Merge branch 'next' into for-linus

Prepare input updates for 5.11 merge window.

1 files changed, 109 insertions, 87 deletions

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index ddcde093c433..55af8b504b65 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -15,6 +15,7 @@
 #include <asm/assembler.h>
 #include <asm/asm-offsets.h>
 #include <asm/asm_pointer_auth.h>
+#include <asm/bug.h>
 #include <asm/cpufeature.h>
 #include <asm/errno.h>
 #include <asm/esr.h>
@@ -23,6 +24,7 @@
 #include <asm/mmu.h>
 #include <asm/processor.h>
 #include <asm/ptrace.h>
+#include <asm/scs.h>
 #include <asm/thread_info.h>
 #include <asm/asm-uaccess.h>
 #include <asm/unistd.h>
@@ -125,8 +127,10 @@ alternative_else_nop_endif
 	add	\dst, \dst, #(\sym - .entry.tramp.text)
 	.endm
 
-	// This macro corrupts x0-x3. It is the caller's duty
-	// to save/restore them if required.
+	/*
+	 * This macro corrupts x0-x3. It is the caller's duty  to save/restore
+	 * them if required.
+	 */
 	.macro	apply_ssbd, state, tmp1, tmp2
 #ifdef CONFIG_ARM64_SSBD
 alternative_cb	arm64_enable_wa2_handling
@@ -171,14 +175,18 @@ alternative_cb_end
 	ldr_this_cpu	tsk, __entry_task, x20
 	msr	sp_el0, tsk
 
-	// Ensure MDSCR_EL1.SS is clear, since we can unmask debug exceptions
-	// when scheduling.
+	/*
+	 * Ensure MDSCR_EL1.SS is clear, since we can unmask debug exceptions
+	 * when scheduling.
+	 */
 	ldr	x19, [tsk, #TSK_TI_FLAGS]
 	disable_step_tsk x19, x20
 
 	apply_ssbd 1, x22, x23
 
-	ptrauth_keys_install_kernel tsk, 1, x20, x22, x23
+	ptrauth_keys_install_kernel tsk, x20, x22, x23
+
+	scs_load tsk, x20
 	.else
 	add	x21, sp, #S_FRAME_SIZE
 	get_current_task tsk
@@ -206,28 +214,9 @@ alternative_cb_end
 	add	x29, sp, #S_STACKFRAME
 
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
-	/*
-	 * Set the TTBR0 PAN bit in SPSR. When the exception is taken from
-	 * EL0, there is no need to check the state of TTBR0_EL1 since
-	 * accesses are always enabled.
-	 * Note that the meaning of this bit differs from the ARMv8.1 PAN
-	 * feature as all TTBR0_EL1 accesses are disabled, not just those to
-	 * user mappings.
-	 */
-alternative_if ARM64_HAS_PAN
-	b	1f				// skip TTBR0 PAN
+alternative_if_not ARM64_HAS_PAN
+	bl	__swpan_entry_el\el
 alternative_else_nop_endif
-
-	.if	\el != 0
-	mrs	x21, ttbr0_el1
-	tst	x21, #TTBR_ASID_MASK		// Check for the reserved ASID
-	orr	x23, x23, #PSR_PAN_BIT		// Set the emulated PAN in the saved SPSR
-	b.eq	1f				// TTBR0 access already disabled
-	and	x23, x23, #~PSR_PAN_BIT		// Clear the emulated PAN in the saved SPSR
-	.endif
-
-	__uaccess_ttbr0_disable x21
-1:
 #endif
 
 	stp	x22, x23, [sp, #S_PC]
@@ -281,34 +270,9 @@ alternative_else_nop_endif
 	.endif
 
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
-	/*
-	 * Restore access to TTBR0_EL1. If returning to EL0, no need for SPSR
-	 * PAN bit checking.
-	 */
-alternative_if ARM64_HAS_PAN
-	b	2f				// skip TTBR0 PAN
+alternative_if_not ARM64_HAS_PAN
+	bl	__swpan_exit_el\el
 alternative_else_nop_endif
-
-	.if	\el != 0
-	tbnz	x22, #22, 1f			// Skip re-enabling TTBR0 access if the PSR_PAN_BIT is set
-	.endif
-
-	__uaccess_ttbr0_enable x0, x1
-
-	.if	\el == 0
-	/*
-	 * Enable errata workarounds only if returning to user. The only
-	 * workaround currently required for TTBR0_EL1 changes are for the
-	 * Cavium erratum 27456 (broadcast TLBI instructions may cause I-cache
-	 * corruption).
-	 */
-	bl	post_ttbr_update_workaround
-	.endif
-1:
-	.if	\el != 0
-	and	x22, x22, #~PSR_PAN_BIT		// ARMv8.0 CPUs do not understand this bit
-	.endif
-2:
 #endif
 
