Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 2206912..3fd3ef3 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  *  PowerPC version 
  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
@@ -11,11 +12,6 @@
  *
  *  This file contains the system call entry code, context switch
  *  code, and exception/interrupt return code for PowerPC.
- *
- *  This program is free software; you can redistribute it and/or
- *  modify it under the terms of the GNU General Public License
- *  as published by the Free Software Foundation; either version
- *  2 of the License, or (at your option) any later version.
  */
 
 #include <linux/errno.h>
@@ -46,6 +42,7 @@
 #include <asm/exception-64e.h>
 #endif
 #include <asm/feature-fixups.h>
+#include <asm/kup.h>
 
 /*
  * System calls.
@@ -54,6 +51,9 @@
 SYS_CALL_TABLE:
 	.tc sys_call_table[TC],sys_call_table
 
+COMPAT_SYS_CALL_TABLE:
+	.tc compat_sys_call_table[TC],compat_sys_call_table
+
 /* This value is used to mark exception frames on the stack. */
 exception_marker:
 	.tc	ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER
@@ -69,19 +69,20 @@
 	bne	.Ltabort_syscall
 END_FTR_SECTION_IFSET(CPU_FTR_TM)
 #endif
-	andi.	r10,r12,MSR_PR
 	mr	r10,r1
-	addi	r1,r1,-INT_FRAME_SIZE
-	beq-	1f
 	ld	r1,PACAKSAVE(r13)
-1:	std	r10,0(r1)
+	std	r10,0(r1)
 	std	r11,_NIP(r1)
 	std	r12,_MSR(r1)
 	std	r0,GPR0(r1)
 	std	r10,GPR1(r1)
-	beq	2f			/* if from kernel mode */
+#ifdef CONFIG_PPC_FSL_BOOK3E
+START_BTB_FLUSH_SECTION
+	BTB_FLUSH(r10)
+END_BTB_FLUSH_SECTION
+#endif
 	ACCOUNT_CPU_USER_ENTRY(r13, r10, r11)
-2:	std	r2,GPR2(r1)
+	std	r2,GPR2(r1)
 	std	r3,GPR3(r1)
 	mfcr	r2
 	std	r4,GPR4(r1)
@@ -112,16 +113,18 @@
 	addi	r9,r1,STACK_FRAME_OVERHEAD
 	ld	r11,exception_marker@toc(r2)
 	std	r11,-16(r9)		/* "regshere" marker */
+
+	kuap_check_amr r10, r11
+
 #if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC_SPLPAR)
 BEGIN_FW_FTR_SECTION
-	beq	33f
-	/* if from user, see if there are any DTL entries to process */
+	/* see if there are any DTL entries to process */
 	ld	r10,PACALPPACAPTR(r13)	/* get ptr to VPA */
 	ld	r11,PACA_DTL_RIDX(r13)	/* get log read index */
 	addi	r10,r10,LPPACA_DTLIDX
 	LDX_BE	r10,0,r10		/* get log write index */
-	cmpd	cr1,r11,r10
-	beq+	cr1,33f
+	cmpd	r11,r10
+	beq+	33f
 	bl	accumulate_stolen_time
 	REST_GPR(0,r1)
 	REST_4GPRS(3,r1)
@@ -158,7 +161,7 @@
 	li	r10,IRQS_ENABLED
 	std	r10,SOFTE(r1)
 
-	CURRENT_THREAD_INFO(r11, r1)
+	ld	r11, PACA_THREAD_INFO(r13)
 	ld	r10,TI_FLAGS(r11)
 	andi.	r11,r10,_TIF_SYSCALL_DOTRACE
 	bne	.Lsyscall_dotrace		/* does not return */
@@ -171,9 +174,9 @@
  * based on caller's run-mode / personality.
  */
 	ld	r11,SYS_CALL_TABLE@toc(2)
-	andi.	r10,r10,_TIF_32BIT
+	andis.	r10,r10,_TIF_32BIT@h
 	beq	15f
-	addi	r11,r11,8	/* use 32-bit syscall entries */
+	ld	r11,COMPAT_SYS_CALL_TABLE@toc(2)
 	clrldi	r3,r3,32
 	clrldi	r4,r4,32
 	clrldi	r5,r5,32
@@ -181,7 +184,7 @@
 	clrldi	r7,r7,32
 	clrldi	r8,r8,32
 15:
-	slwi	r0,r0,4
+	slwi	r0,r0,3
 
 	barrier_nospec_asm
 	/*
@@ -195,6 +198,7 @@
 	mtctr   r12
 	bctrl			/* Call handler */
 
