Merge tag 'arc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC updates from Vineet Gupta:

 - fixes for -Wmissing-prototype warnings

 - missing compiler barrier in relaxed atomics

 - some uaccess simplification, declutter

 - removal of massive glocal struct cpuinfo_arc from bootlog code

 - __switch_to consolidation (removal of inline asm variant)

 - use GP to cache task pointer (vs. r25)

 - misc rework of entry code

* tag 'arc-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (24 commits)
  ARC: boot log: fix warning
  arc: Explicitly include correct DT includes
  ARC: pt_regs: create seperate type for ecr
  ARCv2: entry: rearrange pt_regs slightly
  ARC: entry: replace 8 byte ADD.ne with 4 byte ADD2.ne
  ARC: entry: replace 8 byte OR with 4 byte BSET
  ARC: entry: Add more common chores to EXCEPTION_PROLOGUE
  ARC: entry: EV_MachineCheck dont re-read ECR
  ARC: entry: ARcompact EV_ProtV to use r10 directly
  ARC: entry: rework (non-functional)
  ARC: __switch_to: move ksp to thread_info from thread_struct
  ARC: __switch_to: asm with dwarf ops (vs. inline asm)
  ARC: kernel stack: INIT_THREAD need not setup @init_stack in @ksp
  ARC: entry: use gp to cache task pointer (vs. r25)
  ARC: boot log: eliminate struct cpuinfo_arc #4: boot log per ISA
  ARC: boot log: eliminate struct cpuinfo_arc #3: don't export
  ARC: boot log: eliminate struct cpuinfo_arc #2: cache
  ARC: boot log: eliminate struct cpuinfo_arc #1: mm
  ARCv2: memset: don't prefetch for len == 0 which happens a alot
  ARC: uaccess: elide unaliged handling if hardware supports
  ...

arch/arc/Kconfig

@@ -27,6 +27,8 @@ config ARC
 	select GENERIC_SCHED_CLOCK
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_IOREMAP
+	select GENERIC_STRNCPY_FROM_USER if MMU
+	select GENERIC_STRNLEN_USER if MMU
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if ARC_MMU_V4
@@ -491,11 +493,11 @@ config ARC_KVADDR_SIZE
 	  kernel-user gutter)
 
 config ARC_CURR_IN_REG
-	bool "Dedicate Register r25 for current_task pointer"
+	bool "cache current task pointer in gp"
 	default y
 	help
-	  This reserved Register R25 to point to Current Task in
-	  kernel mode. This saves memory access for each such access
+	  This reserves gp register to point to Current Task in
+	  kernel mode eliding memory access for each access
 
 
 config ARC_EMUL_UNALIGNED

arch/arc/Makefile

@@ -28,14 +28,14 @@ cflags-y				+= $(tune-mcpu-def-y)
 endif
 endif
 
-
 ifdef CONFIG_ARC_CURR_IN_REG
 # For a global register definition, make sure it gets passed to every file
 # We had a customer reported bug where some code built in kernel was NOT using
-# any kernel headers, and missing the r25 global register
+# any kernel headers, and missing the global register
 # Can't do unconditionally because of recursive include issues
 # due to <linux/thread_info.h>
 LINUXINCLUDE	+=  -include $(srctree)/arch/arc/include/asm/current.h
+cflags-y	+= -ffixed-gp
 endif
 
 cflags-y				+= -fsection-anchors
@@ -67,7 +67,7 @@ cflags-$(CONFIG_ARC_DW2_UNWIND)		+= -fasynchronous-unwind-tables $(cfi)
 # small data is default for elf32 tool-chain. If not usable, disable it
 # This also allows repurposing GP as scratch reg to gcc reg allocator
 disable_small_data := y
-cflags-$(disable_small_data)		+= -mno-sdata -fcall-used-gp
+cflags-$(disable_small_data)		+= -mno-sdata
 
 cflags-$(CONFIG_CPU_BIG_ENDIAN)		+= -mbig-endian
 ldflags-$(CONFIG_CPU_BIG_ENDIAN)	+= -EB

arch/arc/include/asm/arcregs.h

@@ -23,7 +23,7 @@
 #define ARC_REG_ICCM_BUILD	0x78	/* ICCM size (common) */
 #define ARC_REG_XY_MEM_BCR	0x79
 #define ARC_REG_MAC_BCR		0x7a
-#define ARC_REG_MUL_BCR		0x7b
+#define ARC_REG_MPY_BCR		0x7b
 #define ARC_REG_SWAP_BCR	0x7c
 #define ARC_REG_NORM_BCR	0x7d
 #define ARC_REG_MIXMAX_BCR	0x7e
@@ -177,7 +177,7 @@ struct bcr_isa_arcv2 {
 #endif
 };
 
-struct bcr_uarch_build_arcv2 {
+struct bcr_uarch_build {
 #ifdef CONFIG_CPU_BIG_ENDIAN
 	unsigned int pad:8, prod:8, maj:8, min:8;
 #else
@@ -185,6 +185,59 @@ struct bcr_uarch_build_arcv2 {
 #endif
 };
 