 	.if	\el == 0
@@ -328,21 +292,8 @@ alternative_if ARM64_WORKAROUND_845719
 alternative_else_nop_endif
 #endif
 3:
-#ifdef CONFIG_ARM64_ERRATUM_1418040
-alternative_if_not ARM64_WORKAROUND_1418040
-	b	4f
-alternative_else_nop_endif
-	/*
-	 * if (x22.mode32 == cntkctl_el1.el0vcten)
-	 *     cntkctl_el1.el0vcten = ~cntkctl_el1.el0vcten
-	 */
-	mrs	x1, cntkctl_el1
-	eon	x0, x1, x22, lsr #3
-	tbz	x0, #1, 4f
-	eor	x1, x1, #2	// ARCH_TIMER_USR_VCT_ACCESS_EN
-	msr	cntkctl_el1, x1
-4:
-#endif
+	scs_save tsk, x0
+
 	/* No kernel C function calls after this as user keys are set. */
 	ptrauth_keys_install_user tsk, x0, x1, x2
 
@@ -372,11 +323,11 @@ alternative_else_nop_endif
 	.if	\el == 0
 alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-	bne	5f
+	bne	4f
 	msr	far_el1, x30
 	tramp_alias	x30, tramp_exit_native
 	br	x30
-5:
+4:
 	tramp_alias	x30, tramp_exit_compat
 	br	x30
 #endif
@@ -386,8 +337,54 @@ alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0
 	sb
 	.endm
 
+#ifdef CONFIG_ARM64_SW_TTBR0_PAN
+	/*
+	 * Set the TTBR0 PAN bit in SPSR. When the exception is taken from
+	 * EL0, there is no need to check the state of TTBR0_EL1 since
+	 * accesses are always enabled.
+	 * Note that the meaning of this bit differs from the ARMv8.1 PAN
+	 * feature as all TTBR0_EL1 accesses are disabled, not just those to
+	 * user mappings.
+	 */
+SYM_CODE_START_LOCAL(__swpan_entry_el1)
+	mrs	x21, ttbr0_el1
+	tst	x21, #TTBR_ASID_MASK		// Check for the reserved ASID
+	orr	x23, x23, #PSR_PAN_BIT		// Set the emulated PAN in the saved SPSR
+	b.eq	1f				// TTBR0 access already disabled
+	and	x23, x23, #~PSR_PAN_BIT		// Clear the emulated PAN in the saved SPSR
+SYM_INNER_LABEL(__swpan_entry_el0, SYM_L_LOCAL)
+	__uaccess_ttbr0_disable x21
+1:	ret
+SYM_CODE_END(__swpan_entry_el1)
+
+	/*
+	 * Restore access to TTBR0_EL1. If returning to EL0, no need for SPSR
+	 * PAN bit checking.
+	 */
+SYM_CODE_START_LOCAL(__swpan_exit_el1)
+	tbnz	x22, #22, 1f			// Skip re-enabling TTBR0 access if the PSR_PAN_BIT is set
+	__uaccess_ttbr0_enable x0, x1
+1:	and	x22, x22, #~PSR_PAN_BIT		// ARMv8.0 CPUs do not understand this bit
+	ret
+SYM_CODE_END(__swpan_exit_el1)
+
+SYM_CODE_START_LOCAL(__swpan_exit_el0)
+	__uaccess_ttbr0_enable x0, x1
+	/*
+	 * Enable errata workarounds only if returning to user. The only
+	 * workaround currently required for TTBR0_EL1 changes are for the
+	 * Cavium erratum 27456 (broadcast TLBI instructions may cause I-cache
+	 * corruption).
+	 */
+	b	post_ttbr_update_workaround
+SYM_CODE_END(__swpan_exit_el0)
+#endif
+
 	.macro	irq_stack_entry
 	mov	x19, sp			// preserve the original sp
+#ifdef CONFIG_SHADOW_CALL_STACK
+	mov	x24, scs_sp		// preserve the original shadow stack
+#endif
 
 	/*
 	 * Compare sp with the base of the task stack.
@@ -405,15 +402,25 @@ alternative_insn eret, nop, ARM64_UNMAP_KERNEL_AT_EL0
 