+	/* syscall_exit can exit to kernel mode, via ret_from_kernel_thread */
 .Lsyscall_exit:
 	std	r3,RESULT(r1)
 
@@ -205,14 +209,9 @@
 	ld	r3,RESULT(r1)
 #endif
 
-	CURRENT_THREAD_INFO(r12, r1)
+	ld	r12, PACA_THREAD_INFO(r13)
 
 	ld	r8,_MSR(r1)
-#ifdef CONFIG_PPC_BOOK3S
-	/* No MSR:RI on BookE */
-	andi.	r10,r8,MSR_RI
-	beq-	.Lunrecov_restore
-#endif
 
 /*
  * This is a few instructions into the actual syscall exit path (which actually
@@ -228,18 +227,14 @@
 	/*
 	 * Disable interrupts so current_thread_info()->flags can't change,
 	 * and so that we don't get interrupted after loading SRR0/1.
+	 *
+	 * Leave MSR_RI enabled for now, because with THREAD_INFO_IN_TASK we
+	 * could fault on the load of the TI_FLAGS below.
 	 */
 #ifdef CONFIG_PPC_BOOK3E
 	wrteei	0
 #else
-	/*
-	 * For performance reasons we clear RI the same time that we
-	 * clear EE. We only need to clear RI just before we restore r13
-	 * below, but batching it with EE saves us one expensive mtmsrd call.
-	 * We have to be careful to restore RI if we branch anywhere from
-	 * here (eg syscall_exit_work).
-	 */
-	li	r11,0
+	li	r11,MSR_RI
 	mtmsrd	r11,1
 #endif /* CONFIG_PPC_BOOK3E */
 
@@ -255,15 +250,7 @@
 	bne	3f
 #endif
 2:	addi    r3,r1,STACK_FRAME_OVERHEAD
-#ifdef CONFIG_PPC_BOOK3S
-	li	r10,MSR_RI
-	mtmsrd	r10,1		/* Restore RI */
-#endif
 	bl	restore_math
-#ifdef CONFIG_PPC_BOOK3S
-	li	r11,0
-	mtmsrd	r11,1
-#endif
 	ld	r8,_MSR(r1)
 	ld	r3,RESULT(r1)
 	li	r11,-MAX_ERRNO
@@ -279,6 +266,18 @@
 	andi.	r6,r8,MSR_PR
 	ld	r4,_LINK(r1)
 
+	kuap_check_amr r10, r11
+
+#ifdef CONFIG_PPC_BOOK3S
+	/*
+	 * Clear MSR_RI, MSR_EE is already and remains disabled. We could do
+	 * this later, but testing shows that doing it here causes less slow
+	 * down than doing it closer to the rfid.
+	 */
+	li	r11,0
+	mtmsrd	r11,1
+#endif
+
 	beq-	1f
 	ACCOUNT_CPU_USER_EXIT(r13, r11, r12)
 
@@ -286,6 +285,14 @@
 	HMT_MEDIUM_LOW
 END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	std	r8, PACATMSCRATCH(r13)
+#endif
+
+	/*
+	 * We don't need to restore AMR on the way back to userspace for KUAP.
+	 * The value of AMR only matters while we're in the kernel.
+	 */
 	ld	r13,GPR13(r1)	/* only restore r13 if returning to usermode */
 	ld	r2,GPR2(r1)
 	ld	r1,GPR1(r1)
@@ -296,8 +303,10 @@
 	RFI_TO_USER
 	b	.	/* prevent speculative execution */
 
-	/* exit to kernel */
-1:	ld	r2,GPR2(r1)
+1:	/* exit to kernel */
+	kuap_restore_amr r2
+
+	ld	r2,GPR2(r1)
 	ld	r1,GPR1(r1)
 	mtlr	r4
 	mtcr	r5
@@ -336,7 +345,7 @@
 