+struct bcr_mmu_3 {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	unsigned int ver:8, ways:4, sets:4, res:3, sasid:1, pg_sz:4,
+		     u_itlb:4, u_dtlb:4;
+#else
+	unsigned int u_dtlb:4, u_itlb:4, pg_sz:4, sasid:1, res:3, sets:4,
+		     ways:4, ver:8;
+#endif
+};
+
+struct bcr_mmu_4 {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	unsigned int ver:8, sasid:1, sz1:4, sz0:4, res:2, pae:1,
+		     n_ways:2, n_entry:2, n_super:2, u_itlb:3, u_dtlb:3;
+#else
+	/*           DTLB      ITLB      JES        JE         JA      */
+	unsigned int u_dtlb:3, u_itlb:3, n_super:2, n_entry:2, n_ways:2,
+		     pae:1, res:2, sz0:4, sz1:4, sasid:1, ver:8;
+#endif
+};
+
+struct bcr_cache {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	unsigned int pad:12, line_len:4, sz:4, config:4, ver:8;
+#else
+	unsigned int ver:8, config:4, sz:4, line_len:4, pad:12;
+#endif
+};
+
+struct bcr_slc_cfg {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	unsigned int pad:24, way:2, lsz:2, sz:4;
+#else
+	unsigned int sz:4, lsz:2, way:2, pad:24;
+#endif
+};
+
+struct bcr_clust_cfg {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	unsigned int pad:7, c:1, num_entries:8, num_cores:8, ver:8;
+#else
+	unsigned int ver:8, num_cores:8, num_entries:8, c:1, pad:7;
+#endif
+};
+
+struct bcr_volatile {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+	unsigned int start:4, limit:4, pad:22, order:1, disable:1;
+#else
+	unsigned int disable:1, order:1, pad:22, limit:4, start:4;
+#endif
+};
+
 struct bcr_mpy {
 #ifdef CONFIG_CPU_BIG_ENDIAN
 	unsigned int pad:8, x1616:8, dsp:4, cycles:2, type:2, ver:8;
@@ -302,48 +355,6 @@ struct bcr_generic {
 #endif
 };
 
-/*
- *******************************************************************
- * Generic structures to hold build configuration used at runtime
- */
-
-struct cpuinfo_arc_mmu {
-	unsigned int ver:4, pg_sz_k:8, s_pg_sz_m:8, pad:10, sasid:1, pae:1;
-	unsigned int sets:12, ways:4, u_dtlb:8, u_itlb:8;
-};
-
-struct cpuinfo_arc_cache {
-	unsigned int sz_k:14, line_len:8, assoc:4, alias:1, vipt:1, pad:4;
-};
-
-struct cpuinfo_arc_bpu {
-	unsigned int ver, full, num_cache, num_pred, ret_stk;
-};
-
-struct cpuinfo_arc_ccm {
-	unsigned int base_addr, sz;
-};
-
-struct cpuinfo_arc {
-	struct cpuinfo_arc_cache icache, dcache, slc;
-	struct cpuinfo_arc_mmu mmu;
-	struct cpuinfo_arc_bpu bpu;
-	struct bcr_identity core;
-	struct bcr_isa_arcv2 isa;
-	const char *release, *name;
-	unsigned int vec_base;
-	struct cpuinfo_arc_ccm iccm, dccm;
-	struct {
-		unsigned int swap:1, norm:1, minmax:1, barrel:1, crc:1, swape:1, pad1:2,
-			     fpu_sp:1, fpu_dp:1, dual:1, dual_enb:1, pad2:4,
-			     ap_num:4, ap_full:1, smart:1, rtt:1, pad3:1,
-			     timer0:1, timer1:1, rtc:1, gfrc:1, pad4:4;
-	} extn;
-	struct bcr_mpy extn_mpy;
-};
-
-extern struct cpuinfo_arc cpuinfo_arc700[];
-
 static inline int is_isa_arcv2(void)
 {
 	return IS_ENABLED(CONFIG_ISA_ARCV2);

arch/arc/include/asm/atomic-llsc.h

@@ -18,7 +18,7 @@ static inline void arch_atomic_##op(int i, atomic_t *v)			\
 	: [val]	"=&r"	(val) /* Early clobber to prevent reg reuse */	\
 	: [ctr]	"r"	(&v->counter), /* Not "m": llock only supports reg direct addr mode */	\
 	  [i]	"ir"	(i)						\
-	: "cc");							\
+	: "cc", "memory");						\
 }									\
 
 #define ATOMIC_OP_RETURN(op, asm_op)				\
@@ -34,7 +34,7 @@ static inline int arch_atomic_##op##_return_relaxed(int i, atomic_t *v)	\
 	: [val]	"=&r"	(val)						\
 	: [ctr]	"r"	(&v->counter),					\
 	  [i]	"ir"	(i)						\
-	: "cc");							\
+	: "cc", "memory");						\
 									\
 	return val;							\
 }
@@ -56,7 +56,7 @@ static inline int arch_atomic_fetch_##op##_relaxed(int i, atomic_t *v)	\
 	  [orig] "=&r" (orig)						\
 	: [ctr]	"r"	(&v->counter),					\
 	  [i]	"ir"	(i)						\
-	: "cc");							\
+	: "cc", "memory");						\
 									\
 	return orig;							\
 }

arch/arc/include/asm/atomic64-arcv2.h

@@ -60,7 +60,7 @@ static inline void arch_atomic64_##op(s64 a, atomic64_t *v)		\
 	"	bnz     1b		\n"				\
 	: "=&r"(val)							\
 	: "r"(&v->counter), "ir"(a)					\
-	: "cc");							\
+	: "cc", "memory");						\
 }									\
 
 #define ATOMIC64_OP_RETURN(op, op1, op2)		        	\
@@ -77,7 +77,7 @@ static inline s64 arch_atomic64_##op##_return_relaxed(s64 a, atomic64_t *v)	\
 	"	bnz     1b		\n"				\
 	: [val] "=&r"(val)						\
 	: "r"(&v->counter), "ir"(a)					\
-	: "cc");	/* memory clobber comes from smp_mb() */	\
+	: "cc", "memory");						\
 									\
 	return val;							\
 }
@@ -99,7 +99,7 @@ static inline s64 arch_atomic64_fetch_##op##_relaxed(s64 a, atomic64_t *v)	\
 	"	bnz     1b		\n"				\
 	: "=&r"(orig), "=&r"(val)					\
 	: "r"(&v->counter), "ir"(a)					\
-	: "cc");	/* memory clobber comes from smp_mb() */	\
+	: "cc", "memory");						\
 									\
 	return orig;							\
 }

arch/arc/include/asm/current.h

@@ -13,7 +13,7 @@
 
 #ifdef CONFIG_ARC_CURR_IN_REG
 
-register struct task_struct *curr_arc asm("r25");
+register struct task_struct *curr_arc asm("gp");
 #define current (curr_arc)
 
