Merge tag 'arc-4.11-final' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC fix from Vineet Gupta:
 "Last minute fixes for ARC:

   - build error in Mellanox nps platform

   - addressing lack of saving FPU regs in releavnt configs"

* tag 'arc-4.11-final' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARCv2: entry: save Accumulator register pair (r58:59) if present
  ARC: [plat-eznps] Fix build error

Author: torvalds

arch/arc/Kconfig

@@ -406,6 +406,14 @@ config ARC_HAS_DIV_REM
 	bool "Insn: div, divu, rem, remu"
 	default y
 
+config ARC_HAS_ACCL_REGS
+	bool "Reg Pair ACCL:ACCH (FPU and/or MPY > 6)"
+	default n
+	help
+	  Depending on the configuration, CPU can contain accumulator reg-pair
+	  (also referred to as r58:r59). These can also be used by gcc as GPR so
+	  kernel needs to save/restore per process
+
 endif	# ISA_ARCV2
 
 endmenu   # "ARC CPU Configuration"

arch/arc/include/asm/atomic.h

@@ -17,10 +17,11 @@
 #include <asm/barrier.h>
 #include <asm/smp.h>
 
+#define ATOMIC_INIT(i)	{ (i) }
+
 #ifndef CONFIG_ARC_PLAT_EZNPS
 
 #define atomic_read(v)  READ_ONCE((v)->counter)
-#define ATOMIC_INIT(i)	{ (i) }
 
 #ifdef CONFIG_ARC_HAS_LLSC
 

arch/arc/include/asm/entry-arcv2.h

@@ -16,6 +16,11 @@
 	;
 	; Now manually save: r12, sp, fp, gp, r25
 
+#ifdef CONFIG_ARC_HAS_ACCL_REGS
+	PUSH	r59
+	PUSH	r58
+#endif
+
 	PUSH	r30
 	PUSH	r12
 
@@ -75,6 +80,11 @@
 	POP	r12
 	POP	r30
 
+#ifdef CONFIG_ARC_HAS_ACCL_REGS
+	POP	r58
+	POP	r59
+#endif
+
 .endm
 
 /*------------------------------------------------------------------------*/

arch/arc/include/asm/ptrace.h

@@ -86,6 +86,10 @@ struct pt_regs {
 
 	unsigned long r12, r30;
 
+#ifdef CONFIG_ARC_HAS_ACCL_REGS
+	unsigned long r58, r59;	/* ACCL/ACCH used by FPU / DSP MPY */
+#endif
+
 	/*------- Below list auto saved by h/w -----------*/
 	unsigned long r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11;
 

arch/arc/kernel/setup.c

@@ -319,7 +319,8 @@ static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
 static void arc_chk_core_config(void)
 {
 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
-	int fpu_enabled;
+	int saved = 0, present = 0;
+	char *opt_nm = NULL;;
 
 	if (!cpu->extn.timer0)
 		panic("Timer0 is not present!\n");
@@ -346,17 +347,28 @@ static void arc_chk_core_config(void)
 
 	/*
 	 * FP hardware/software config sanity
-	 * -If hardware contains DPFP, kernel needs to save/restore FPU state
+	 * -If hardware present, kernel needs to save/restore FPU state
 	 * -If not, it will crash trying to save/restore the non-existant regs
-	 *
-	 * (only DPDP checked since SP has no arch visible regs)
 	 */
-	fpu_enabled = IS_ENABLED(CONFIG_ARC_FPU_SAVE_RESTORE);
 
-	if (cpu->extn.fpu_dp && !fpu_enabled)
-		pr_warn("CONFIG_ARC_FPU_SAVE_RESTORE needed for working apps\n");
-	else if (!cpu->extn.fpu_dp && fpu_enabled)
-		panic("FPU non-existent, disable CONFIG_ARC_FPU_SAVE_RESTORE\n");
+	if (is_isa_arcompact()) {
+		opt_nm = "CONFIG_ARC_FPU_SAVE_RESTORE";
+		saved = IS_ENABLED(CONFIG_ARC_FPU_SAVE_RESTORE);
+
+		/* only DPDP checked since SP has no arch visible regs */
+		present = cpu->extn.fpu_dp;
+	} else {
+		opt_nm = "CONFIG_ARC_HAS_ACCL_REGS";
+		saved = IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS);
+
+		/* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */
+		present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp;
+	}
+
+	if (present && !saved)
+		pr_warn("Enable %s for working apps\n", opt_nm);
+	else if (!present && saved)
+		panic("Disable %s, hardware NOT present\n", opt_nm);
 }
 
 /*