 	/* Repopulate r9 and r10 for the syscall path */
 	addi	r9,r1,STACK_FRAME_OVERHEAD
-	CURRENT_THREAD_INFO(r10, r1)
+	ld	r10, PACA_THREAD_INFO(r13)
 	ld	r10,TI_FLAGS(r10)
 
 	cmpldi	r0,NR_syscalls
@@ -351,10 +360,6 @@
 	b	.Lsyscall_exit
 	
 .Lsyscall_exit_work:
-#ifdef CONFIG_PPC_BOOK3S
-	li	r10,MSR_RI
-	mtmsrd	r10,1		/* Restore RI */
-#endif
 	/* If TIF_RESTOREALL is set, don't scribble on either r3 or ccr.
 	 If TIF_NOERROR is set, just save r3 as it is. */
 
@@ -386,10 +391,9 @@
 
 4:	/* Anything else left to do? */
 BEGIN_FTR_SECTION
-	lis	r3,INIT_PPR@highest	/* Set thread.ppr = 3 */
-	ld	r10,PACACURRENT(r13)
+	lis	r3,DEFAULT_PPR@highest	/* Set default PPR */
 	sldi	r3,r3,32	/* bits 11-13 are used for ppr */
-	std	r3,TASKTHREADPPR(r10)
+	std	r3,_PPR(r1)
 END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 
 	andi.	r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP)
@@ -474,6 +478,11 @@
 	bl	sys_clone
 	b	.Lsyscall_exit
 
+_GLOBAL(ppc_clone3)
+       bl      save_nvgprs
+       bl      sys_clone3
+       b       .Lsyscall_exit
+
 _GLOBAL(ppc32_swapcontext)
 	bl	save_nvgprs
 	bl	compat_sys_swapcontext
@@ -528,6 +537,7 @@
 	/* Save LR into r9 */
 	mflr	r9
 
+	// Flush the link stack
 	.rept 64
 	bl	.+4
 	.endr
@@ -537,6 +547,11 @@
 	.balign 32
 	/* Restore LR */
 1:	mtlr	r9
+
+	// If we're just flushing the link stack, return here
+3:	nop
+	patch_site 3b patch__flush_link_stack_return
+
 	li	r9,0x7fff
 	mtctr	r9
 
@@ -589,6 +604,8 @@
 	std	r23,_CCR(r1)
 	std	r1,KSP(r3)	/* Set old stack pointer */
 
+	kuap_check_amr r9, r10
+
 	FLUSH_COUNT_CACHE
 
 	/*
@@ -624,6 +641,10 @@
 
 	addi	r6,r4,-THREAD	/* Convert THREAD to 'current' */
 	std	r6,PACACURRENT(r13)	/* Set new 'current' */
+#if defined(CONFIG_STACKPROTECTOR)
+	ld	r6, TASK_CANARY(r6)
+	std	r6, PACA_CANARY(r13)
+#endif
 
 	ld	r8,KSP(r4)	/* new stack pointer */
 #ifdef CONFIG_PPC_BOOK3S_64
@@ -672,13 +693,15 @@
 
 	isync
 	slbie	r6
+BEGIN_FTR_SECTION
 	slbie	r6		/* Workaround POWER5 < DD2.1 issue */
+END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
 	slbmte	r7,r0
 	isync
 2:
 #endif /* CONFIG_PPC_BOOK3S_64 */
 
-	CURRENT_THREAD_INFO(r7, r8)  /* base of new stack */
+	clrrdi	r7, r8, THREAD_SHIFT	/* base of new stack */
 	/* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE
 	   because we don't need to leave the 288-byte ABI gap at the
 	   top of the kernel stack. */
@@ -729,7 +752,7 @@
 	mtmsrd	r10,1		  /* Update machine state */
 #endif /* CONFIG_PPC_BOOK3E */
 
-	CURRENT_THREAD_INFO(r9, r1)
+	ld	r9, PACA_THREAD_INFO(r13)
 	ld	r3,_MSR(r1)
 #ifdef CONFIG_PPC_BOOK3E
 	ld	r10,PACACURRENT(r13)
@@ -840,13 +863,7 @@
 	 * sure we are soft-disabled first and reconcile irq state.
 	 */
 	RECONCILE_IRQ_STATE(r3,r4)
-1:	bl	preempt_schedule_irq
-
-	/* Re-test flags and eventually loop */
-	CURRENT_THREAD_INFO(r9, r1)
-	ld	r4,TI_FLAGS(r9)
-	andi.	r0,r4,_TIF_NEED_RESCHED
-	bne	1b
+	bl	preempt_schedule_irq
 