 #else

arch/arc/include/asm/dwarf.h

@@ -10,23 +10,31 @@
 
 #ifdef ARC_DW2_UNWIND_AS_CFI
 
-#define CFI_STARTPROC	.cfi_startproc
-#define CFI_ENDPROC	.cfi_endproc
-#define CFI_DEF_CFA	.cfi_def_cfa
-#define CFI_REGISTER	.cfi_register
-#define CFI_REL_OFFSET	.cfi_rel_offset
-#define CFI_UNDEFINED	.cfi_undefined
+#define CFI_STARTPROC		.cfi_startproc
+#define CFI_ENDPROC		.cfi_endproc
+#define CFI_DEF_CFA		.cfi_def_cfa
+#define CFI_DEF_CFA_OFFSET	.cfi_def_cfa_offset
+#define CFI_DEF_CFA_REGISTER	.cfi_def_cfa_register
+#define CFI_OFFSET		.cfi_offset
+#define CFI_REL_OFFSET		.cfi_rel_offset
+#define CFI_REGISTER		.cfi_register
+#define CFI_RESTORE		.cfi_restore
+#define CFI_UNDEFINED		.cfi_undefined
 
 #else
 
 #define CFI_IGNORE	#
 
-#define CFI_STARTPROC	CFI_IGNORE
-#define CFI_ENDPROC	CFI_IGNORE
-#define CFI_DEF_CFA	CFI_IGNORE
-#define CFI_REGISTER	CFI_IGNORE
-#define CFI_REL_OFFSET	CFI_IGNORE
-#define CFI_UNDEFINED	CFI_IGNORE
+#define CFI_STARTPROC		CFI_IGNORE
+#define CFI_ENDPROC		CFI_IGNORE
+#define CFI_DEF_CFA		CFI_IGNORE
+#define CFI_DEF_CFA_OFFSET	CFI_IGNORE
+#define CFI_DEF_CFA_REGISTER	CFI_IGNORE
+#define CFI_OFFSET		CFI_IGNORE
+#define CFI_REL_OFFSET		CFI_IGNORE
+#define CFI_REGISTER		CFI_IGNORE
+#define CFI_RESTORE		CFI_IGNORE
+#define CFI_UNDEFINED		CFI_IGNORE
 
 #endif	/* !ARC_DW2_UNWIND_AS_CFI */
 

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

@@ -18,7 +18,6 @@
  *              |      orig_r0      |
  *              |      event/ECR    |
  *              |      bta          |
- *              |      user_r25     |
  *              |      gp           |
  *              |      fp           |
  *              |      sp           |
@@ -49,14 +48,18 @@
 /*------------------------------------------------------------------------*/
 .macro INTERRUPT_PROLOGUE
 
-	; (A) Before jumping to Interrupt Vector, hardware micro-ops did following:
+	; Before jumping to Interrupt Vector, hardware micro-ops did following:
 	;   1. SP auto-switched to kernel mode stack
 	;   2. STATUS32.Z flag set if in U mode at time of interrupt (U:1,K:0)
 	;   3. Auto save: (mandatory) Push PC and STAT32 on stack
 	;                 hardware does even if CONFIG_ARC_IRQ_NO_AUTOSAVE
-	;   4. Auto save: (optional) r0-r11, blink, LPE,LPS,LPC, JLI,LDI,EI
+	;  4a. Auto save: (optional) r0-r11, blink, LPE,LPS,LPC, JLI,LDI,EI
 	;
-	; (B) Manually saved some regs: r12,r25,r30, sp,fp,gp, ACCL pair
+	; Now
+	;  4b. If Auto-save (optional) not enabled in hw, manually save them
+	;   5. Manually save: r12,r30, sp,fp,gp, ACCL pair
+	;
+	; At the end, SP points to pt_regs
 
 #ifdef CONFIG_ARC_IRQ_NO_AUTOSAVE
 	; carve pt_regs on stack (case #3), PC/STAT32 already on stack
@@ -72,15 +75,16 @@
 .endm
 
 /*------------------------------------------------------------------------*/
-.macro EXCEPTION_PROLOGUE
+.macro EXCEPTION_PROLOGUE_KEEP_AE
 
-	; (A) Before jumping to Exception Vector, hardware micro-ops did following:
+	; Before jumping to Exception Vector, hardware micro-ops did following:
 	;   1. SP auto-switched to kernel mode stack
 	;   2. STATUS32.Z flag set if in U mode at time of exception (U:1,K:0)
 	;
-	; (B) Manually save the complete reg file below
+	; Now manually save rest of reg file
+	; At the end, SP points to pt_regs
 
-	sub	sp, sp, SZ_PT_REGS	; carve pt_regs
+	sub	sp, sp, SZ_PT_REGS	; carve space for pt_regs
 
 	; _HARD saves r10 clobbered by _SOFT as scratch hence comes first
 
@@ -100,6 +104,16 @@
 	; OUTPUT: r10 has ECR expected by EV_Trap
 .endm
 
+.macro EXCEPTION_PROLOGUE
+
+	EXCEPTION_PROLOGUE_KEEP_AE	; return ECR in r10
+
+	lr  r0, [efa]
+	mov r1, sp
+
+	FAKE_RET_FROM_EXCPN		; clobbers r9
+.endm
+
 /*------------------------------------------------------------------------
  * This macro saves the registers manually which would normally be autosaved
  * by hardware on taken interrupts. It is used by
@@ -135,10 +149,10 @@
  */
 .macro __SAVE_REGFILE_SOFT
 