 	/* switch to the irq stack */
 	mov	sp, x26
+
+#ifdef CONFIG_SHADOW_CALL_STACK
+	/* also switch to the irq shadow stack */
+	adr_this_cpu scs_sp, irq_shadow_call_stack, x26
+#endif
+
 9998:
 	.endm
 
 	/*
-	 * x19 should be preserved between irq_stack_entry and
-	 * irq_stack_exit.
+	 * The callee-saved regs (x19-x29) should be preserved between
+	 * irq_stack_entry and irq_stack_exit, but note that kernel_entry
+	 * uses x20-x23 to store data for later use.
 	 */
 	.macro	irq_stack_exit
 	mov	sp, x19
+#ifdef CONFIG_SHADOW_CALL_STACK
+	mov	scs_sp, x24
+#endif
 	.endm
 
 /* GPRs used by entry code */
@@ -728,20 +735,9 @@ el0_error_naked:
 SYM_CODE_END(el0_error)
 
 /*
- * Ok, we need to do extra processing, enter the slow path.
- */
-work_pending:
-	mov	x0, sp				// 'regs'
-	bl	do_notify_resume
-#ifdef CONFIG_TRACE_IRQFLAGS
-	bl	trace_hardirqs_on		// enabled while in userspace
-#endif
-	ldr	x1, [tsk, #TSK_TI_FLAGS]	// re-check for single-step
-	b	finish_ret_to_user
-/*
  * "slow" syscall return path.
  */
-ret_to_user:
+SYM_CODE_START_LOCAL(ret_to_user)
 	disable_daif
 	gic_prio_kentry_setup tmp=x3
 	ldr	x1, [tsk, #TSK_TI_FLAGS]
@@ -753,7 +749,19 @@ finish_ret_to_user:
 	bl	stackleak_erase
 #endif
 	kernel_exit 0
-ENDPROC(ret_to_user)
+
+/*
+ * Ok, we need to do extra processing, enter the slow path.
+ */
+work_pending:
+	mov	x0, sp				// 'regs'
+	bl	do_notify_resume
+#ifdef CONFIG_TRACE_IRQFLAGS
+	bl	trace_hardirqs_on		// enabled while in userspace
+#endif
+	ldr	x1, [tsk, #TSK_TI_FLAGS]	// re-check for single-step
+	b	finish_ret_to_user
+SYM_CODE_END(ret_to_user)
 
 	.popsection				// .entry.text
 
@@ -900,7 +908,9 @@ SYM_FUNC_START(cpu_switch_to)
 	ldr	lr, [x8]
 	mov	sp, x9
 	msr	sp_el0, x1
-	ptrauth_keys_install_kernel x1, 1, x8, x9, x10
+	ptrauth_keys_install_kernel x1, x8, x9, x10
+	scs_save x0, x8
+	scs_load x1, x8
 	ret
 SYM_FUNC_END(cpu_switch_to)
 NOKPROBE(cpu_switch_to)
@@ -1029,13 +1039,16 @@ SYM_CODE_START(__sdei_asm_handler)
 
 	mov	x19, x1
 
+#if defined(CONFIG_VMAP_STACK) || defined(CONFIG_SHADOW_CALL_STACK)
+	ldrb	w4, [x19, #SDEI_EVENT_PRIORITY]
+#endif
+
 #ifdef CONFIG_VMAP_STACK
 	/*
 	 * entry.S may have been using sp as a scratch register, find whether
 	 * this is a normal or critical event and switch to the appropriate
 	 * stack for this CPU.
 	 */
-	ldrb	w4, [x19, #SDEI_EVENT_PRIORITY]
 	cbnz	w4, 1f
 	ldr_this_cpu dst=x5, sym=sdei_stack_normal_ptr, tmp=x6
 	b	2f
@@ -1045,6 +1058,15 @@ SYM_CODE_START(__sdei_asm_handler)
 	mov	sp, x5
 #endif
 
+#ifdef CONFIG_SHADOW_CALL_STACK
+	/* Use a separate shadow call stack for normal and critical events */
+	cbnz	w4, 3f
+	adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_normal, tmp=x6
+	b	4f
+3:	adr_this_cpu dst=scs_sp, sym=sdei_shadow_call_stack_critical, tmp=x6
+4:
+#endif
+
 	/*
 	 * We may have interrupted userspace, or a guest, or exit-from or
 	 * return-to either of these. We can't trust sp_el0, restore it.