 	/*
 	 * arch_local_irq_restore() from preempt_schedule_irq above may
@@ -931,17 +948,13 @@
 	ld	r4,_XER(r1)
 	mtspr	SPRN_XER,r4
 
+	kuap_check_amr r5, r6
+
 	REST_8GPRS(5, r1)
 
 	andi.	r0,r3,MSR_RI
 	beq-	.Lunrecov_restore
 
-	/* Load PPR from thread struct before we clear MSR:RI */
-BEGIN_FTR_SECTION
-	ld	r2,PACACURRENT(r13)
-	ld	r2,TASKTHREADPPR(r2)
-END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
-
 	/*
 	 * Clear RI before restoring r13.  If we are returning to
 	 * userspace and we take an exception after restoring r13,
@@ -962,11 +975,17 @@
 	andi.	r0,r3,MSR_PR
 	beq	1f
 BEGIN_FTR_SECTION
-	mtspr	SPRN_PPR,r2	/* Restore PPR */
+	/* Restore PPR */
+	ld	r2,_PPR(r1)
+	mtspr	SPRN_PPR,r2
 END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	ACCOUNT_CPU_USER_EXIT(r13, r2, r4)
 	REST_GPR(13, r1)
 
+	/*
+	 * We don't need to restore AMR on the way back to userspace for KUAP.
+	 * The value of AMR only matters while we're in the kernel.
+	 */
 	mtspr	SPRN_SRR1,r3
 
 	ld	r2,_CCR(r1)
@@ -989,9 +1008,19 @@
 	ld	r2,_NIP(r1)
 	mtspr	SPRN_SRR0,r2
 
+	/*
+	 * Leaving a stale exception_marker on the stack can confuse
+	 * the reliable stack unwinder later on. Clear it.
+	 */
+	li	r2,0
+	std	r2,STACK_FRAME_OVERHEAD-16(r1)
+
 	ld	r0,GPR0(r1)
 	ld	r2,GPR2(r1)
 	ld	r3,GPR3(r1)
+
+	kuap_restore_amr r4
+
 	ld	r4,GPR4(r1)
 	ld	r1,GPR1(r1)
 	RFI_TO_KERNEL
@@ -1118,7 +1147,7 @@
 _GLOBAL(enter_rtas)
 	mflr	r0
 	std	r0,16(r1)
-        stdu	r1,-RTAS_FRAME_SIZE(r1)	/* Save SP and create stack space. */
+        stdu	r1,-SWITCH_FRAME_SIZE(r1) /* Save SP and create stack space. */
 
 	/* Because RTAS is running in 32b mode, it clobbers the high order half
 	 * of all registers that it saves.  We therefore save those registers
@@ -1250,7 +1279,7 @@
 	ld	r8,_DSISR(r1)
 	mtdsisr	r8
 
-        addi	r1,r1,RTAS_FRAME_SIZE	/* Unstack our frame */
+        addi	r1,r1,SWITCH_FRAME_SIZE	/* Unstack our frame */
 	ld	r0,16(r1)		/* get return address */
 
 	mtlr    r0
@@ -1261,7 +1290,7 @@
 _GLOBAL(enter_prom)
 	mflr	r0
 	std	r0,16(r1)
-        stdu	r1,-PROM_FRAME_SIZE(r1)	/* Save SP and create stack space */
+        stdu	r1,-SWITCH_FRAME_SIZE(r1) /* Save SP and create stack space */
 
 	/* Because PROM is running in 32b mode, it clobbers the high order half
 	 * of all registers that it saves.  We therefore save those registers
@@ -1318,8 +1347,8 @@
 	REST_10GPRS(22, r1)
 	ld	r4,_CCR(r1)
 	mtcr	r4
-	
-        addi	r1,r1,PROM_FRAME_SIZE
+
+        addi	r1,r1,SWITCH_FRAME_SIZE
 	ld	r0,16(r1)
 	mtlr    r0
         blr