-	ST2	gp, fp, PT_r26		; gp (r26), fp (r27)
-
-	st	r12, [sp, PT_sp + 4]
-	st	r30, [sp, PT_sp + 8]
+	st	fp,  [sp, PT_fp]	; r27
+	st	r30, [sp, PT_r30]
+	st	r12, [sp, PT_r12]
+	st	r26, [sp, PT_r26]	; gp
 
 	; Saving pt_regs->sp correctly requires some extra work due to the way
 	; Auto stack switch works
@@ -153,30 +167,30 @@
 
 	; ISA requires ADD.nz to have same dest and src reg operands
 	mov.nz	r10, sp
-	add.nz	r10, r10, SZ_PT_REGS	; K mode SP
+	add2.nz	r10, r10, SZ_PT_REGS/4	; K mode SP
 
 	st	r10, [sp, PT_sp]	; SP (pt_regs->sp)
 
-#ifdef CONFIG_ARC_CURR_IN_REG
-	st	r25, [sp, PT_user_r25]
-	GET_CURR_TASK_ON_CPU	r25
-#endif
-
 #ifdef CONFIG_ARC_HAS_ACCL_REGS
 	ST2	r58, r59, PT_r58
 #endif
 
 	/* clobbers r10, r11 registers pair */
 	DSP_SAVE_REGFILE_IRQ
+
+#ifdef CONFIG_ARC_CURR_IN_REG
+	GET_CURR_TASK_ON_CPU	gp
+#endif
+
 .endm
 
 /*------------------------------------------------------------------------*/
 .macro __RESTORE_REGFILE_SOFT
 
-	LD2	gp, fp, PT_r26		; gp (r26), fp (r27)
-
-	ld	r12, [sp, PT_r12]
+	ld	fp,  [sp, PT_fp]
 	ld	r30, [sp, PT_r30]
+	ld	r12, [sp, PT_r12]
+	ld	r26, [sp, PT_r26]
 
 	; Restore SP (into AUX_USER_SP) only if returning to U mode
 	;  - for K mode, it will be implicitly restored as stack is unwound
@@ -188,10 +202,6 @@
 	sr	r10, [AUX_USER_SP]
 1:
 
-#ifdef CONFIG_ARC_CURR_IN_REG
-	ld	r25, [sp, PT_user_r25]
-#endif
-
 	/* clobbers r10, r11 registers pair */
 	DSP_RESTORE_REGFILE_IRQ
 
@@ -249,7 +259,7 @@
 
 	btst	r0, STATUS_U_BIT	; Z flag set if K, used in restoring SP
 
-	ld	r10, [sp, PT_event + 4]
+	ld	r10, [sp, PT_bta]
 	sr	r10, [erbta]
 
 	LD2	r10, r11, PT_ret
@@ -264,8 +274,8 @@
 
 .macro FAKE_RET_FROM_EXCPN
 	lr      r9, [status32]
-	bic     r9, r9, STATUS_AE_MASK
-	or      r9, r9, STATUS_IE_MASK
+	bclr    r9, r9, STATUS_AE_BIT
+	bset    r9, r9, STATUS_IE_BIT
 	kflag   r9
 .endm
 

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

@@ -140,7 +140,7 @@
  *
  * After this it is safe to call the "C" handlers
  *-------------------------------------------------------------*/
-.macro EXCEPTION_PROLOGUE
+.macro EXCEPTION_PROLOGUE_KEEP_AE
 
 	/* Need at least 1 reg to code the early exception prologue */
 	PROLOG_FREEUP_REG r9, @ex_saved_reg1
@@ -151,14 +151,6 @@
 	/* ARC700 doesn't provide auto-stack switching */
 	SWITCH_TO_KERNEL_STK
 
-#ifdef CONFIG_ARC_CURR_IN_REG
-	/* Treat r25 as scratch reg (save on stack) and load with "current" */
-	PUSH    r25
-	GET_CURR_TASK_ON_CPU   r25
-#else
-	sub     sp, sp, 4
-#endif
-
 	st.a	r0, [sp, -8]    /* orig_r0 needed for syscall (skip ECR slot) */
 	sub	sp, sp, 4	/* skip pt_regs->sp, already saved above */
 
@@ -178,7 +170,23 @@
 	PUSHAX	erbta
 
 	lr	r10, [ecr]
-	st      r10, [sp, PT_event]    /* EV_Trap expects r10 to have ECR */
+	st      r10, [sp, PT_event]
+
+#ifdef CONFIG_ARC_CURR_IN_REG
+	/* gp already saved on stack: now load with "current" */
+	GET_CURR_TASK_ON_CPU   gp
+#endif
+	; OUTPUT: r10 has ECR expected by EV_Trap
+.endm
+
+.macro EXCEPTION_PROLOGUE
+
+	EXCEPTION_PROLOGUE_KEEP_AE	; return ECR in r10
+
+	lr  r0, [efa]
+	mov r1, sp
+
+	FAKE_RET_FROM_EXCPN		; clobbers r9
 .endm
 
 /*--------------------------------------------------------------
@@ -208,11 +216,8 @@
 	POP	gp
 	RESTORE_R12_TO_R0
 
-#ifdef CONFIG_ARC_CURR_IN_REG
-	ld	r25, [sp, 12]
-#endif
 	ld  sp, [sp] /* restore original sp */
-	/* orig_r0, ECR, user_r25 skipped automatically */
+	/* orig_r0, ECR skipped automatically */
 .endm
 
