include/asm/types.h

@@ -15,6 +15,14 @@
 
 #include <uapi/asm/types.h>
 
+#ifdef __powerpc64__
+#if defined(_CALL_ELF) && _CALL_ELF == 2
+#define PPC64_ELF_ABI_v2
+#else
+#define PPC64_ELF_ABI_v1
+#endif
+#endif /* __powerpc64__ */
+
 #ifndef __ASSEMBLY__
 
 typedef __vector128 vector128;

arch/powerpc/kernel/entry_64.S

@@ -453,7 +453,7 @@ _GLOBAL(ret_from_kernel_thread)
 	REST_NVGPRS(r1)
 	mtlr	r14
 	mr	r3,r15
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 	mr	r12,r14
 #endif
 	blrl

arch/powerpc/kernel/ftrace.c

@@ -608,7 +608,7 @@ unsigned long __init arch_syscall_addr(int nr)
 }
 #endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_PPC64 */
 
-#if defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF != 2)
+#ifdef PPC64_ELF_ABI_v1
 char *arch_ftrace_match_adjust(char *str, const char *search)
 {
 	if (str[0] == '.' && search[0] != '.')
@@ -616,4 +616,4 @@ char *arch_ftrace_match_adjust(char *str, const char *search)
 	else
 		return str;
 }
-#endif /* defined(CONFIG_PPC64) && (!defined(_CALL_ELF) || _CALL_ELF != 2) */
+#endif /* PPC64_ELF_ABI_v1 */

arch/powerpc/kernel/head_64.S

@@ -401,7 +401,7 @@ generic_secondary_common_init:
 	ld	r12,CPU_SPEC_RESTORE(r23)
 	cmpdi	0,r12,0
 	beq	3f
-#if !defined(_CALL_ELF) || _CALL_ELF != 2
+#ifdef PPC64_ELF_ABI_v1
 	ld	r12,0(r12)
 #endif
 	mtctr	r12

arch/powerpc/kernel/kprobes.c

@@ -506,12 +506,10 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 
 	/* setup return addr to the jprobe handler routine */
 	regs->nip = arch_deref_entry_point(jp->entry);
-#ifdef CONFIG_PPC64
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 	regs->gpr[12] = (unsigned long)jp->entry;
-#else
+#elif defined(PPC64_ELF_ABI_v1)
 	regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
-#endif
 #endif
 
 	return 1;

arch/powerpc/kernel/misc_64.S

@@ -661,7 +661,7 @@ _GLOBAL(kexec_sequence)
 
 #ifndef CONFIG_PPC_BOOK3E
 	/* clear out hardware hash page table and tlb */
-#if !defined(_CALL_ELF) || _CALL_ELF != 2
+#ifdef PPC64_ELF_ABI_v1
 	ld	r12,0(r27)		/* deref function descriptor */
 #else
 	mr	r12,r27

arch/powerpc/kernel/module_64.c

@@ -41,7 +41,7 @@
    this, and makes other things simpler.  Anton?
    --RR.  */
 
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 
 /* An address is simply the address of the function. */
 typedef unsigned long func_desc_t;
@@ -132,7 +132,7 @@ static u32 ppc64_stub_insns[] = {
 	/* Save current r2 value in magic place on the stack. */
 	0xf8410000|R2_STACK_OFFSET,	/* std     r2,R2_STACK_OFFSET(r1) */
 	0xe98b0020,			/* ld      r12,32(r11) */
-#if !defined(_CALL_ELF) || _CALL_ELF != 2
+#ifdef PPC64_ELF_ABI_v1
 	/* Set up new r2 from function descriptor */
 	0xe84b0028,			/* ld      r2,40(r11) */
 #endif

arch/powerpc/kvm/book3s_interrupts.S

@@ -25,7 +25,7 @@
 #include <asm/exception-64s.h>
 
 #if defined(CONFIG_PPC_BOOK3S_64)
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 #define FUNC(name) 		name
 #else
 #define FUNC(name) 		GLUE(.,name)

arch/powerpc/kvm/book3s_rmhandlers.S

@@ -36,7 +36,7 @@
 
 #if defined(CONFIG_PPC_BOOK3S_64)
 
-#if defined(_CALL_ELF) && _CALL_ELF == 2
+#ifdef PPC64_ELF_ABI_v2
 #define FUNC(name) 		name
 #else
 #define FUNC(name) 		GLUE(.,name)