 /* Dummy ECR values for Interrupts */
@@ -229,13 +234,6 @@
 
 	SWITCH_TO_KERNEL_STK
 
-#ifdef CONFIG_ARC_CURR_IN_REG
-	/* Treat r25 as scratch reg (save on stack) and load with "current" */
-	PUSH    r25
-	GET_CURR_TASK_ON_CPU   r25
-#else
-	sub     sp, sp, 4
-#endif
 
 	PUSH	0x003\LVL\()abcd    /* Dummy ECR */
 	sub	sp, sp, 8	    /* skip orig_r0 (not needed)
@@ -255,6 +253,10 @@
 	PUSHAX	lp_start
 	PUSHAX	bta_l\LVL\()
 
+#ifdef CONFIG_ARC_CURR_IN_REG
+	/* gp already saved on stack: now load with "current" */
+	GET_CURR_TASK_ON_CPU   gp
+#endif
 .endm
 
 /*--------------------------------------------------------------
@@ -282,11 +284,7 @@
 	POP	gp
 	RESTORE_R12_TO_R0
 
-#ifdef CONFIG_ARC_CURR_IN_REG
-	ld	r25, [sp, 12]
-#endif
-	ld  sp, [sp] /* restore original sp */
-	/* orig_r0, ECR, user_r25 skipped automatically */
+	ld  sp, [sp] /* restore original sp; orig_r0, ECR skipped implicitly */
 .endm
 
 /* Get thread_info of "current" tsk */

arch/arc/include/asm/entry.h

@@ -13,6 +13,8 @@
 #include <asm/processor.h>	/* For VMALLOC_START */
 #include <asm/mmu.h>
 
+#ifdef __ASSEMBLY__
+
 #ifdef CONFIG_ISA_ARCOMPACT
 #include <asm/entry-compact.h>	/* ISA specific bits */
 #else
@@ -89,7 +91,7 @@
  * Helpers to save/restore callee-saved regs:
  * used by several macros below
  *-------------------------------------------------------------*/
-.macro SAVE_R13_TO_R24
+.macro SAVE_R13_TO_R25
 	PUSH	r13
 	PUSH	r14
 	PUSH	r15
@@ -102,9 +104,11 @@
 	PUSH	r22
 	PUSH	r23
 	PUSH	r24
+	PUSH	r25
 .endm
 
-.macro RESTORE_R24_TO_R13
+.macro RESTORE_R25_TO_R13
+	POP	r25
 	POP	r24
 	POP	r23
 	POP	r22
@@ -119,81 +123,31 @@
 	POP	r13
 .endm
 
-/*--------------------------------------------------------------
- * Collect User Mode callee regs as struct callee_regs - needed by
- * fork/do_signal/unaligned-access-emulation.
- * (By default only scratch regs are saved on entry to kernel)
- *
- * Special handling for r25 if used for caching Task Pointer.
- * It would have been saved in task->thread.user_r25 already, but to keep
- * the interface same it is copied into regular r25 placeholder in
- * struct callee_regs.
- *-------------------------------------------------------------*/
+/*
+ * save user mode callee regs as struct callee_regs
+ *  - needed by fork/do_signal/unaligned-access-emulation.
+ */
 .macro SAVE_CALLEE_SAVED_USER
-
-	mov	r12, sp		; save SP as ref to pt_regs
-	SAVE_R13_TO_R24
-
-#ifdef CONFIG_ARC_CURR_IN_REG
-	; Retrieve orig r25 and save it with rest of callee_regs
-	ld	r12, [r12, PT_user_r25]
-	PUSH	r12
-#else
-	PUSH	r25
-#endif
-
+	SAVE_R13_TO_R25
 .endm
 
-/*--------------------------------------------------------------
- * Save kernel Mode callee regs at the time of Contect Switch.
- *
- * Special handling for r25 if used for caching Task Pointer.
- * Kernel simply skips saving it since it will be loaded with
- * incoming task pointer anyways
- *-------------------------------------------------------------*/
-.macro SAVE_CALLEE_SAVED_KERNEL
-
-	SAVE_R13_TO_R24
-
-#ifdef CONFIG_ARC_CURR_IN_REG
-	sub     sp, sp, 4
-#else
-	PUSH	r25
-#endif
-.endm
-
-/*--------------------------------------------------------------
- * Opposite of SAVE_CALLEE_SAVED_KERNEL
- *-------------------------------------------------------------*/
-.macro RESTORE_CALLEE_SAVED_KERNEL
-
-#ifdef CONFIG_ARC_CURR_IN_REG
-	add     sp, sp, 4  /* skip usual r25 placeholder */
-#else
-	POP	r25
-#endif
-	RESTORE_R24_TO_R13
-.endm
-
-/*--------------------------------------------------------------
- * Opposite of SAVE_CALLEE_SAVED_USER
- *
- * ptrace tracer or unaligned-access fixup might have changed a user mode
- * callee reg which is saved back to usual r25 storage location
- *-------------------------------------------------------------*/
+/*
+ * restore user mode callee regs as struct callee_regs
+ *  - could have been changed by ptrace tracer or unaligned-access fixup
+ */
 .macro RESTORE_CALLEE_SAVED_USER
+	RESTORE_R25_TO_R13
+.endm
 
-#ifdef CONFIG_ARC_CURR_IN_REG
-	POP	r12
-#else
-	POP	r25
-#endif
-	RESTORE_R24_TO_R13
+/*
+ * save/restore kernel mode callee regs at the time of context switch
+ */
+.macro SAVE_CALLEE_SAVED_KERNEL
+	SAVE_R13_TO_R25
+.endm
 
-	; SP is back to start of pt_regs
-#ifdef CONFIG_ARC_CURR_IN_REG
-	st	r12, [sp, PT_user_r25]
-#endif
+.macro RESTORE_CALLEE_SAVED_KERNEL
+	RESTORE_R25_TO_R13
 .endm
 
 /*--------------------------------------------------------------
@@ -229,10 +183,10 @@
 
 #ifdef CONFIG_SMP
 
-/*-------------------------------------------------
+/*
  * Retrieve the current running task on this CPU
- * 1. Determine curr CPU id.
- * 2. Use it to index into _current_task[ ]
+ *  - loads it from backing _current_task[] (and can't use the
+ *    caching reg for current task
  */
 .macro  GET_CURR_TASK_ON_CPU   reg
 	GET_CPU_ID  \reg
@@ -254,7 +208,7 @@
 	add2 \tmp, @_current_task, \tmp
 	st   \tsk, [\tmp]
 #ifdef CONFIG_ARC_CURR_IN_REG
-	mov r25, \tsk
+	mov gp, \tsk
 #endif
 
 .endm
@@ -269,21 +223,20 @@
 .macro  SET_CURR_TASK_ON_CPU    tsk, tmp
 	st  \tsk, [@_current_task]
 #ifdef CONFIG_ARC_CURR_IN_REG
-	mov r25, \tsk
+	mov gp, \tsk
 #endif
 .endm
 
 #endif /* SMP / UNI */
 
-/* ------------------------------------------------------------------
+/*
  * Get the ptr to some field of Current Task at @off in task struct
- *  -Uses r25 for Current task ptr if that is enabled
+ *  - Uses current task cached in reg if enabled
  */
-
 #ifdef CONFIG_ARC_CURR_IN_REG
 
 .macro GET_CURR_TASK_FIELD_PTR  off,  reg
-	add \reg, r25, \off
+	add \reg, gp, \off
 .endm
 
 #else
@@ -295,4 +248,23 @@
 
 #endif	/* CONFIG_ARC_CURR_IN_REG */
 
+#else	/* !__ASSEMBLY__ */
+
+extern void do_signal(struct pt_regs *);
+extern void do_notify_resume(struct pt_regs *);
+extern int do_privilege_fault(unsigned long, struct pt_regs *);
+extern int do_extension_fault(unsigned long, struct pt_regs *);
+extern int insterror_is_error(unsigned long, struct pt_regs *);
+extern int do_memory_error(unsigned long, struct pt_regs *);
+extern int trap_is_brkpt(unsigned long, struct pt_regs *);
+extern int do_misaligned_error(unsigned long, struct pt_regs *);
+extern int do_trap5_error(unsigned long, struct pt_regs *);
+extern int do_misaligned_access(unsigned long, struct pt_regs *, struct callee_regs *);
+extern void do_machine_check_fault(unsigned long, struct pt_regs *);
+extern void do_non_swi_trap(unsigned long, struct pt_regs *);
+extern void do_insterror_or_kprobe(unsigned long, struct pt_regs *);
+extern void do_page_fault(unsigned long, struct pt_regs *);
+
+#endif
+
 #endif  /* __ASM_ARC_ENTRY_H */

arch/arc/include/asm/irq.h

@@ -25,5 +25,6 @@
 #include <asm-generic/irq.h>
 
 extern void arc_init_IRQ(void);
+extern void arch_do_IRQ(unsigned int, struct pt_regs *);
 
 #endif

arch/arc/include/asm/mmu.h

@@ -14,6 +14,8 @@ typedef struct {
 	unsigned long asid[NR_CPUS];	/* 8 bit MMU PID + Generation cycle */
 } mm_context_t;
 
+extern void do_tlb_overlap_fault(unsigned long, unsigned long, struct pt_regs *);
+
 #endif
 
 #include <asm/mmu-arcv2.h>

arch/arc/include/asm/processor.h

@@ -22,7 +22,6 @@
  * struct thread_info
  */
 struct thread_struct {
-	unsigned long ksp;	/* kernel mode stack pointer */
 	unsigned long callee_reg;	/* pointer to callee regs */
 	unsigned long fault_address;	/* dbls as brkpt holder as well */
 #ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
@@ -33,9 +32,7 @@ struct thread_struct {
 #endif
 };
 
-#define INIT_THREAD  {                          \
-	.ksp = sizeof(init_stack) + (unsigned long) init_stack, \
-}
+#define INIT_THREAD  { }
 
 /* Forward declaration, a strange C thing */
 struct task_struct;
@@ -56,7 +53,7 @@ struct task_struct;
  * Where about of Task's sp, fp, blink when it was last seen in kernel mode.
  * Look in process.c for details of kernel stack layout
  */
-#define TSK_K_ESP(tsk)		(tsk->thread.ksp)
+#define TSK_K_ESP(tsk)		(task_thread_info(tsk)->ksp)
 
 #define TSK_K_REG(tsk, off)	(*((unsigned long *)(TSK_K_ESP(tsk) + \
 					sizeof(struct callee_regs) + off)))

arch/arc/include/asm/ptrace.h

@@ -12,6 +12,17 @@
 
 #ifndef __ASSEMBLY__
 
+typedef union {
+	struct {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+		unsigned long state:8, vec:8, cause:8, param:8;
+#else
+		unsigned long param:8, cause:8, vec:8, state:8;
+#endif
+	};
+	unsigned long full;
+} ecr_reg;
+
 /* THE pt_regs: Defines how regs are saved during entry into kernel */
 
 #ifdef CONFIG_ISA_ARCOMPACT
@@ -40,23 +51,10 @@ struct pt_regs {
 	 * 	Last word used by Linux for extra state mgmt (syscall-restart)
 	 * For interrupts, use artificial ECR values to note current prio-level
 	 */
-	union {
-		struct {
-#ifdef CONFIG_CPU_BIG_ENDIAN
-			unsigned long state:8, ecr_vec:8,
-				      ecr_cause:8, ecr_param:8;
-#else
-			unsigned long ecr_param:8, ecr_cause:8,
-				      ecr_vec:8, state:8;
-#endif
-		};
-		unsigned long event;
-	};
-
-	unsigned long user_r25;
+	ecr_reg ecr;
 };
 
-#define MAX_REG_OFFSET offsetof(struct pt_regs, user_r25)
+#define MAX_REG_OFFSET offsetof(struct pt_regs, ecr)
 
 #else
 
@@ -64,28 +62,14 @@ struct pt_regs {
 
 	unsigned long orig_r0;
 
-	union {
-		struct {
-#ifdef CONFIG_CPU_BIG_ENDIAN
-			unsigned long state:8, ecr_vec:8,
-				      ecr_cause:8, ecr_param:8;
-#else
-			unsigned long ecr_param:8, ecr_cause:8,
-				      ecr_vec:8, state:8;
-#endif
-		};
-		unsigned long event;
-	};
+	ecr_reg ecr;		/* Exception Cause Reg */
 
-	unsigned long bta;	/* bta_l1, bta_l2, erbta */
+	unsigned long bta;	/* erbta */
 
-	unsigned long user_r25;
-
-	unsigned long r26;	/* gp */
 	unsigned long fp;
-	unsigned long sp;	/* user/kernel sp depending on where we came from  */
-
-	unsigned long r12, r30;
+	unsigned long r30;
+	unsigned long r12;
+	unsigned long r26;	/* gp */
 
 #ifdef CONFIG_ARC_HAS_ACCL_REGS
 	unsigned long r58, r59;	/* ACCL/ACCH used by FPU / DSP MPY */
@@ -94,6 +78,8 @@ struct pt_regs {
 	unsigned long DSP_CTRL;
 #endif
 
+	unsigned long sp;	/* user/kernel sp depending on entry  */
+
 	/*------- Below list auto saved by h/w -----------*/
 	unsigned long r0, r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11;
 
@@ -134,13 +120,13 @@ struct callee_regs {
 /* return 1 if PC in delay slot */
 #define delay_mode(regs) ((regs->status32 & STATUS_DE_MASK) == STATUS_DE_MASK)
 
-#define in_syscall(regs)    ((regs->ecr_vec == ECR_V_TRAP) && !regs->ecr_param)
-#define in_brkpt_trap(regs) ((regs->ecr_vec == ECR_V_TRAP) && regs->ecr_param)
+#define in_syscall(regs)    ((regs->ecr.vec == ECR_V_TRAP) && !regs->ecr.param)
+#define in_brkpt_trap(regs) ((regs->ecr.vec == ECR_V_TRAP) && regs->ecr.param)
 
 #define STATE_SCALL_RESTARTED	0x01
 
-#define syscall_wont_restart(reg) (reg->state |= STATE_SCALL_RESTARTED)
-#define syscall_restartable(reg) !(reg->state &  STATE_SCALL_RESTARTED)
+#define syscall_wont_restart(regs) (regs->ecr.state |= STATE_SCALL_RESTARTED)
+#define syscall_restartable(regs) !(regs->ecr.state &  STATE_SCALL_RESTARTED)
 
 #define current_pt_regs()					\
 ({								\
@@ -181,6 +167,9 @@ static inline unsigned long regs_get_register(struct pt_regs *regs,
 	return *(unsigned long *)((unsigned long)regs + offset);
 }
 
+extern int syscall_trace_entry(struct pt_regs *);
+extern void syscall_trace_exit(struct pt_regs *);
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ASM_PTRACE_H */

arch/arc/include/asm/setup.h

@@ -35,11 +35,11 @@ long __init arc_get_mem_sz(void);
 #define IS_AVAIL3(v, v2, s)	IS_AVAIL1(v, s), IS_AVAIL1(v, IS_DISABLED_RUN(v2))
 
 extern void arc_mmu_init(void);
-extern char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len);
-extern void read_decode_mmu_bcr(void);
+extern int arc_mmu_mumbojumbo(int cpu_id, char *buf, int len);
 
 extern void arc_cache_init(void);
-extern char *arc_cache_mumbojumbo(int cpu_id, char *buf, int len);
-extern void read_decode_cache_bcr(void);
+extern int arc_cache_mumbojumbo(int cpu_id, char *buf, int len);
+
+extern void __init handle_uboot_args(void);
 
 #endif /* __ASMARC_SETUP_H */

arch/arc/include/asm/smp.h

@@ -29,6 +29,8 @@ extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
 extern void __init smp_init_cpus(void);
 extern void first_lines_of_secondary(void);
 extern const char *arc_platform_smp_cpuinfo(void);
+extern void arc_platform_smp_wait_to_boot(int);
+extern void start_kernel_secondary(void);
 
 /*
  * API expected BY platform smp code (FROM arch smp code)

arch/arc/include/asm/thread_info.h

@@ -37,16 +37,16 @@
  */
 struct thread_info {
 	unsigned long flags;		/* low level flags */
+	unsigned long ksp;		/* kernel mode stack top in __switch_to */
 	int preempt_count;		/* 0 => preemptable, <0 => BUG */
-	struct task_struct *task;	/* main task structure */
-	__u32 cpu;			/* current CPU */
+	int cpu;			/* current CPU */
 	unsigned long thr_ptr;		/* TLS ptr */
+	struct task_struct *task;	/* main task structure */
 };
 
 /*
- * macros/functions for gaining access to the thread information structure
- *
- * preempt_count needs to be 1 initially, until the scheduler is functional.
+ * initilaize thread_info for any @tsk
+ *  - this is not related to init_task per se
  */
 #define INIT_THREAD_INFO(tsk)			\
 {						\

arch/arc/include/asm/uaccess.h

@@ -146,8 +146,9 @@ raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 	if (n == 0)
 		return 0;
 
-	/* unaligned */
-	if (((unsigned long)to & 0x3) || ((unsigned long)from & 0x3)) {
+	/* fallback for unaligned access when hardware doesn't support */
+	if (!IS_ENABLED(CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS) &&
+	     (((unsigned long)to & 0x3) || ((unsigned long)from & 0x3))) {
 
 		unsigned char tmp;
 
@@ -373,8 +374,9 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 	if (n == 0)
 		return 0;
 
-	/* unaligned */
-	if (((unsigned long)to & 0x3) || ((unsigned long)from & 0x3)) {
+	/* fallback for unaligned access when hardware doesn't support */
+	if (!IS_ENABLED(CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS) &&
+	     (((unsigned long)to & 0x3) || ((unsigned long)from & 0x3))) {
 
 		unsigned char tmp;
 
@@ -584,7 +586,7 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 	return res;
 }
 
-static inline unsigned long __arc_clear_user(void __user *to, unsigned long n)
+static inline unsigned long __clear_user(void __user *to, unsigned long n)
 {
 	long res = n;
 	unsigned char *d_char = to;
@@ -626,17 +628,10 @@ static inline unsigned long __arc_clear_user(void __user *to, unsigned long n)
 	return res;
 }
 
-#ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
-
 #define INLINE_COPY_TO_USER
 #define INLINE_COPY_FROM_USER
 
-#define __clear_user(d, n)		__arc_clear_user(d, n)
-#else
-extern unsigned long arc_clear_user_noinline(void __user *to,
-		unsigned long n);
-#define __clear_user(d, n)		arc_clear_user_noinline(d, n)
-#endif
+#define __clear_user			__clear_user
 
 #include <asm-generic/uaccess.h>
 

arch/arc/kernel/Makefile

@@ -5,6 +5,8 @@
 
 obj-y	:= head.o arcksyms.o setup.o irq.o reset.o ptrace.o process.o devtree.o
 obj-y	+= signal.o traps.o sys.o troubleshoot.o stacktrace.o disasm.o
+obj-y	+= ctx_sw_asm.o
+
 obj-$(CONFIG_ISA_ARCOMPACT)		+= entry-compact.o intc-compact.o
 obj-$(CONFIG_ISA_ARCV2)			+= entry-arcv2.o intc-arcv2.o
 
@@ -24,11 +26,4 @@ ifdef CONFIG_ISA_ARCOMPACT
 CFLAGS_fpu.o   += -mdpfp
 endif
 
-ifdef CONFIG_ARC_DW2_UNWIND
-CFLAGS_ctx_sw.o += -fno-omit-frame-pointer
-obj-y += ctx_sw.o
-else
-obj-y += ctx_sw_asm.o
-endif
-
 extra-y := vmlinux.lds

arch/arc/kernel/asm-offsets.c

@@ -20,13 +20,13 @@ int main(void)
 
 	BLANK();
 
-	DEFINE(THREAD_KSP, offsetof(struct thread_struct, ksp));
 	DEFINE(THREAD_CALLEE_REG, offsetof(struct thread_struct, callee_reg));
 	DEFINE(THREAD_FAULT_ADDR,
 	       offsetof(struct thread_struct, fault_address));
 
 	BLANK();
 
+	DEFINE(THREAD_INFO_KSP, offsetof(struct thread_info, ksp));
 	DEFINE(THREAD_INFO_FLAGS, offsetof(struct thread_info, flags));
 	DEFINE(THREAD_INFO_PREEMPT_COUNT,
 	       offsetof(struct thread_info, preempt_count));
@@ -46,7 +46,8 @@ int main(void)
 	BLANK();
 
 	DEFINE(PT_status32, offsetof(struct pt_regs, status32));
-	DEFINE(PT_event, offsetof(struct pt_regs, event));
+	DEFINE(PT_event, offsetof(struct pt_regs, ecr));
+	DEFINE(PT_bta, offsetof(struct pt_regs, bta));
 	DEFINE(PT_sp, offsetof(struct pt_regs, sp));
 	DEFINE(PT_r0, offsetof(struct pt_regs, r0));
 	DEFINE(PT_r1, offsetof(struct pt_regs, r1));
@@ -61,13 +62,9 @@ int main(void)
 	DEFINE(PT_r26, offsetof(struct pt_regs, r26));
 	DEFINE(PT_ret, offsetof(struct pt_regs, ret));
 	DEFINE(PT_blink, offsetof(struct pt_regs, blink));
+	OFFSET(PT_fp, pt_regs, fp);
 	DEFINE(PT_lpe, offsetof(struct pt_regs, lp_end));
 	DEFINE(PT_lpc, offsetof(struct pt_regs, lp_count));
-	DEFINE(PT_user_r25, offsetof(struct pt_regs, user_r25));
-
-	DEFINE(SZ_CALLEE_REGS, sizeof(struct callee_regs));
-	DEFINE(SZ_PT_REGS, sizeof(struct pt_regs));
-
 #ifdef CONFIG_ISA_ARCV2
 	OFFSET(PT_r12, pt_regs, r12);
 	OFFSET(PT_r30, pt_regs, r30);
@@ -80,5 +77,8 @@ int main(void)
 	OFFSET(PT_DSP_CTRL, pt_regs, DSP_CTRL);
 #endif
 
+	DEFINE(SZ_CALLEE_REGS, sizeof(struct callee_regs));
+	DEFINE(SZ_PT_REGS, sizeof(struct pt_regs));
+
 	return 0;
 }